772 Nuclear Instrnments and Methods in Physics Research B59/60 (1991) 772-777 North-Holland Improvement of corrosion resistance of M50 bearing steel by implantation with metal ions * B.R. Nielsen and B. Torp Danfysik A/S, DK-4040 Jyllinge, Denmark C.M. Rangel, M.H. Simplicio and A.C. Consiglieri Dept. of ~urerials Technofo~, LNETI, P-1699 L&boa, Portugal M.F. DaSilva and F. Paszti Dept. of Physics. LNETI, P-2685 Sacavem, Portugal J.C. Soares Cenrre of Nuclear Physrcs, University of Lisbon, P-1699 Lisboa, Portugal A. Dodd and J. Kinder Bearings Research Centre, RffP Bearings Ltd., Newark NG24 -?IF, England. UK M. Pitaval and P. Thevenard Dept. of Ph.vsic.q, ~ni~~ersit~ de Claude Bernard, F-69622 Villeurbarme, France R.G. Wing kfateri& Laboroto? L2. Roiis Royce PLC. Watford WD2 7BZ, England, [iK With the overall objective to improve the service life and reliability of gas turbine engine bearings by increasing their corrosion resistance and rolling contact fatigue life a collaborative project under the EEC BRITE/EURAM programme has been initiated. The project is aimed at developing an ion implantation technique to implant bearing components with metallic species and to optimise tht process particularly for applications where salt-water contamination of the lubricating oil might occur. Prior to implanting into bearing components. test specimens of MS0 bearing steel implanted with Cr+ and Ta+ at several doses have been character&d by various techniques. This article reports on the implantation work, the RBS and NRA analysis for depth profiling and independent dose measurement, and the corrosion resistance measurements which have been performed in order to determine the optimum treatment. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA 1. Introduction The service life of gas turbine engine bearings is often limited by corrosion, which causes excessive wear of the bearing components. It has been proven that even minor corrosion pitting of the bearing raceways reduces life considerably. The corrosion problems are particu- * This project is funded by the EEC under BRITE/EU~AM contract no. RIlB-284. larly important in situations where a risk of salt-water contamination of the lubricating oil exists. such as in carrier-based aircrafts and helicopters in service at oil rigs. The fact that up to 80% of the bearings are removed from service due to corrosion problems em- phasises the importance of improving corrosion resis- tance of these parts for safety reasons as well as from economical considerations. With the overall objective to improve the service life and reliability of gas turbine engine bearings by increas- ing their corrosion resistance and rolling contact fatigue 0168-583X/91/$03.50 6 1991 - Elsevier Science Publishers B.V. (North-Holland)