Plasma sprayed diamond reinforced molybdenum coatings

Highlights: • Diamond-reinforced composite molybdenum coatings were prepared from ball-milled powder feedstock. • The micro-structure of the composite coatings contains both semi-molten and fully molten phases. • Diamond could be retained in the composite coatings. • Increase in hardness (∼10%) and elastic modulus (∼15%) was observed in composite coatings. The present investigation deals with the fabrication of a novel thermally sprayed coating using a diamond reinforced molybdenum feedstock. Molybdenum powders were ball-milled with 10 wt% mono-crystalline diamond particles to produce a powder feedstock. Both milled and as-received powders were deposited on steel substrates using air plasma spraying to produce coatings with a thickness in the range of 250–280 μm. Characterisation of the coatings was performed in terms of micro-structure, phases, hardness, elastic modulus and residual stress. Retention of diamond in the composite coating was confirmed using Raman imaging. Micro-hardness and elastic modulus of coatings improved with diamond reinforcements.