NITROGEN IMPLANTATION INTO STEEL TOOLS

Implantation consists in doping the treated material by means of bombarding its surface with ions produced in an ion source and accelerated in vacuum across a potential difference of several tens to a few hundred kilovolts. At the end of the acceleration path the particles travel within a beam at a velocity of a few hundred to a few thousand kilometres per second. The beam strikes the treated material surface (target) with a kinetic energy sufficient to penetrate its bulk to distances on the order of a fraction of one micrometer. Since the process is kinetic in nature, practically any material may be doped with any element. Highly energetic ions also etch the treated material surface (so-called sputtering), but high dopant concentrations (even as high as 50%) are possible to obtain in thin surface or sub-surfece layers of the target (depending on the ion mean energy and the target material, the implanted layer may be buried below the surface). The target temparature may be freely regulated.

Implantation is routinely used in the microelectronics industry to dope semiconductor wafers: around 3000 industrial implanters are currently in use worldwide. Systematic research on modifying properties of other materials have been carried out for more than 25 years. Improvement of such material parameters as wear resistance, corrosion resistance, friction coefficient etc. was being sought.

Most of the so-far conducted research and the implemented applications have dealt with implantation of nitrogen into steels, non-ferrous metal alloys and carbides. The most characteristic features of this treatment methode include:

Ion implantation method of improving tools or machine parts is cost-effective only if a tool/machine part must be replaced as soon as several micrometers of its surface gets worn and the tool/machine part is expensive or else shutting down the production line to replace the tool/machine part is expensive. Typical examples include: precision cutting tools, knifes used in paper industry, plungers, dies, etc.

Our Institute offers nitrogen implantation into steel tools and machine parts. All relevant information may be obtained from the staff of the Ion Implantation Laboratory:
NAME PHONE FAX E-MAIL
Zbigniew Werner (22) 718-0545 (22) 779-3481 wernerz@ipj.gov.pl
Jacek Jagielski 0-502 095 524 (22) 779-3481 jagiel_j@sp.itme.edu.pl
Jerzy Piekoszewski (22) 718-0603 (22) 779-3481 jpiekosz@ipj.gov.pl

We invite you to use our service.

OUR LABORATORY

The implanter may accelerate gaseous ions to an energy in the range up to 80 keV. Maximum beam current is 1 mA. The target chamber diameter 800 mm and length 1200 mm makes possible to implant elements with maximum dimensions 300x350 mm and weight up to 50 kg. Long sleeves may be additionally attached to the chamber sides, which enables implantation of narrow, prolonged elements up to 150 cm long and 13 cm wide (e.g. paper knives).

Surface of the to-be-implanted element must be suitably prepared: all foreign layers (paint, anti-corrosion protection, oil, grease) must be removed prior to the treatment. We have a suitable washing/de-greasing equipment in our laboratory. Our mechanic shop may produce necessary holders for items of a complex shape. The items may be scanned along two axes, rotated, and inclined during the treatment, which provides for precise implantation of all critical surfaces of the treated tool/machine part. During the treatment the ion energy, the implanted dose and the treated item temperature are constantly monitored and controlled.

Our Laboratory is also equipped with some instruments necessary to verify basic tribological effects of the implantation treatment, including a pin-on-disc wear tester and a Hommel-Werke precision profilometer.

We have also at our disposal some advanced characterization techniques, including EDX microanalyser, scanning electron microscope, Mössbauer spectrometer, X-ray diffractometer, Auger electron spectrometer, secondary ion spectrometer, and atomic force microscope. Direct link between the conducted scientific research and industrial practice, as well as many-year-long experience of our staff guarantees a high quality and reliability of our service.

AN EXAMPLE OF APPLICATION

Beneficial effects have been for example obtained for paper cutting knives. Long guillotine knives as well as short knives for cutting newspapers were treated. Operational lifetime of the latter has increased almost 7 times. After 150 hours of operation just about 3.5 micrometres of the treated knife has been worn i.e. a thickness much beyond the implanted ion range. However, the wear rate was still much lower than that in the un-treated knife (4 times slower). It means that beneficial effects of a short range implantation treatment may in fact reach to a much greater depth into the material bulk.