Work

Mechanical properties, microstructure, and tribological performance of coated polyether-ketone-ketone (PEKK) polymer

Year: 2025

Type: article

Abstract: This study investigates the mechanical properties, microstructure, and tribological performance of CrN and CrAlN coatings. The coatings were deposited by low power DC reactive magnetron sputtering (PVD) on semicrystalline polyether-ketone-ketone (PEKK) substrates. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed PEKK's thermal stability, with a glass transition temperature of 158.0 °C and a melting point of 309.1 °C, ensuring compatibility with low-temperature coating processes. Microstructural analysis revealed dense, columnar coatings, with CrAlN exhibiting finer grains but minor interfacial voids/cracks that unaffected its adhesion. Tribological tests against stainless steel balls (SS) showed that CrN outperformed CrAlN, reducing the coefficient of friction (COF) by 39 % and specific wear volume by 78 % compared to uncoated PEKK, owing to its higher hardness and the formation of a protective Cr-oxides tribolayer. These results establish CrN as the superior coating for enhancing PEKK's durability and tribological performance, highlighting its potential for applications demanding high durability and wear resistance. • CrN and CrAlN coatings deposited on PEKK using low-power DC magnetron sputtering. • PEKK showed high thermal stability, enabling low-temperature PVD coating. • CrN coating achieved superior tribological performance than CrAlN coating. • CrN reduced friction by 39 % and wear by 78 % compared to uncoated PEKK.

Source: Surface and Coatings Technology

DOI: 10.1016/j.surfcoat.2025.132872

Authors: Abbas AL-Rjoub, Talha Bin Yaqub, Irfan Nadeem, Albano Cavaleiro, Mitjan Kalin, Nazanin Emami