Parameters of formation of coatings obtained by detonation spraying of spherical titanium on concrete

The possibility of obtaining photocatalytic coatings by detonation spraying on a concrete substrate is considered. A study was conducted to select the optimal parameters for detonation spraying of titanium spherical powder on the surface of heavy concrete. The analysis of the results of experimental studies of a series of 25 concrete samples with coatings obtained at different spraying parameters was performed using X-ray phase analysis and evaluation of photocatalytic activity by the degree of degradation of methylene blue in the solution. The presence of four phases in the coatings was established: titanium, anatase, rutile and titanium monoxide. It was found that at spraying distances less than 100 mm and speeds less than 1000 mm/min, the process becomes unstable, causing destruction of the concrete surface layer due to dehydration of crystal hydrates. Increasing the spraying distance to more than 130 mm and speeds more than 1600 mm/min helps to reduce the content of anatase and rutile due to a decrease in the thermal effect of the detonation process. A correlation was found between the increase in the content of these phases and the enhancement of photocatalytic activity, which is consistent with the data on the effect of phase composition on the photocatalytic properties of materials. A rational spraying mode was established – the distance to the substrate is 120 mm, the spraying speed is 1500 mm/min.