| 摘要 |
A lead base alloy consists of 98,5 per cent to 82 per cent lead, 1 per cent to 15 per cent tin and 0,5 per cent to 3 per cent copper. Preferably the alloy consists of 86 per cent lead, 12 per cent tin and 2 per cent copper. An aluminium base backing consists of 1 per cent-10 per cent silicon, 0,25 per cent to 5 per cent cadmium and the remainder aluminium. Preferably the silicon content is 3,5 per cent to 4 per cent and the cadmium content 0,75 to 1,40 per cent. |
