High-temperature Oxidation Resistance of Zr-alloyed Layer Formed on Austenite Stainless Steel by Plasma Technique

High-temperature oxidation resistance in static air of 0Cr18Ni9Ti stainless steel(substrate for short),and the substrates after treated respectively by zirconizing process,zirconizing+carburizing process,zirconizing+oxidizing process,and zirconizing+carburizing+oxidizing process were investigated.After oxidizing in static air at 1150℃for 20h,the ratios of oxidation mass gains of the samples after zirconizing+carburizing+pre-oxidizing process,zirconizing+pre-oxidizing process,zirconizing+carburizing process and zirconizing process to oxidation mass gains of untreated substrate are just 0.04,0.07,0.09,0.12,which indicates that their oxidation resistance is largely improved than untreated substrate,especially is that of after zirconizing+carburizing+pre-oxidizing process,followed in turn are that of the samples respectively after zirconizing+pre-oxidizing process,zirconizing+carburizing process and zirconizing process.And after oxidized,the surface of stainless steel is oxidized severely.The oxidation layer exfoliates many times,and the cross-section appears very wide cracks.The surface density the and the cross-section morphology of the samples after zirconizing process,zirconizing+carburizing process,zirconizing+pre-oxidizing process,and zirconizing+carburizing+pre-oxidizing process respectively becomes successively gradually better samples of zirconizing process,zirconizing+carburizing process,zirconizing+pre-oxidizing process,and zirconizing+carburizing+pre-oxidizing process,which shows their high-temperature oxidation resistance successively relatively increased,especially the sample after zirconizing+carburizing+pre-oxidizing process,whose cross-section has not holes and cracks,whose structure is very dense,and whose surface is very smooth.There exists an interface between matrix and modified layer,and the combination matrix and modified layer is very strong.