Abstract：CoNiCrAlY coatings were prepared by cold spray process. After deposition, the pre-oxidation of the coating was performed by vacuum heat-treatment. The microstructure and phase constituent of coating were characterized by XRD, FE-SEM and TEM. The corrosion behavior and mechanisms of as-sprayed and pre-oxidized coatings in molten 75%Na2SO4+25%NaCl (mass fraction, the same below) at 900℃ were also studied. The results show that the as-sprayed coating presents a nanocrystalline structure with low porosity (less than 0.28% volume fraction) and low oxygen content (0.12%). Vacuum pre-oxidation treatment improves the bonding status of particle interface and forms a continuous, uniform and dense α-Al2O3 layer, with an average thickness of 0.26μm. As-sprayed and pre-oxidized coatings can protect the substrate from hot corrosion due to the formation of the continuous and dense α-Al2O3 layer. Moreover, the vacuum pre-oxidation treatment can alleviate the diffusion of S and Cl into coating and thus lead to an increase of one time in the hot corrosion resistance than the as-sprayed coatings.
张林伟, 王鲁, 王全胜, 宁先进. 真空预氧化对冷喷涂CoNiCrAlY涂层组织及热腐蚀性能的影响[J]. 材料工程, 2013, 0(4): 12-16.
ZHANG Lin-wei, WANG Lu, WANG Quan-sheng, NING Xian-jin. Effect of Vacuum Pre-oxidation on Microstructure and Hot Corrosion Behavior of CoNiCrAlY Coating Prepared by Cold Spray. Journal of Materials Engineering, 2013, 0(4): 12-16.