N,N'-(4,4'-diphenylmethane)bismaleimide is an aromatic bismaleimide resin known for its excellent high temperature resistance and mechanical properties. It is a high melting point yellow powder with strong chemical resistance.In the electronics field, BMI resins manufactured by Yangchen tech is used to make heat-resistant laminates and electrical insulation materials for harsh conditions (H/F grades).

In contrast, traditional epoxy resins are widely used in PCB laminates and adhesives due to their low cost and ease of use, but they begin to lose strength and degrade at high temperatures. This blog compares the material properties and application differences of 4,4′-bismaleimide (BMI) and epoxy resins in electronic devices.

The rigid, highly conjugated structure of N,N'-(4,4'-diphenylmethane) bismaleimide gives it a high melting point (about 150-160°C) and glass transition temperature. It is almost insoluble in water/ethanol, but soluble in polar organic solvents such as acetone or DMF. High curing temperatures (usually 200-250°C) make BMI crosslinked into a dense three-dimensional network structure with excellent thermal stability.Commercial systems usually mix BMI with vinyl or allyl comonomers (e.g. DABA, vinyl phenol) to improve toughness. Cured BMI is still harder and stronger than most epoxies at high temperatures.

Technical Indicators

• The significant advantage of 4,4′-bismaleimide (BMI) resins is thermal stability. Unlike standard epoxy resins, which soften and lose modulus above about 120-150°C, BMI-based networks maintain mechanical integrity at temperatures well above 200°C.
• BMIs maintain strength and stiffness in high temperature environments (e.g., aerospace engines, gas turbines) where epoxies tend to fail.
• In fact, high-Tg BMI laminates or prepregs maintain excellent mechanical properties up to about 250°C.
• In contrast, most epoxy-based electronic materials have a Tg below 150°C, limiting them to low-grade insulation applications. BMI also has excellent mechanical strength and stiffness. Its rigid aromatic backbone gives it high tensile and flexural strength. Compared to epoxies, BMI composites can withstand greater static and dynamic loads without deformation.
• For example, parts made with a 4,4′-BMI matrix, such as aircraft fuselage panels or connector housings, will exhibit higher compression and impact resistance than equivalent epoxy-based parts. In tests, BMI composites have demonstrated improved durability under heavy loads and high-velocity impacts, thereby extending the service life and improving the safety of high-performance equipment.
• While epoxies are tough at room temperature, they tend to become brittle or creep at elevated temperatures, while the network rigidity of BMI remains strong. Another key advantage is its chemical and environmental resistance. BMI resins are more resistant to corrosion from solvents, acids, and other chemicals than typical epoxy formulations.

The ideal characteristics of silver coated copper powder largely depend on the perfection and consistency of the silver coating at the microscopic level. High quality silver coated copper powder is a prerequisite for realizing its application value. The core goal and difficulty of the preparation process is to achieve uniform, dense, continuous, and thickness controllable silver layer coverage on the surface of copper powder particles. At present, the preparation methods of silver coated copper powder mainly include mechanical ball milling, melting spray, chemical plating, etc
01 Mechanical ball milling method
The mechanical ball milling method is to mix copper powder and silver powder in proportion and place them in a ball mill. By relying on the intense impact, friction, and cold welding effects generated by the high-speed rotating grinding ball, silver is forcibly squeezed, adhered, and cold welded to the surface of copper particles. The advantage of this method lies in its relatively simple equipment, concise process, high theoretical yield, and low cost, without involving complex chemical reactions or waste liquid treatment issues. However, the "silver layer" formed is essentially silver fragments or clumps mechanically attached and cold welded, making it difficult to achieve a uniform, continuous, pore free, and dense complete coating layer. There are problems with incomplete coverage, weak bonding force, and weak control over the coating morphology. To improve the coating effect of traditional ball milling methods, copper powder is generally shaped into flakes during the ball milling process, significantly increasing the contact area between copper powder and silver particles while shortening the diffusion path of silver atoms. This is conducive to the more effective diffusion of silver substances on the surface of copper sheets, ultimately forming silver coated copper sheets with stronger bonding force, relatively denser and more uniform coating. However, the mechanical ball milling method is prone to introducing wear impurities from the grinding balls and the tank body, posing potential challenges to the stability and long-term reliability of product performance.
02 Melting spray method

The melt atomization method is to atomize molten droplets containing copper and silver and solidify them under rapid cooling conditions. Due to the higher fluidity of silver compared to copper at higher temperatures (>900 ℃), it can migrate to the surface of copper particles and achieve coating of copper particles. Using this technology to prepare silver coated copper powder, its silver content is extremely low, but the surface silver content is very high, and the silver content gradually decreases from the surface to the interior, showing a ladder like distribution. However, the preparation process is relatively complex, the production cost is high, and it is not suitable for large-scale production.

03 Chemical plating method
Chemical silver plating is the process of reducing silver ions in a solution to elemental silver through an oxidation-reduction reaction, and depositing and coating it on the surface of a copper substrate. The advantages of chemical plating method are good uniform plating and deep plating ability, which can be applied to non-metallic and semiconductor materials. The equipment is simple and the operation is easy. It is currently the most widely used method for preparing silver coated copper powder. According to the sedimentation mechanism, chemical plating can be divided into two types: displacement method and reduction method:
① Substitution method
The displacement method utilizes the characteristic that the reduction potential of copper is lower than that of silver. When copper powder is immersed in a solution containing silver ions (Ag ⁺), an electrochemical displacement reaction occurs: 2Ag ⁺+Cu ->2Ag+Cu ² ⁺. Silver ions are reduced and deposited on the surface of copper powder, while copper atoms are oxidized into copper ions and enter the solution. However, due to the displacement reaction between copper powder and silver source, the copper powder is enveloped by silver coating, which hinders the progress of the displacement reaction. At the same time, the reaction rate between copper powder and silver source solution is fast, and the silver coating quickly deposits on the surface of the copper powder. Therefore, silver coated copper powder prepared by displacement method often has the problem of thin and loose coating, which affects its performance. Generally, chelating agents (such as ammonia water) can be added during the preparation process to reduce the reaction rate, allowing silver metal to slowly deposit on the surface of copper powder, or multiple silver plating can be used to improve the morphology and coating rate of silver coated copper powder.

② Restoration method
The reduction method uses reducing agents (such as formaldehyde, glucose, hydrazine hydrate, ascorbic acid) to reduce silver ions (Ag ⁺) in the solution to elemental silver and deposit it on the surface of copper powder. The reaction mechanism consists of two stages: firstly, due to the higher activity of copper (Cu) than silver (Ag), copper powder first undergoes a displacement reaction with Ag ⁺: 2Ag ⁺+Cu → 2Ag+Cu ² ⁺, forming a thin layer of silver on the copper surface. As the replacement silver layer covers the copper surface, it hinders direct contact between copper and Ag ⁺, and the replacement reaction stops. At this point, the Ag ⁺ in the solution mainly relies on the reducing agent to undergo a reaction (such as 2Ag ⁺+reducing agent → 2Ag+oxidation product), and silver continuously and uniformly deposits and thickens on the initial displacement layer, forming a denser silver coating layer.

SAT NANO is a best supplier of silver coated copper powder in China, we can supply nano particle size and micro particle size, if you have any enquiry, please feel free to contact us at admin@satnano.com

High-grade AlN powder is the cornerstone of the aluminum nitride industry, characterized by low oxygen content, high specific surface area, narrow particle size distribution, excellent sintering activity, and moisture resistance.

Oxygen Content in Powder

This is a critical indicator for high-grade AlN powder. The oxygen in AlN primarily comes from surface-adsorbed oxygen, existing as a mixture of Al₂O₃ and AlOOH coating the powder particles. During sintering, oxygen easily diffuses into the AlN lattice, forming structural defects such as aluminum vacancies. These defects scatter phonons, reducing their mean free path and ultimately degrading the material's thermal conductivity.

Specific Surface Area & Particle Size Distribution

Generally, as particle size decreases and specific surface area increases, the powder's surface energy rises, enhancing its reactivity and sintering driving force. The specific surface area, dispersibility, particle size, and distribution are key factors determining densification and the final performance of sintered products.

Other Impurities & Their Content

Besides oxygen, other impurities can dissolve into the AlN lattice, introducing defects that further reduce thermal conductivity.

Moisture Resistance

AlN powder is prone to hydrolysis in humid air, reacting with water vapor to form Al(OH)₃ and NH₃, as shown in Equation (1). The loose byproducts fail to protect the powder, leading to continuous oxidation and even deterioration. Therefore, AlN powder must be stored in a dry, sealed environment. To improve storage, transportation, and usability, surface modification can enhance its hydrolysis resistance.

AlN + 3H₂O → Al(OH)₃ + NH₃  (1)

Conclusion

With the advancement of semiconductors, aerospace, new energy, and 5G communications, thermal management in high-power and high-heat-flux devices has become a major challenge affecting performance and reliability. As a high-performance thermal conductive material, AlN is gaining broader applications.

About Xiamen Juci Technology Co., LTD

Xiamen Juci Technology Co., Ltd. is China's leading manufacturer of aluminum nitride (AlN) powder by production volume. Our high-purity aluminum nitride powder and customized AlN ceramic products deliver superior thermal conductivity and cost-effective performance, making them ideal for advanced thermal management applications.

We specialize in innovative thermal solutions tailored for industries such as 5G communications, semiconductors, new energy, and aerospace, helping clients achieve optimal heat dissipation and system reliability.

Media Contact:
Xiamen Juci Technology Co., Ltd.

Phone: +86 592 7080230
Email: miki_huang@chinajuci.com

Website: www.jucialnglobal.com

Disposable nursing pads are mainly made of the following raw materials:

PE film: PE film is polyethylene film, which has good waterproof properties and can effectively prevent liquid leakage. It is a common material for the bottom layer of nursing pads.

Non-woven fabric: Non-woven fabric is a material made by physically bonding fibers together. It has the characteristics of lightness, breathability, softness and skin-friendliness. In nursing pads, non-woven fabrics are often used in the surface and middle layers, providing good touch and breathability, and also helping the rapid penetration and distribution of liquids.

Fluff pulp: Fluff pulp is a kind of wood pulp or waste paper pulp that has been specially processed and has good water absorption and fluffiness. In nursing pads, fluff pulp is the main material of the absorption layer, which can quickly absorb and store liquids and keep the surface dry.

Polymer absorbent material: Polymer absorbent materials such as super absorbent resin (SAP) have super strong water absorption capacity, can absorb hundreds of times its own volume of water, and firmly lock the liquid to prevent leakage. This material serves as the core absorption layer in the nursing pad, ensuring that the product has excellent water absorption and liquid retention properties.

In addition, according to the specific product design and production process requirements, disposable nursing pads may also contain other auxiliary materials, such as elastic materials, hot melt adhesives, etc. These materials play the role of fixing, fitting, and bonding in the nursing pad, which helps to improve the comfort and use effect of the product.

In summary, the raw materials of disposable nursing pads mainly include PE film, non-woven fabrics, fluff pulp and polymer absorbent materials, etc., which together constitute the structural and functional basis of the nursing pad.

For more information, please click www.glinknonwoven.com

Aluminum nitride (AlN) substrates possess ultra-high thermal conductivity, excellent electrical insulation, and thermal expansion properties similar to semiconductor materials like silicon wafers, making them widely applicable in the electronics packaging industry.

The market leader in China for raw aluminum nitride powder is Xiamen Juci Technology Co., Ltd., with an annual production capacity of 700 tons of AlN powder. Xiamen Juci Technology primarily employs the carbothermal reduction method to produce high-purity electronic-grade aluminum nitride powder. The advantage of the carbothermal reduction method is its ability to utilize a wide range of raw materials (Al₂O₃) while maintaining stable process control.

The principle of the carbothermal reduction process involves heating a uniformly mixed blend of Al₂O₃ and carbon in a nitrogen atmosphere. First, Al₂O₃ is reduced, and the resulting aluminum reacts with nitrogen to form AlN. The chemical reaction is as follows: Al₂O₃(s) + 3C(s) + N₂(g) → 2AlN(s) + 3CO(g). This method is simple, yields high-purity powder with small and uniformly distributed particle sizes, but requires a long synthesis time and high nitridation temperatures. Additionally, excess carbon must be removed after the reaction. Incomplete carbon removal leads to excessive residual carbon content in the aluminum nitride powder, which significantly impacts its performance.

Excessive residual carbon content primarily affects aluminum nitride ceramics in the following ways:

1. Impact on the Sintering Process

During the sintering of aluminum nitride ceramics, residual carbon content influences the densification and microstructure of the sintered body. Excessive residual carbon may lead to the formation of pores or cracks in the sintered body, thereby reducing the material's mechanical properties and thermal stability.

2. Impact on Thermal Conductivity

The presence of residual carbon directly affects the thermal conductivity of aluminum nitride ceramics. Since carbon has much lower thermal conductivity than aluminum nitride, an increase in residual carbon content will reduce the overall thermal conductivity of the ceramic.

3. Impact on Mechanical Properties

Residual carbon content also affects the mechanical properties of aluminum nitride ceramics, such as flexural strength and fracture toughness. Experimental studies have shown that as temperature decreases, aluminum nitride ceramics with an appropriate amount of residual carbon exhibit improved flexural strength and fracture toughness. However, excessively high residual carbon content may lead to internal stress concentration, thereby degrading mechanical performance.

4. Impact on Electrical Properties

For applications requiring high electrical insulation, the presence of residual carbon may reduce the electrical insulation performance of aluminum nitride ceramics. Since carbon is inherently conductive, excessive residual carbon content increases the material's electrical conductivity, negatively impacting its use in electronic applications.

About Xiamen Juci Technology Co., LTD

Xiamen Juci Technology Co., Ltd. is the leading manufacturer of aluminum nitride powder in China in terms of output. The aluminum nitride powder and customized ceramics produced by Xiamen Juci Technology Co., Ltd. feature higher thermal conductivity and more competitive prices. We are committed to providing customers with advanced thermal management technologies and offering effective thermal management solutions for industries such as 5G, semiconductors, new energy, aerospace, etc.

Media Contact:
Xiamen Juci Technology Co., Ltd.

Phone: +86 592 7080230
Email: miki_huang@chinajuci.com

Website: www.jucialnglobal.com

Application Background

The cow leg separator is a ground-mounted component used in modern milking parlors to gently guide dairy cows into a stable stance, automatically separating their hind legs to facilitate milking.

This device often features mounting holes for spray nozzles, allowing for automated cleaning or sanitizing of the udder and legs using water or disinfectant spray.

Previously, the separator was typically made from short glass fiber reinforced plastic.

However, under repeated load, hoof impact, and exposure to harsh farm environments—such as manure, moisture, and cleaning chemicals—short fiber materials often suffered from insufficient strength, deformation, cracking, or premature aging.

Material Upgrade

Advantages of PA6 Long Glass Fiber 30% (LGF-PA6)

• High Load-Bearing Strength
PA6 reinforced with 30% long glass fiber (LGF-PA6) forms an internal continuous-fiber skeleton during molding, significantly boosting mechanical strength. This allows the separator to safely withstand the full bodyweight of cows stepping or standing on it without deformation or breakage, ensuring safety and long-term structural stability.

• Excellent Chemical Resistance
Farm environments expose equipment to a mix of urine, feces, disinfectants, and detergents. LGF-PA6 exhibits strong resistance to chemical corrosion and environmental degradation, maintaining its integrity and mechanical properties over time—critical for hygienic and durable milking operations.

• Superior Impact and Fatigue Performance
Unlike short fiber composites, LGF-PA6 offers enhanced fatigue durability, effectively handling daily stress from cow movement, hoof impact, and vibrations without cracking or weakening, reducing maintenance and replacement costs.

• Dimensional Stability and Clean Finish
With reduced shrinkage and warping during injection molding, LGF-PA6 ensures tight dimensional tolerances for secure fitting of spray system components. The smooth molded surface enhances appearance, reduces dirt buildup, and simplifies cleaning, supporting farm hygiene standards.

Performance Comparison

PA6 reinforced with 30% long glass fiber

Ready to Upgrade Your Milking Equipment?
Discover how PA6 Long Glass Fiber 30% can deliver the strength, durability, and chemical resistance your cow leg separators and other agricultural components demand.

Whether you're improving existing parts or developing new equipment, our material experts are here to support you with tailored solutions.

Contact us today to request samples, technical data, or discuss how long fiber thermoplastics can enhance your product performance across a range of agricultural applications.

The essence of sintering is that the powder block is heated in an appropriate environment or atmosphere, and through a series of physical and chemical changes, the bonding between powder particles undergoes a qualitative change. The strength and density of the block increase rapidly, and other physical and mechanical properties are also significantly improved. The performance of ceramic materials is not only related to their chemical composition, but also closely related to their microstructure. After the formulation, mixing, forming and other processes are completed, sintering is the key process to obtain the expected microstructure of the material and endow it with various properties.

Sintering is a process that reduces pores in the formed body, increases the bonding between particles, and improves mechanical strength. During the sintering process, as the temperature increases and the heat treatment time prolongs, the number of pores decreases and the bonding force between particles increases. When a certain temperature and heat treatment time are reached, the grain size increases and the mechanical strength decreases. According to thermodynamic principles, sintering is a process in which the total energy of a system is reduced. Compared to bulk materials, powders have a large specific surface area, and surface atoms have much higher energy than internal atoms. At the same time, various lattice defects also exist inside the powder particles during the manufacturing process. Any system has a tendency to transition to the lowest energy state, which is the driving force of the sintering process, that is, the transition from the compact to the sintered compact is the process of the system transitioning from a metastable state to a stable state.

However, sintering generally cannot be carried out automatically because its inherent energy cannot overcome the energy barrier and must be heated to a certain temperature before it can proceed. Sintering is a complex process of physical and chemical changes. After long-term research, the sintering mechanism can be summarized as follows: ① fluidity, ② evaporation and agglomeration; ③ Volume diffusion; ④ Surface diffusion: grain boundary diffusion; Plastic flow, etc. Practice has proven that it is difficult to explain all sintering processes using any single mechanism. Sintering is a complex process that is the result of the interaction of multiple mechanisms. During the sintering process, the main changes occur in the size and shape of grains and pores. Taking the sintering process of Al2O3 ceramics as an example to illustrate the sintering process of ceramic materials: Al2O3 ceramics generally contain several tens of percent of pores during growth and failure, and there is only point contact between particles. Under the driving force of reduced surface energy, the substance fills the neck and pore areas between particles through different diffusion pathways, causing the neck to gradually grow and the volume occupied by the pores to gradually decrease. Grain boundaries gradually form between small particles, and the area of the grain boundaries continues to expand, making the body denser. During this considerable process, the connected pores continuously shrink, and the grain boundaries between two particles meet adjacent grain boundaries, forming a grain boundary network: the grain boundaries move and the grains gradually grow. The result is a reduction in porosity and an increase in densification, until the pores are no longer connected to each other, forming isolated pores distributed at the intersection of several grains.


At this point, the density of the green body reaches over 90% of the theoretical density, and the early stage of sintering ends here. Continuing into the later stage of sintering, isolated pores diffuse to the grain boundaries to eliminate them, or in other words, substances on the grain boundaries continue to diffuse and fill the pores, allowing densification to continue while the grains continue to grow uniformly. Generally, pores move along with grain boundaries until densification occurs, resulting in a dense ceramic material. If sintering continues at high temperatures thereafter, it will be a simple process of grain boundary movement and grain growth. The growth of the grain boundary is not the mutual bonding of small particles, but the result of grain boundary movement. The movement of grain boundaries with different shapes varies. Curved grain boundaries always move towards the center of curvature. The smaller the curvature radius, the faster the movement. During the grain growth process in the later stage of sintering, there may be a phenomenon where the migration rate of pores is significantly lower than that of grain boundaries. At this time, pores detach from the grain boundaries and are wrapped inside the grains. Subsequently, due to factors such as the lengthening of the material diffusion path and the decrease in diffusion rate, it became almost impossible to continue with the further reduction and elimination of pores. In this case, further sintering is difficult to improve the degree of densification, but the grain size will continue to grow, and even abnormal growth of a few grains may occur, causing more residual small pores to be trapped deep in the larger grains.

After sintering, the macroscopic changes of Al2O3 ∝ ceramic body are: volume shrinkage, density increase, and strength increase. Therefore, the degree of sintering can be measured by indicators such as the shrinkage rate, porosity, or the ratio of bulk density to theoretical density of the green body.

The sintering of ceramics can be divided into solid-phase sintering and liquid-phase sintering. High purity substances usually do not exhibit liquid phase at sintering temperature and belong to solid-state sintering. For example, high-purity oxide structured ceramics are mostly sintered into ceramics through solid-state sintering. And some often have liquid phase during sintering, which belongs to liquid-phase sintering. In addition, sintering can be divided into two categories based on the presence or absence of external pressure: pressureless sintering and pressure sintering. Pressure sintering, also commonly known as hot pressing sintering.

Pure oxide or compound powders are formed into green bodies with only point contacts between particles, resulting in low strength. However, through sintering, although there is no external force or chemical reaction during sintering, the particles in point contact can tightly bond into a hard and high-strength ceramic body, driven by the surface energy of the powder particles.

SAT NANO is a best supplier of sintering material in China, we can offer Al2O3 nanopowder, ZrO2 nanopowder, and MgO nanopowder for sintering, if you need other materials for sintering, please feel free to contact us at admin@satnano.com

The composition of TC4 titanium alloy is Ti-6AI-4V, which belongs to the (a+β) type titanium alloy. It has good comprehensive mechanical properties, high specific strength, excellent corrosion resistance, good biocompatibility, and is widely used in aerospace, petrochemical, biomedical and other fields. This article selects the plasma rotating electrode method to prepare titanium alloy powder, and discusses the spheroidization mechanism of titanium alloy powder. The evolution law of its microstructure is explored, and the main heat treatment methods are discussed, providing necessary theoretical basis for the application of TC4 titanium alloy in 3D printing technology.

2.1 Experimental Materials and Methods: TC4 alloy powder was prepared by plasma rotating electrode atomization method, and its chemical composition was analyzed by instruments, as shown below.

According to the table, the H, N, and O content in the powder is relatively low, which meets the requirements for printing high-performance products. The shape of the powder particles prepared by this process is very close to spherical, with a smooth surface, good flowability, and no excessive impurities. The SEM image observed under a scanning electron microscope is shown in Figure 1, and the individual powder particles are shown in Figure 2. Through observation, when the geometric shape of TC4 titanium alloy powder particles is spherical, the formability is good, while elliptical powder has poor flowability and formability. Spherical titanium alloy powder has good flowability during laser 3D printing preparation.

2.2 Experimental Results and Analysis 2.2.1 Ball Forming Mechanism of TC4 Titanium Alloy Powder In 3D printing technology, metal powder material is the raw material for metal 3D printing, and its basic properties have a significant impact on the quality of the final product formation. It is also one of the material basis and key elements for achieving rapid prototyping. The TC4 alloy powder prepared by plasma rotating electrode atomization method has a particle shape that is very close to spherical, with a smooth surface and good flowability. The mechanism of powder balling mainly consists of three processes, as shown in Figure 3. In the first process, the molten alloy droplets are impacted by high-speed airflow, causing them to grow into a wavy liquid film and move away from the gas center at high speed; In the second process, due to the pressure, the elongated alloy droplets are unstable. Under the surface tension of the liquid, they are then blown and broken, forming elliptical droplets; In the third process, the elliptical droplet continues to break again under the action of air pressure and liquid surface tension, and is segmented into several small droplets. Under the action of surface tension, the droplet tends to shrink into a spherical shape during the descent process, and the cooling accelerates, immediately solidifying into a spherical shape.

This experiment can obtain TC4 titanium alloy particle sizes mainly distributed in the range of 50-160 μ m by controlling the relevant parameters of the experiment. The particle size distribution is narrow and meets the requirements of 3D printing.
2.2.2 Microstructure of TC4 Titanium Alloy Sample The metallographic structure of the cross-section of the TC4 titanium alloy sample is shown in Figure 4. When the ion beam acts on the TC4 titanium alloy powder, a circular molten pool is formed. Within the molten pool, the temperature gradually decreases from the center to the edge, showing a Gaussian distribution. The difference in temperature results in varying degrees of melting of TC4 titanium alloy powder, with powders at lower temperatures in the edge region remaining unmelted or insufficiently melted, leading to differences in grain microstructure and size between the melt pool and the edge region. The use of pulse dot mode for metal powder cladding can reduce the influence of temperature gradient on the heat affected zone. When the latter heat source acts on the alloy powder, it also supplements energy to the edge area of the previous spot for remelting. After obtaining the energy, the grains continue to grow along the direction of energy absorption.

The metallographic structure photo of the longitudinal section of TC4 titanium alloy sample is shown in Figure 5. Through metallographic microscope observation, the microstructure is coarse β - columnar products. As shown in Figure 5, the grain boundaries can be clearly observed, and the columnar crystals grow along the stacking layer direction, with different growth directions. The growth stops at the β - columnar crystal boundary, and at the same time, the columnar crystals far away from the substrate continue to grow epitaxially, with grain growth phenomenon. After analysis, it was found that the temperature generated during the preparation of TC4 alloy by 3D printing has an impact on the microstructure of titanium alloy. When some of the alloy powder is melted by ion beam, the front part of the alloy is reheated. However, the beta phase self diffusion coefficient of TC4 alloy is relatively large, and smaller energy can promote grain growth. Therefore, columnar crystals are prone to growth and overheating during reheating.

Therefore, controlling the energy of the heat source can effectively alter the microstructure of TC4 alloy.

2.2.3 Solid solution and aging heat treatment Figure 6 shows the metallographic structure of TC4 alloy in three different heat treatment states: as deposited (a), 970 ° C/1h+540 ° C/4h (b), and 970 ° C/1h (c). The deposited TC4 alloy has a mixed microstructure of alpha solid solution and beta solid solution; After heat treatment at 970 ° C/1h+540 ° C/4h (b), the metallographic structure transformed into a mesh basket structure; After further heat treatment at 970 ° C/FC/1h (c), the structure transformed into a bimodal structure consisting of a basket like structure and spheroidized alpha phase. Among them, the high-temperature creep performance, strength, and plasticity of the basket structure are good, while the plasticity of the bimodal structure is low and the strength is high.

Through analysis, it is known that solid solution and aging heat treatment can effectively improve the strength and plasticity of TC4 titanium alloy, but the cooling rate has a significant impact on the strength and plasticity of TC4 titanium alloy, and appropriate cooling methods should be adopted in production.
Figure 7 shows the microscopic images of the microstructure of TC4 titanium alloy mesh basket under different cooling methods. When TC4 titanium alloy is air-cooled, a semi diffusion phase transformation occurs. After solid solution and aging treatment, the β phase solid solution between the primary α phase solid solution will appear as small secondary α phase solid solution, as shown in Figure 7 (a); When TC4 titanium alloy is cooled in a furnace, diffusion type phase transformation occurs. After solid solution treatment, a bimodal structure is formed. The β phase solid solution between the primary α phase solid solution in the alloy does not produce secondary α phase solid solution due to the lack of subsequent aging heat treatment, as shown in Figure 7 (b); By comparison, it can be seen that under furnace cooling conditions, the grain boundaries and intragranular alpha phase solid solution are coarser than under air cooling conditions. When TC4 titanium alloy is subjected to external forces, cracks are more likely to initiate and propagate at the grain boundaries, resulting in reduced plasticity, and printing molding is not utilized.

Summary: (1) TC4 titanium alloy powder prepared by plasma rotating electrode method, (Tianjiu Metal can customize TC4 titanium alloy powder with different processes according to customer needs), the powder particle shape is very close to spherical, the surface is smooth, the flowability is good, and it has good powder characteristics, which meets the requirements of 3D printing.
(2) The microstructure of the cross-section of TC4 titanium alloy shows radiating columnar crystals from the temperature center to the edge, while the microstructure of the longitudinal section shows columnar crystals growing along the stacking layer direction. The control of heat source energy can effectively improve the microstructure of TC4 titanium alloy.
(3) The heat treatment method of solid solution+aging and air cooling effectively improves the strength and plasticity of the deposited TC4 titanium alloy, making its performance meet the requirements of TC4 titanium alloy 3D printing.

is a best supplier of TC4 alloy powder titanium alloy powder in China, we can offer 15-45um, 15-53um, 45-105um particle and other particle size, if you have any enquiry, please feel free to contact us at admin@satnano.com

In recent years, with the rapid development of 3D printing technology, NiTi alloy powder has attracted much attention as a key raw material for biomedical implants. As the foundation of 3D printing, the quality of powder raw materials is crucial, and the plasma rotating electrode atomization method has attracted much attention.

Preparation method of plasma rotating electrode

The PREP method is used to prepare NiTi alloy powder, and the equipment mainly includes a rotary feed mechanism, an atomization chamber, a plasma gun device, and a feeding mechanism. Using NiTi alloy rods as raw materials, they are made into electrode rods and melted at high temperatures generated by plasma gun arcs. By utilizing the centrifugal force generated by the high-speed rotation of the electrode rod itself, melted metal is instantly ejected and rapidly solidified into spherical powder in a cooling medium. During the preparation process, high-purity argon gas is used as a protective gas with a purity of 4N (99.99%). By adjusting parameters such as plasma gun main current, spindle speed, and bar feed rate, the preparation conditions were optimized.

Powder characteristics
The powder particle size is mainly distributed between 60 and 125 μ m. Through scanning electron microscopy observation, it was found that the condensed tissue of larger particles (≥ 178 μ m) is a cellular crystal structure with poor surface smoothness; Small particles (≤ 40 μ m) have a smooth surface and no obvious crystalline structure.

Microstructure
The microstructure of powders with different particle sizes was observed by scanning electron microscopy and transmission electron microscopy. It was found that as the particle size decreased, the microstructure of the powder gradually refined, and the cellular crystal structure gradually disappeared, transforming into a finer equiaxed crystal structure. At the same time, more dislocations and twinning structures appeared in powders with smaller particle sizes, which had a significant impact on the phase transition behavior and mechanical properties of the powder.

The spherical NiTi alloy powder prepared by PREP method has the advantages of high sphericity, less hollow powder and satellite powder, and is very suitable as a raw material powder for 3D printing technology. The results of this study have important guiding significance for improving the performance of 3D printed products and optimizing 3D printing processes

SAT NANO is a best supplier of spherical nickel titanium alloy particle NiTi alloy powder in China, we can offer 15-53um particle size. if you have any enquiry, please feel free to contact us at admin@satnano.com

1. Classification of Scanning Electron Microscopes
Scanning electron microscopy can be divided into thermal electron emission type and field emission type according to the different ways of electron generation. The filament used for thermal electron emission type is mainly tungsten filament electron microscopy. Field emission type
The distinction between hot field emission and cold field emission.

2. Classification of Transmission Electron Microscopy
Transmission electron microscopy can be divided into thermal electron emission type and field emission type according to the different ways of electron generation. The filaments used for thermionic emission mainly include tungsten filaments and lanthanum hexaboride filaments. There are two types of field emission: thermal field emission and cold field emission.

3. The similarities and differences between scanning electron microscopy and transmission electron microscopy
The two have similar requirements for the sample: solid, as dry as possible, as free as possible from oil contamination, and the external dimensions meet the size requirements of the sample chamber.
The difference is:
(1) On sample preparation: The penetration ability of TEM electrons is very weak. Transmission electron microscopy often uses high-energy electron beams of several hundred kilovolts, but it still requires grinding or ion thinning of the sample or ultra-thin slicing to micro nano scale thickness, which is the most basic requirement. SEM hardly requires sample preparation and allows for direct observation. Most non-conductive materials require the production of conductive films (such as gold coating).

(2) On imaging: During SEM imaging, the electron beam does not penetrate the sample but scans its surface. During TEM imaging, the electron beam penetrates the sample. The spatial resolution of SEM is generally between XY-3-6nm,
The spatial resolution of TEM can generally reach 0.1-0.5nm.

4. What is the thickness requirement for the sample when conducting TEM testing?
The thickness of the TEM sample should preferably be less than 100nm. If it is too thick, the electron beam is not easily transmitted, resulting in unclear images and poor imaging.

5. What are the requirements for the sample when conducting TEM testing?
-The sample is generally required to be dry. If the sample is a solution, it needs to be dropped onto a certain substrate (such as glass), dried, and then sprayed with carbon. If the sample itself is conductive, there is no need to spray carbon.

6. How to perform TEM on nanoparticles in aqueous solution?
TEM samples must be tested under high vacuum conditions, while nanoparticles in aqueous solutions cannot be directly measured. Usually, micro grids or copper mesh are used to remove the sample and place it in a sample pre extractor. After drying, it can be placed in an electron microscope for testing. If the sample size is small and only a few nanometers, use a non porous carbon film to scoop up the sample.

7. Thickness requirements for high-resolution samples
When taking high-resolution TEM images, it is best to control the sample thickness below 20nm. Thinner samples can reduce electron beam scattering, thereby improving image resolution. For powders with a diameter less than 20nm, they can be directly removed and observed on carbon support films or small pore micro grids. If the particle diameter is greater than 20nm, it is best to embed it first, and then use ion thinning technology to thin the sample to a thickness suitable for observation.

8. How to make TEM for powdered samples?
The key to preparing powder samples is to have a good supporting film and disperse the powder evenly with moderate concentration. After the supporting membrane is completely dry, it should be placed into an electron microscope for observation to avoid rupture of the supporting membrane under electron beam irradiation.
① Pre attach a thin support film to the copper mesh;
② Select a reasonable dispersant based on the properties of the powder sample;
③ Disperse the powder evenly through ultrasound to form a suspension;
④ Place the powder solution on a copper mesh using drop or scoop methods and dry it;
⑤ Ensure that the powder sample is evenly distributed on the copper mesh and free of contaminants;
⑥ Gently blow the copper mesh with an ear wash ball to ensure that there is no easily falling powder.

9. Why spray gold on non-conductive or poorly conductive samples?
SEM imaging is the process of obtaining signals of secondary electrons and backscattered electrons through a detector. If the sample is non-conductive or has poor conductivity, it will cause the accumulation of excess electrons or free particles on the surface of the sample that cannot be guided away in a timely manner. After a certain degree, repeated charging and discharging phenomena will occur, ultimately affecting the transmission of electronic signals, causing image distortion, deformation, shaking, and other phenomena. After gold spraying, the conductivity of the sample surface will be enhanced, thereby avoiding the phenomenon of accumulation.

10. Does spraying gold affect the morphology of the sample?
After spraying gold on the surface of the sample, only a few to a dozen layers of gold atoms are covered on its surface, with a thickness of only a few nanometers to a dozen nanometers, which has almost no effect on the morphology.

11. How to demagnetize magnetic powder?
Magnetic powders can be prepared using Zeiss field emission electron microscopy without demagnetization, following the preparation of conventional powder samples. If some block shaped strong magnetic materials can be demagnetized by heating or applying an external magnetic field, there are specialized demagnetizers in the market.

12. Why are magnetic particles generally not allowed to undergo transmission electron microscopy?
Because the sample needs to be dropped onto a dedicated support film when making magnetic materials, the magnetic material may be attracted to the lens, affecting TEM resolution and contaminating the electron microscope.


13. Why do different instruments produce different effects on the same sample?

If the camera parameters are set similarly, the effect will not be significantly different. Only different instruments have different parameter settings (probe, voltage, beam current, etc.) during shooting, and the specific impact of which parameters needs to be analyzed based on the shooting results.

14. What are the specific application scenarios for spraying gold, platinum, and carbon?
Metal targets such as Au and Pt can increase conductivity, increase the generation of secondary electrons and backscattered electrons, have good signal-to-noise ratio, and reduce electron beam penetration, with the aim of obtaining high-quality images. C target material, suitable for analysis of EDS, EBSD, WDS and other components.

15. When taking SEM photos. Why spray gold or carbon on non-conductive or poorly conductive samples?
When observed with a scanning electron microscope, when the incident electron beam hits the sample, charge accumulation occurs on the surface of the sample, forming charging and discharging effects that affect the observation and photographic recording of the image. Therefore, before observation, conductive treatment should be carried out, such as spraying gold or carbon, to make the surface of the sample conductive.

16. The sample does not contain carbon element, but the result shows a content higher than 70%, which deviates too much from the actual situation. How to handle it?
The energy spectrum is insensitive to elements with atomic numbers less than 11, and errors in carbon, nitrogen, and oxygen are common. In addition, carbon pollution comes from a wide range of sources, such as conductive adhesives, contact between samples and hands, DP pumps, air dust, and so on. Special attention should be paid to the unsuitability of light elements such as carbon, nitrogen, and oxygen for energy spectrum analysis. In addition, if Mapping testing is required, there may be obvious carbon, nitrogen, and oxygen in the background other than the sample, which may not be distinguishable from the sample, Mapping pays special attention to light elements such as carbon, nitrogen, and oxygen. If the content is higher than the actual value, it can be artificially reduced.

17. The reason for the unclear results of the morphology shooting
The poor conductivity of the sample leads to unclear shooting results; The shooting requirements are too high, and the instrument itself cannot meet them; Focusing or astigmatism is not adjusted properly, which is generally rare; It is also related to device configuration and installation environment.

18. In the SEM images of some samples, obvious electron beam black spots can be seen. How to remove the electron beam spots in the interface?
Electron beam black spots may indicate that the sample is relatively dirty and has accumulated carbon. It is recommended to pay attention to the storage environment or conduct timely testing on the prepared sample.

19. What is the reason for the ethanol dispersion sample taking morphology, which shows a layer of film on the substrate?
The reason for the appearance resembling a film is due to the dispersion of ethanol followed by gold spraying.

20. Why does transmission electron microscopy have no color?
Color is determined by the color of light, that is, the frequency of electromagnetic waves, and the light of an electron microscope is not natural light, but an electron beam light source, so it cannot display colorful colors. Transmission electron microscopy can reveal fine structures smaller than 0.2um that cannot be clearly seen under an optical microscope, which are called submicroscopic structures or ultrafine structures. To see these structures clearly, it is necessary to choose a light source with a shorter wavelength to improve the resolution of the microscope. In 1932, Ruska invented the transmission electron microscope with an electron beam as the light source. The wavelength of the electron beam is much shorter than that of visible light and ultraviolet light, and the wave of the electron beam is

The length is inversely proportional to the square root of the voltage of the emitted electron beam, which means that the higher the voltage, the shorter the wavelength. At present, the resolution of TEM can reach 0.2nm, and the images obtained by electron microscopy are "grayscale images" that reflect the number of electrons (i.e. brightness), without color information.

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