Abstract
Contact-bars of electromagnetic switchgears are required high precision and high quality at bonds. For the purposes, the Vapor Shielded Pressure Bonding (V.S.P.B) process and its inprocess control system are successfully developed.
To control the material deformation, thermo-characteristics by resistance heating while bonding are examined, and the optimum electrode materials and their constitution are selected as described in the report-1 and -2
Then, the examination of bonding quality and its improvement by vapor shield process are described in the report-3.
In this study, the mechanism of vapor shielding on cleaning action at the bonding interface and the fundamental properties of bonds are investigated.
Moreover, the basic constitution of Vapor Shielded Pressure Bonding Process are examined and the each optimum condition is clarified.
The main results obtained are as follows;
1) The follow facts about surface oxidation of materials are clarified by AES.
a) Material heating in air atmosphere accelerates the striking oxidation.
b) Vapor shield can effectively control the oxidation while heating.
2) The essential factors of vapor shield process and the typical features of bonds are clarified.
a) Liquid composed by 15%-ethanol solution in water is good for vapor shield.
b) Compounds both at bonds and expelled metal obtained under vapor shield are of eutectic of Ag and Cu.
c) Vapor shield can raise the bond strength of 28% comparing with the one in air atmosphere.
3) V.S.P.B process for high precision and high quality of bonds consists of the suitable vapor shielding condition and the optimum resistance heating conditions
