Study on Preparation Technique of SiC/Cu-Al Composite by Pressureless Infiltration

In order to improve the compatibility between SiC particles and aluminum, the SiC/Cu composite powders were prepared by using chemical plating method to coat a Cu layer on the SiC particles surface. The obtained powders were made into preform and then put it into molten aluminium. SiC/Cu-Al composite were produced by using pressureless infiltration method under argon gas. By scanning electron microscopy (SEM), optical microscopy (OM), X-ray diffraction (XRD),the phase structure and microstructure of SiC/Cu composite powders and SiC/Cu-Al composite were analysed. Moreover, the temperature and soaking time on the effect of SiC/Cu-Al composite infiltration depth and effect were studied. The results show that: Cu coating on the SiC particles surface distributed uniformly; SiC/Cu-Al composite prepared at the condition of 800°C and 2 hours soaking time has a densification microstructure, SiC particles uniformly distributed in the aluminum matrix and there is no Al4C3 brittle phase formation; at 700°C～900°C infiltration, as the temperature growing, infiltration depth increases at first and then decreases; the microstructure of SiC/Cu-Al composite which infiltrated 2 hours is more compact than that 1 hour; Cu coating effectively improved the wettability between SiC particles and molten aluminum, and inhibited the formation of harmful interfacial reaction.