Direct Bonding of SUS304 Stainless Steel by Metal Salt Generation Bonding Technique with Formic Acid

In this study, the effect of the metal salt generation bonding technique on the strength of a direct-bonded SUS304 stainless steel interface was investigated. SUS304 stainless steel surfaces were modified by boiling in 50% formic acid, and direct bonding was performed at a bonding temperature of 1023-1123 K under a pressure of 147 N (for a bonding time of 900 s). After direct bonding, the specimens were subjected to the peel test for evaluating their strength. As a result of the surface modification, bonded joints were obtained at bonding temperature of 30 K lower than that required for the unmodified surfaces, and the peel strength was comparable to that of the maximum load. On the basis of the experimental results, it was established that metal salt generation processing is effective for removing oxide films on SUS304 stainless steel.