The surface composition of passive hot pressed and sintered stainless steel was investigated by AES analysis. A maximum in the Mo concentration was observed in the depth of about 6 Å, in all the sintered stainless steel samples, regardless of the composition, indicating the important role of the Mo in the passivation process of the stainless steel. It was also found that the oxide film thickness of passive samples containing Au, Pd and Pt was about 120-150 Ä, as compared to 20-30 Å for passive sintered 316 stainless steel, or to passive samples containing Ni. The behavior of the passive sintered stainless steel containing Au, Pd and Pt indicates higher cathodic activity and lower electrical isolation of the passive layer, as compared to Ni-containing sampels. Cu is markedly enriched on the surface of passive samples after exposure to H2SO4, as compared to samples containing Au, Pd or Pt.