| 引用本文: | 李勇， 李太江， 李巍， 李聚涛， 刘刚， 米紫昊.水轮机过流部件表面WC-CoCr涂层的失效机理[J].中国表面工程,2014,27(1):18~24 |
| LI Yong, LI Taijiang, LI Wei, LI Jutao, LIU Gang, MI Zihao.Failure Mechanism of the WC-CoCr Coatings Deposited on Flow Passage Components of Hydraulic Turbines[J].China Surface Engineering,2014,27(1):18~24 |
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| 摘要: |
| 应用于多泥沙河流水轮机过流部件的超音速火焰喷涂WCCoCr涂层在服役中受到泥沙作用而发生磨蚀。喷涂扁平粒子内部的WC硬质相受到泥沙作用而发生脱落。WC扁平粒子碎片或喷涂飞溅部分在泥沙磨蚀作用下发生整体脱落。文中基于涂层现场采样分析和空蚀、冲蚀、磨损等试验研究超音速火焰喷涂WCCoCr涂层的现场服役失效机理。结果表明：WC涂层的抗磨损性能约为基体的16倍；但其30°攻角下的抗冲蚀性能并不明显；经过8 h空蚀试验后，WC涂层的空蚀率下降至母材的70%。空蚀过程中，涂层的损伤从孔隙部位开始扩展，在空蚀的作用下，涂层磨蚀损伤加剧。在真实服役环境下WC颗粒的剥落、喷涂涂层粒子的剥落以及涂层中的孔隙诱发空蚀损伤是导致涂层失效的主要因素。 |
| 关键词: 水轮机 冲蚀 空蚀 超音速火焰喷涂 失效机理 |
| DOI：10.3969/j.issn.1007-9289.2014.01.003 |
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| Failure Mechanism of the WC-CoCr Coatings Deposited on Flow Passage Components of Hydraulic Turbines |
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LI Yong, LI Taijiang, LI Wei, LI Jutao, LIU Gang, MI Zihao
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Xi'an Thermal Power Research Institute Co. Ltd., Xian 710032
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| Abstract: |
| High velocity oxygen fuel（HVOF） sprayed WCCoCr coatings were employed to protect flow passage components in hydraulicturbine from erosion and cavitation suffer damage caused by sediment erosion. The failure mechanisms were studied by analyzing on the collected samples and experimental tests including cavitation erosion, solid particle erosion and abrasive wear test. The WC hard phases spall from the bond phase during sediment erosion. The WCCoCr lamellae or fragments spall as an entirety during sediment erosion. The individual experimental results indicate that abrasive wear weight loss of HVOF sprayed WCCoCr coating is 16 times as high as the substrate used in this study. The cavitaiton erosion test results show that WCCoCr coating exhibit no advantage over the substrate material under the attack angle of 30°. After 8 h test, the cavitation ratio decreased to about 70% of the substrate. Cavitation concaves propagate from pores in coating, which prompt the coating damage. Results show that the peelingoff of WC hard phase in coating, the spalling of deposited lamella and the cavitation damage induced by pores lead to the failure of HVOF sprayed WCCoCr coating serving at infield situation. |
| Key words: hydraulic turbine erosion cavitation high velocity oxygen fuel spraying(HVOF) failure mechanism |
