The both techniques Differential Scanning Calorimetry and X Ray Diffractometry are used to analyse different ceramic powders and thermal spray coatings to optimize thermal spray processes. In this paper it was proposed the study and characterisation of TiO2 powders and coatings obtained by different thermal spray processes. We try to understand the thermal effect of thermal spray on powders as a function of process parameters to elaborate coatings with anatase crystalline phase. These coatings must be use to photocatalyse applications to remove pollutants in environment. And numerous papers are shown that anatase crystalline phase less stable than rutile phase was more efficiency for this environment application. Thus using these both techniques are defined and controlled the optimization of thermal spraying parameters.