ISSN   1004-0595

CN  62-1224/O4

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Ni基软硬复合涂层减摩耐磨性能研究

Anti-Friction and Wear Resistance of Ni-Based Soft and Hard Composite Coatings

  • 摘要: 为了解决硬质涂层减摩耐磨性能难以兼顾及润滑性能难控等问题,提出并制备了Ni基软硬复合涂层结构. 以20CrMo钢为基体材料,采用激光熔覆技术将Ni20与WC粉末熔覆至基体表面,得到Ni基硬质涂层,制备含二硫化钼(MoS2)的聚四氟乙烯(PTFE)乳液,通过喷涂-热固化的工艺在Ni基硬质涂层表面制备PTFE软质涂层,获得Ni基软硬复合涂层,以期实现材料优异的减摩耐磨性能. 研究了Ni基软硬复合涂层的成形微观组织结构及不同载荷下的摩擦磨损性能,结果表明,Ni基软硬复合涂层硬度相较于基体提升20%以上,摩擦试验表明在宽载荷范围(3~15 N)内Ni基软硬复合涂层的摩擦系数持续稳定在0.15左右的较低数值范围内,在中载荷(6 N)时性能最优,此时,Ni基软硬复合涂层试样的摩擦系数相比基体和Ni基硬质涂层试样分别降低83%和80%,磨损量也相较于基体降低87%,FTFE软质涂层中PTFE和MoS2与Ni基硬质涂层中的Ni20和WC的协同作用是材料摩擦磨损性能提升的主导原因,研究结果可为摩擦功能结构设计提供一定指导.

     

    Abstract: In order to solve the difficulties faced by hard coatings in balancing the friction reduction and wear resistance performance and the difficulty in controlling the self-lubricating performance, this study proposed and successfully prepared a new type of composite coating structure with an integrated structure of soft and hard coatings, and this composite coating structure skillfully combined the hard coating with the soft coating, with the main purpose of improving the overall tribological performance of the coating. Through this soft and hard composite coating structure, it could overcome the problem that the coating only focused on hardness and wear resistance but failled to provide good self-lubricating performance, and the optimization of the coating performance was achieved by the interaction between the hard coating and the soft coating. In this experimental study, we used 20CrMo steel as the substrate material, and use the laser cladding technology to melt Ni20 and WC powder on the substrate surface in a certain ratio, and obtain Ni-based hard coatings after fine grinding treatment. In order to further enhance the friction reduction performance of the coating, a polytetrafluoroethylene (PTFE) composite solution containing an appropriate amount of molybdenum disulfide (MoS2) was prepared using vibratory mixing technology, and a PTFE soft coating was prepared on the surface of the Ni-based hard coating through the spraying-heat curing process, so that a Ni-based soft and hard composite coating with an integrated hard and soft structure was obtained. With this innovative coating structure, in order to expect to realize the excellent friction and wear reduction properties of the material. This study focused on investigating the microstructure of the Ni-based hard coating and Ni-based soft-hard composite coating and their friction and wear performance under different loads. The results showed that the average hardness of the Ni-based hard and soft composite coatings was increased by more than 20% compared with that of the substrate, and the friction experiments showed that the friction coefficient of the Ni-based hard and soft composite coatings was continuously stabilized at a low level of about 0.15 in a wide range of loads (3~15 N). Notably, the Ni-based soft and hard composite coatings showed the best tribological performance under medium load (6 N) conditions; under such conditions, the friction coefficients of the Ni-based soft and hard composite coatings were reduced by 83% and 80%, respectively, compared with those of the matrix and the Ni-based hard coatings. In addition, the wear of the Ni-based soft-hard composite coating was also reduced by 87% relative to the matrix. The enhancement of the friction and wear performance of this material mainly stemed from the synergistic effect of MoS2 and PTFE inside the soft coating with Ni20 and WC inside the hard coating. The results of the study provided some guidance for the design of friction functional structures.

     

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