Microstructure of surface composite Al2O3/Ni on copper substrate produced by vacuum infiltration casting

This present work reports on the microstructure and hardness of infiltrated Al2O3/Ni layers on the copper substrate. The infiltrated layer was produced by vacuum infiltration casting technique (VICT) using Ni-based powder and Al2O3 particulates with different content. By optimizing the processing parameters, a compact infiltrated layer is achievable as confirmed through SEM observation. The infiltrated layer is composed of surface composite layer and transition layer, and the thickness of the transition layer decreases with the increasing content of Al2O3. The hardness of the surface composite has been evaluated. The macro-hardness of the layer is about HRC 65.0 and the distribution of micro-hardness shows a gradient change. The average micro-hardness of the infiltrated layer is about HV700.