High Temperature Insulating Properties of Aerosol Deposited Alumina Films

Title data

Schubert, Michael ; Leupold, Nico ; Kita, Jaroslaw ; Moos, Ralf:
High Temperature Insulating Properties of Aerosol Deposited Alumina Films.
2018
Event: 42nd International Conference and Expo on Advanced Ceramics and Composites : ICACC18 , 21.-26.01.2018 , Daytona Beach, Fla., USA.
(Conference item: Conference , Poster )

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Abstract in another language

Due to its very low electrical conductivity, alumina is a widely used material for high insulating films. As alumina is typically sintered above 1200 °C, low melting substrates like polymers or low-melting metals are excluded for applications. The Aerosol Deposition Method (ADM) is a novel ceramic coating technique. It allows manufacturing of dense ceramic films at room tempera-ture directly from ceramic powders without any high temperature sintering steps. Thereby, it is possible to produce high insulating alumina films on nearly all types of substrates. As known from liter-ature, the functional properties of aerosol deposited films directly after deposition are not completely identical with bulk samples. Nevertheless, annealing at temperatures around 500 °C can improve these properties. Therefore, it is necessary to know the electrical resistivity of aerosol deposited alumina films after deposition and after annealing. In this study, alumina films were deposited by ADM on a three-electrode setup with guard ring and the electrical conductivity was measured between 400 °C and 900 °C by direct current measurements according to ASTM D257 or IEC 60093. The measured conductivities correlate well with literature values and can be improved by annealing at 900 °C. The processed films show an even higher resistivity than conventional alumina substrates.