Development of titanium diboride coatings deposited by PACVD

TiB2 appears to be a promising material for the wear protection in various tribological systems, e.g. the diecasting of Al. This study focuses on the development of titanium boride coatings deposited by PACVD, a deposition me thod which is most suitable for the coating of substrates with complex shap es. All layers analysed are very smooth and exhibit a quasi-amorphous fract ure surface. XRD and TEM analysis indicate a nanocrystalline structure with grain sizes in the order of 2 nm. The diffraction patterns can well be cor related to titanium diboride. WDS reveals an over stoichiometric B/Ti ratio . The layer hardness reaches the value of 33 GPa and the critical load in s cratch tests rises to 35 N. Neither 100Cr6 nor Al as a counterpart in pin-o n-disk tests leads to wear of the coating. (C) 2000 Elsevier Science B.V. A ll rights reserved.