A mathematical model of the powder particle in-flight behaviour during plasma spraying is further developed by including the influence of the particle mass loss due to evaporation on the mechanical behaviour of the particle. The effects of the particle mass loss and plasma–particle interactions are included in the model in a simple analytical form. Analytical equations for estimating the particle mass loss, the time of complete particle melting and the degree of plasma cooling caused by the plasma–particle interaction are obtained and are shown to be consistent with the modelling results. The kinetics of particle melting are studied in detail. On the basis of the model developed, mathematical simulation of the mechanical and thermal behaviour of the powder particles made of alloyed steel 316 L has been undertaken.