Microstructure and wear resistance of TiB2-TiC/Fe composite coatings on Q235 steel prepared by plasma cladding
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摘要: 采用等离子熔覆技术,以Fe55、Ti、B4C混合粉末为原料,在Q235低碳钢表面获得了TiB2-TiC/Fe复合涂层,并分析了涂层的物相组成、组织结构,测试了显微硬度和摩擦磨损性能,探讨了其磨损机制。TiB2-TiC/Fe复合涂层的主要物相为TiB2、TiC、α-Fe,其中TiB2呈多边形和矩形,TiC则呈不规则块状;随着原始粉末中Ti、B4C含量的增加,TiB2、TiC尺寸逐渐增大,TiB2-TiC/Fe涂层与基体之间结合紧密,呈冶金结合;随着TiB2-TiC/Fe复合涂层陶瓷相含量的增加,涂层硬度和耐磨性显著提高,当陶瓷相含量增加到一定程度(35wt%)时,涂层耐磨性能有所降低,TiB2-TiC/Fe复合涂层的磨损方式主要是磨粒磨损和剥层磨损。Ti+B4C陶瓷相含量为30wt%的等离子熔覆涂层耐磨性能较好,约为Q235钢基体的7倍,当Ti+B4C含量持续增加时,TiB2、TiC尺寸增大、缺陷增多,最终使TiB2-TiC/Fe复合涂层耐磨性降低。Abstract: TiB2-TiC/Fe composite coatings were fabricated on the surface of Q235 steel via plasma cladding by used Ti, B4C, and Fe55 as precursor materials. The phase composition, structure, microhardness and friction wear resistance of TiB2-TiC/Fe coatings were analyzed, and the wear mechanism was also discussed. The results show that the TiB2-TiC/Fe composite coatings mainly consist of TiB2, TiC and α-Fe. TiB2 phase presents rectangle or multilateral shape, and TiC phase is irregular patch shape. With the increase of ceramic content in TiB2-TiC/Fe composite coatings, the sizes of TiB2 and TiC enlarge gradually and the TiB2-TiC/Fe composite coatings are closely and metallurgically combined with Q235 steel substrate. The wear resistance and hardness of TiB2-TiC/Fe composite coatings can improve with the increasing of ceramic contents in the coatings, while the wear resistance declines when ceramic content increases to some extent (35wt%) in TiB2-TiC/Fe composite coatings. The wear mechanism of TiB2-TiC/Fe composite coatings are mainly abrasive and delaminate wear. The plasma cladding coating with 30wt% ceramic content has lower wearing volume, and the wear resistance of the coating is 7 times to that of Q235 steel. When the content of Ti+B4C continues to increase, the size and defects of ceramic phase increase and the wear resistance of the coatings reduces eventually.
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Key words:
- plasma cladding /
- TiB2-TiC /
- composite coating /
- structure /
- microhardness /
- wear resistance
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