Synthesis of SiAlCO Coatings by Thermal Anodic Evaporation of Al and Decomposition of Tetraethoxysilane in an Arc Discharge with a Sectional Anode

Abstract

For the first time, SiAlCO polymer derived ceramic coatings were obtained by thermal anodic evaporation of aluminum in a low-pressure arc discharge vapor–gas medium Ar + O₂ + Al + tetraethoxysilane (TEOS). It is shown that a gas discharge system with a sectional anode functions stably in a chemically active medium in a wide range of discharge currents and partial pressures of reactive components. Plasma spectra have been studied by optical emission spectroscopy under conditions of metal evaporation and decomposition of the organosilicon precursor TEOS. The influence of the Al vapor flow, arc discharge current and fluxes of reactive components on the intensification of the decomposition of TEOS and O₂ dissociation is shown. This method provides both deep decomposition of the organosilicon precursor and a high degree of oxygen dissociation (up to 45%). Trial SiAlCO coatings with a homogeneous structure and good adhesion on a metal substrate with a thickness of 4.5–7 μm were obtained with a deposition rate of up to 5–7 μm/h, the hardness of SiAlCO coatings reached 10 GPa. The elemental composition and surface morphology of the coatings were studied using the SEM method, and the effect of deposition parameters on their chemical composition was also shown.