Cu-Al合金内氧化的热力学分析——Ⅱ热力学函数的应用

这是(Cu-Al合金内氧化的热力学分析》一文的第Ⅱ部分。对Cu-Al合金内氧化的热力学条件进行了分析，绘制了内氧化的热力学条件区位图。结果表明：区位图中择优氧化区位很大，范围由上、下限氧分压确定，其中：lgPo2max=(-17611／T) 12．91，lgPo2min=(-55830／T)-(4／3)lg％Al] 19．95，但实际的内氧化区位是靠近上限Po2的一个很小区域；溶度积Ksp和残余Al浓度都是极小量，内氧化可进行得很彻底；内氧化控制中温度和氧分压的调节必须同步：理想的内氧化工艺条件应是：采用1223K左右的高温，介质中的氧分压力求接近或等于上限Po2;为了避免氧化，降温过程宜采用通H2急冷的方法。

Thermodynamic Analysis of Internal Oxidation of Cu-Al Alloy

The thermodynamic requirements of internal oxidation of Cu-Al alloy were systematically analyzed, and a zone chart of internal oxidation thermodynamics was drawn. The results indicate that the preferential oxidation zone is quite large in the zone chart, and is determined by the maximum and minimum partial pressure of oxygen, where=(max)O2lgP(17 611/T)+12.91,=(min)O2lgP (55 830/T)(4/3)lg%Al]+19.95. In fact the practical internal oxidation zone is a small part of the preferential oxidation zone near the maximum partial pressure of oxygen. The volume concentration product Ksp and concentration of residual aluminum are so low that the internal oxidation can procede completely. The temperature and partial pressure of oxygen should be adjusted synchronously during the control of internal oxidation. The optimum conditions for internal oxidation are heat treatment at a high temperature of about 1 223 K, and a high oxygen partial pressure approaching or even equal to the upper limit. Rapid cooling with hydrogen is used to prevent oxidation of the copper.