In these composite materials, tungsten copper is the most ideal material for the liner. Tungsten copper alloy is Cu difference between two kinds of physical and chemical properties of W and face-centered cubic structure of the body-centered cubic structure is neither large nor the formation of pseudo alloy intermetallic compounds. It not only has high hardness, high strength, high density, low thermal expansion coefficient and excellent abrasion resistance of W and also has plasticity and excellent electrical and thermal conductivity of Cu. Tungsten jet head with a higher speed, when penetrating armor can shorten the time through, thereby facilitating against reactive armor. But it is brittle and the powder adhesion is poor, the added copper powder with good ductility can contribute to the shaping process and improve the jet stability, avoid breaking.

However, tungsten copper alloy material prepared by the conventional powder metallurgy method, since good metal powder flowability and there are many random factors hard to be controlled in mechanized packing, press-forming and other processes, it will cause some problems, such as coarse grains, poor uniformity and density distribution, depth fluctuations, which can not meet the requirements of the weapon. In addition, the tungsten copper composite liner is very sensitive to the height of burst; under the big height of burst the penetration depth has a rapid decline and the ideal height of burst is 3 times than the diameter.

This is also the commonness of composite liner, which means under small height of burst, the armor depth increase by 30% than the pure copper liner, but under big height of burst it is difficult to obtain the good jet ductility. For the reason, the researchers have proposed a kind of new process that spray pyrolysis milling – wet milling – liquid-phase sintering to fabricate tungsten copper liner. Wherein the spray pyrolysis milling precipitated nano-scale tungsten phase approximately spherical and uniformly distributed on the Cu substrate, improving both activity; wet ball milling can reduce the powder oxidation and prevent metal grains from gathering and growing; liquid-phase sintering is beneficial for higher densification and better uniformity.

With the development of military modernization, anti-missile capability has been greatly improved in a number of armored tanks, armored vehicles and so on. As it is now already have a high anti-missile capability reactive armor scaly, lean axle loads armor, ceramic composite armor, explosive reactive armor, which gives the more severe challenges to anti-armor weapons. The combination of shaped charge and precision guidance is the most effective anti-armor weapon, and the liner is key component of the shaped charge, whose performance will directly affect the jet armor penetration capability and stability.

So the new material for liner has become the hotspot of related researchers and scholars. Research focused on how to enhance the ductility of the material, increase the density of the material and refine the grain structure. The ductility enhancement helps form long projectile, thereby increasing the penetration depth; the density increases will enhance the impact force; refine the grain structure is conducive to increase the length of the jet. Due to the single component, traditional liner is not sufficient to meet the performance requirements today. With further research, the liner made by composite material appears. It is combining with a variety of different properties of metals or alloys to meet the design requirements liner. Compared with single metal liner, it has many advantages, such as high energy conversion efficiency, high energy efficiency, more reasonable absorption mechanism and excellent armor performance, which is the inevitable trend of liner development.

Obtained tungsten billet by powder metallurgy method, should to go through swaging, drawing, straightening, polishing and other follow-up process, which can be processed into various size and length tungsten electrode. Swaging, also known as rotary forging, is forging a special forged. Using swaging to process plastic working on tungsten electrode can reduce electrode‘s diameter and increase the length, while improving the physical and chemical properties of the electrode, to improve the plasticity and other properties of the electrodes. Swaging process operation by swaging machine, through high-speed rotation, drives rollers and swaging dies to operate and makes swaging die to linearly reciprocate, to forge tungsten billet. In the plastic working is generally subjected to initial deformation, recrystallization annealing and second return deformation.

In the process of swaging, to process deformation on tungsten billet easily lead to electrode inside and outside organization uneven. In general, the degree of surface deformation is large and center deformation is small, so the stress of electrode distribution is also not uniformly. Therefor, between the first and second deformation to process recrystallization annealing can adjust the electrode internal fibrous structure, thereby improving the processing performance of the electrode. Swaging process is the first deformation of the electrode, and it plays an important role for successful subsequent processing. So the reasonable swaging process can produce beneficial to plastic deformation microstructure. In addition, during swaging process, the processing temperature and processing passes is an important factor of swaging effect, so should be strictly controlled.

In the swaging process, the tungsten bar in stress state is in favor of deformation processing. In addition, small passes deformation, high forging frequency can make tungsten bar to distort at small deformation force, but the swaging process required more molds. Due to the small amount of deformation always starts from the surface of tungsten bar, so easy to make tungsten electrode uneven distribution of stress and deformation, resulting in defects in subsequent processing.

Metal halide is kind of discharge lamp, and it can produce arc in the mixed steam of mercury and rare metal halide. Besides, it is a daylight colour new energy-saving light source. Metal halide having a high luminous efficiency, good color, long life and other advantages, is widely as indoor lighting used in stadiums, exhibition centers, shopping malls, industrial buildings, streets and squares, railway stations, docks and other places

Tungsten electrode is usually as electrode material used in metal halide lamp, having a certain impact on the performance of metal halide. So to produce high quality tungsten electrodes in favor of extend metal halide lamps’ application and prolong its service life. Earlier, people often used pure tungsten electrode and thorium tungsten electrode as tungsten material in metal halide, but thorium tungsten electrode has radioaction and pure tungsten electrodes has poor performance, so many manufacturers began to study different rare earth tungsten electrodes’ performance in the metal halide.

To further study metal halide’s electrode materials found using liquid-solid mixing method for raw materials mixing, and then using the powder metallurgy method to obtain tungsten billet, finally after swaging, annealing, straightening and other processes can produce excellent performance electrode material. Observing the performance of different rare earth tungsten electrodes used in metal halide discovery found, yttrium and cerium tungsten electrode color temperature, luminous flux and luminous efficiency is low. But thorium tungsten electrode and dysprosium tungsten electrode has higher color temperature and, luminous flux and luminous efficiency. Among them, lanthanum tungsten has minimum color rendering index, and dysprosium tungsten has highest color rendering index. Comparison the application effect of different rare earth in metal halide found dysprosium tungsten electrode and dysprosium yttrium tungsten electrodes has similar lighting parameters with thorium tungsten electrode. In addition, the starting, splash and corrosion resistance performance of dysprosium tungsten and yttrium dysprosium tungsten electrodes can reach a similar level to thorium tungsten electrode.

Tungsten oxide is a kind of transition metal oxide, its special property makes it be widely used in electrochromic device, gas sensor, separating material and so on. W ion in tungsten bronze belongs to changeable valence state, when introduce transition metal into crystalline structure, valence state of W transits between Ｗ^６＋，Ｗ^５＋ and Ｗ^４＋, unstable oxygen valance will form in lattice, surface of material will show defects. As a result, tungsten oxide shows special physical and chemical property. Tantalum belongs to transition metal which can be used as electrode material. Also dimension of Ta5+ is small and active, we can judge that doping tantalum can have great influence on its electric chemical property.

Preparation
1. Weighing 2g Na₂WO₄.2H₂O in reaction still with politef lining. Add in redistilled water, magnetic stirring and dissolving.
2. Adding a certain amount of 3 mol/L hydrochloric acid, control the whole reaction system pH lower than 1.5. Adding 0.05 mol/L TaCl5 and 0.5 mol/L NH₄(SO₄)2, stirring for 2hours and sealed the reaction still.
3. Heating it for 48h under 170 ℃, wash the reaction producer with distilled water to neutral, then put it in －40℃ lyophilizer.

Lead tantalum into hexagonal tungsten oxide structure by hydrothermal method, nano wire structure TaxWO₃ is obtained, the sample is even and with high purity. When Ta and W ratio in TaxWO₃ is 0.04, it reaches the settled limiting value of tantalum doping in tungsten oxide. Doping low valance state and big diameter tantalum ion into tungsten oxide, its cell parameters get affected, lattice is changed, oxygen valence on the surface of material ratio enlarged, the electron transition ability decreases, the catalytic property of material improves. Under acid condition, reduction of TaxWO₃ for H+ is more stable, it has potential application in fuel cell field.

Introduction
Cesium tungsten oxide (CsxWO₃) is a kind of functional compound which has nonstoichiometry ratio and oxygen octahedral, it has low electrical resistivity and low temperature superconducting property. CsxWO₃ is discovered to have great near infrared shielding property which is expected to take replace of ITO as raw material for smart window, it has wide application prospect in automobile and architecture field.

Preparation
Citric acid induction thermal synthesis method
According to chemical formula CsxWO₃（0<x<0.33）, valance state of W is at reduction state. With the increasing of Cs ion, low valance state of W ion also increases. It means synthesis of CsxWO₃ needs a certain reduction atmosphere.

During this process, citric acid and ethanol is used as reducing agent, carboxyl and hydroxyl will be oxidation into carbon dioxide under high temperature and pressure. And W⁶⁺ can be reduced into W⁵⁺ and W⁴⁺. Cs ion added into tungsten bronze which the process is like following:

1. Preparation of CsxWO₃ powder
1) Use AR grade sodium tungstate Na₂WO₄·2H₂O as raw material, configurating sodium tungstate solution for concentration of 0.5 mol/L;
2) Obtain tungstic acid solution by ion exchange resin method, adding citric acid solution of concentration 1mol/L or 2 mol/L and 0.3mol/L Cs₂CO₃ solution, stick it evenly, the precursor solution is obtained;
3) Adding precursor solution into autoclave, reacting for 3days under 90℃, after ultrasonic washing, alcohol washing, centrifugal and dry the CSxWO₃ is obtained.

2. Preparation of CsxWO₃ thin film
Grinding CsxWO₃ powder, ultrasonic dispersing it in citric acid solution for 1hour, then add into citric acid solution for ultrasonic dispersing for 1h, then adding 0.1g/ml PVA solution, stirring it for 30min then aging 1day to get latex. Use sol-gcl dip-coating method to prepare CsxWO₃ thin film on glass slide.

Property and application:
Near infrared shielding property and heat insulating property
Near infrared shielding material often refers to a kind of functional thin film material which has strong absorbance or reflect ability of near infrared and won’t affect its visible light transmission. As transparent insulating material, it has wide application prospect in architecture and automobile insulating glass.

CsxWO₃ thin film can shield near infrared for wave length longer than 1100nm. The near infrared shielding property and heat insulating property of glass after coated with CsxWO₃ thin film increases with the Cs content in CsxWO₃. Compared to common glass, the insulating temperature difference can reach 13.5℃. 

Hydrogen tungsten bronze(HxWO₃，0≤x≤1) is non stoichiometric compound, it has ring channel and special space tunnel structure. This structure is useful for disembedding and exchange for ion, thus makes it capable of offering and accepting proton.

Proton exchange membrane fuel cell (PEMFC) has advantages of low reacting temperature, high power density, high efficiency and no pollution. It is being widely used in portable power supply, dynamical power and power station. Traditional catalyst uses Pt as main content, which is quite expensive. So adding auxiliary catalyst is an effective method to lower the using amount of Pt and promote its catalytic activity. Hydrogen tungsten bronze as auxiliary catalyst to combine with Pt, the proton will accelerate the oxygen reduction of Pt by offering, by accepting proton can accelerate the oxygen catalytic of Pt to methyl alcohol. As a result, it has wide application broad as PEMFC.

Preparation
1) APT (NH₄)10(H₂W₁₂O₄₂)7H₂O is decomposed to (NH₄ )10(W₁₂O₄₁)5H₂O under heating to 100 ～200 ℃.
2) (NH₄)10(W₁₂O₄₁)5H₂O keeps decomposing to (NH₄)_0.33WO₃ under 200-250 ℃.
3) Under 250-575 ℃, (NH₄)_0.33WO₃ converts into H_0.33WO₃ and WO₃.

Among which (NH₄)xWO₃ can be decomposed into HxWO₃ under 150-350 ℃ with change in crystalline structure, chemical equation is: (NH₄)xWO₃=HxWO₃+xNH₃(g).

Composition and structure
Crystalline structure of NaxWO₃ is affected by value of x. When x<0.1, NaxWO₃ is WO₃ structure, it uses WO₆ octahedral as unit structure. When 0.1 <x <0.35, NaxWO₃ is tetragonal crystalline. When 0.35 <x <1, Nax WO3 has perovskite structure with Na+ vacancy. These two crystalline structure has WO₆ octahedral structure unit. Under different temperature, WO₆ octahedral can flex in different directions to make the temperature change of crystalline structure. It offers the possibility of synthesis for different materials.

Lattice imperfection
NaxWO₃ equals to NaWO₃ without (1-x) Na⁺. NaWO₃ belongs to complete perovskite structure which is cubic system. There is no space in lattice for they are being taken by Na⁺、W^(v)，O^2-. When NaWO₃ loses Na+ and becomes NaxWO₃, lattice appears (1-x) Na⁺ space, Na⁺ space made the incomplete of lattice, that’s why NaxWO₃ appears single ion default.

Synthesis
X value of NaxWO₃ is determined by synthesis condition. Under high temperature, Na⁺ would disperse into lattice or spread out from it, it makes the content of sodium changes in NaxWO₃. Using mixture of sodium tungstate and tungsten oxide and heat them with proper reductant would get the product, the reductant is often W、WO₂、H₂. Also, by electrolysis of sodium tungstate and tungsten oxide can also obtain the product. Chemical equation is as following:
3xNa₂WO₄ + (6-4x) WO₃ +xW=6NaxWO₃
xNa₂WO₄ + (2 -2x) WO₃ +xWO₂ =2NaxWO₃
xNa₂WO₄ + (2 -x) WO₃=2NaxWO₃ +x/2O₂

Property
Close packed structure, chemical inertness and metal luster
NaxWO3 belongs to fake and default ABO₃ perovskite structure. In such structure, O^2- and Na⁺ are in cubic close packing, W and O becoming WO₆ octahedron and share the same vertex, Na+ lies in the interspace of WO₆ octahedron. So NaxWO₃ can resist all kinds of hydrofluoric acid, insoluble in water, shows ultimate chemical inertness to acid. Its close packed structure makes it have metal luster and inert metal property. As a result sodium tungsten bronze can be used as great anti-corrosion material.

Unstable oxidation state and reduction of W in NaxWO₃
Average oxidation number of W in NaxWO₃ is between V-VI, xmol of W is +V oxidation state, but the most stable is +VI, it makes NaxWO₃ have strong reducing property under alkali condition. NaxWO₃ is oxidized when heating in the air, it can be soluble in the strong alkali solution, and can reducing ammonium solution of nitrate.

Color of NaxWO₃ changes with the x value. The reason why crystalline has coloration is there is default in it which is called color center. Different x value of NaxWO₃ would cause difference in absorbing visible light wavelength, thus the crystalline color is different. When x value is bigger, electron transition mainly absorbs short wave blue-purple light, the crystalline would show yellow-orange; as the decrease of x value, electron transition absorbs long wave red-orange light,

Electrical conductivity
Sodium tungsten bronze has electrical conductivity which is related to its composition. When x>0.25, NaxWO₃ shows metallic electrical conductivity, rate decreases with rising temperature. When x<0.25, NaxWO₃ shows semiconductor metallic electrical conductivity, rate increases with rising temperature. This special property makes it become newly solid electrolyte, there is already NaxWO₃ used as ion reversible electrode. Synthesis and research on solid electrolyte is an active field of inorganic solid chemistry. Solid electrolyte replaces regular electrolyte solution has become revolution of electrical chemistry. The crystalline shows blue-purple.