Due to tungsten copper material is composed of two kinds of metals with a great difference in melting point, which copper evaporates and takes off part of heat for equipments working well at high temperature. Especially in some electronic components with high power and easily heated, tungsten copper as heat sink has wide applications. However, with the rapid development of electronic science and technology, electronic components have become smaller and more precise, which places a greater demand on tungsten copper sheet and heat sine materials. Conventional process of tungsten copper sheet has some defects in thickness and density, so it is difficult to meet the requirements of the properties of heat sink materials. In order to fabricate tungsten copper sheet with uniform thickness and high density, the researchers study on three levels, which include continuous liquid phase sintering, cold rolling and re-sintering.

In the process of continuous liquid phase sintering, the preparation of raw material is also crucial. It should be noticed that the content of elements and granularity, the additives, the stirring time, the granulation process, drying temperature, forming pressure, blank density detection and many parameters controlling. Continuous liquid phase is conducted in molybdenum wire furnace under the protection of hydrogen. It puts tungsten copper sheet in the high temperature zone and holds a period of time, and then push to end cooled rapidly cooled to obtain the sintered sample. Afterwards, The sintered samples in the two-roll cold rolling mill and cold rolling deformation measurements, observed by optical microscopy that is rolling a longitudinal section (parallel to the rolling direction), the evolution of the cross-section (perpendicular to the rolling direction) of the microstructure. Finally, re-sinter tungsten copper sheet after cold rolling in the molybdenum wire furnace under the protection of hydrogen, and temperature should be controlled 1300℃ (above the melting point of Cu), in the high temperature zone without holding time in case of grain growth.

Lanthanum tungsten electrode is mainly produced by powder metallurgy method. It is added 1%, 1.5% or 2% lanthanum oxide to tungsten powder, after doping, reduction, vertical melt, swaging and stretching to obtain lanthanum tungsten electrode. Lanthanum tungsten electrodes have good welding performance, long service life, and no radioactive contamination, so it is considered the best substitute for thorium tungsten electrode and it is widely used in tungsten inert gas welding (TIG welding), plasma welding and cutting field. By comparison electrical property found, lanthanum tungsten electrode’s electrical property is superior to cerium tungsten electrode and thoriated tungsten electrode. Lanthanum oxide, having low mobility and evaporation rate, can form a good lap dovetail organization, so lanthanum tungsten electrode has good high temperature creep performance.

After swaging process, La₂O₃ particle is evenly distributed over the tungsten grain and boundaries. If not properly control billet processing, it is prone to delamination or peeling. On the other hand, if feeding too fast in swaging process can also cause delamination or peeling.

After electrical property analysis understand the La and Ce distribution in lanthanum tungsten electrode and cerium tungsten electrode. At DC 200A, for 20min, the electrode tip working at high temperature 2600 ~ 3000 ℃, La₂O₃ and Ce₂O₃ from the center migrate to the surface and to the tip. Their average content decreased gradually from the edge to the center portion and there has almost no La₂O₃ andCe₂O₃. Ce₂O₃ has faster migration and evaporation rate.

After electrical property test observed electrode’s microstructure found that the electrode grains grow along axial direction. The grains aspect ratio of cerium tungsten electrodes and lanthanum tungsten electrode is respectively (3: 1 to 15: 1), (3: 1 to 7: 1). In lanthanum tungsten electrode there are a large number of bubbles and a small amount of La₂O₃ particle. Besides, grain boundaries are dovetail lap organizations which can impede grain boundary sliding laterally, so it has better thermal shock, creep performance. Lanthanum tungsten electrode electrical property is better than other electrodes.