Life cycle assessment of using powder and liquid precursors in plasma spraying: The case of yttria-stabilized zirconia

Plasma spraying using liquid precursors makes possible the production of finely-structured coatings and thin coatings. This technology has been investigated for nearly ten years in many laboratories and applications are now emerging, using conventional plasma equipment except for the feedstock injection system. While superior quality is expected from the nano-structured coatings, the question remains as to the impacts of using liquid precursors on the environment. In this study, we used the life cycle assessment (LCA) methodology to compare the conventional plasma spray process using powder feedstock, with injection of the precursor in the form of a liquid solution or suspension. The LCA methodology consists of identifying and comparing the environmental impacts of feedstock, energy inputs, products and emissions (solid, liquid and gaseous) of these two alternatives. The LCA study was carried out using the SimaPro program developed in the Netherlands and a peer-reviewed database of upstream materials and energy (EcoInvent v.2). The specific application studied was the plasma spraying of yttria-stabilized zirconia.