STRUCTURE AND PROPERTIES OF BORON COATING DEPOSITED BY MAGNETRON SPUTTERING AND MODIFIED BY ELECTRON BEAM

10.25712/ASTU.1811-1416.2022.04.013

Abstract

A technique for deposition of boron coatings on a surface using a planar DC magnetron with a target made from pure crystalline, non-electrically-conducting (under normal conditions) boron has been developed. The deposition rate of the boron coating with a magnetron discharge of 40 W power was about 3.5 nm/min. The coating was modified by an electron beam in a nitrogen atmosphere. The electron energy of the beam was 5 keV and a beam current density was 5 mA/cm². The parameters and properties of those coatings with a thickness of 1.1± 0.1µm, deposited on stainless steel 12Cr18Ni10Ti, are presented. Density, coating morphology, microhardness and Young's modulus of boron coatings were investigated. The effect of electron-beam modification on the coating surface was determined, and its elemental composition was studied. It was shown that the fraction of boron atoms in the coating varies from 70.7 to 88.5 at. %. Using X-ray diffraction analysis and transmission electron microscopy, it was found that the boron coating is amorphous-crystalline, i.e. contains crystalline inclusions with sizes of 3-7 nm in the volume of the amorphous phase. The presence of phases of borides and hexaborides of chromium in the subsurface regions was found.