A systematic review on advanced surface coating technologies for high-pressure piston pumps

Piston pumps are extensively employed in the industrial and aerospace sectors, particularly in applications that demand high-pressure operation and precise flow regulation. However, the inherent structural complexity of these components, coupled with their frequent exposure to adverse operating conditions, leads to various forms of surface degradation in friction pair elements. To address these challenges, researchers have pursued the development of advanced coating technologies aimed at enhancing surface hardness, reducing friction coefficients, and improving wear resistance. These coatings typically include metallic coatings, ceramic coatings, and diamond-like carbon (DLC) coatings, along with more cutting-edge yet highly promising high-entropy alloy (HEA) coatings. As a novel class of materials, HEA coatings hold considerable potential to overcome the inherent limitations of conventional coating systems. This review provides a comprehensive overview of recent advances in piston pump coating technologies, with particular emphasis on deposition methodologies, microstructural characteristics, and tribological performance. By establishing microstructure-property relationships within these coating systems, this study proposes future research directions for optimizing surface engineering approaches in hydraulic pump applications.