Tribological assessment of the SiO2 coating deposited by sol–gel process toward cutting tool coating

A more economic and thinner coating than the commercial ones was developed to improve the tribological behavior of high-speed steel (HSS) tools. This work focuses on performance of the SiO 2 coating was compared to uncoated HSS pins as well as coated ones (titanium nitride (TiN)) deposited by physical vapor deposition (PVD). The pin-on-disk test was carried out under a constant normal load of 10 N by applying sliding speeds of 40, 55, and 70 m·min −1 . The lowest values of the friction coefficient (µ) and the specific wear coefficient (k) were found for the coated pins. SiO 2 coating presented performance equivalent to the commercial TiN coating for the sliding speeds of 40 and mainly 55 m·min −1 , revealing a mild abrasive wear mechanism with the ferritic spheroidal graphite iron (SGI) interface surface. Thus, the sol-gel coating suggests being a promising protection for cutting tools submitted to abrasive wear when machining SGI workpiece at cutting speeds 3 times higher than those used with uncoated HSS tools, e.g., in drilling and tapping processes. Hereupon, SiO 2 is capable of substituting TiN coating for cutting speeds up to 55 m·min −1 with advantage of being an easier deposition process applied to any geometry without needing of high temperatures.