Effect of the mechanical properties on drilling resistance of Al2O3–TiO2 coatings manufactured by atmospheric plasma spraying

Al2O3 with 13 and 45 wt.% TiO2 microsized powders (6–22 and 13–41 μm for each chemical composition) were used as raw materials to coat AISI 1040 steel by atmospheric plasma spraying. The mechanical properties of the coatings were measured by micro-indentation tests, and drilling experiments were carried out using high speed steel (HSS) rotary drill bits of various diameters and varying the load on the drill bits. In order to reduce the effect of the wear on the bit, a new bit was used for each test. According to the results, the drilling test is proposed as a method of determining the mechanical properties of these coatings from the correlation found between coating hardness and drilling resistance.

► The alumina titania coatings were manufactured by atmospheric plasma spraying. ► The microhardness Vickers was measured on the polished surface of the alumina titania coatings cross section. ► The alumina titania coatings were pierced using HSS drill bits. ► Drilling tests were carried out varying the drill bits diameter and the load applied on them. ► The drilling resistance was correlated with the microhardness Vickers of alumina titania coatings.