五、性能: 1.体积改变:银汞合金在凝固反应时具有微小的体积改变。依照A、D、A、N01要求,银汞合金的收缩和膨胀不超过20μm/cm。最大的膨胀为0.2％,最小收缩为0.1％。当汞与合金粉研磨后20分钟开始收缩,这由于合金颗粒溶解于汞中,颗粒变小,γ_1晶体生长所形成的收缩,当γ_1晶体硬固,向外生长互相撞碰发生膨胀,如果含汞太多,也会使银汞合金膨胀。当汞含量少,研磨时间长等都可以引起收缩,高铜合金在1～2小时收缩后即持续性膨胀(表2)。含锌的银汞 Fifth, the performance: 1. Volume change: silver amalgam in the solidification reaction with a small volume change. According to A, D, A, N01 requirements, amalgam contraction and expansion does not exceed 20μm / cm. The maximum expansion is 0.2% and the minimum shrinkage is 0.1%. When mercury and alloy powder begin to shrink after 20 minutes, the particles become smaller and the shrinkage caused by the growth of γ_1 crystal will occur. When γ_1 crystal is hard and solidified, Too much mercury can also cause the amalgam to swell. When the mercury content is low, long grinding time can cause contraction, high copper alloy after 1 to 2 hours of continuous expansion (Table 2). Zinc-containing silver mercury