Stainless steel coatings performed by thermal spraying are used for the protection of steel component surfaces exposed to corrosive solutions. Chemical compositions of the stainless steel powders generally follow these of bulk structral stainless steels. However, oxidation reaction at high temperature in the spray process leads to great changes in the composition of the formed coatings. Oxidation and evaporation of Cr in the alloys hinder ability of the coating to form a passive film against corrosion. Suppressing Cr oxidation of Fe-Cr based and Ni-Cr based alloys by addition of elements that have a strong affinity for oxygen, such as Si and B in APS process has been found by the authors. In this study, two kinds of alloy powder were designed and prepared by co-addition of Si and B to stainless steel. The powders were sprayed onto steel substrates to form coatings by APS and HVOF. The coatings sprayed with the designed alloy powders revealed a markedly decreased content of oxide, bringing about an improved corrosion resistance.
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