Mechanisms of sliding wear of metals and alloys at elevated temperatures

Tribological behaviour of plasma-sprayed WC coatings with and without laser remelting

The microstructural dependence of wear and indentation behaviour of some plasma-sprayed alumina coatings

This paper reports an investigation of the effects of laser surface treatment on the corrosion and wear performance for Inconel 625, and Inconel 625-based WC HVOF-sprayed MMC coatings. Examination of the laser-treated surface was conducted in terms of microstructural morphology, chemical composition and phase analysis. Corrosion resistance using potentiodynamic polarisation in 3.5% NaCl solution and dry sliding wear behavior of the various coatings before and after laser treatment was evaluated. The results indicated that significant improvement of corrosion and wear resistance can be achieved after laser treatment as a result of the elimination of discrete splat-structure, microcrevice and porosity, and also the reduction of microgalvanic driving force between the WC and the metal matrix. In addition, the formation of faceted dendritic structure of the WC phase was considered to be beneficial for the wear performance.

Improving corrosion and wear performance of HVOF-sprayed Inconel 625 and WC-Inconel 625 coatings by high power diode laser treatments

Thermal spraying has emerged as a suitable and effective surface engineering technology and is widely used to apply wear, erosion and corrosion protective coatings for various kinds of industrial applications. Cr3C2-based coatings have been applied to a wide range of industrial components. Cr3C2–NiCr coatings offer greater corrosion and oxidation resistance, also having a high melting point and maintaining high hardness, strength and wear resistance up to a maximum operating temperature of 900 °C. The corrosion resistance is provided by NiCr matrix while the wear resistance is mainly due to the carbide ceramic phase. This paper reviews the performance, developments and applications of Cr3C2–NiCr thermal spray coatings for corrosion/erosion-corrosion under different types of environments and outlines the characterization of Cr3C2–NiCr coatings with respect to their microstructure and mechanical properties, together with some brief characterisation work by the author for HVOF sprayed 75Cr3C2-25NiCr coating on T91 boiler steel.

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R. Vijande

Papers

Tribological properties of plasma sprayed and laser remelted 75/25 Cr3C2/NiCr coatings

Comparison of wear behaviour of plasma-sprayed Al2O3 coatings with and without laser treatment