With the development of technology, the grinding methods of tungsten carbide ball are developing rapidly. There are conventional grinding methods (includes single V-slot, double V-slot and conical slot), fluid polishing (magnetic fluid, non-magnetic fluid) and high precision grinding (eccentric V-slot, active control of rotation), etc. Single V-slot grinding, the value of rotation angle depends on the angle and ball milled blank disc slot diameter, in a closed loop process almost from the corner does not change, and since the angle is very small, but only for a relatively compact carbide balls orientation change (i.e. ball billet rotation axis and the revolution axis angle of the same size) grinding motion.

The contact point of blank ball and polishing discs trace ball billet was formed on the surface of the center axis of the rotation axis of the ring. The defect of this method is that it can not ensure quickly billet surface grinding ball uniform, thereby reducing the efficiency and accuracy of carbide and sphericity processing. Therefore, the related researchers modified in part designed to travel around the grinding disc moving grooves, making the ball spin axis changes can be made randomly. Compared with single V-slot grinding, both of the upper and lower grinding tray of tungsten carbide ball double V-slot grinding are V-shaped, while single V-slot only the lower grinding tray is V-shaped.

You may have seen a wide variety of glass products in life, such as mobile phones glass, glass vases, glass windows, glass roofs, glass lid, glass cups, and so on. They all have one thing in common, and that is: they are transparent. But did you have seen the glassy tungsten trioxide? How it is prepared? Is it transparent?

Tungsten trioxide are yellow powder, it dissolves in water, dissolves in alkali, slightly dissolves in acid. It is mainly used to restore the production of calcined tungsten powder and tungsten carbide powder, and then for the production of carbide products, such as tool and die manufacturing. It also can be used in the manufacture of pure tungsten products, tungsten electrode; and the use of counterweight and radiation shielding material. In the shipbuilding industry, the tungsten trioxide is used as important anti-corrosion paint and coatings material. Due to extensive use of tungsten trioxide, more and more people increase research efforts on the tungsten trioxide, at present, the study shows that glassy tungsten trioxide is unique performance oxidation, it is able to meet the needs of production and processing areas.

Preparing glassy tungsten trioxide, the first steep is adding tungsten powder (diameter 1μm) 15% to hydrogen peroxide capacity of 25ml (H₂O₂), stirring for 3-10 minutes, and the tungsten powder is almost completely dissolved. As colorless solution, it is strongly acidic to remove small amount of undissolved impurities. The second steep is meshing Pt, Pt-plated to reduce the excess H₂O₂. Finally, drying solution at room environment, we can obtain paint yellow glassy tungsten trioxide.

Cyclohexanone is organic compound, it is carbonyl carbon atom including the six-membered ring saturated cyclic ketone; it is colorless and transparent liquid, it containing traces of phenol. Cyclohexanone impurities are yellow. Cyclohexanone has a carcinogenic effect; it is mainly used in industrial organic synthesis of raw materials and solvents. Cyclohexanone is an important chemical raw materials, it is widely used in nylon, caprolactam and adipic acid intermediate principal. It is also an important industrial solvent, such as for paints, in particular for nitrocellulose, vinyl chloride polymers and copolymers or methacrylic acid ester polymer paint.

In the process of preparation, a suitable solvent for the reaction is very important. We can see from the data in Table 1-1, the methanol is the best solvent for reaction.

1-1 Effect of different solvents on the yield of cyclohexanone

1-2 Effect of the amount methanol on the yield cyclohexanone

Table 1-1 shows that methanol is the best solvent for the reaction. As we can see from the data in Table 1-2, the yield of cyclohexanone decreases with increasing amount of methanol. Due to the increased amount of methanol, this results the concentration of reactants and the cyclohexanol conversion rate reducing.

Using impregnation method to produce barium tungsten electrode it has good emission properties, high current density, smooth electrode surface and long service life and other good performance. However, this method has the disadvantage of complex processes and processing difficult.

To produce barium tungsten electrode by impregnation method there are two elements, tungsten cavernous spongisum and emitting material and the production processes are as following:

1. Tungsten cavernous spongisum production:
Raw materials: tungsten powder (250 mesh / cm2): 97g, paraffin: 3g, aviation gasoline: 30~40cc, glycerol;
Production processes: Pour gasoline into paraffin to make paraffin melted, then pour them into tungsten powder (about 180 ℃) with rapid stirring, until the smell of gasoline is gone. And then compress it into blocks. The compacted tungsten powder was processed low-temperature sintering, and before sintering temperature slowly raised to 600 ℃the temperature is 100~150 ℃/ h, but at 600 ~ 1400 ℃ the temperature is 200 ℃/h (heating preservation for 1 hour). When the temperature at 1700℃ the product is molding. Finally, high temperature sintering, high temperature sintering temperature is about 2000 ℃ (about half an hour).

2. Emitting material: barking barium aluminum in oven at about 100 ℃,after grinding and compressing put it into molybdenum boat for sintered with Al2O3 doping when the sintering temperature reaches to 700 ~ 800 ℃, heating preservation for 1 hour, when the sintering temperature is 1400 ℃, heating preservation for 2 hours, after sintering pulverized it into pieces to get finished.

3. Barium tungsten electrode: putting barium aluminum into nitrocellulose stir into a paste, applied to the surface of the tungsten cavernous. And then burn to 1750 ℃, until the product surface shows light green color. Then the sintered electrode in pumping quartz vessel prepared products roast vacuum high frequency. Finally, the electrodes are placed dried in a vacuum environment for storage.

Barium tungsten electrode Use Notes:
1. Can not make it wet or long-term exposure to the atmosphere, deposited in a vacuum state for the best;
2. Can not direct contact with the to prevents sweat marks shows on the surface of the electrode;
3. Electrode texture is light and crispy, using gently;
4. Improper storage electrode surface will oxidation, you can process burn hydrogen treatment to remove surface dark spots, and then continue to use;
5. The transmission side of electrode has cracks or broken, to stop using it.

Barium tungsten electrode is a high intensity discharge lamp electrode material. It is produced for improve the properties of tungsten electrode which is changing the low electrons emission ability of pure tungsten electrodes, increasing electrons and electron current density, improving gas discharge lamp ignition speed, reducing electrode working temperature so it can apply in different fields. Barium tungsten electrode has high electron emission capability, low work function, high electron emission electron current density, good gas discharge lamp ignition speed, low working temperature and other good performances. In addition, the barium tungsten electrode is a non-radioactive poison electrode and has anti-poisoning ability.

Because barium tungsten electrode having the above excellent performances often used in optoelectronic products, navigation mark identification, target tracking, laser mercury pump, medical positioning light treatment and military weapons field and so on. For example, because it having low work function (φ = 1.6 ev), high current density (10A / cm2), good starting performance, large power output and other characteristics, are widely used in HID lamps. In addition, barium tungsten electrode having low work function, so often used to make electric vacuum and laser device in which the electron emission performance of light products can be achieved from low to high repetition rate (1 ~ 40 times / sec). The start-up performance of stroboscope lamp has been significantly improved which is produced by barium tungsten electrode. On the other hand, because current density of the electrode is high, so the luminance of stroboscope lamp increases by about 15%. At the same time, using barium tungsten electrodes to produce high frequency stroboscope lamp has long service life, up to 500 million times. Besides, during working there are not occur leakage flash, chain lightning and other problems.

The main function of packaging materials includes mechanical support, signal transduction, heat radiating, sealing and protecting products, so they requested that the material has a certain mechanical strength, good electrical and thermal capacity, chemical stability, and product line expansion coefficient matched material, easily for producing Conventional substrates has been difficult to meet the rising temperature of the circuit and to ensure steady long run, this will affect the reliability of electronic components to some certain extent. Therefore, tungsten copper material becomes more and more significant in microelectronics packaging. Electronic components and packaging material due to small size, complex structure and other reasons, it is difficult for mass production by conventional pressing sintering process method, which makes tungsten copper powder injection molding technology has been further developed.

Related researchers uses 10%, 15%, 20% content of copper for powder injection molding, which after infiltration obtained, fine-grained tungsten-copper composite materials, have reached a density more than 99%, transverse rupture strength reaches 1500MPa. Some scholars have also done the injection molding parameters tungsten copper W-30Cu nano-composites T-die, and after forming the binder removal process to obtain a good surface quality, regular shape of the compact, the adhesive extrusion rate reached more than 99%, can be obtained through direct sintering manner relative density higher than 96% of tungsten-copper composite parts. However, the process will caused by tungsten (W) powder loading of different or the intake air in the mixing process and lead to material gathered in the stress state, a certain amount of defects such as large irregularly shaped cracks or holes generated in the process of degreasing, it is easy leading to infiltration of copper pool and closed pores formed.

Inspired from powder injection molding of conventional powder metallurgy (PM), tungsten-copper composite powder injection molding technology is based on the injection of tungsten skeleton is formed, and it breaks the limitations of conventional Infiltration produced tungsten-copper composite. Metal injection molding (MIM) is a kind of process that suitable for fabricating the products with complex or irregular shape, and it was first extended by the plastic injection molding industry. In recent years, a substantial increase in the content of the solid particles and the binder is completely removed during sintering densification of the compact, resulting in metal products with high strength, excellent wear and corrosion resistance.

Its basic steps is that choose the metal powder meet the requirements of MIM (includes shape of powder, the granularity, the content, specific surface and so on) and corresponding binder (MIM is the core technology, with enhanced liquidity and maintain compact shape function), At a certain temperature using appropriate methods uniformly mixing the powder with a binder feed, injection molding after granulating, injection molding and degreasing obtained the products. Tungsten-copper composite material due to its high strength, high density, high melting point, good chemical stability, and is a good electrical and thermal conductivity of the heat sink material, not only from the field of military aviation in a number of electrical contacts and electrodes have a wide range the use of some of the tightness in demanding electronic packaging materials is also a good choice.

Specific steps are as follows:
1. Preparing precursor solution
Dissolve APT in deionized water, then add a certain amount of dispersing agent and modifier, continually stir in the magnetic stirrer for 3-5 hours, and then stand constantly in the water bath environment at 70-90℃ to generate precursor solution;
2. Coating
Coat at substrate by dip-coating or spin-coating method, and dry under a suitable temperature condition. The substrate should be washed and other pre-dealing;
3. Roasting
Roasting the substrate at high-temperature (350-600) in a temperature controllable procedures muffle furnace for 2-5 hours after it is dried, and finally gets the nano tungsten trioxide film.

Its obvious advantages lay in:
1. Take APT as precursor, by adding dispersant and a modifier, final get nano tungsten trioxide film firmly adhesion to substrate;
2. The precursor solution can be stored for more than 3 months with a stable state and no precipitation phenomenon produced, it also can be reused, easy to operate, greatly reduced the production cost;
3. The dispersant and modifier added into precursor solution are entirely organic matter which can easily be oxidation and removed at high temperature, without introducing metal elements except W, especially metallic element of the alkali metal (Na+, K+), also it does not affect the performance of the photocatalytic activity of W0₃ and photoelectric conversion;
4. Nano tungsten trioxide film prepared is of excellent photoelectric properties.