TC4合金激光熔覆耐磨自润滑涂层的组织与性能研究

发布时间：2018-01-22 12:05

本文关键词： 钛合金激光熔覆自润滑涂层 h-BN Ti_3SiC_2 摩擦磨损　出处：《天津工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：钛合金的弹性模量低、比强度高、具有优异的耐腐蚀性与耐热性,普遍使用在航空、石油、汽车和化工等领域。然而钛合金的摩擦系数大、耐磨性能差等不足限制了它的应用领域。激光熔覆金属-陶瓷复合涂层很大水平上增强了钛合金的硬度和耐磨性。常选用Ni基合金与陶瓷粉末的混合粉末作为熔覆材料制备Ni基耐磨复合涂层,使熔覆涂层的硬度与耐摩性大幅度提高。但随着现代工业的不断发展,不仅需要提高熔覆涂层的耐磨性,还要求涂层具备自润滑性来满足难以使用润滑油的工况。因此,常在熔覆涂层中加入一定的固体润滑剂,如在Ni基合金中加入h-BN、WS2、CaF2等来制备Ni基耐磨减摩涂层。本文选用h-BN、Ti3SiC2作为润滑剂来制备Ni基自润滑耐磨减摩涂层,使用XRD、SEM、EDS等设备观察涂层的显微组织并分析其物相构成,使用显微硬度仪、摩擦磨损试验机、电化学工作站测试了涂层的硬度、耐磨性及耐蚀性能,解释了熔覆材料对熔覆层的强化机理与润滑机制。研究结果如下:Ni60+h-BN熔覆涂层物相主要由TiC、TiB、TiB2、CrB、Ni3B、Ni2B和较少的h-BN组成。当h-BN含量为10%,P=3kW,V=8mm/s时获得最大硬度值在1200 HV0.5左右,并获得了最小摩擦系数在0.37～0.4之间比Ni60熔覆涂层降低36%,最小磨损量2.6 mg与Ni60涂层相差不多。Ni60+10%h-BN涂层随扫描速度的增加,腐蚀电位均正向移动,在V=10mm/s的耐腐蚀性最佳。Ni60+Ti3SiC2 熔覆涂层物相主要由 TiC、TiB2、Ti3SiC2、Ti5Si3、γ-Ni 固溶体、(Ti,V)C金属化合物组成。当Ti3SiC2含量为7.5%,P=3kW,F=10mm/s时熔覆层获得了最大显微硬度,在1150～1300HV0.2之间;当Ti3SiC2含量为10%,P=3 kW,V=12 mm/s时熔覆层获得了最小的摩擦系数在0.2～0.24之间比Ni60涂层降低将近40%,获得最小磨损量1.1 mg比Ni60涂层降低50%左右。涂层的耐腐蚀随Ti3SiC2含量的增加性能呈现先增强后减弱的趋势,含量为7.5%时获得最佳的耐腐蚀性能。
[Abstract]:Titanium alloys have low elastic modulus, high specific strength, excellent corrosion resistance and heat resistance, and are widely used in aviation, petroleum, automobile and chemical industry. However, the friction coefficient of titanium alloys is large. Its application field is limited by its poor wear resistance. Laser cladding metal-ceramic composite coating enhances the hardness and wear resistance of titanium alloy to a great extent. The mixed powder of Ni-based alloy and ceramic powder is often chosen as the mixture of titanium alloy and ceramic powder. Ni-based wear-resistant composite coatings were prepared by cladding materials. The hardness and friction resistance of the cladding coating are greatly improved, but with the development of modern industry, it is not only necessary to improve the wear resistance of the cladding coating. It is also required that the coating be self-lubricating to meet the operating conditions which are difficult to use. Therefore, a certain solid lubricant is added to the cladding coating, such as h-BNN WS2 in Ni-base alloy. In this paper, the Ni-based self-lubricating anti-friction coating was prepared by using h-BNNTi3SiC2 as lubricant, and the Ni-base self-lubricating anti-friction coating was prepared by XRD-SEM. EDS and other equipment observed the microstructure of the coating and analyzed its phase composition. The hardness, wear resistance and corrosion resistance of the coating were tested by microhardness tester, friction and wear tester and electrochemical workstation. The mechanism of strengthening and lubricating of the cladding layer by cladding materials is explained. The results are as follows: the phase of the cladding coating is mainly composed of TiB2TiB2CrBN3B. When the content of h-BN is 10%, the maximum hardness is about 1 200 HV0.5 when the content of h-BN is 10 ~ 3 kW / s. The minimum friction coefficient is 36% lower than that of Ni60 cladding coating. The minimum wear amount of 2.6mg is not much different from that of Ni60 coating. The corrosion potential of Ni60 10h-BN coating moves forward with the increase of scanning speed. The best corrosion resistance of V _ (10) mm / s. Ni60 Ti3SiC2 cladding coating is mainly composed of TiCnTiB2Ti3SiC2Ti5Si3. The composition of 纬 -Ni solid solution is composed of TiNV C metal compounds. The maximum microhardness of the cladding layer is obtained when the Ti3SiC2 content is 7.5 kWF 10 mm / s. Between 1150 and 1300 HV0.2; The content of Ti3SiC2 was 10kW. The minimum friction coefficient of the cladding layer was 40% lower than that of Ni60 coating at VX 12 mm/s. The minimum wear amount of 1. 1 mg was about 50% lower than that of Ni60 coating. The corrosion resistance of the coating increased firstly and then decreased with the increase of Ti3SiC2 content. The optimum corrosion resistance is obtained when the content is 7.5.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.4

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