Journal of Inorganic Materials ›› 2010, Vol. 25 ›› Issue (5): 527-531.DOI: 10.3724/SP.J.1077.2010.00527

• Research Paper • Previous Articles     Next Articles

Influence of AlPO4 Crystalline Structure on Microstructure and Antioxidation Property of Multi-layer Coating

YANG Wen-Dong, HUANG Jian-Feng, CAO Li-Yun, XIA Chang-Kui   

  1. Key Laboratory of Auxiliary Chemistry & Technology for Chemical Industry, Ministry of Education, Shaanxi University of Science & Technology, Xi’an 710021, China
  • Received:2009-10-22 Revised:2009-12-09 Online:2010-05-20 Published:2010-05-12
  • Contact: HUANG Jian-Feng

Abstract:

An SiC/AlPO4 multilayers coating was fabricated on the carbon/carbon (C/C) composites by using the pack cementation and the hydrothermal electrophoretic deposition method. Phase compositions and microstructures of the as-prepared multi-layers coating were characterized by XRD and SEM. The influences of AlPO4 crystalline structure on microstructure and antioxidation property of the as-prepared multi-layers coating were investigated respectively. Results show that AlPO4 crystalline structure has strongly influence on the microstructure and antioxidation property of multi-layers coating. The porous coating with many defects is obtained using berlinite-type (B-AlPO4) powder. Coating density and uniformity have been greatly improved by using tridymite-type AlPO4 (T-AlPO4) powder, but there are some small holes, and scale of cracks between the coating and the substrate can be observed. Very dense and homogeneous coating is obtained using cristobalite-type AlPO4 (C-AlPO4) powder. No visible micro-cracks and other defects at the interface between C-AlPO4 coating and substrate can be observed. The C-AlPO4 coating exhibits better antioxidation property. The as-prepared C-AlPO4 coating could effectively protect C/C composites from oxidation at 1500℃  in air for 21h with a weight loss of 0.41wt%.

Key words:  aluminum phosphate, crystalline structure, coatings, oxidation

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