Dielectric Breakdown Strength of Thermally Sprayed Ceramic Coatings: Effects of Different Test Arrangements
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Dielectric Breakdown Strength of Thermally Sprayed Ceramic Coatings : Effects of Different Test Arrangements. / Niittymäki, Minna; Lahti, Kari; Suhonen, Tomi; Metsäjoki, Jarkko.
In: Journal of Thermal Spray Technology, Vol. 24, No. 3, 2015, p. 542-551.Research output: Contribution to journal › Article › Scientific › peer-review
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TY - JOUR
T1 - Dielectric Breakdown Strength of Thermally Sprayed Ceramic Coatings
T2 - Effects of Different Test Arrangements
AU - Niittymäki, Minna
AU - Lahti, Kari
AU - Suhonen, Tomi
AU - Metsäjoki, Jarkko
N1 - EXT="Metsäjoki, Jarkko"
PY - 2015
Y1 - 2015
N2 - Dielectric properties (e.g., DC resistivity and dielectric breakdown strength) of insulating thermally sprayed ceramic coatings differ depending on the form of electrical stress, ambient conditions, and aging of the coating, however, the test arrangements may also have a remarkable effect on the properties. In this paper, the breakdown strength of high velocity oxygen fuel-sprayed alumina coating was studied using six different test arrangements at room conditions in order to study the effects of different test and electrode arrangements on the breakdown behavior. In general, it was shown that test arrangements have a considerable influence on the results. Based on the results, the recommended testing method is to use embedded electrodes between the voltage electrode and the coating at least in DC tests to ensure a good contact with the surface. With and without embedded electrodes, the DBS was 31.7 and 41.8 V/µm, respectively. Under AC excitation, a rather good contact with the sample surface is, anyhow, in most cases acquired by a rather high partial discharge activity and no embedded electrodes are necessarily needed (DBS 29.2 V/µm). However, immersion of the sample in oil should strongly be avoided because the oil penetrates quickly into the coating affecting the DBS (81.2 V/µm).
AB - Dielectric properties (e.g., DC resistivity and dielectric breakdown strength) of insulating thermally sprayed ceramic coatings differ depending on the form of electrical stress, ambient conditions, and aging of the coating, however, the test arrangements may also have a remarkable effect on the properties. In this paper, the breakdown strength of high velocity oxygen fuel-sprayed alumina coating was studied using six different test arrangements at room conditions in order to study the effects of different test and electrode arrangements on the breakdown behavior. In general, it was shown that test arrangements have a considerable influence on the results. Based on the results, the recommended testing method is to use embedded electrodes between the voltage electrode and the coating at least in DC tests to ensure a good contact with the surface. With and without embedded electrodes, the DBS was 31.7 and 41.8 V/µm, respectively. Under AC excitation, a rather good contact with the sample surface is, anyhow, in most cases acquired by a rather high partial discharge activity and no embedded electrodes are necessarily needed (DBS 29.2 V/µm). However, immersion of the sample in oil should strongly be avoided because the oil penetrates quickly into the coating affecting the DBS (81.2 V/µm).
KW - AlO
KW - breakdown strength
KW - coating
KW - dielectric
KW - HVOF
KW - thermal spraying
U2 - 10.1007/s11666-014-0211-1
DO - 10.1007/s11666-014-0211-1
M3 - Article
VL - 24
SP - 542
EP - 551
JO - Journal of Thermal Spray Technology
JF - Journal of Thermal Spray Technology
SN - 1059-9630
IS - 3
ER -