Tribological behaviour of Ag–BN coatings prepared by plasma spraying

Abstract

Hexagonal boron nitride (h-BN) particles were added to a sliver metal matrix to improve the tribological properties of the prepared Ag–BN coatings, which were deposited via plasma spraying technique. The morphology, flowability and apparent density of Ag–BN composite powders were characterized, as well as the phase composition, microstructure and friction properties of Ag–BN coatings were systematically investigated. Results of XRD showed that Ag–BN coatings were successfully prepared, morphologies of SEM showed dense structures of Ag–BN coatings. The friction and wear behaviour of Ag–BN coatings was investigated from ambient temperature up to 800°C. The results showed that the coatings exhibited excellent tribological properties in this temperature range. The main wear mechanisms of Ag–BN coating were adhesive wear and ploughing. Layered h-BN reduced the friction coefficient and improved abradable property of Ag–BN coatings. Ag as the metal phase effectively protected the Si₃N₄ ball from wear.