A Comparative Study of Ready to use YSZ suspensions and coatings

The demand for suspensions used in thermal spray processes is expanding from research labs using the lab prepared suspensions toward various industrial sectors. Industrial applications dictate reduced production time and effort which may in turn justify the development of the market for ready to use suspensions. To this end, some of the powder suppliers have already taken steps forward by introducing to the market the suspensions of some of the most used materials such as YSZ, Alumina, Titania. There is, however, a need to find the possible differences in the suspension characteristics over time and the resulting coatings when using these suspensions as compared with the freshly prepared home-made suspensions. In this work, such comparison is done using YSZ suspensions of the sub-micron to a few micron powders. In addition, some modification to the suspensions' formula was performed as a tool to vary the coatings’ microstructures in a more predictable way, without variation of spray parameters. The coatings were generated using both radial and axial techniques for injection of the suspensions into the plasma spray torches 9MB and axial III, respectively.