AN AUGER-ELECTRON SPECTROSCOPIC STUDY OF PHOSPHORUS SEGREGATION IN THE GRAIN-BOUNDARIES OF NICKEL-BASE ALLOY 600

The segregation of P was of the equilibrium (McLean) type, whereas Si did not segregate appreciably to grain boundaries. The results explain the influence of P and the virtual absence of influence of Si on the sensitivity to intergranular corrosion in HNO//3 plus Cr**6** plus solutions. They also indicate that segregation of P is not the cause of intergranular stress corrosion cracking in pure water and caustic environment, and that hydrogen embrittlement is unlikely to be the mechanism.