High-temperature wear behavior of Tribaloy 400 deposited 17-4 PH stainless steel using spark plasma sintering

Abstract

Surface modification techniques are extensively utilized to improve the performance of the engineering components in their service life when exposed to elevated temperatures. Herein, the Tribaloy 400 (T 400) particles were deposited on the 17-4 PH stainless steel through the spark plasma sintering (SPS) technique to improve the high-temperature wear resistance of exhaust valve components which are typically manufactured using 17-4 PH stainless steel. The identification of phases, microstructure and the morphology of phases in the coatings, elemental composition and distribution, interfacial behavior, and defects like porosities were investigated using advanced characterization techniques. The obtained results revealed the presence of FCC and HCP – Co along with 52 vol% of laves phases (CoMoSi). The presence of laves phases in the Co matrix, fine grained structure and superior interfacial bond strength were promoted the hardness of the coating (~885 HV) than the substrate (~363 HV). The ball-on-disc wear studies were carried out using alumina balls as counter material at room temperature and high temperature (650 °C). The T 400 coating specimen provided better wear properties than the substrate at both temperature. The specific wear rate obtained for the T 400 coated specimen and 17-4PH substrate at room temperature was found to be 1.29 × 10−5 mm3/Nm and 120 × 10−5 mm3/Nm, whereas at 650 °C, it was found to be 0.037 × 10−5 mm3/Nm and 10.26 × 10−5 mm3/Nm, respectively. In T 400 coating, the developed transparent oxide film at 650 °C decreased the possibilities for metal-to-metal contact between the specimen and the counterpart.