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July 14, 2023
Preparation Method of Tungsten Copper Sheet
Tungsten copper alloy is commonly used as heat sink and packaging materials for microelectronics due to its excellent thermal conductivity and low expansion coefficient of copper and tungsten. By adjusting the proportion of tungsten and copper, the material can be more matched with the chip. In addition, tungsten copper alloy has the characteristics of good strength and stiffness, and good weldability. The following processing steps are generally adopted in the preparation of tungsten copper sheet:
1. Steel die pressing: the tungsten copper dispersion powder is pressed into a hydraulic steel die to obtain a steel die forming compact
2. Cold isostatic repressing: the steel die forming compact is repressed in the cold isostatic press to obtain the repressed compact
3. High temperature sintering: the compound compact is placed in the vacuum furnace for high temperature sintering to obtain the sintered blank
4. Rolling (according to the order of hot rolling, warm rolling and cold rolling) : the sintered billet is hot rolled with two high rollers, and then annealed. The hot rolling and annealing steps are repeated according to the thickness of the sintered billet to obtain the annealed hot-rolled tungsten copper sheet, and then the surface treatment of the annealed hot-rolled tungsten copper sheet is carried out; The annealed hot rolled sheet was warm rolled and then annealed to get the warm rolled tungsten copper sheet. After cold rolling, annealing and flattening, tungsten copper sheet can be obtained. The materials produced by this technology have the characteristics of uniform microstructure, dense, qualified air tightness, high production efficiency, high material utilization rate and low cost.
After pressing the tungsten copper powder mixture, it is produced by liquid phase sintering at a temperature of 1300-1500°. However, the uniformity of the material prepared by this method is not good, there are more closed gaps, and the density is usually less than 98%. We can by adding a small amount of nickel active sintering method, mechanical alloying method or oxide reduction method, to prepare ultra-fine, nano powder can improve the sintering activity, thereby improving the density of tungsten copper alloy. However, the conductive and thermal properties of the material can be significantly reduced by nickel activation sintering. Mechanical alloying also reduces the material conductivity by introducing impurities. The process of oxide supply reduction method is complicated, the production efficiency is low, and it is difficult to mass production. Therefore, in the future, the preparation process needs to continue to develop, tungsten copper products as the most commonly used alloy products, has a very good market prospects.
Tungsten Copper Sheet Picture: