超临界CO2脉冲电沉积钴基纳米合金薄膜的形成机理、结构控制及摩擦磨损行为研究

By combining supercritical fluid with pulse electrodeposition technology, the project focus on the preparation of nanocrystalline Cobalt (Co) base alloy film by pulse electrodeposition from an emulsified supercritical carbon dioxide (sc-CO2) bath. The formation mechanism and microstructure characteristics of nanocrystalline Co base alloy film deposited under different deposited conditions will be systemically investigated. The influence of the microstructure properties on the hardness, the adhesion strength to the metal substrate, and the friction and wear behavior under different tested condition for the deposited nanocrystalline Co based alloy film will be evaluated. The friction and wear mechanism of the film under different tested condition will be also studied in the project. Based on the study results, the correlation between the deposited conditions of the sc-CO2 assisted-pulse electrodeposition, the microstructure of the prepared Co base alloy film, and the tribological and mechanical property of the film will be discussed to establish the process-structure-property model for the prepared deposit. Eventually, the deposited condition of sc-CO2 assisted-pulse electrodeposition will be optimized to obtain the nanocrystalline Co base alloy film with multi-layered and gradient structure to decrease the internal and thermal stress in the deposits, increase its adhesion strength to the metal substrate, and improve its friction-reducing and anti-wear ability. The conduct of the project has an important significance to develop the sc-CO2 assisted electrodeposition technology and theory and to promote the development of the friction and wear mechanism for metal film materials. Moreover, it will provide a new technology, and its corresponding theory, for the preparation of nanocrystalline alloy film with super anti-wear and mechanical properties.

本项目将超临界技术与脉冲电沉积技术结合,采用sc-CO2脉冲电沉积制备Co基纳米合金薄膜材料。研究Co基纳米合金薄膜材料在各种sc-CO2脉冲电沉积条件下的形成机理和组织结构特征,研究其组织结构特征对其硬度、与基材结合强度及不同条件下摩擦磨损行为的影响及影响机理，分析Co基纳米合金薄膜在不同条件下的摩擦磨损机理和抗疲劳磨损机制。在此基础上，探讨Co基纳米合金薄膜材料的超临界电沉积条件-组织结构特征-摩擦磨损性能间内在联系，建立其制备工艺-结构-性能的关系模型。最终阐明这些机理和关系，优化sc-CO2脉冲电沉积条件实现Co基纳米合金薄膜的多层梯度结构控制，降低其内热应力，改善其与基体的结合强度和摩擦学性能，揭示sc-CO2在脉冲电沉积过程中的作用机理。本项目的实施对促进超临界电沉积技术和理论的发展及金属薄膜材料摩擦磨损机理的研究都具有重要意义，为制备高性能耐磨薄膜材料提供新方法和理论依据。

本项目主要开展纳米晶钴基合金及复合薄膜材料的超临界脉冲电沉积制备及其在不同条件下的摩擦磨损及耐腐蚀性能研究，重点关注钴基合金/复合薄膜材料的微观组织结构及形貌对其摩擦磨损和耐腐蚀性的影响机制及各种条件下的摩擦磨损机理。取得了一些重要的研究成果：1）采用多种脉冲电沉积技术在不同金属基材表面构筑了纳米晶钴（Co）及钴-钨（Co-W）合金薄膜材料，揭示了脉冲电沉积技术对纳米晶Co及Co-W的晶粒尺寸、结晶取向及晶粒形貌等结构特征的影响机制，揭示了各种结构Co及Co-W在不同条件下的摩擦磨损机理及耐腐蚀机理，阐明了纳米晶Co及Co-W合金薄膜的“脉冲电沉积技术-微观形态结构-摩擦学行为”之间的关系。2）在纳米晶Co、Co-Ni、Co-Ni-P电沉积制备过程中引入超临界CO2调控薄膜材料的结晶取向及微观形貌结构，改善其耐磨与耐腐蚀性能，揭示了超临界CO2在电沉积制备纳米晶Co、Co-Ni、Co-Ni-P薄膜过程中的作用机理，揭示了超临界CO2对制备的钴及其合金薄膜的组分结构（晶粒尺寸、结晶取向、表面微观形貌）、与基体结合界面、摩擦磨损性能与机理、耐腐蚀性能与机理的影响机制。3）引入第三相纳米碳材料（碳纳米管及石墨烯)制备了纳米晶钴基复合薄膜材料。通过电沉积技术、表面处理技术、超声波辅助工艺等有机结合，实现了纳米晶钴基复合薄膜材料的晶粒尺寸、结晶取向、第三相分布与分散、表面形貌及与基体结合界面的综合控制，提出了钴基复合薄膜材料的各相、各组分对其摩擦磨损和耐腐蚀性的影响机制，阐述了增强相对复合薄膜摩擦学与耐腐蚀性能的改善机理。研究成果第一/通讯作者共发表论文14篇，其中SCI收录13篇（其中一区且为ESI高引论文1篇，二区6篇，三区5篇），授权国家发明专利3件。