Robust ceramic based self-lubricating coating on Al–Si alloys prepared via PEO and spin-coating methods

• Published in: Wear 2020-10, Vol.458-459, p.203405, Article 203405
• Main Authors: Fu, Jingguo, Li, Meng, Liu, Gengshuo, Ma, Shenglin, Zhu, Xinhe, Ma, Chunsheng, Cheng, Dong, Yan, Zhijun
• Format: Article
• Language: English
• Subjects: Aluminum base alloys; Ceramic coatings; Ceramic glazes; Ceramics; Chemical composition; Coefficient of friction; Hard ceramic coating; Morphology; Oxidation; PEO ceramic coating; Polyimide composite; Protective coatings; Self lubricating materials; Silicon; Soft self-lubricating coating; Solid phases; Spin coating; Tribological properties; Tribology; Tungsten disulfide; Wear rate
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/j.wear.2020.203405

Ceramic based self-lubricating coating was successfully fabricated on Al-based plasma electrolytic oxidation (PEO) ceramic coating in this work. The coating was reinforced with thermosetting polyimide (PI) containing tungsten disulfide (WS2) fillers. The morphology, chemical composition and phase structure of the PEO, PEO/PI and PEO/PI/WS2 coatings were observed by SEM, EDS and XRD, respectively. Tribological properties of the coatings were comparatively investigated using a reciprocating pin-on-block tribotester under different conditions. Under dry sliding conditions, the friction coefficient of PEO/PI/WS2 coating was about 0.4, which was 50% lower than that of PEO coating. Meanwhile, the wear rate of counter pin cooperated with PEO/PI/WS2 coating was only 0.04 mg min−1, which was 90.9% lower than that of PEO coating. Under step loading conditions, the load was ultimately increased to 70 N and the total duration time was about 35 min, while the corresponding values of PEO coating were 30 N and 13 min, respectively. These are owed to the hard ceramic coating and the soft self-lubricating coating, which can improve the load capacity and decrease the friction, of the ceramic based self-lubricating coating. [Display omitted] •A self-lubricating coating was successfully fabricated on ZL109 aluminum alloy.•The introduction of WS2 in the self-lubricating coating shows excellent tribological properties.•The combination of soft lubricating coating and hard supporting ceramic coating is the main anti-friction mechanism.