Nb alloyed layer was prepared by plasma surface alloying technology on surface of stainless steel substrates.Microstructure morphology

depth profiling of the elemental composition and phase structure of the alloyed layer were analyzed.Corrosion performance of the Nb alloyed layer was investigated.The results show that the optimum parameters were: temperature

1100oC;air pressure

80 Pa

holding time 3 h

source voltage

900–700 V;and cathode voltage

600–450 V.The thickness of Nb alloyed layer was about 60 μm.The alloyed layer was mainly composed of NbC and Nb6C5

Cr2Nb and Fe2Nb.The surface Nb content was 50%

which decreased sharply in the first several microns of depths and then gradually in further depths.The Nb alloyed layer has improved resistance to intergranular corrosion and uniform corrosion.