Nano and micron WC particles reinforced Hastelloy C22 coatings manufactured by directed energy deposition

Abstract

The performance of Hastelloy C22 matrix composite with different reinforced particles is strongly related to microstructural aspect of the coating. In this study, a novel approach for fabricating advanced and high wear resistant nickel-based high-temperature composites by directed energy deposition (DED) was investigated, which enhances the Hastelloy C22 matrix by blending nano and micron WC particles. The microstructure and phase composition of the WC/C22 composite coatings were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The main phases of WC/C22 composite coating are γ-Ni, M6C, WC, W2C and M12C, where M12C and M6C are distributed at grain boundaries to inhibit grain growth and play the role of fine grain strengthening. In performance testing, the nano/micron WC/C22 composite coating showed a 71.04% increase in microhardness, a 92.3% reduction in mass loss, and significantly improved electrochemical corrosion performance compared to the C22 coating.