As part of an investigation of the dynamics that occur in the plume of a thermal spray torch, an experimental and analytical study of the deposition of yttria-stabilized zirconia has been accomplished. Experiments were conducted using a Taguchi fractional factorial design. Nominal spray parameters were: 900 A, 36 kW, 100 scfh argon primary gas flow, 47 scfh helium secondary gas flow, 11.5 scfh argon powder carrier gas flow, 3.5 lb/h powder feed rate, 3 in. spray distance, and an automated traverse rate of 20 in./s. The coatings were characterized for thickness, hardness, and microstructural features with optical microscopy, scanning electron microscopy, and x-ray diffraction. Attempts are made to correlate the features of the coatings with the changes in operating parameters. Numerical models of the physical processes in the torch column and plume were used to determine the temperature and flow fields. Computer simulations of particle injection (10 to 75 μm zirconia particles) are presented.