Title

The Role of Bulk Nucleation in the Formation of Crystalline Cordierite Coatings Produced by Air Plasma Spraying

Abstract

Near stoichiometric cordierite (2MgO-2Al2O3-5SiO2) glasses doped with 6.3, 8.3 and 10.1 weight percent (wt.%) TiO2 were plasma sprayed onto SiO2-based refractory concrete substrates. Substrate temperatures were controlled such that the maximum surface temperature exceeded the crystallization temperature during plasma spraying. Only the cordierite powders containing 8.3 and 10.1 wt.% TiO2 produced crystalline coatings. For compositions with less than 8 wt.% TiO2 the crystallization is believed to be controlled by surface nucleation at imperfections. Surface nucleation became more difficult with increasing preheat temperature and is related to improved wetting between coating splats. Bulk nucleation-controlled crystallization was observed at compositions above 8 wt.% TiO2 and the presence of Al2TiO5 was detected in these compositions.

Department(s)

Materials Science and Engineering

Sponsor(s)

Boeing Company. Commercial Airplane Group

Keywords and Phrases

Plasma Spray

Library of Congress Subject Headings

Cordierite
Crystallization

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2003 Elsevier, All rights reserved.


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