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Microstructures and high-temperature self-lubricating wear-resistance mechanisms of graphene-modified WC-12Co coatings
Friction ( IF 6.3 ) Pub Date : 2020-05-11 , DOI: 10.1007/s40544-019-0346-7
Haoliang Tian , Changliang Wang , Mengqiu Guo , Yongjing Cui , Junguo Gao , Zhihui Tang

To reduce the friction coefficient of cobalt-cemented tungsten carbide (WC-12Co) wear-resistant coatings, graphene was compounded into WC-12Co powder via wet ball milling and spray granulation. Self-lubricating and wear-resistant graphene coatings were prepared via detonation gun spraying. The presence, morphologies, and phase compositions of graphene in the powders and coatings that are obtained through different powder preparation processes were analyzed. The analysis was performed using the following technologies: energy-dispersive X-ray-spectroscopy (EDXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. The mechanical properties of the coatings were studied using a microhardness tester and a universal drawing machine. The friction and wear properties of the coatings were studied using an SRV-4 friction and wear tester. The results showed that the graphene content in the WC-12Co coating modified with graphene was higher than that without modification; graphene was embedded in the structure in a transparent and thin-layer state. The adhesive strength of this coating at approximately 25 °C was approximately 60.33 MPa, and the hardness was approximately 984 HV0.3. After high-temperature treatment, the adhesive strength and hardness of the graphene oxide (GO)/WC-12Co coating decreased slightly (the lowest adhesive strength of 53.16 MPa was observed after treatment at 400 °C, and the lowest hardness of approximately 837 HV0.3 was observed after treatment at 300 °C). Compared to the friction coefficient (0.6) of the WC-12Co coating obtained at room temperature, the friction coefficient of the GO/WC-12Co coating was decreased by approximately 50% of that value. The graphene-modified coating was continuously exposed to the wear tracks on the surface of the contacting materials during friction, and a lubricating film was formed in the microareas in which the wear tracks were present. The coating exhibited improved self-lubricating and wear-resistant effects compared to the unmodified WC-12Co coating. The results of this study demonstrated that graphene could be effective in self-lubrication and wear-reduction in a temperature range of 100–200 °C, as a friction coefficient of 0.3 was maintained.



中文翻译:

石墨烯改性的WC-12Co涂层的组织和高温自润滑耐磨机理

为了降低钴结碳化钨(WC-12Co)耐磨涂层的摩擦系数,通过湿式球磨和喷涂造粒将石墨烯混入WC-12Co粉中。通过起爆枪喷涂制备自润滑和耐磨的石墨烯涂层。分析了通过不同粉末制备工艺获得的粉末和涂层中石墨烯的存在,形态和相组成。使用以下技术进行分析:能量色散X射线光谱法(EDXS),扫描电子显微镜(SEM),透射电子显微镜(TEM)和拉曼光谱。使用显微硬度测试仪和通用拉伸机研究了涂层的机械性能。使用SRV-4摩擦磨损测试仪研究了涂层的摩擦磨损性能。结果表明,石墨烯改性的WC-12Co涂层中的石墨烯含量高于未改性的WC-12Co涂层。石墨烯以透明和薄层状态嵌入结构中。该涂层在约25°C时的粘合强度约为60.33 MPa,硬度约为984 HV0.3。高温处理后,氧化石墨烯(GO)/ WC-12Co涂层的粘合强度和硬度略有下降(在400°C处理后观察到的最低粘合强度为53.16 MPa,最低硬度约为837 HV 0.3在300°C处理后观察到)。与在室温下获得的WC-12Co涂层的摩擦系数(0.6)相比,GO / WC-12Co涂层的摩擦系数降低了该值的50%。在摩擦期间,石墨烯改性的涂层连续暴露于接触材料表面上的磨损痕迹,并且在存在磨损痕迹的微区域中形成润滑膜。与未改性的WC-12Co涂层相比,该涂层表现出改善的自润滑和耐磨性。这项研究的结果表明,石墨烯可以在100-200°C的温度范围内有效地自润滑和减少磨损,因为摩擦系数保持为0.3。

更新日期:2020-05-11
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