【摘要】 燃煤火力发电厂的风机叶片在服役期间不仅会受到脱硫脱硝不彻底而出现的SO_x和NO_x的侵蚀，还可能会受到沿海盐雾的腐蚀。除此之外，风机叶片在高温的烟气氛围中，与燃烧环境中存在的高灰分腐蚀性颗粒发生碰撞后会加速其磨蚀。为了提高风机叶片的耐腐蚀性和磨蚀性，采用“二步法”氧-乙炔火焰喷焊技术在Q355D低合金结构钢基体表面制备Ni60A+WC喷焊层，通过磨损试验和电化学试验探究了不同质量分数WC硬质相的喷焊层的耐磨性以及其在3种不同腐蚀溶液中的耐蚀性。结果表明：Ni60A+WC喷焊层可以显著提高风机叶片的耐磨性和耐蚀性，起到良好的保护作用；且当配比为65%Ni60A+35%WC时，喷焊层的耐磨性和耐蚀性能相对最好，且其耐Cl~-的腐蚀性能最好，而对硫化物和氮化物的耐蚀性较差。高速粒子造成裂纹的萌生与扩展形成疲劳源是喷焊层磨损失效的主要机理。硬质相和碳化物与基体间的电偶腐蚀是喷焊层的主要腐蚀机理，喷焊层的腐蚀失效形式为选择性腐蚀。本工作对进一步延长火电厂风机叶片的使用寿命与节约成本有一定的借鉴意义。更多还原

【Abstract】 Wind turbine blades of coal-fired thermal power plants are not only subject to erosion from SO_x and NO_x due to incomplete desulfurization and denitrification during service, but also face corrosion from coastal salt spray. In addition, in the high-temperature flue gas atmosphere, the abrasion of wind turbine blades will be accelerated after collision with high ash corrosive particles in the combustion environment. In order to improve the corrosion resistance and wear resistance of wind turbine blades, the “two-step” oxygen-acetylene flame welding technology was used to prepared Ni60A + WC spray welded layers on the surface of Q355D low alloy steel substrate, and the wear resistance and corrosion resistance of spray welded layers with different mass fraction of WC hard phase in three corrosion solutions were evaluated by means of wear test and electrochemical test. Results showed that Ni60A+WC spray welded layer could significantly improve the wear resistance and corrosion resistance of the wind turbine blades, and played a good protective role. When the mass fraction of WC hard phase was 65%Ni60A+35%WC, the spray welded layer had the best wear resistance and corrosion resistance; Moreover, the spray welded layer had the best corrosion resistance to Cl~-, but poor corrosion resistance to sulfides and nitrides. The initiation and propagation of cracks caused by high-speed particles and the formation of fatigue sources were the main mechanisms of wear failure in spray welded layers. In particular, the galvanic corrosion between hard phases and carbides and the substrate was the main corrosion mechanism of the spray welded layer, and the corrosion failure mode of the spray welded layer was selective corrosion. This work has certain reference significance for further extending the service life and cost saving of fan blades in thermal power plants.更多还原