Abstract
The atmospheric-pressure plasma spray (APS) of tungsten coating was performed using tungsten carbide (WC) powder by means of DC plasma torch equipped with a stepped anode nozzle as a potential method of W coating on graphite plasma-facing component of fusion reactors. This nozzle configuration allows Helmholtz oscillation mode dominating in APS arc fluctuation, and the variation of auto-shroud effect with Helmholtz oscillation characteristics can be investigated. Tungsten coating made from WC powder has lower porosity and higher tungsten purity than that made from pure tungsten powder. The porosity and chemical composition of coatings were investigated by mercury intrusion porosimetry and x-ray photoelectron spectroscopy, respectively. The purity of tungsten coating layer is increased with the increasing frequency of Helmholtz oscillation and the increasing arc current. The modulation of Helmholtz oscillation frequency and magnitude may enhance the decarburization of WC to deposit tungsten coating without W-C and W-O bond from WC powder.
| Original language | English |
|---|---|
| Pages (from-to) | 756-763 |
| Number of pages | 8 |
| Journal | Journal of Thermal Spray Technology |
| Volume | 22 |
| Issue number | 5 |
| DOIs | |
| State | Published - Jun 2013 |
| Externally published | Yes |
Bibliographical note
Funding Information:This study was supported by Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (MEST) under the Project No. NRF-2012-0000578
Keywords
- Helmholtz oscillation
- atmospheric-pressure plasma spray (APS)
- auto-shroud effect
- in-flight oxidation
- plasma facing component (PFC)
- tungsten carbide (WC)