摘要
目的通过热喷涂涂层,解决350 MW超临界机组再热第一级静叶栅的高温冲蚀问题。方法采用超音速火焰喷涂制备了NiCr-Cr3C2涂层,测试了涂层的显微组织、孔隙率、显微硬度、结合强度及高温冲蚀性能,并对涂层在冲蚀条件下的失效机理进行分析。结果实验室条件下,NiCr-Cr3C2涂层孔隙率为0.98%,显微硬度达到1061.2HV0.3,结合强度约为80 MPa。装机试车时,0.22 mm厚的NiCr-Cr3C2涂层可使再热第一级静叶的寿命延长3倍左右。结论采用NiCr-Cr3C2涂层可显著延长静叶寿命,小角度粒子犁削冲蚀是涂层加速失效的主要原因。
Objective To solve the problem of high temperature erosion, thermal spray coating was prepared and studied on 350 MW supercritical unit reheated level stator cascade. Methods High velocity oxygen fuel spraying （HVOF） was used to prepare NiCr-Cr3C2 coating. A series of coating performance were tested, such as microstruc- ture, porosity, micro-hardness, adhesion strength and high temperature erosion performance. And then the failure mechanism of coating in the erosion conditions was analyzed. Results Under the laboratory conditions, the coating porosity was 0.98% , the value of micro-hardness HV0.3 was 1061.2, and the bonding strength was about 80 MPa. Under the working conditions of the stream turbine, when the thickness of coating was 0.22 mm, the service life of the first reheated level stator cascade was 3 times longer than the original. Conclusion The service life of stator cascade can be prolonged after using NiCr-Cr3 C2 coating. The main reason for the accelerated failure of the coating is plough e- rosion of small angle particles.
出处
《表面技术》
EI
CAS
CSCD
北大核心
2013年第6期63-65,77,共4页
Surface Technology
