Microstructure and Mechanical Properties of Copper Matrix Composites Reinforced by Cu-Coated Β-Si3n4 Whiskers

Abstract

In this study, in order to enhance interfacial bonding between copper and β-Si3N4 whiskers in copper matrix composites, Cu coating was deposited on the surface of β-Si3N4 whiskers using an electroless plating method, and Cu-coated β-Si3N4 whiskers reinforced copper matrix composites (CSCMCs) were prepared by hot-press sintering. After electroless plating, Cu coating was successfully deposited on the surface of β-Si3N4 whiskers, which solved the problem of agglomeration of whiskers during the subsequent sintering. In addition, the introduction of Cu coating provided a wetting layer at the interface of the two phases, which resulted in a good bonding of β-Si3N4 whiskers with the copper matrix and no reaction product generation near the interface. The results indicated that the Cu coating effectively enhanced the relative density and mechanical properties of the composites. Compared to uncoated β-Si3N4 whiskers reinforced copper matrix composites (USCMCs), the CSCMCs exhibited superior performance when the Cu coating content was 0.5 vol.% and the β-Si3N4 whisker content was 10 vol.%. Under these conditions, the relative density increased from 93.49% to 97.25%, with flexural strength and hardness reaching 332 MPa and 91 HV, respectively.

Keywords: Cu matrix composites, β-Si3N4 whisker, Interface, Mechanical properties