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Kim, K. R.

Paper Title Page
WEPCH183 Enhancement of Mechanical Properties of High Chromium Steel by Nitrogen Ion Implantation 2361
 
  • B.S. Kim, S.-Y. Lee
    Hankuk Aviation University, KyungKi-Do
  • K. R. Kim, J.S. Lee
    KAERI, Daejon
  
  This article reports the study of mechanical properties of high chromium steel after N-ion implantation. The samples are implanted with 120keV N-ion at doses ranging from 1x1017ions/square cm to 4x1018ions/square cm. Mechanical properties of implanted samples are compared with those of Cr-plated samples. The compositions of the N-ion implanted layer were measured by Auger electrons spectroscopy(AES). Their mechanical properties as a function of N-ion doses were characterized by nano-indentation, sliding and impact wear tests. The results reveal that the hardness and mechanical properties of ion implanted samples were found to depend strongly on the ion doses. The hardness of the N-ion implanted sample with 2x1018ions/? was measured to be approximately 9 GPa, which is approximately 2.3 times higher than that of un-implanted sample (H=3.8 GPa). Also wear properties of N-ion implanted samples with 2x1018ions/? were largely improved ;compared to the Cr-plated samples, the width of wear track and friction coefficient developed on the N-ion implanted samples are about 60% and 40% smaller, respectively.  
WEPCH184 Mechanical Properties of WC-Co by Nitrogen Ion Implantation: Improvement of Industrial Tools 2364
 
  • Y. Noh, B.Y. Kim, K. R. Kim, J.S. Lee
    KAERI, Daejon
  
  Ion implantation of WC-Co has been widely investigated for the improvement of wear resistance, but rarely for friction behavior. Although friction is closely associated with wear, more factors influence friction than wear, and low wear does not generally lead to low friction w6x. Therefore, we focus our study on the effects of ion implantation on the mechanical properties in WC-Co cermets, with particular interest in tool industry applications.  
WEPCH189 Design of the 20 MeV User Facilities of Proton Engineering Frontier Project 2376
 
  • K. R. Kim, Jae-Keun Kil. Kil, C.-Y. Lee, J.S. Lee, B.-S. Park
    KAERI, Daejon
  
  The user facilities of PEFP (Proton Engineering Frontier Project) was designed. It is composed of two beamlines at the first stage and has possibility of expansion to five beamlines. One is low flux beamline for the technology developments in the fields of biological and space sciences and the other is high flux beamline for the utilization in the fields of nano and material sciences. The flux density is 1E+8~1E+10 protons/cm2-sec and 1E+10~1E+13 protons/cm2-sec each. The available energy range is 5~20MeV and the irradiation area is larger than 10cm in diameter with uniformity more than 90% for both. The specifications of these beamlines mentioned above were decided on the basis of result of user demand survey and operation experience of 45MeV proton beam test beamline installed at the MC-50 cyclotron of KIRAMS (Korea Institute of Radiological and Medical Science). The key components of these beamlines are bending magnets, magnetic quadrupole doublet or triplet, collimators, scanning magnets, target stage with water cooling system, degrader for energy control, scattering foils for flux control, etc. The beam optics was calculated using TRANSPORT and TRACE 3D simulation code.  
WEPCH190 A Ridge Filter for 36 MeV Proton Beam Applied to BT and ST 2379
 
  • Y.K. Lim, K. R. Kim
    KAERI, Daejon
  
  We designed a ridge filter to obtain a uniform depth-dose distribution as well as to deliver high linear energy transfer along the depth of a target for 36MeV proton beam. Aluminum was chosen as the material of the filter to reduce the radioactivity induced by proton irradiation. The designed ridge filter has a continuous cross-sectional line shape of ridges so that the smoothly varying depth-dose distribution can be maintained before the distal fall-off for lower proton energy than 36MeV. The height of the ridge is 6 mm, its period is also 6 mm and the minimum thickness is 0.3 mm. A Monte Carlo simulation code, MCNPX 2.5.0., was used to calculate the dose distributions. The width of the calculated uniform dose region was 11 mm for 36MeV proton beam in a water-equivalent sample.