Journal of Inorganic Materials ›› 2016, Vol. 31 ›› Issue (4): 393-400.doi: 10.15541/jim20150402

• Orginal Article • Previous Articles     Next Articles

Effects of Al and O Content on Transformation from SiAlCO to Si(Al)C Fibers after High Temperature Treatment

Qin YUAN(), Yong-Cai SONG()   

  1. Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, National University of Defense Technology, Changsha 410073, China
  • Received:2015-08-27 Revised:2015-11-16 Online:2016-04-20 Published:2016-03-25
  • About author:YUAN Qin. E-mail: yinzi863@163.com
  • Supported by:
    Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province; Aid Program for Innovative Group of National University of Defense Technology, China(CJ12-01-01)

Abstract:

Continuous SiAlCO fibers were prepared by polymer-derived method using polyaluminocarbosilane (PACS) with various Al contents as precursor. The O content of the fibers was controlled by different curing methods. The effects of the Al and O content on SiCxOy decomposition, β-SiC grain growth, and fiber morphological evolution in the heat-treatment process were investigated. The results reveal that SiCxOy decompostion initiates at 1300℃ and completes at 1700℃ for all kinds of fibers, which is irrelevant to Al and O contents. Al in the fibers is beneficial to reduction of both coarse SiC crystallites and interconnected pores on the surface, and increases suppressing effects on the growth of β-SiC under the tempertature above 1700℃, resulting in densification. Excessive carbon is eliminated as CO and CO2 by oxygen from SiAlCO fibers during annealing process. However, excessive oxygen creates big pores in fibers, harmful to densification. A densified Si(Al)C fiber with a decently large crystallite size of β-SiC can be achieved with an optimal Al and O content of 0.6wt% and 9wt%, respectively.

Key words: SiAlCO fibers, SiCxOy decomposition, β-SiC, densification, Si(Al)C fibers

CLC Number: 

  • TQ174