Nuclear Technology / Volume 169 / Number 3 / March 2010 / Pages 271-278
Technical Paper / Materials for Nuclear Systems
Experimental results of the diffusion of chromium(II) in natural diamond powder (Cr:NDP) of 60 to 80 m using modified field enhanced diffusion with optical activation (MOD:FEDOA) are presented. MOD:FEDOA is a promising technique for incorporation of impurities into wide band gap powders in the nanometer-to-micrometer range. MOD:FEDOA uses a combination of thermal diffusion with electrical potential, thermal ionization, and optical ionization combined in one setup, developed as a primary tool for the diffusion of various impurities into diamond. The effect of the diffusion process was studied with micro-Raman and a scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (EDS). Raman analysis shows an increase in disorder in the treated sample. The main Raman peak in diamond was identified at 1332 cm-1 , indicating that the sample maintained the diamond crystal structure after the incorporation of chromium (Cr). Secondary electron images show an increase in surface roughness, rounding of crystalline faces by oxidation, and microfractures in the treated diamond powder. Backscattered electron images revealed deposition of impurities on the surfaces of diamonds after doping. EDS and Raman shift confirmed the presence of Cr in diamond particles after treatment. Other impurities, Si and O, were also identified by EDS and micro-Raman. This work presents strong evidence that Cr can be incorporated into natural diamond. It also suggests that Cr:NDP is suitable for applications in nuclear industries such as radiation shield and cladding material. Further, this work offers the possibility to develop novel diamond-based materials that can be used in the nuclear field.