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Ti-B-N coatings of variable composition have been sputter-deposited from a heterogeneously composed Ti-BN target, consisting of a boron nitride base plate on which small Ti platelets were regularly arranged. By varying the number of platelets the concentration ratio c(Ti)/c(B) of the target and therefore also of the coating could easily be varied. Inhomogeneities in the chemical composition were in the +/- 4 % range. Very hard coatings of up to 55 GPa were obtained by sputtering with a substrate bias of -150 V at a substrate temperature of 400 C. The hardness maximum was found at a chemical composition where both the TiB(2) and the TiN phases coexist in equal concentrations. All coatings show very broad diffraction peaks indicating average grain sizes in the nanometre range where the Hall-Petch relation is no longer valid. With coatings composed of very small grains an inverse Hall-Petch effect was observed. The tribological performance of the Ti-B-N coatings is promising; however, in general it is worse than that observed with TiN coatings. The main reason seems to be the relatively low cohesive strength of the material.

Additional information

Authors: HAMMER P ET AL., JRC Ispra (IT)
Bibliographic Reference: Paper presented: International Conference on Metallurgical Coatings and Thin Films, San Diego (US), April 25-29, 1994
Availability: Available from (1) as Paper EN 38158 ORA
Record Number: 199510291 / Last updated on: 1995-03-08
Original language: en
Available languages: en