In-situ formation, structural transformation and mechanical properties Cr[sbnd]N coatings prepared by MPCVD

Abstract

This study innovatively employed the microwave plasma chemical vapor deposition (MPCVD) technique to fabricate CrN coatings. The influence of preparation temperature on chemical composition, crystalline phase, morphology, and mechanical properties of the coatings were analyzed systematically. The increase of preparation temperature resulted in the structural transformation of the CrN coatings from the duplex of Cr2N/CrN to the single-phased Cr2N. The coatings with dense and flat surface were obtained at ≤800 °C; however, the decomposition of CrN to Cr2N and N2 led to the formation of pores at ≥850 °C and consequently an increase in friction coefficient and wear. The hardness and elastic modulus increased with increasing temperature because of the structural evolution of the CrN coating and phase transformation. 800 °C was the optimal preparation temperature as the coating exhibited a dense surface and possessed the best overall mechanical properties.