Cold solid-phase welding under ultra-high vacuum and pure argon gas atmospheres. Development of cold solid-phase welding. (Report 1).

In case of bonding materials at room temperature, it is necessary to remove the contamination of oxide-films and absorbed gas from the surface of materials. Such cold solid-phase welding has been studied to joint materials without large deformation. Two processes of cold solid-phase welding were developed under ultra-high vacuum atomosphere and under pure inert gas atomosphere.Under ultra-high vacuum atomosphere, 10-6 Pa, the effect of metal friction for making the clean metal surface, the vacuum level and friction time are discussed. The specimens of copper and aluminum were able to bond each other by rotating 24 rpm for 5 minutes and bonding pressure was 120 MPa.Next, under pure argon gas atomosphere less than 10 ppm oxygen, the effect of radio-frequency discharge time and roughness of material surface are discussed. The copper and aluminum were bonded by 8 and 5 minutes discharge respectively.