| High-temperature wear and corrosion of heated tubes is one of the technical problems confronted by domestic Circulating Fluidized Bed Boiler, which should be solved urgently. Coating technology for protecting and repairing is the current research focus in the material field. In this thesis, the present research situation was analyzed about high-temperature protecting coatings for boilers at home and abroad. The result showed that high cost of investment and difficulty of operating in boiler were the main problems of some coatings used now. Therefore, after the working condition, failure mechanism of heated tubes and the application status of thermal spraying were analyzed, a new kind of metal/ceramic cored wire was designed and developed in this thesis. Arc spraying technology was used to produce Fe/B-Fe coating which had high performance and price ratio. Plasma sprayed 75Cr3C2/25NiCr coating and oxy-acetylene flame sprayed and fused Ni60/35%WC coating were adopted as the other two schemes for comparison. In the thesis experiments such as microstructure, mechanical performance, resistance to wear and high-temperature corrosion, etc., were carried out. The results showed that the resistance to wear and corrosion of Fe/B-Fe coating was respectively 16 times and 5 to 6 times higher than those of 20g, which was usually used in boilers. Compared with the other two coatings, Fe/B-Fe coating not only had excellent performance, but also had outstanding features including low investment of materials and equipments, simple manufacturing process, and the convenience of operating inside boilers. Theses advantages greatly approved the feasibility of Fe/B-Fe coating to be sprayed in large area in Circulating Fluidized Bed Boiler, therefore, this coating was worthy to be widely used all over our country.
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