AVS 45th International Symposium
    Vacuum Metallurgy Division Monday Sessions
       Session VM-MoA

Paper VM-MoA7
Improvement of Tribological Properties of Pure Aluminium by Isotropic ECR Ion Implantation

Monday, November 2, 1998, 4:00 pm, Room 328

Session: Plasma Assisted Surface Treatments and Coatings
Presenter: D. Popovici, INRS-Energie et Materiaux, Canada
Authors: D. Popovici, INRS-Energie et Materiaux, Canada
B. Terreault, INRS-Energie et Materiaux, Canada
A. Sarkissian, INRS-Energie et Materiaux, Canada
B.L. Stansfield, INRS-Energie et Materiaux, Canada
R.W. Paynter, INRS-Energie et Materiaux, Canada
G.G. Ross, INRS-Energie et Materiaux, Canada
Correspondent: Click to Email
There are serious limitations to using Al and its alloys for light-weight components: in the absence of lubrification they have relatively poor tribological properties such as high friction and wear rates in sliding contact. These characteristics are due to a low flow stress of the metal and the brittleness of the aluminum oxide. The improvement of the tribological characteristics of Al, by conventional and high energy(@>=@50keV)nitrogen and oxygen implantation has already been demonstrated. In the case of N@super +@ implantation the increase in hardness is due to the formation of an AlN film. Because relatively high substrate temperatures(400-500°C)are necessary when conventional plasma nitriding is used, the difference in the thermal expansion coefficients of Al and AlN leads to microcracks in the AlN coatings. In the case of O@super +@ implantation, the formation of a maetstable phase is followed by a thermal annealing, inducing the synthesis of nanoprecipitates of Al@sub 2@O@sub 3@ which are dense enough to pin all dislocations. In this study, we used a low temperature, low energy (30keV)isotropic PBII whith an ECR plasma source, to investigate and compare near-surface N@super +@ and O@super +@ implantation into high purity (99,99%) Al. The surface chemical composition and chemical bond formation of the implanted Al layer were investigated by AES, XPS and RBS. The surface tribological properties, structure and cristallinity were analysed by lateral force microscopy (LFM), nanoindentation and XRD. Implantation depth profiles were determined for several implantation times and sample-plasma geometries. The profiles were found to agree with TRIM simulations that supposed a monoenergetic ion source. The implantation of monoenergetic ions by our PBII technique, using a high frequency pulsed plasma and a steady high voltage for ion acceleration, allows for a precise tailoring of the implantation depth profile.