Cr3C2-25NiCr Cermet Coating: Preparation, PTFE Sealant, Wear and Corrosion Resistances.

In this study, Cr3C2-25NiCr cermet coatings were fabricated by atmospheric plasma spraying on 304 stainless steel substrate. Then, the coatings were sealed with a Polytetrafluoroethylene (PTFE) emulsion by using two methods: conventional impregnation and ultrasonic vibration. The phase composition, surface morphology, porosity, permeability of PTFE emulsion into the coating, wear and corrosion resistance of the coatings were investigated. The results showed that in the PTFE sealed coatings, besides carbide phases, a PTFE phase with an hexagonal crystal structure was formed. The PTFE covered the surface of the coating. The ultrasonic vibration method increased the permeability of the PTFE emulsion into the coating by more than 2 times that of the conventional impregnation method. The PTFE sealed coating by ultrasonic vibration method had a lower porosity, higher wear and corrosion resistances in 3.5 wt.% NaCl solution than the PTFE coating sealed by conventional impregnation method and PTFE unsealed coating. [ABSTRACT FROM AUTHOR]