Identification of Precipitates in Diffusion Zones Using the Electron Probe Microanalyzer

With the electron probe microanalyzer it is possible to identify and analyze individual precipitates and determine which impurity element is responsible for the interaction when small precipitates form in intermetallic diffusion zones due to interaction with impurities such as carbon, nitrogen, oxygen. phosphorus, or sulfur contained in the parent metals. When iron of the same quality was diffused in one case with niobium and another case with chromium, the precipitates formed in the iron were Nb/sub 2/S/sub 5/ for the Nb-- Fe system and CrN/sub 2/ or Cr/sub 2/N/sub 5/ for the Cr--Fe system. This indicates that impurity activity varies with the diffusing metal atoms. (auth)