Quantification of particle morphologies in view of quality control of the thermal spray process

The relationships between processing parameters, deposit microstructures, and deposit properties are not well understood, mainly due, on the one hand, to the numerous parameters governing the thermal spray process and, on the other, to the random mode of deposition of the material (for example, individual impacts of molten particles). The interactions are mainly related to the impact, spreading, and solidification of the material droplets onto the substrate, or previously deposited layers. A methodology was implemented to quantify individual splat morphologies using size and shape factors referring to an equivalent diameter, an elongation factor, and a degree of splashing, and also three-dimensional profilometry and stereology. This approach is mainly based on the use of an image analysis system and statistical tools. A few examples of the potential of this method are given. Such a lowcost and low-time-consuming protocol could be easily implemented for an optimization purpose.