| 摘要 |
PURPOSE:To prevent the diffusion of the brazing metal into the grain boundary in the surface of the alloy on purpose to make possible the good brazing, by employing Ni-Fe alloy or Ni-Co-Fe alloy for the sealing alloy, adding to this a metal of great oxygen affinity. CONSTITUTION:The sealing alloy is Ni-Fe alloy or Ni-Co-Fe alloy, whose ratio of alloy constituents is so settled as to make its thermal expansion coefficient to coincide with that of ceramic, hard glass, etc., which are involved in sealing together with above sealing alloy. For the activated metal to be added to the alloy for selective oxidation, aluminum and silicon are especially suitable. When the rare earth element is independently or compositely added, that effectively causes the selective oxidation of the activated metal. The condition for the selective oxidation of the activated metal is the heat treatment within a weak oxidizing atmosphere with the partial pressure of oxygen 10<-18>-10<-35> atm, and at the temperature 700-1200 deg.C. The object of the brazing metal is the silver solder or gold solder mainly consisting of 72% silver-copper alloy, etc. |
