Influence of the technological conditions of detonation coatings application on their phase composition

Introduction. Detonation spraying is an effective method for applying high-quality coatings to various materials, widely used in industry to improve wear resistance and corrosion resistance of surfaces. This article examines the influence of key process parameters, such as gun-to-substrate distance and nozzle velocity, on the structure and properties of the resulting coatings. Materials and methods of research. The Ti–TiO2 coatings on hot-rolled carbon steel are studied. The spray distance and the speed of nozzle passage are varied while the rest spraying parameters are fixed. The obtained coatings were studied using scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. Results and discussion. It is found that the phase composition of the coating changes depending on the detonation spray conditions. The fraction of rutile exceeds the fraction of anatase in the obtained samples except for the samples obtained with the fastest nozzle passage. The rutile fraction monotonically decreases with an increase in the spray distance with fixed values of the rest parameters of spraying process. It is found a nonmonotonic changing the rutile fraction with an increase in the speed of nozzle passage and found its optimal values. Two new theoretical models for the spray process based on differential equations are proposed, the solutions of which sufficiently describe the dependencies of the rutile fraction on the distance and speed of the nozzle, respectively. Conclusion. It has been demonstrated that the theoretical values of the parameters, calculated using the formulated equations, are in good agreement with the experimentally measured values