Chinatungsten's Tungtsen,Tungten Carbide & Tungsten Alloy in the development and application status
 

Currently, the refractory material from the traditional study of "high purity, ultra-fine, uniform" to evolve into "nanotechnology, composites design and integrated manufacturing." Through these advanced technologies, tungsten alloy refractory materials not only be able to retain their own, such as high melting point, the good corrosion resistance performance, but also significantly improve the overall mechanical properties. Currently, the refractory metals research and application relative to other metallic materials, there will be some distance, through technological transformation under different application areas of the properties, at the request of various tungsten alloy materials processing technology for further optimization and improvement is the focus of current research. tungsten carbide

Tungsten and tungsten alloy with high-density, high-strength, low coefficient of thermal expansion, excellent corrosion resistance and mechanical properties and processing in aerospace, military equipment, electronic, chemical and many other areas which have been widely used. milling inserts

Its main application areas include : (a) for the cutting, welding and the carbide spray, such as tungsten carbide. (2) for the electronics industry and the large number of filament cathode tube, high temperature resistance furnace heating elements, such as the current study of more Seismic tungsten wire, rare earth compound of tungsten electrodes. (3) high temperature for the area, as well as the production of military armor-piercing ammunition, medicine and other type enclosures.

Tungsten and tungsten alloy plastic material, reducing its plastic - brittle transition temperature further improve its performance heat-tungsten alloy has been an area of lasting hot. Therefore, the research and development of tungsten are the main contents of the plastic material - brittle transition behavior and high temperature strength properties, welding and composites, manufacturing technology of the best. Around these elements of technological research and development : purification, refinement, and toughening Complex.

Chinatungsten oxide purification mostly from the purification, solvent extraction, ion exchange and repeatedly re-crystallization process, improve APT's chemical purity, will be able to produce more than 99.95% purity and impurity content less than 100mg/kg total of APT and tungsten powder purity of greater than 99.99% .

Refinement study, the largest number of nano powder and tungsten nanocrystalline tungsten-based alloy composite powder, the preparation methods are mechanical alloying, spray drying method, sol-gel method, condensation-drying method, vapor deposition method, the reaction injection method, vacuum plasma spray deposition, mechanical - thermo-chemical synthesis, commonly used method for the first three, mainly used in high-density tungsten alloy, tungsten matrix composite materials (such as : W-Cu), Carbide and so on.

For tungsten composite mainly to the study of structural composites, composite strengthen mechanisms and organizations Composite (gradient composite), more research is mainly used for the electrode, contact materials, semiconductor components of the W-Cu composite material. The material molding method is isostatic pressing (CIP), a new method to improve the process are : (1) fiber; (2) specific structure; (3) arc-melting method; (4) metal injection molding; (5) rapid directional Condensate Solid law.

• Seismic tungsten wire characteristics and development trends

According to information on foreign and domestic application of the findings indicate that all Seismic tungsten wire were doped tungsten-based, add small amount of Co, or small amounts of elements such as Re, with better high-temperature ductility, reinforced tungsten filament Seismic Performance. Therefore, the Seismic Research tungsten wire must first focus on the theme of doping system for the optimal control, synchronous enhanced tungsten wire high temperature strength, creep resistance and high temperature crystallization temperature strength after the goal, thus obtaining better Seismic Performance with the tungsten filament; On the other quality-doped tungsten filament composite added on the basis of solid solution strengthening effect with the cobalt, or rhenium, to enhance its recrystallization of room temperature ductility.

• Nano-tungsten alloy materials research and application

Nano tungsten preparation methods are mechanical alloying, spray drying method, sol-gel method, drying, vapor deposition method, the reaction injection method, vacuum plasma spray deposition, mechanical-thermal chemical synthesis, commonly used method for the first three, mainly used in high-density tungsten alloy , tungsten matrix composite materials (such as : W-Cu), Carbide and so on.

Plasma Activated sintering process using nano powder sintering temperature can be reduced by about 200K and above. Grain size of 280 nm by the tungsten powder densification can receive upon a μ m below the grain. Currently, research is pressing, pressure hot isostatic pressing and sintering, the grain growth further control played a good result.

Nano foreign scholars from tungsten alloy powders sintering technology to the research have done some in-depth research. In particular, the nano-powder preparation process of the mechanism, nano powder physical and chemical properties of nano powder near-net shape forming, nano powder sintering of nanotechnology tungsten alloy powder sintering process in the grain growth control has done a more detailed research work, and have made some breakthrough progress.

• Tungsten matrix composites of the status quo

Currently, the main use is the second phase of the dispersion strengthening tungsten matrix composite materials, and foreign research shows the second phase of mass fraction is often less than 10%. In recent years, China's space industry to adapt to the development and testing of high-temperature materials requirements for the 800 ~ 2000 ℃ use of high-strength materials Die and Fixture, for research and development of high volume fraction (10%, 20%, 30%, 40%) in the first TiC and ZrC two particles strengthen the new super-high-temperature tungsten-based composites. As carbide particles high melting point and density of small (ZrC as the melting point of 3530 ° C, density only 6.74g/cm3), a large number of carbide particles addition of tungsten matrix composites density decreased, the space components very favorable.

China's self-developed TiCp / W and zrC / W composites of the largest room temperature flexural strength and fracture toughness of 889MPa respectively, 10.5MPa M1 / 2 and 843MPa, 10.1MPa M1 / 2. These two types of tungsten-matrix composites have excellent high-temperature mechanical properties, high temperature bending strength with the rise of temperature has not reduced instead of increased, to overcome the general refractory tungsten-based alloy strength with increasing temperature significantly lower shortcomings, in 1000 ℃ bending strength at room temperature reached 7.5 times the .

W-Cu composite material copper tungsten powder metallurgy composite materials is high melting point, high hardness of tungsten and high conductivity, thermal conductivity of copper as the alloy composition. Because of the good corrosion resistance arc, and anti-welded high strength, high hardness of the advantages of being widely used as an electrical contact material, resistance welding, EDM and plasma electrode materials, electrothermal alloy and high-density alloy, the military uses special materials (such as rocket nozzles, aircraft Throat), and computer central processing system, the LSI lead frame, solid-state microwave tube electronic devices such as heat sink base unit. Its main molding method is isostatic pressing (CIP), a new technology to improve the way : ① fiber; ② specific structure; ③ arc-melting method; Five metal injection molding; ⑤ rapid directional solidification method.

Special micro-structure of the W-Cu composite material

1, nano-structure of W-Cu composite material structure of nanometer copper tungsten composite material has almost fully dense relative density and can meet high-strength materials, high-hermetic requirements; MIM nearly Forming Technology enables the use of nano-structure W-Cu composite material structure not only uniform, high density, easy access to high precision, net shape of complex products. At present, the simple metal tungsten and copper ultrafine, diffuse mixed powder manufacturing difficulties, but the chemical synthesis of metal oxide powder as a total reduction, chemical evaporation condensation, chemical mechanical law is easily obtained ultrafine, diffuse, uniform, high-purity compound powder, thereby obtaining nanocrystalline copper tungsten composite material .

2, gradient structure W-Cu composite material layered loaded with powder, packed powder particle size of a small, cold, sintering, electricity loss after gradient with porosity of tungsten blank, and then infiltrating copper can be obtained with the continuous changes in the composition of copper tungsten gradient materials. In addition, plasma spraying can also prepared various components of the W-Cu FGM. The powder method first two components of the system from a completely different adobe copper tungsten, copper was relatively high, the thermal conductivity of the large adobe embedded in another adobe less, receive low expansion coefficient and high thermal conductivity good match FGM. On this basis the invention of a new Tungsten Copper (Mo-Cu) gradient structure functional materials, the types of materials from the gradient to W-Cu (Mo-Cu) as the main metal parts and AlN-based Al ceramic components, a good part of the two combining it with excellent integrated performance, particularly its high thermal conductivity, low coefficient of expansion to meet high-power devices to the use of cooling requirements.
 
• Drug type of research enclosures

  Drug-type enclosures with broken good, eroding power and higher permeability characteristics, thereby requiring drug liner material density, scalability, and so that the jet before erosion fully extend without fracture. Because tungsten high melting point (3400 C), high-density (19.3g/cm3), velocity (4.03km / s), good ductility characterized as very promising new drug liner material.  we have open a new website about tungsten carbide products http//www.zzkrt.com, you are welcome to visit it

For more details about Chinatungaten and it's tungsten products, please visit the web at www.chinatungsten.com.