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.

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.

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.

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.