PROFILING THE RESIDUAL-STRESS AND INTEGRAL STRAIN DISTRIBUTION IN YTTRIUM IMPLANTED TITANIUM NITRIDE

The residual stress in ceramic materials is affected by ion implantati on down to depths well below the zone where the implant resides, e.g. the implantation of TiN with Ni-Ti dual or nitrogen ions has been show n to reduce the residual stress down to depths of the order of 0.40-1. 6 mu m. In the present work, the effect of implantation into TiN with the large, heavy ion, yttrium on the residual stress is measured over the wider x(e) range 0.10-2.6 mu m to include the implanted zone. ions from a vacuum are source were accelerated at voltages of 35 and 70 kV implanted to a dose of 10(17) ions per square centimetre. The results show that a high tensile stress is developed in the implanted zone ac companied by a wide distribution of strain, indicative of local disord er. Below this, in the implantation affected zone, the stress shows a profile, tensile down to a depth of some 2 mu m, and becoming compress ive again below that. The results confirm that ion implantation causes the residual stress in the plane of the coating to become more tensil e down to depths well beyond the implanted zone. (C) 1997 Elsevier Sci ence Ltd. All rights reserved.