不同基体超音速火焰喷涂Cr3C2-20NiCr涂层的性能

Properties of Cr3C2-20NiCr Coatings Sprayed on Different Substrates byHigh Velocity Oxygen Fuel(HVOF)

采用超音速火焰(HVOF)喷涂技术在不同基体(38CrMoAl和316L)上制备了Cr3C2-20NiCr涂层。利用扫描电镜(SEM)、X射线衍射(XRD)仪、拉曼(Raman)光谱仪分别对涂层的微观结构和物相进行分析,并利用万能力学试验机、冲击试验机、马弗炉、高温摩擦试验机和高温维氏显微硬度计分别测试涂层的拉伸结合强度、抗机械冲击性能、抗热冲击性能、耐磨损性能及高温显微硬度。结果表明:采用HVOF喷涂技术在38CrMoAl、316L基体上制备的Cr 3C 2-20NiCr涂层均表现出良好的拉伸断裂强度(均超过70 MPa),拉伸断裂机理主要表现为脆性断裂,局部表现为韧性断裂;机械冲击失效形式主要为层间开裂和涂层内部硬质颗粒剥离两种方式;316L基体硬度较38CrMoAl高,粉末颗粒冲击较硬基体使其变形充分,从而使316L基体涂层具有相对较低的孔隙率(3.83%),因此,316L基体涂层的抗热冲击、抗氧化和耐磨损性能相比38CrMoAl基体涂层好;两种涂层室温时主要发生磨粒磨损,600℃时涂层硬度降低,主要磨损机理为氧化磨损、剥层磨损并伴随着轻微的磨粒磨损。

The Cr3C2-20NiCr coatings were prepared on 38CrMoAl and 316L substrate by high velocity oxygen fuel(HVOF)spraying.The microstructure and phase of the coatings were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD)and Raman spectrometer,and the bonding strength,mechanical impact resistance,thermal shock resistance,wear resistance and high temperature microhardness of the Cr3C2-20NiCr coatings were tested.The results showed that Cr3C2-20NiCr coatings deposited on both 38CrMoAl and 316L substrate by HVOF exhibited good bonding strength(more than 70 MPa),and the tensile fracture mechanisms of the coatings were mainly characterized by brittle fracture and localized ductile fracture.The mechanical impact failure forms were mainly two ways of interlayer cracking and detachment of hard particles from bond phase inside the coatings.The hardness of 316L substrate was higher than that of 38CrMoAl substrate,and the impact of powder particles on 316L substrate made them fully deformed,resulting in a relatively low porosity(3.83%).Therefore,the thermal shock resis-tance,oxidation resistance and wear resistance of the coatings deposited on 316L substrate were better than that of the coatings deposited on 38CrMoAl substrate.Abrasive wear mainly occurred in the two coatings at room temperature,while hardness of the coatings decreased at 600℃and the main wear mechanisms were oxidation wear and delamination wear,accompanied by slight abrasive wear.