Spark Plasma Sintering of NiCrSiBC Alloys

Abstract

Nickel-based alloys of the NiCrSiBC system (colmonoy alloys) are normally deposited on stainless-steel substrates for coating applications, once they present high resistance to wear and corrosion at high temperatures. Typically, deposition occurs through welding processes, such as PTA (plasma transferred arc) or laser cladding. This study mainly aims to evaluate the effectiveness of the spark plasma sintering (SPS) process through the evaluation of the sintered body density, and structural and microstructural analysis of the Colmonoy-5. SPS sintering occurred at 900°C under 50 MPa for 15 minutes. Powder morphology was evaluated by confocal microscopy. The sintered samples were evaluated according to their density (Archimedes’ method), phase composition, microstructure, and hardness (Vickers hardness). Results showed that the Colmonoy-5 alloy can be effectively produced through SPS sintering, reaching densification above 90%. Microstructural analysis showed that there was the formation of hardening phases, such as borides and chromium carbides. The same phases are found in colmonoy alloys deposited on the stainless-steel substrate.