Research on microstructure of copper coatings on AlN ceramic surface by laser cladding and brazing

Abstract

The preparation of Cu-based coatings on AlN ceramic surface was accomplished by laser cladding and brazing technology. The Cu-based coating was prepared by both copper powder and titanium powder on ceramic surface. The microstructure and properties were tested by x-ray diffraction, metallurgical microscope, scanning electron microscope, energy dispersive spectrometer and microhardness tester. The novelties of this paper in the method of laser cladding and brazing were used to prepare Cu-coating on ceramic surface and the addition of Ti could improve the properties of Cu-based coating. The addition of Ti improved the wettability of ceramic surface. According to the results of EDS, Ti could better get into the Cu-based coating and formed metallurgical bonding in the laser cladding. The microhardness of laser cladding was higher than brazing, which could be concluded that it was due to the rapid cooling rate during the laser cladding could restrain grain growth and element segregation.