Liquid Phase Diffusion Bonding of AC2C/ADC12 Aluminum Casting Alloy by Using Metal Salt Coated Zn Sheet

Currently, the common way of bonding aluminum together is brazing. However, brazing creates problem when the high brazing temperature causes the formation of brittle intermetallic compound in between the joints prompting the need to circumvent this difficulty by considering transient liquid phase diffusion bonding method as a possible alternative. Being considered as a possible alternative solution, transient liquid phase diffusion bonding is not without problems that need to be overcome. One of these problems is the presence of oxide film on the insert material surface (Zn) necessitating the need to remove or destroy the oxide film without using high temperature and high load. Hence, in this study, the aim is to treat the bonding surface with formic acid for the removal of oxide film and substitution to a metal salt to determine the effectiveness of such treatment by performing tensile test and observation on the fractured surface of samples. From this study, it is found out that the tensile strength of the joint increased with the rise in bonding temperature with or without metal salt generation processing. However, it is understood that with metal salt generation processing, high strength joint can be obtained with lower bonding temperature compared with unmodified joints. It is hypothesized that this is because metallic zinc is generated as a result of surface modification and thermal decomposition of formate in the bond interface at low bonding temperatures.