كليدواژه :
Cobalt , Based Alloy , Alumina Coating , Electrophoretic deposition , monochloroacetic acid
چكيده فارسي :
In this research, in order to improve the surface properties of a cobalt alloy for use as an orthopedic implant, alumina coating is formed by the electrophoretic deposition method. The cobalt-base alloy is produced by the hot powder forging method based on the ASTM F1537 standard. For this purpose, high purity (Merck, A85, Ultra-High Purity) gamma alumina powder (gamma Al2O3) with a particle size of 0.05 micrometers was used. Isopropanol solvent (ARMAN SINA, Extra Pure) was employed as the dispersing agent for alumina particles in the suspension solution. To investigate the effect of monochloroacetic acid (MCAA) on the properties of the created coating, MCAA was added to the suspension solution in various amounts (0 gr, 1 gr, 2 gr, and 3 gr). Scanning electron microscopy was used to examine the effect of adding MCAA on the thickness, quality, and morphology of the coatings. Based on the results, an increase in the amount of monochloroacetic acid leads to a decrease in the thickness of the coatings, also making the surface of the coatings smoother and more uniform. Furthermore, with an increase in the amount of MCAA, a decrease in the surface pits is observed, which results in a more uniform, homogeneous, and denser coating. To measure the microhardness of the coatings, a Vickers microhardness device model MH1 was utilized. The hardness value of the sample without MCAA was 582 ± 43, whereas the sample with 3 gr MCAA showed an increased hardness value of 703 ± 21 Vickers. The wear properties and the effect of adding MCAA on the wear properties of the coated samples are measured by a dry wear test using a pin-on-disk device according to the ASTM G99 standard. The results indicated that adding MCAA and increasing its concentration decreased the amount of weight loss in the coated samples. It was also observed that adding MCAA reduced the wear rate of the coatings.
