Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 17 No. 2 April 2007|
（State Key Laboratory for Fabrication and Processing of Nonferrous Metals,
Beijing General Research Institute for Non-ferrous Metals, Beijing 100088, China）
Abstract:A novel Si-Al alloy was prepared by spray forming process for electronic packaging. Property measurements on spray-formed Si-Al alloys after hot pressing were carried out. The results indicate that the alloys (Si-(30%−40%)Al) have advantageous physical and mechanical characteristics, including low coefficient of thermal expansion (6.9×10−6−8.7×10−6/K), high thermal conductivity (118−127 W/(m·K)), low density (2.421×103−2.465×103 kg/m3), high ultimate flexural strength (180−220 MPa) and Brinell hardness (162−261). The alloys are easy to machine to tight tolerances using standard machine tools and they can be electroplated with gold finishes and soldered with Sn-Pb alloy without any difficulty.
Key words: spray forming; Si-Al alloy; electronic packaging material; coefficient of thermal expansion