Wohaibi Saleh Al, Mohammed Abdul Samad, Laoui Tahar, Hakeem Abbas Saeed, Adesina Akeem Yusuf, Patel Faheemuddin
Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
Department of Mechanical and Nuclear Engineering, University of Sharjah, Sharjah 27272, UAE.
Materials (Basel). 2019 Mar 20;12(6):920. doi: 10.3390/ma12060920.
The present study investigates the high temperature tribological performance of spark plasma sintered, nano- and micron-sized tungsten carbide (WC) bonded by 9 wt.% cobalt (Co). The composites were fabricated using a two-step procedure of mixing followed by spark plasma sintering (SPS). Ball-on-disc wear tests were conducted at a normal load of 30 N, linear speed of 0.1 m/s under dry conditions and at three different temperatures (room temperature, 300 °C and 600 °C). Field emission scanning electron microscopy (FESEM), optical profilometry and energy dispersive X-ray (EDS) spectroscopy were used to analyze the surface morphology and the wear track area. At room temperature, it was observed that the nano-sized WC composites exhibited better wear resistance than the micron-sized WC composites. The wear resistance of the nano-sized samples declined significantly relative to that of the micron-sized samples with an increase in temperature. This decline in performance was attributed to the higher surface area of nano-sized WC particles, which underwent rapid oxidation at elevated temperatures, resulting in poor wear resistance. The wear rate observed at 600 °C for the micron-sized WC composites was 75% lower than that of the nano-sized cemented carbide. Oxidative wear was observed to be the predominant wear mechanism for both cemented carbide samples at elevated temperatures.
本研究考察了通过火花等离子体烧结制备的、由9 wt.%钴（Co）粘结的纳米和微米尺寸碳化钨（WC）的高温摩擦学性能。采用混合后火花等离子体烧结（SPS）的两步法制备复合材料。在30 N的法向载荷、0.1 m/s的线速度、干燥条件下以及三种不同温度（室温、300℃和600℃）下进行球盘磨损试验。使用场发射扫描电子显微镜（FESEM）、光学轮廓仪和能量色散X射线（EDS）光谱分析表面形貌和磨损轨迹区域。在室温下，观察到纳米尺寸WC复合材料比微米尺寸WC复合材料表现出更好的耐磨性。随着温度升高，纳米尺寸样品的耐磨性相对于微米尺寸样品显著下降。性能下降归因于纳米尺寸WC颗粒的较高表面积，其在高温下经历快速氧化，导致耐磨性差。在600℃下观察到的微米尺寸WC复合材料的磨损率比纳米尺寸硬质合金低75%。在高温下，氧化磨损被观察到是两种硬质合金样品的主要磨损机制。
