Debadhyan Behera

A facile approach for morphosynthesis of Pd nanoelectrocatalysts

A facile approach has been developed for synthesis of highly-structured, anisotropic Pd nanostructures. The dendritic Pd nanostructures show superior performance toward oxidation of formic acid and methanol for fuel cell application.

Erosive Wear Analysis of Plasma-Sprayed Cu Slag–Al Composite Coatings

This article depicts the solid particle erosion response of plasma-sprayed composite coatings using an industrial waste product (i.e., copper slag) and aluminum. The influence of five operating parameters—that is, impact velocity, erodent size, erodent temperature, impingement angle, and aluminum content of feedstock with four different levels each—on performance output (i.e., erosion rate) are studied using Taguchis L16 orthogonal array design. Out of the five parameters, impact velocity has been found to be most influential factor on the erosion wear rate of coated samples. Maximum erosion takes place at an impingement angle of 60°, showing the semiductile response of the coating to solid particle erosion. In addition, a multilinear mathematical equation is proposed in order to predict the wear rate. The percentage of error between experimental data and predicted data was small, with a very high correlation coefficient (r2) of 0.997 showing the correctness of the mathematical equation used.

Deposition of plasma sprayed copper slag coatings on metal substrates

Abstract Copper slag is a waste product obtained during matte smelting and refining of copper. The present work explores the coating potential of copper slag by plasma spraying. This work shows that copper slag is eminently coatable. When premixed with alumina powder, the coating exhibits higher interfacial adhesion as compared to pure copper slag coatings. Maximum adhesion strengths of about 23 and 27 MPa are recorded in for the coatings of copper slag with 15 wt.% of alumina on aluminium and mild steel substrates respectively. The input power to the plasma torch is found to affect the coating deposition efficiency and morphology of the coatings.

High temperature nitriding of grey cast iron substrates in arc plasma heated furnace

Abstract Grey cast iron substrates were case nitrided at 1000–1100°C by varying several process parameters such as nitriding time, flowrate of N2 and nitriding gas configuration. Ar and H2 were mixed with N2 to change the configuration and to observe their influence on the nitrided case. Nitriding was carried out in a specially designed arc plasma heated reactor with water cooled steel casing. X‐ray diffraction studies show that the nitride peaks arise due to growth of iron nitride phases such as γ′ (Fe4N: 5·7–6·1%N), ϵ (Fe3N: 8–11·2%N) and carbon nitride (C3N4). Typical surface morphologies of the 10–30 μm nitride layer were studied by SEM. Microhardness studies exhibited twofold improvement of surface hardness. Nanoindentation test indicated poor plastic behaviour of the surface. Micro‐Raman spectra of the nitided case established the presence of β‐C3N4, a superhard phase. Nitrided grey cast iron may find use in wear and corrosion resistant dies, machine components and parts in various industrial applications.

Improvement of microstructural and mechanical properties of plasma sprayed Mo coatings deposited on Al-Si substrates by pre-mixing of Mo with TiN powder

The present work embodies development of a new class of mechanically improved Mo-TiN coating material using plasma spray technique. The coatings are developed on Al-Si alloy at different torch input power levels ranging from 15 kW to 30 kW. Pre-mixing of TiN with molybdenum enhances adhesion strength and hardness of the coatings. Maximum adhesion strength of 22 MPa (±0.75) and hardness of 748 HV (±30) are found for the coating when molybdenum is pre-mixed with 10% TiN. FESEM micrographs of the as-sprayed coatings showed formation of plate-like structures of splats which indicates TiN sites as reinforcement in Mo matrix. X-ray diffraction study reveals the formation of both MoO2 and TiN as minor phases in the coating microstructure. The significant enhancement of mechanical properties like adhesion strength and hardness is attributed towards the presence of these phases.