Abrasive wear behavior of sprayed hydroxyapitite coatings by gas tunnel type plasma spraying

Hydroxyapatite (HA) coatings were sprayed using gas tunnel type plasma spraying at different arc currents. Abrasive wear test was carried out for the coatings sprayed at different arc currents under unlubricated conditions in air atmosphere. The abrasive wear rate was measured at different coatings thickness to study the effect of coating thickness on the anti-abrasion resistance of HA coatings. The results showed that the abrasive wear resistance of HA coatings increases as the operating arc current of the plasma torch increases. On the other hand, the abrasive wear rate reaches a minimum value near the substrate with coating thickness less than 50 μm. The results showed that the coating hardness increases in the region near the substrate and increases as the arc current increases. The experimental results indicated that there is a relation between the abrasion resistance and hardness properties of HA coatings.