Effects of Heat Treatment on the Interfacial Structure of Nickel-Aluminum Coating Composites
Nickel(Ni) layer was applied to the surface of pure aluminum(Al) by electrodeposition for 15 minutes using a direct current (DC) condition at 0.13 Acm-2. Heat treatment was employed subsequently for 1, 2.25 and 4 hours at the temperatures of 600 and 650oC, which are below and above the eutectic temperature of Al-NiAl3, respectively. All samples were characterized by OM, SEM, EDS and GIXD. DTA was also performed to study heat release in the reactions. After heat treatment at 600oC, the specimens exhibit the non-uniform formation of Ni2Al3 and NiAl3, even after 4 hours of heat treatment where local melting possibly occurs due to the exothermic heat of formation. In contrast, owing to fast interdiffusion of Al and Ni as assisted by a liquid phase formation, multi-layer of Ni2Al3 and NiAl3 was uniformly formed along the interface of the specimens heat treated at 650oC.
Zhengyi Jiang, Xianghua Liu and Jinglong Bu
A. Issariyapat et al., "Effects of Heat Treatment on the Interfacial Structure of Nickel-Aluminum Coating Composites", Advanced Materials Research, Vols. 154-155, pp. 1462-1467, 2011