Nanocrystalline Cermet Coatings for Erosion–Corrosion Protection

Abstract

The processing techniques, microstructural characteristics, and erosion corrosion behaviour of Cr3C2–NiCr and tungsten carbide (WC)-based cermet coatings are reviewed in this work. Conventional and nanocrystalline Cr3C2–NiCr and WC-based cermet coatings are generally synthesized using thermal spray technique. The wear, erosion, and corrosion protection ability of conventional and nanocermet coatings are compared based on available literature. In Cr3C2–NiCr coatings, the corrosion resistance is offered by NiCr metal matrix while the wear resistance is provided by the carbide ceramic phase, making it suitable for erosion–corrosion protection. The nanocrystalline cermet coatings exhibits better erosion–corrosion resistance as compared to the conventional coatings. The nanocrystalline coatings reduces the erosion–corrosion rate significantly compared to conventional coatings. It is attributed to the presence of the protective NiCr metallic binder that allows easier and faster re-passivation when the coating is subjected to wear and the fine-grain structure with homogeneous distribution of the skeleton network of hard carbide phases. In addition, corrosion-accelerated erosion dominates the reaction mechanism of erosion–corrosion and, therefore, higher hardness, strength, and better wear resistance of nanocermet coating along with its faster repassivation kinetics accounts for improved corrosion resistance as compared to conventional coatings.

Novel Liquid Fuel HVOF Torches Fueled with Ethanol: Optimization and Erosion Wear Response of Cr3C2-NiCr Coatings

“…The thermal spraying process has been recognized as one of the main surface strengthening technologies in industry. Cr 3 C 2 -NiCr coatings deposited by thermal spraying technology are widely used to improve the erosion resistance [4,5], wear resistance [6,7], and high temperature oxidation resistance [8,9] of the workpiece surface. In particular, HVOF technology has become a mainstream technology for the preparation of carbide-based cermet coating with low porosity, good coating adhesion and a reduced quantity of detrimental reaction products [10][11][12].…”

Erosion-Corrosion Protection Due to Cr3C2-NiCr Cermet Coating on Stainless Steel

“…The fine grain structure with a homogeneous distribution of the skeleton network of hard carbide phases provides excellent erosion resistance and is therefore a better alternative to hard oxide coatings [9,11,[21][22][23][24]. The coatings with better wear resistance and corrosion resistance are used in various environmental conditions, as reported in the literature [5,[25][26][27][28][29][30][31][32][33][34][35][36][37][38]. The corrosion and wear resistance of the substrate vary with the angle of impact of erodent particles [29,30].…”

Electrodeposited Biocoatings, Their Properties and Fabrication Technologies: A Review

“…Many functional coatings have been so far proposed and developed. Just recently, for example, gas-barrier thin film coatings for food and beverages [1], the coatings for automotive brake discs [2], tribological coatings [3], functional textile coatings [4], super-hydrophobic anticorrosion coatings [5], and cermet coatings for erosion-corrosion-protection [6] were investigated.…”