Understanding solid phase diffusion-bonding process of Ni (000)/α-Al2O3 (0001) interface

The dynamic processes and characteristics of solid phase diffusion-bonding of interfacial atoms at high temperatures and the effect of that on bonding strength of Ni (111)/α-Al₂O₃ (0001) interface were investigated through molecular dynamics. It is shown that atomic diffusion occurs at the Ni/Al₂O₃ interface in the temperature range from 698 K to 1,098 K, and proceeds mainly from the Ni side to the Al₂O₃ side. The interface was previously reconstructed by solid bonding below the melting temperature, leading to the amorphization of the interface. Besides, the intermetallic complexes such as Al_mNi_n (e.g., AlNi₃), metal oxide NiO and Ni-Al-O bonds were formed gradually during the diffusion process of atoms. The formation mechanisms of the Ni-Al, Ni-O, and Ni-Al-O bonds are revealed. Based on the reconstructed structure, the adhesion effort at the interface is compared. The higher the temperature, the larger the bond number and the higher the interfacial bonding strength.