Investigation of microstructural and tribological behavior of Metco 41C+WC-12Co composite coatings sprayed via HVOF process

Abstract

The present work deals with developing an elevated-temperature sliding, wear-resistant, iron-based (Metco 41C) composite coating on the boiler steel substrate using high-velocity oxy fuel (HVOF) system. Prior to coating, Metco 41C (70%) and WC-12Co (30%) were mixed mechanically using ball milling process. Later, feedstock was employed into the HVOF system to develop the coating. The coating samples were subjected to metallurgical and mechanical characterization techniques under required conditions. Further substrate and coating were taken for wear test without employing lubrication through pin on disc apparatus. Wear test was carried out by selecting 10 and 20 N loads at room temperature, 200°C, and 300°C parameters. The sliding distance and the velocity were kept constant. The worn-out samples were analyzed for microstructural changes and formation of phases using SEM and XRD methods, respectively. The wear properties of friction coefficient, wear rate, and loss of volume were calculated. Deposited coating exhibited hard phases such as Cr3C2, Ni3C, W2C, Fe2C, and SiC along with intermetallic phases like Mo2C and Co3W3C. The result is improvement in hardness and better wear resistance with respect to the substrate. © 2022 selection and editorial matter, Lalit Thakur, Hitesh Vasudev. All rights reserved.