The development of biomass materials can effectively mitigate the scarcity of energy and minimize resource waste. In this work, onion-like biomass carbon nanoparticles (OLCs) were prepared using rice husk ash (RHA) which was subjected to a high-temperature graphitization reaction catalyzed by iron nitrate. OLCs/molybdenum disulfide (MoS₂) composite particles were prepared and incorporated into polyimide (PI), and a composite coating of OLCs/MoS₂/PI with excellent tribological properties was successfully prepared. The tribological properties of coatings were evaluated using a controlled atmosphere tribometer (WMT-2E) under dry friction conditions. The related friction and wear mechanism of PI coatings including particles was clarified by the SEM/EDS, XPS, HRTEM and DFT theory. Results show that the wear rate of the three composite coatings of polyimide with OLC, MoS₂, and OLC/MoS₂ particles were reduced by 52.9 %, 48.2 %, and 58.1 %, respectively. For the coefficient of friction, PI-0.20 OLC/MoS₂ coating material decreased by 16.1 %. Anti-wear and friction reduction mechanism is attributed to the presence of a transfer film on the surface of the steel balls. The addition of MoS₂ facilitated the deposition of nanoparticles, which further improved the stability and densification of the friction film, resulting in better protection of the metal surface against severe wear. Besides, the component structure changes of OLCs and MoS₂ and adsorption energy of friction products on the surface of tribo-pairs were also important reasons for clarifying the modification tribological behavior of PI coatings including three kinds of nanoparticles.

中文翻译：

---

洋葱状碳/MoS2 聚酰亚胺涂层的制备和干摩擦学行为研究


生物质材料的发展可以有效缓解能源的稀缺性，最大限度地减少资源浪费。在本工作中，使用稻壳灰 （RHA） 制备了洋葱状生物质碳纳米颗粒 （OLCs），并在硝酸铁催化下进行高温石墨化反应。制备了 OLCs/二硫化钼 （MoS₂） 复合颗粒并将其掺入聚酰亚胺 （PI） 中，并成功制备了具有优异摩擦学性能的 OLCs/MoS₂/PI 复合涂层。在干摩擦条件下，使用可控气氛摩擦计 （WMT-2E） 评估涂层的摩擦学性能。通过 SEM/EDS、XPS、HRTEM 和 DFT 理论阐明了 PI 涂层（包括颗粒）的相关摩擦和磨损机制。结果表明，OLC、MoS₂ 和 OLC/MoS₂ 颗粒的聚酰亚胺三种复合涂层的磨损率分别降低了 52.9 %、48.2 % 和 58.1 %。对于摩擦系数，PI-0.20 OLC/MoS₂ 涂层材料降低了 16.1 %。抗磨损和减摩机构归因于钢球表面存在传输膜。MoS₂ 的添加促进了纳米颗粒的沉积，这进一步提高了摩擦膜的稳定性和致密化，从而更好地保护金属表面免受严重磨损。此外，OLCs和MoS₂的组分结构变化以及摩擦产物在摩擦对表面的吸附能也是阐明PI涂层（包括3种纳米颗粒）的改性摩擦学行为的重要原因。