AC-HVAF 喷涂微纳米复合 WC 涂层在水电设备抗空蚀工程中的应用

水轮机过流部件的空蚀损伤引起设备本体材料流失， 破坏机组结构， 降低机组运行安全性。 涂层防护是抗空蚀损伤的主要手段， 本文拟通过降低涂层孔隙率提高涂层的抗空蚀性能。 采用空气助燃超音速火焰喷涂技术(AC-HVAF) 制备了微纳米复合 WC 涂层， 分别采用静态振动空蚀试验和高速流体空蚀试验进行涂层抗空蚀性能表征， 结果表明， AC-HVAF 喷涂的微纳米复合 WC 涂层孔隙率为 0.2%， 涂层孔隙细小， 分布均匀， 涂层抗空蚀性能优于传统 HVOF 喷涂涂层。 在水电站现场应用结果表明， 经过 5.5 年运行后， 涂层完好。 AC-HVAF 喷涂微纳米复合 WC 涂层可有效提高水电设备的抗空蚀能力， 提高了机组的安全性。

Application of AC-HVAF Micro-nano WC Composite Coating againstCavitation Damage in Equipment of Hydropower Station

The cavitation damage of the overflow components of the hydraulic turbines causes the removing ofthe equipment materials, thus damage unit structure and degrades the safety of units. Thermal sprayed coatingsare effective method against cavitation damage. This paper intends to improve the cavitation corrosion resistanceof the coating by reducing the porosity of the coatings. Micro-nano composite WC coatings were fabricated byair-combusted high-velocity oxygen fuel spray (AC-HVAF). Static vibration cavitation test and high-speed fluidcavitation test were respectively used to characterize the cavitation resistance performance of the coatings. Theresults showed that the micro-nano WC composite coatings by AC-HVAF exhibited a homogeneous and densemicrostructure with porosity of 0.2%. Compared with the same coatings deposited by HVOF, higher resistanceto cavitation is examined during vibration cavitation test and high speed fluid cavitation test for micro-nano WCcomposite coatings prepared by AC-HVAF. After 5.5 years operation, the coatings remained intact. The micronano composite WC coatings deposited by AC-HVAF can effectively improve the anti-cavitation ability ofhydropower equipment and the safety of the unit.