Abram Lyutovich

(Cr-Al) bi-layer coatings obtained by ion assisted EB PVD on C/C-SiC composites and Ni-based alloys

Abstract Cr and (Cr–Al) bi-layers were deposited on carbon reinforced composites (C/C–SiC) and Ni-based alloy substrates by ion assisted EB PVD. The ion current in the substrate region was measured using a special ion detector. Surface morphology of the films was studied using optical, scanning electron, and atomic force microscopy. The variation of the deposited elements was determined by means of a line-scan electron probe on the cross-sections of the samples. Interdiffusion of the deposited elements at the interface was observed. It could have been caused by ‘ion mixing’ during the deposition process. X-ray diffraction (XRD) investigations show the formation of intermetallic compounds Cr3Si andCrAl. Comparative measurements proved that the microhardness of Cr layers on Ni-base alloys, obtained by ion assisted deposition was higher than that of Cr layers deposited without the acceleration of ions.

Characterisation of the generation of ions in electron beam evaporator for the control of metal deposition processes

By means of a specially designed ion detector, the dependence of ion current at the substrate on the electron emission current of the e-gun and bias-potential for the evaporation of Ti, Al, and Cr is investigated. It is illustrated by distinction of morphology of metal films, that the control of the parameters of bombarding ions can be a key for the control of the ion-assisted electron beam physical vapour deposition (EB-PVD) process.