等离子熔覆NiCr-Cr3C2复合涂层摩擦磨损性能的研究

目的研究碳化铬含量及磨损载荷力对复合涂层摩擦磨损性能的影响,探究不同磨损载荷下的磨损机制。方法采用5种Ni55和NiCr-Cr_3C_2的混合粉末(Ni Cr-Cr_3C_2质量分数分别为10%、20%、30%、40%、50%),通过等离子熔覆技术制备金属基复合涂层。采用XRD、SEM对涂层物相进行检测分析,使用Rtec万能摩擦磨损试验机对复合涂层表面进行不同载荷下的摩擦磨损性能测试。对涂层组织、摩擦系数、磨损体积及磨损表面微观形貌进行对比分析,探究碳化铬的含量以及摩擦载荷对复合涂层摩擦磨损性能的影响。结果 NiCr-Cr_3C_2在熔覆过程中发生熔化,XRD测得涂层中的碳化物主要以Cr_7C_3为主,其他主要物相包括Cr_3C_2、Cr_(23)C_6、Cr_5B_3、Ni_3Si。复合涂层的硬度及耐磨性能随着碳化铬含量的增加而增大,硬度最高达1500HV以上,耐磨性是基体Q235的2～16倍。当磨损载荷低于80 N时,主要发生磨粒磨损;当磨损载荷为100 N时,主要发生粘着磨损和磨粒磨损,其中S5的磨损机制为疲劳磨损和磨粒磨损。结论加入碳化铬,随着碳化铬含量增加,复合涂层的耐磨性不断提高,并且随着磨损载荷的增大,涂层磨损机制发生转变。

Wear Resistance of Plasma Cladding Deposited Ni-based Cr3C2 Composite Coating

The work aims to study the effects of chromium carbide content and wear load on wear resistance of the composite coating and the wear mechanisms under different loads. Metal composite coatings were fabricated with Ni-based (Ni55) mixed powder with NiCr-Cr3C2 mass fraction of 10%, 20%, 30%, 40% and 50% by plasma transferred arc (PTA) cladding technology. The phase compositions of these coatings were detected and analyzed by XRD and SEM and the wear resistance under different loads was tested by Rtec universal friction and wear tester. The microstructures, friction coefficient, wear body and wear surface morphologies of the coatings were analyzed by comparison to study the effects of chromium carbide content and wear load on wear resistance of the composite coating. NiCr-Cr3C2 was melted during cladding. By XRD, the carbide in the coating mainly consisted of Cr7C3 and other main phases included Cr3C2, Cr23C6, Cr5B3 and Ni3Si. The microhardness and wear resistance of the coatings gradually increased with increasing abundance of the chromium carbide. The maximum microhardness of the coatings was up to 1500HV, and the wear resistance was enhanced 2~16 times over that of the Q235 substrate. When load was lower than 80 N, abrasive wear was mainly wear mechanism, while when the load reached 100 N, the wear mechanism changed from abrasive wear to adhesive wear. The wear mechanism of S5 was fatigue wear and abrasive wear. The wear resistance of composite coating increases continuously due to the increasing chromium carbide and the wear mechanism changes as the wear load increases.