Cr2C3–NiCr VPS thermal spray coatings as candidate for chromium replacement

Abstract

The present investigation has been carried out with the aim of determining the tribological behavior of a VPS chromium carbide coating both in the as-deposited and heat-treated conditions. A commercial powder of Cr 2 C 3-25% NiCr was sprayed employing a VPS system (Medicoat AG, Switzerland) onto plain low carbon steel coupons. The samples were subsequently annealed for 2 h at 600°C, 800°C and 900°C in Ar. The microstructural characterization was carried out by using SEM and XRD before and after the heat treatment of the samples. SEM observations were employed for determining the degradation mechanisms that took place during the wear tests. When the coated systems rubbed against alumina under a 5 N normal load in air, a progressive change in the mechanism, from a mixed adhesive and abrasive, to a predominant abrasive was observed, as the heat treatment temperature increased. The wear constants were found to be of the order of approximately 10 −6 mm 3 /N.m, which indicates a wear resistance of nearly 4 times higher in comparison with the wear results reported in the literature for similar coating systems obtained by employing HVOF deposition. However, the heat treatment carried out at 900°C brought about only 20% increase in the sliding wear resistance of the coated system.

Improvement of thermally sprayed WC–Co/NiCr coatings by surface laser processing

“…When the material consolidates, it forms coarser morphological structure. Before further processing and for practical applications, the workpiece should be ground again, as it is generally done after the thermal spray deposition [18], to level off the asperities and gain a uniform and homogeneous morphology. Although being a limiting assumption, in this work, the following characterizations were performed on the as-treated coatings to avoid the influence of reprocessing on material properties.…”

Analyzing Microstructural Features, Surface Topography, and Scratch Resistance of Innovative Nano-Composites Coated with High Velocity Air-Fuel Technology

“…Coatings made of tungsten carbide are frequently applied to the restriction grit and slide gate orifices of catalytic towers in the chemical industry to offer wear and cavitation resistance [14]. Chromium carbide-based coatings: These coatings are frequently applied to different components, including boiler tubes and turbine blades, in the power generation sector to provide high-temperature erosion resistance [15]. The study aims to enhance the understanding of the microstructural and surface characteristics of the nano-composites coated with high velocity air-fuel technology, as well as their scratch resistance properties.…”

Structural and Mechanical Properties of Arc-Sprayed Ni–Cr Coating Post-Treated by Surface Mechanical Attrition Treatment (SMAT)

“…Many studies [22][23][24][25][26][27][28] focused on the effects of heat treatments on the microstructure and mechanical properties evolution of thermally sprayed Ni-based coatings. It was shown that coatings heat-treated at 700 and 900 • C have a dense structure and low porosity.…”