Surface modification of titanium oxide in pulse-modulated induction thermal plasma

Citation
T. Ishigaki et al., Surface modification of titanium oxide in pulse-modulated induction thermal plasma, THIN SOL FI, 390(1-2), 2001, pp. 20-25
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
THIN SOLID FILMS
ISSN journal
0040-6090 → ACNP
Volume
390
Issue
1-2
Year of publication
2001
Pages
20 - 25
Database
ISI
SICI code
0040-6090(20010630)390:1-2<20:SMOTOI>2.0.ZU;2-4
Abstract
Recently, it was reported that RF induction plasma of a purse-modulated ope rating mode had been successfully generated, for the first time, at a suffi ciently high electric power level for materials processing. The unique cond itions in the plasma, such as a non-equilibrium situation at the instance o f pulse-on and -off and the increase of chemically reactive radical species , as well as the time-dependent change of plasma temperature, is expected t o offer the unique physico-chemical conditions necessary for materials proc essing. As the first step of the work directed to materials processing, the thermal and chemical interactions between plasma and solid materials were examined for both cases of pulse-modulated and continuous modes. Green comp acts of titanium dioxide (TiO2), whose characteristics strongly depend on t he formation of lattice defects and the incorporation of hydrogen, were tre ated in Ar-H-2 plasma of continuous and pulse-modulated generation modes. T he oxide disks were placed at the downstream of plasma flow. The sample pos ition and the plasma generation pressure were changed as processing paramet ers. The plasma-treated specimens were characterized by X-ray diffractometr y and the hydrogen content was measured. The plasma treatment gave a therma l effect, rather than a chemical one, on the surface of oxide specimens. Th e oxides were thermally reduced by the plasma treatment and showed a change of color at the surface, while XRD did not show a change of crystal struct ure. Comparing specimens treated in the pulse-modulated plasma with those t reated in the continuous plasma, the disk specimens had less of a thermal e ffect on the plasma. (C) 2001 Elsevier Science B.V. All rights reserved.