Combined Effect of Ion Implantation and Ion Beam Mixing on Metal Surface
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COMBINED EFFECT OF ION IMPLANTATION AND ION BEAM MIXING ON METAL SURFACE Tian Wei, Peng Tau Wuhan Iron and Steel University, Wuhan, Hubei,
China
ABSTRACT The article is an account of the development of a new technique to improve the surface properties of materials by ion beam bombardment combined effect of ion implantation and ion beam mixing. Ti+ ion beam has been used to mix the surface of Cr-deposited on to Fe or to implant Ti+ into the surface of Fe. By comparing the electrochemical properties, it has been shown that the corrosion resistance of Cr-deposited Fe surface mixed with Ti + ion beam is much better than that of Ti+ ion implanted Fe surface, the critical current density Ic and minimum anodic passive current density Im are decreased by one order of magnitude in deacrated 1M CH COONa-CH COOH solution (pH 7.3, 25°C). AES and SIMS observation show Nhat the gombined effect of implantation and mixing has been really achieved.
INTRODUCTION The properties of materials, such as hardness, strength, fatigue, wear resistance and corrosion resistance, oxidation at elevated temperature, can be improved by ion implantation or ion beam mixing. A series of useful results have been reported. By choosing the substrate and suitable implanted Ion or the appropriate conditions of bombardment new surface alloys can be formed, including various alloys with equilibrium phases, metastable phases and a number of amorphous alloys. And it has been shown that the Gaussian distribution dominates the concentration of implanted ions. Novel ion beams have been used to mix the film and the substrate and to form the new surface alloys. These amorphous alloys, tiny crystals and metastable phases can be obtained after high dose ion beam mixing. We take advantage of both of ion implantation and ion beam mixing and aim to investigate the combined effect on further amelioration of the aqueous corrosion resistance of iron, so as to inquire into a new approach towards developing innovated corrosion - resistant surface alloys. (1-3) PREPARATION OF TEST SAMPLES AND CONTROL OF CONDITIONS FOR ION BEAM BAMBARDMENT Sample ($lOX5mm) were prepared from pure iron (composition:O.014%C O.012%Si, 0.26"Mn, 0.007%P, o.oo4%S, 0.001%Al and Fe), after annealing and metallographically abraded and polished down to lu with diamond paste, and then cleaned and dried. The sample were put into vacuum chamber (iXiO- torr) for the deposition of a pure chromium film (-4001). Thickness of films were determined by a microbalance with a reading error no more than 10- 5 g. The Cr-de osited Fe samples and the pure iron samples were bombarde by a T' ion biam at the energy level 300Kev and a dose of 1X1019, 2X101t, 5X10•6Ti+/cmc respectively, the beam urrent density being 11.5-17.5MA/cm2 . The vacuum is lower than 1XIO- 2 torr during implantation. There were more than ten samples being treated in order to assure as far as possible a good reproductibility. Mat. Res. Soc. Symp. Proc. Vo. 100. 01908 Materials Research Society
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Table 1. Main Efectrochemical Parameters ubstr
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