Effect of Boehmite Nanoparticles on the Structural, Corrosion, and Diffusion Properties of Microarc Biocoatings

The results of studying the morphology, porous structure, and corrosion and diffusion properties of boehmite-containing calcium phosphate coatings formed by microarc oxidation on titanium substrates are presented. Boehmite nanoparticles obtained as a result of the AlN hydrolysis were deposited on the surface of microarc coatings with a developed relief. With an increase in the duration of the preliminary ultrasonic treatment (UST) of the AlN suspension in the interval of 20–60 min, the size of agglomerates of boehmite nanoparticles on the coating surface is decreased from 200 to 40 μm. The surface porosity of the modified coatings and the area occupied by boehmite particles are decreased from 36 to 33% and from 27 to 10%, respectively. Agglomerates with boehmite nanoparticles after 60 min of UST of an AlN powder suspension are distributed in the coating more uniformly than after 20 min of treatment. When the duration of UST of the initial suspensions is increased, the effective diffusion coefficients of the model biological fluid in porous coatings is decreased from 7.98 × 10 –11 to 7.25 × 10 –11 m 2 /s. Modification of calcium phosphate coatings with boehmite nanoparticles by varying the duration of UST of AlN powder increases the corrosion resistance of the surface layers.