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Comparison of the electrical properties of Al3O3 sprayed coatings from feedstock powders and aqueous suspensions

 
: Toma, F.-L.; Scheitz, S.; Langner, S.; Berger, L.-M.; Sauchuk, V.; Kusnezoff, M.

Deutscher Verband für Schweißen und Verwandte Verfahren e.V. -DVS-; The Thermal Spray Society -TSS-; International Institute of Welding -IIW-:
ITSC 2011, International Thermal Spray Conference & Exposition. CD-ROM : Abstracts; Including manuscripts on CD-ROM, of the conference in Hamburg on September 27 - 29, 2011 in the context of DVS Congress and DVS Expo
Düsseldorf: DVS Media, 2011 (DVS-Berichte 276)
ISBN: 3-87155-268-2
ISBN: 978-3-87155-268-7
ISSN: 0418-9639
pp.a227/1-a227/6
International Thermal Spray Conference & Exposition (ITSC) <2011, Hamburg>
Deutscher Verband für Schweißen und Verwandte Verfahren (DVS Studentenkongress) <2011, Hamburg>
English
Conference Paper
Fraunhofer IKTS ()
Fraunhofer IWS ()

Abstract
In this paper the characteristics (microstructure, phase compns.) and elec. insulating properties of thermally sprayed alumina coatings produced by suspension-HVOF (S-HVOF) process and conventional HVOF spray method are compared. The elec. resistance (elec. resistivity) and dielec. strength were investigated using DC-elec. resistance measurements, electrochem. impedance spectroscopy (EIS) and dielec. breakdown test. The elec. resistance was detd. at room temp. at different relative air humidity (RH) levels, from 6% RH up to 97% RH. Differences in the elec. insulating properties due to the different coating characteristics are discussed. The suspension-sprayed Al2O3 coatings showed better elec. resistance stability at high humidity levels (> 75% RH), which could be explained by a spec ific microstructure and retention of a higher content of a-Al2O3. Nonetheless, the values of dielec. breakdown voltage and dielec. strength recorded for suspension sprayed coatings were lower than those of HVOF coatings.

: http://publica.fraunhofer.de/documents/N-209990.html