To improve the lubricity of the as-prepared food-grade calcium-based grease, the effects of nano-additive carbon nano onions (CNOs) on the tribological properties are systematically investigated using a ball-disc wear tester. The properties of CNOs-containing food-grade calcium sulfonate complex greases (CSCG-FG) were characterised by thermogravimetric analyser, rheometer and electrochemical workstation, Listeria monocytogenes, X-ray photoelectron spectrometer and Raman spectrometer. The results revealed that pure and CNOs-containing CSCG-FG were proved to be safe. The average coefficient of friction (aCoF) and wear volume of the disc at CSCG-FG of 0.10 wt% CNOs were the minimal values, which were 31.4 and 70.0% less than that of pure CSCG-FG at 25°C and greatly lower than that of similar commercial food-grade grease. At high temperature, CNOs-containing CSCG-FG had lower aCoFs and torques. CSCG-FG of 0.10 wt% CNOs would be most possibly used in engineering applications and the results will provide valuable insight into developing food-grade lubricants.

中文翻译：

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碳纳米洋葱对食品级复合磺酸钙润滑脂摩擦学性能的影响

为了提高所制备的食品级钙基润滑脂的润滑性，使用球盘磨损试验机系统地研究了纳米添加剂碳纳米洋葱 ( CNOs ) 对摩擦学性能的影响。采用热重分析仪、流变仪和电化学工作站、单核细胞增生李斯特菌、X射线光电子能谱仪和拉曼光谱仪对含CNOs的食品级磺酸钙复合润滑脂( CSCG-FG )的性能进行了表征。结果表明，纯的和含有CNOs的CSCG-FG被证明是安全的。盘的平均摩擦系数(aCoF)和磨损量0.10 wt% CNOs 的CSCG-FG为最小值，在 25°C 时比纯CSCG-FG低 31.4% 和 70.0%，远低于同类商业食品级润滑脂。在高温下，含有CNOs的CSCG-FG具有较低的aCoFs和扭矩。0.10 wt% CNOs 的CSCG-FG最有可能用于工程应用，结果将为开发食品级润滑剂提供有价值的见解。