Multifunctional hybrid T-PI-MPS composite coating: Corrosion resistance, low-wear/friction and heat-resistance

Despite methylphenylsiloxane (MPS) possesses heat-resistance and corrosion resistance, the brittleness hinders its widespread application. Herein, the polyimide (PI) and Ti3AlC2 were introduced for modifying MPS, thereby preparing the T-PI-MPS coating. The bilayer structure of surface-enriched MPS and internal-enriched PI was achieved by controlling the addition amount along with the density difference. The results indicate that the T -PI-MPS coating achieved a contact angle of 95.1 degrees and exhibited corrosion resistance to salt spray for 28 days. Compared to PI-MPS, the wear rate of T-PI-MPS was reduced by 85 % and the friction coefficient declined from 0.75 to 0.58. As expected, T-PI-MPS exhibited exceptional excellent heat-resistance. The exceptional performance is attributed to the following three factors: I. the MPS-enriched layer is characterized by a stable Si-O chain organization. This structure gives the corrosion resistance and water resistance, and prevents the hydrolytic swelling of PI. II. the PI-enriched layer is constructed from imide bonds, which give the coating superior friction performance due to its high load-bearing capacity. III. the incorporation of Ti3AlC2 plays a role in mitigating internal defects, prolonging the corrosion path, and inhibiting cracks due to its unique nanolayered structure, high temperature resistance, and hardness.