Hot-corrosion behavior of Co-10Cr

Co-25Cr and Co-10Cr-5Al alloys with Na2SO4 film in the air at 900 ℃ was observed.The results indicate that the corrosion weight-increment of Co-10Cr alloy becomes the highest and then Co-10Cr-5Al alloy

Co-25Cr alloy.The corrosion products of Co-10Cr are composed of three layers

the outside layer of CoO

the middle layer of Cr2O3 and the inside layer with small amount of Cr2S3.The corrosion products of Co-10Cr-5Al consist of three layers

the outside layer of CoO

the middle layer of Cr2O3 and Al2O3

and the inside layer with a small amount of chromium sulfide and aluminum sulfide.Co-25Cr alloy is composed of CoO and Cr2O3 in the outside layer and single Cr2O3 in the inside layer with absence of distinct inside sulfide.