Polyketone-modified Ti3C2Tx composite coatings for enhanced solid lubrication under elevated stress and oxidative environments

Improving the tribological performance of components and systems remains crucial to improve the resulting mechanical efficiency, durability, and sustainability. This study reports the development of composite coatings based on multilayer Ti3C2Tx (ML- Ti3C2Tx) and chemically modified polyketone (PKHEDA) for enhanced solid lubrication. In this regard, PKHEDA was synthesized via the Paal-Knorr reaction to improve MXenes' dispersion as well as coating's adhesion and chemical stability. Composite coatings with varying MXene-polymer ratios 1:3.3 (COM-1), 1:1.6 (COM-2), and 1:1 (COM-3) wt.-%, were spray-coated onto stainless-steel substrates and characterized using complementary materials characterization and tribo-testing. Our results demonstrate that PKHEDA effectively encapsulates ML- Ti3C2Tx, reducing its oxidation tendency and improving the overall coating integrity under mechanical stress. The tribological performance of the composite coatings was notably enhanced compared to pure Ti3C2Tx coatings and non-coated substrates, thus verifying a stable coefficient of friction and a reduction of the wear rate up to 87 %. The composite with a MXene-to-polymer ratio of 1:1.6 (COM-2) exhibited the best balance of load-bearing capacity, durability, and chemical resilience. These findings highlight the synergistic potential of ML-Ti3C2Tx/polyketone composites to develop high-performance, sustainable coatings for demanding tribological environments.