Spray forming silicon aluminum alloy electronic packaging materials with chip to match the thermal expansion coefficient, high thermal conductivity, low density and high stiffness characteristics, mainly application areas is in high-end electronics and precision optics industry.
China has been put into the equipment can produce silicon aluminum alloy ingots that silicon content is 27-70%, ¦300mm × 1200mm. The alloy material of the silicon content is 50%, compared with steel, the weight loss 2/3 or more, double the rate of the thermal conductivity, thermal expansion coefficient is the same. The alloy materials have been used by an Institute of Electronics, material expansion coefficient, thermal conductivity, strength, air tightness and density performance indicators have reached or exceeded the international level of similar products, and verify that the material machining, welding, surface treatment and other process performance, to meet the needs of practical application.
The history of preparing metal materials using injection molding technology is more than 30 years in the international arena, but for a long time this technology and products are blocked and controlled. The researchers engaged in the study of the technology for nearly 20 years, has mastered the injection molding technology to produce high-performance aluminum, aluminum-silicon alloy electronic packaging materials, the core technology of the three types of new materials for high-speed tool steel, and independent intellectual property rights .
For a long time, because of its excellent conductive properties, copper and copper alloys have been to see the first choice for the manufacture of conductive materials, However, with the sharp reduction of the amount of global copper resources and increasingly exhausted, the trading price of copper is soaring. According to the metal powder exporter, the current trading price of per ton of copper reached $ 7,000, resulting in such a high investment cost prices of copper wire and other products, making the world's electricity workers clearly recognize that improving or looking for a new electricity transmission is importance and urgency of the line.
China has been carry out research in this area in 1980s, but are focused direction of high-purity aluminum alloy, that the blind pursuit of lower aluminum alloy content of impurity elements (Si, Fe, Ti, Cu, <1%),in order to improve the conductivity. Thus, many manufacturers have adopted the import lower silicon content aluminum blended with the ordinary aluminum method, reduced the silicon powder content to less than 0.08% wt, and then use the boride treatment to remove the import aluminum introduced Ti, Cr, Mn and other impurities. Obviously, this approach is neither economic nor reasonable, although high-purity Al-Si alloy to meet conductive requirements (the IACS> 45%), but because of the silicon content in the alloy is too low, resulting in low alloy strength, abrasion resistance is not high, still unable to meet the requirements of long distance transmission. For exploration and study of the performance of high silicon aluminum conductive few research institutions for the study of high-silicon aluminum mostly focused on how to improve the silicon element solubility in aluminum matrix, how to improve the strength of the aluminum alloy, abrasion resistance, heat resistance etc.
It is based on the full use of bauxite resources in the high silicon features, in the case of lower silicon content, by adding to the Al-Si-based alloys degenerate elements optimize the structure of in-depth study for the mechanism of high-silicon aluminum alloy conductive as well as the use of advanced preparation process starting by adding rare earth elements (La, Ce, etc.), to make it generate compounds with silicon elements as much as possible, so as to change the grain morphology, particle size, and change the crystal structure, reducing the aluminum atom lattice distortion, improve the conductivity of high silicon aluminum. So the experiment will cast alloy Al-20Si-0.35RE gas atomization to get the ingredients uniformly high silicon aluminum alloy powder of rare earth, follow-up with high-energy ball milling, combined with the multi-pass pressing deformation process, preparation of cerium compounds, lanthanum high silicon compounds as well as primary silicon composite strengthening high-performance aluminum alloy.
Source:http://www.mhcmp.com
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