Tribological And Corrosion Properties Of Cr-B-C Coatings In Aqueous Solution

A series of Cr-B-C coatings were deposited on Si (100) by adjusting target power, bias voltageand deposition temperature using DC and RF magnetron co-sputtering system. The influences ofdeposition parameters on phase structures, microstructures and mechanical properties were studied tooptimize the deposition parameters. The effects of deposition parameters and friction conditions ontribological properties under reciprocating mode were also investigated. Besides, the electrochemicaland tribological properties of Cr-B-C coatings in deionized water, simulated body fluid and seawaterwere compared, and the effects of three lubricants on the friction and wear behaviors of Cr-B-Ccoatings were analyzed:(1)With the sputtering power increasing, the hardness of Cr-B-C coatings increased gradually whilethe critical load first increased and then decreased. With the bias voltage increasing, the hardness andcritical load both exhibited the same variation trend. However, with the temperature increasing, thehardness and critical load exhibited the opposite variation trend. Under the consideration ofmicrostructure and mechanical properties, the optimal deposited parameters could be confirmed assputtering power of200W, bias voltage of-150V and deposition temperature of200℃. Moreover, thelowest friction coefficient (0.323±0.02) could also be obtained under above-mentioned optimaldeposition parameters.(2)When the Cr-B-C coatings under optimal deposition parameters slid against Si3N4balls, thefriction coefficient increased first and then decreased with the normal load and sliding velocityincreasing. As combined with the wear rate of coatings, the best tribological properties were showedat normal load of50g and sliding velocity of6cm/s (the friction coefficient was about0.32).(3)The Cr-B-C coatings under optimal deposition parameters could enhance the anti-corrosioncapacity of Si in three solutions, and the best corrosion resistance was displayed in deionized water(Rp=29596k·cm2, Rct=8.131×107·cm2). However, the anti-corrosion capacity of Cr-B-Ccoatings should be further improved in simulated body fluid and seawater. The friction coefficient ofCr-B-C/Si3N4in three lubricants varied in the range of0.290to0.406, which was further lower than0.729under dry condition. But because of the corrosion effect of simulated body fluids and sea water,the Cr-B-C coatings confronted more serious wear.