X-RAY AND NEUTRON SMALL-ANGLE SCATTERING FROM AMORPHOUS CHROMIUM-CARBON-HYDROGEN-ALLOYS

Amorphous Cr80C10H10 and Cr80C10D10 films were produced by electrodepo sition and investigated by X-ray and neutron small angle diffraction. The surface scattering was separated by the variation of the thickness (X-rays) and by the immersion technique (neutrons). The amorphous spe cimen consists of a Cr-matrix which contains segregates in which the H atoms are replaced by C atoms or vice versa. The diameter of the segr egates is 12 nm and the specimen consists of about 25 vol.% segregates . A phase separation in two amorphous phases, one consisting of a C-en riched chromium-carbide, the other of pure Chromium, occurs after anne aling the alloys at 200 degrees C for a few minutes, Longer annealing time causes a continuous crystallization of the amorphous Cr-phase. Th e correlation length for the amorphous Cr-phase is approximately 7 nm. The event of phase separation may explain the increase in hardness an d corrosion resistance of the alloys observed in previous research. (C ) 1997 Published by Elsevier Science B.V.