Ageing effect of DBD activated ceramic powders: the impact of storage humidity on the electrophoretic deposition rate
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| Year of publication | 2019 |
| Type | Conference abstract |
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| Description | Electrophoretic deposition (EPD) of plasma pre-treated Al2O3 powders results in ceramic layers of substantially improved deposit homogeneity. To evaluate the practical applicability of this phenomenon, we report on the magnitude and dynamics of undesired gradual deterioration on plasma treatment – the ageing effect. Powder samples were treated by diffuse coplanar dielectric barrier discharge (DBD) and sequentially evaluated for their EPD performance for the time span of 30 days. Two sets of powder samples were evaluated. The first was stored in arid environment of 23% RH, the second in humid air of 86% RH. The storage in arid environment resulted in a slow but gradual decline of deposition rate. However, the uniformity of deposited layers remained unaffected. Samples stored in humid environment exhibited a substantially more complex behavior. Already after one week the effect of plasma treatment had disappeared, and the deposition polarity had to be changed from anodic to cathodic. Afterwards gradual increase of deposition rate was observed until the final recurrent decline at fourth week. The results point out the importance of water molecules controlled secondary processes on the treated powder surface. |
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