SURFACE MODIFICATION OF POWDER PARTICLES BY PLASMA DEPOSITION OF THINMETALLIC-FILMS

Iron powder particles with a mean diameter of about 2 mu m have been c harged and trapped in an r.f. plasma with an electron density in the o rder of 10(8)-10(9) cm(-3). The iron particles were coated with a surr ounding aluminum layer by d.c. magnetron sputtering during their confi nement. The plasma parameters at r.f. and magnetron operation were con firmed by Langmuir probes, self-excited electron resonance spectroscop y and energy-resolved mass spectrometry, respectively. The coated powd er particles were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results of the surface analysis indicate that coating iron powder particles with a close and compact aluminum film by d.c. magnetron sputtering while they are tra pped in a weak r.f. plasma is an attractive procedure for powder modif ication. (C) 1998 Elsevier Science S.A. All rights reserved.