Electron probe microanalysis of nickel and chromium in Fe-C-Ni and Fe-C-Cr alloys borided at 850° C

Abstract

Laboratory-cast iron-carbon alloys containing relatively low contents of nickel and chromium, respectively, were powder borided at 850° C for 4, 8 and 15 h. The redistribution of nickel and chromium between boride coatings and substrates was studied by metallography and electron probe microanalysis. It was shown that both the elements enter iron borides, substituting for iron. Chromium, however, concentrates in the coatings depleting the underlying unborided matrix, while nickel preferentially concentrates beneath the boride coatings, allowing low-Ni iron borides to be formed.