等离子喷涂NiCrBSi增强Mo涂层的组织结构和断裂韧性

为了开发既具有较高硬度、可防止黏着磨损、又具有一定孔隙能够储存润滑油的用于气缸内壁和活塞的热喷涂层,采用等离子喷涂制备了纯Mo和Mo-28%NiCrBSi复合涂层,采用图像法定量表征了涂层的孔隙率,采用压痕法测试了涂层的硬度和断裂韧性,研究了添加NiCrBSi对等离子喷涂Mo层的组织结构、孔隙率、硬度和断裂韧性的影响,并与某进口防黏着磨损Mo涂层进行比较。结果表明:等离子喷涂Mo-28%NiCrBSi复合涂层的孔隙率比纯Mo涂层略高,硬度为(561±83)HV3 N,比纯Mo涂层提高19%,比服役过的进口纯Mo涂层高约40%;复合涂层的断裂韧性为8.9 MPa"m1/2,约为纯Mo涂层的4倍,接近Mo块材。

Microstructure and Fracture Toughness of NiCrBSi Reinforced Mo Coatings Fabricated by Air Plasma Spraying

Pure Mo coatings and Mo-28％NiCrBSi composite coatings were prepared by air plasma spraying (APS).The porosity of coatings was characterized quantitatively by an image method,and the hardness and fracture toughness of coatings were measured by an indentation method.Moreover,the effects of additions of NiCrBSi on the microstructure,porosity,hardness and fracture toughness of the Mo coatings were investigated,and the properties of a kind of import adhesive wear resistance Mo coating goods were also studied for comparison.Results show that the porosity of Mo-28％NiCrBSi composite coating was slightly higher than that of pure Mo coating.The hardness of the composite coating was (561±83) HV3N,19％ higher than that of the pure Mo coating and 40％ higher than that of the served import pure Mo coating.The fracture toughness of the prepared composite coating was 8.9 MPa ·m1/2,which was almost two times as that of the pure Mo coating and close to that of bulk Mo material.