Bonding mechanism between the AlN ceramic matrix and the copper-based metal cladding layer

High-temperature brazing and laser cladding methods can form a good metallurgical bond between ceramics and copper cladding. Herein, through these two methods, the preparation of a Cu-based metal cladding layer on the surface of aluminum nitride (AlN) ceramics was carried out. Scanning electron microscopy, X-ray diffraction, energy-dispersive spectroscopy, and other characterization techniques were employed to observe the macroscopic and microscopic morphologies, elemental distribution, and microstructure characteristics of Cu-based metal coatings and transition layers, in order to analyze the interface bonding mechanism. Research has found that the active element titanium (Ti) has a significant promoting effect on the wettability of Cu powder on the surface of ceramics. Metallurgical reactions occur at the interface between ceramics and Cu-based metal coatings. Al and N elements in ceramics react with most of the Ti in the metal coating and Cu in the molten metal also reacts with Ti, generating new compounds, thereby forming a metallurgical bond between ceramics and Cu coatings.