Research of annealing influence on the hardness of detonation coatings from zirconium dioxide

Abstract

The article studied the effect of annealing on the structure and properties of zirconium dioxide coatings obtained by detonation spraying. Detonation spraying was realized on a computerized detonation spraying complex of the new generation CCDS2000. Thermal annealing of coated samples was performed at temperatures of 900 °C, 1000 °C, and 1100 °C. It was determined that the microhardness of zirconium dioxide coatings increases by 10–25 % depending on the annealing temperature after annealing. The results of nanoindentation showed that the nanohardness of the coatings after annealing at 1000 °C increases by 50 %. It was determined that after annealing at 1000 °C, the elastic modulus of the coatings increases, which indicates a decrease in plasticity and an increase in the strength of the coatings.. X-ray diffraction analysis showed that the phase composition of coatings before and after annealing consists of t-ZrO₂. After annealing occurs there is an increase in the degree of t-ZrO₂ tetragonality. Electron microscopic analysis showed that an increase in the number and size of micro-continuity in the form of thin layers after annealing. Determined that increase the hardness of zirconium dioxide after annealing at 900–1100 °C is associated with a higher degree of tetragonality t-ZrO₂ phase.