NiCoCrAlYTa/WC-Co复合涂层的制备及摩擦学性能研究

Preparation and Tribological Properties of NiCoCrAlYTa/WC-Co Composite Coating

目的为了改善MCrAlY涂层的耐磨损性能,通过在NiCoCrAlYTa粉末中添加不同比例的硬质相WC-Co粉末(质量分数为25%、50%、75%),将2种粉末充分地机械混合、振荡均匀后,采用超音速火焰喷涂(HVOF)技术,制备不同配比的NiCoCrAlYTa/WC-Co复合涂层。方法利用SEM、XRD、EDS等分析了复合涂层的微观形貌、物相组成和元素分布规律等;研究该复合涂层的力学性能、摩擦学性能以及摩擦磨损机理等。结果采用HVOF技术制备的NiCoCrAlYTa/WC-Co复合涂层结构致密,各元素及物相分布均匀;硬质相WC-Co的添加提高了涂层的显微硬度,同时也可显著改善复合涂层的耐磨损性能;复合涂层的摩擦因数随着WC-Co含量的增加逐渐增大,而磨损率逐渐减小。当WC-Co的添加量为75%时,复合涂层的摩擦因数最大,约为0.84;磨损率最小,约为9.28×10^(-6) mm^(3)/(N·m)。结论在金属基涂层中引入硬质相WC-Co可有效提高涂层的硬度,并且提升该涂层的耐磨损性能,为金属基涂层发挥优异的摩擦学性能提供理论基础。

The work aims to introduce different proportions of hard phase WC-Co powder(mass fraction:25%,50%and 75%)to NiCoCrAlYTa powder and mix and oscillate these two kinds of powder mechanically and evenly to prepare the NiCoCrAlYTa/WC-Co composite coating by HVOF-sprayed technology,so as to improve the wear resistance of MCrAlY coating.The microstructure,phase composition and element distribution of the composite coating were analyzed by SEM,XRD and EDS.The mechanical properties and the tribological properties as well as the wear mechanism of the composite coating were also studied.The NiCoCrAlYTa/WC-Co composite coating deposited by HVOF was compact and the distribution of elements and phases was uniform.The addition of WC-Co enhanced the microhardness of the coating and improved the friction and wear properties.With the increase of the WC-Co,the friction coefficient of the composite coating increased,but the wear rate decreased.When the content of WC-Co reached 75%,the friction coefficient of the composite coating was the highest(about 0.84),while the wear rate was the lowest,about 9.28×10^(-6) mm^(3)/(N·m).The introduction of WC-Co into the metal-based coating can effectively improve the hardness of the coating and increase the wear resistance,which also provides a theoretical basis for the application of excellent tribological properties of the metal-based coating.