Post-deposition heat treatment effect on microstructure of suspension plasma sprayed bioactive glass coatings

Abstract

This research addresses a simple and easy method to improve the microstructure of suspension plasma sprayed bioactive glass coatings. Based on previous research of the group, a SPS bioactive glass coating was deposited under optimised variables employing a stable suspension feedstock. After the microstructural characterisation, the coatings were subjected to a heat treatment at 400, 500 and 600 ºC peak temperatures. These temperatures have been chosen according to the shrinkage curve of the working glass which results from a hot stage microscope. Results show an improvement of the coatings microstructure (reduction in both porosity and thickness and increment of the adhesion) after a heat treatment at 500 ºC with respect to the original coating. However, for a temperature of 400 ºC the coating microstructure is not altered (porosity, thickness and adherence are the same as those of the original sample) while at 600 ºC the entire coating is completely delaminated.