High-Temperature Electrical Insulation Behavior of Alumina Films Prepared at Room Temperature by Aerosol Deposition and Influence of Annealing Process and Powder Impurities
| Autor: | Jaroslaw Kita, Michael Schubert, Ralf Moos, Nico Leupold, Jörg Exner |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Materials science Annealing (metallurgy) Direct current 02 engineering and technology engineering.material Conductivity 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Surfaces Coatings and Films Coating Impurity Electrical resistivity and conductivity visual_art 0103 physical sciences Materials Chemistry engineering visual_art.visual_art_medium Cubic zirconia Ceramic Composite material 0210 nano-technology |
| Zdroj: | Journal of Thermal Spray Technology. 27:870-879 |
| ISSN: | 1544-1016 1059-9630 |
| DOI: | 10.1007/s11666-018-0719-x |
| Popis: | Alumina (Al2O3) is a widely used material for highly insulating films due to its very low electrical conductivity, even at high temperatures. Typically, alumina films have to be sintered far above 1200 °C, which precludes the coating of lower melting substrates. The aerosol deposition method (ADM), however, is a promising method to manufacture ceramic films at room temperature directly from the ceramic raw powder. In this work, alumina films were deposited by ADM on a three-electrode setup with guard ring and the electrical conductivity was measured between 400 and 900 °C by direct current measurements according to ASTM D257 or IEC 60093. The effects of film annealing and of zirconia impurities in the powder on the electrical conductivity were investigated. The conductivity values of the ADM films correlate well with literature data and can even be improved by annealing at 900 °C from 4.5 × 10−12 S/cm before annealing up to 5.6 × 10−13 S/cm after annealing (measured at 400 °C). The influence of zirconia impurities is very low as the conductivity is only slightly elevated. The ADM-processed films show a very good insulation behavior represented by an even lower electrical conductivity than conventional alumina substrates as they are commercially available for thick-film technology. |
| Databáze: | OpenAIRE |
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