Evolution of Microstructure and Wear Behavior of Heat-Treated and Fused Arc-Sprayed Coatings Containing Fe2B Crystals Dispersed in Different Steel-Based Matrices

Thermal sprayed coatings are mechanically bonded to the substrate and, due to their lamellar microstructure, possess low toughness and open porosity that restrain their application.

This research work was carried out to increase the density and the wear resistance of arc-sprayed coatings containing hard Fe₂B crystals dispersed in mild and alloyed steel-based matrices. These arc-sprayed coatings were: 1) heat-treated in furnace up to 1200⁰C and 2) fused with an oxy-acetylene torch. The specimens were tested in a jet erosion device at low and high angles and the abrasion was evaluated with the G65-B method. The evolution of microstructure is done by SEM and wear damage by time-domain optical coherence tomography.

Heat treating processes considerably enhance the wear resistance of most of the coatings. It is also observed considerable grain growth in heat-treated and fused coatings. Particularly, low-alloyed coatings show the most important grain growth that leads to inferior wear properties.