| 摘要 |
PURPOSE:To obtain the titled lead material causing no cracking of a ceramic board during cooling after silver brazing and having high strength, electric conductivity and heat conductivity by providing a specified composition consisting of Ni, Co, Si, Zn, Sn, Cr and Cu. CONSTITUTION:This lead material for ceramic packaged IC consists of, by weight, 1.0-5.0% Ni, 0.2-1.0% Co, 0.2-1.5% Si, 0.05-5.0% Zn, 0.1-2.0% Sn, 0.001-0.5% Cr and the balance Cu with inevitable impurities. Though the lead material has a high coefft. of thermal expansion not close to the coefft. of thermal expansion of ceramics, a ceramic board is not cracked during cooling after silver brazing at about 800-900 deg.C. The lead material has superior strength, repeated bendability, electric conductivity, heat conductivity, solderability and resistance to stripping under heating by soldering even after brazing. The grain size of the lead material is <=about 50mum. |
