内氧化法制备AgCuONiO电接触材料的热力学分析及其组织演变

采用内氧化法制备了AgCuONiO电接触材料,理论推导了AgCuNi合金发生内氧化的热力学条件,利用光学显微镜、扫描电镜、电子拉力试验机等分析手段对其物理性能和微观结构进行了研究。结果表明:AgCuNi合金内氧化在热力学上是可行的,热力学区位图中择优氧化区的范围由上、下限氧分压共同确定。随着内氧化温度的提高,材料基体中的氧化物颗粒的尺寸有所增加,氧化物颗粒形貌由弥散颗粒状逐渐向链珠状过渡。试样的导电率、显微硬度以及抗拉强度也随内氧化温度的升高而逐步增加,基体中细小弥散的氧化物颗粒的析出是材料力学性能改善的根本原因。

Thermodynamics Analysis and Microstructures Evolution of AgCuONiO Electrical Contact Materials Prepared by Internal Oxidation

AgCuONiO electrical contact material was prepared by internal oxidation and the thermodyna-mics condition of internal oxidation of AgCuNi alloy was calculated in the present paper. Properties and microstructures of the composite were investigated by means of optical microscopy, scanning electron microscopy and electronic tensile testing machine. Results indicate that the internal oxidation of AgCuNi alloy is feasible in thermodynamics, and the preferential oxidcotion zone in thermodynamics location diagram is determined by both the upper and the lower limits of oxygen partial pressure. As the internal oxidation temperature increases, the size of the oxide particles in the material matrix increases and the conductivity, micro-hardness and tensile strength increase gradually also. The high temperature leads to the morphology of the oxide particles transfer from granularity to bead structures. The precipitation of dispersed oxide particles in the matrix is the fundamental cause of the improvement of mechanical properties for the material.