The influence of input spray parameters on the state of plasma-sprayed zirconia powder is studied. The particle temperature, velocity and diameter are measured using an integrated optical monitoring system. The monitoring system allows the investigation of the particles behavior in the spray jet. The collected information is correlated to coating characteristics such as deposition efficiency, microstructure and thermal diffusivity. Results show that, by monitoring the state of sprayed particles, a better understanding of the coating microstructure and properties can be achieved.