Erosive wear of a surface coated hydroturbine steel

Abstract

In the present investigation, stellite-6, Cr 3 C 2 -NiCr and WC-Co-Cr coatings were deposited by DGun on a hot rolled 21Cr-4Ni-N steel meant for fabrication of hydro turbine underwater parts. The coatings have been characterized for microstructure, porosity, microhardness and crystalline nature. The erosion experiments were carried out using an air jet erosion test rig at a velocity of 120 ms -1 and impingement angles of 30° and 90°. Silicon carbide particles of size ranging between 500 and 700 µm were used as erodent. Scanning electron microscopy (SEM) technique was used to analyse the nature and mechanism of erosion. Erosion behaviour is observed to be influenced largely by the nature and extent of porosity in the surface coatings.

Analysis of wear behavior and surface properties of detonation gun-sprayed composite coating of Cr3C2–NiCr–CeO2on boron steel

“…7 Detonation coatings are designed for applying hard materials, especially carbides, on surfaces subject to aggressive wear. [8][9][10] Cr 3 C 2 -NiCr system coatings have major applications in components that are used in high temperature wear resistance and corrosion resistant industries like aerospace and powder engineering.…”

“…7 Detonation coatings are designed for applying hard materials, especially carbides, on surfaces subject to aggressive wear. 8–10…”

Thermal spray coatings in renewable energy applications

“…It has been documented that thermally sprayed coatings with thickness 200-400 mm can effectively protect the components with economic viability (Chauhan et al, 2010). Therefore, for the water with high particles sizes, nickelbased tungsten carbide coating is preferred to increase the ductility of the turbine components.…”

Sintering behaviour and mechanical properties of Cr3C2–NiCr cermets

“…Hussainova et al (2007) investigated the effect of Ni content on the wear behaviour of Cr 3 C 2 -based cermets and found that the wear rate decreases with an increase in hardness due to decreasing Ni content. Chauhan et al (2010) evaluated the high impact angle erosion wear characteristics of Cr 3 C 2 -NiCr and WC-Co cermets coatings, comparatively. 75Cr 3 C 2 -25NiCr coatings showed higher wear resistance than WC-Co coatings at 90 • due to good binder wettability and high ductility of the binder phase which prevent further material removal (Chauhan et al 2010).…”

“…Chauhan et al (2010) evaluated the high impact angle erosion wear characteristics of Cr 3 C 2 -NiCr and WC-Co cermets coatings, comparatively. 75Cr 3 C 2 -25NiCr coatings showed higher wear resistance than WC-Co coatings at 90 • due to good binder wettability and high ductility of the binder phase which prevent further material removal (Chauhan et al 2010). Huang et al investigated the mechanical properties of VC, Cr 3 C 2 and NbC doped WC-Co cermets and found that pure WC-Co cermet had a lower hardness than that of doped cermet.…”