Synthesis, characterization, and ceramization of a carbon-rich SiCw-ZrC-ZrB2 preceramic polymer precursor. Issue 13 (September 2019)

• Record Type: Journal Article
• Authors: Liu, Changqing; Zhang, Luyue; Li, Xu; Chang, Xiaojing; Wu, Yuanting; Wang, Xiufeng
• Is Part Of: Ceramics international. Volume 45:Issue 13(2019)
• Page Start: 16097
• Page End: 16104
• Publication Date: 2019-09
• Subjects: A -- Polymer precursor -- D -- SiCw-ZrC-ZrB2 -- Pyrolysis; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2019.05.126
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: A precursor (PBSZ) for SiCw -ZrC-ZrB2 hybrid powder was synthesized by chemical reaction of phenol, paraformaldehyde, zirconium oxychloride, boric acid and tetraethylorthosilicate. Results show that zirconium, silicon and boron atoms have been successfully introduced into the branched structure. Decomposition of PBSZ is completed at 800 °C, and it gives amorphous carbon, SiO2, B2 O3 and ZrO2 with a yield of 38% at 1200 °C. During the pyrolysis process, ZrB2 and SiC form at about 1500 °C, followed by the appearance of ZrC when the amount of B2 O3 is limited. Highly crystallized ZrB2 –ZrC–C powder with ZrB2 and ZrC grains evenly distributed in the carbon matrix together with randomly distributed SiC whiskers are obtained after heat-treated at 1800 °C. Further heated at 1900 °C, ZrB2 and ZrC grains grow from 200 to 500 nm, while SiC whiskers show a much smaller diameter size and tend to grow on the ZrB2 –ZrC–C block surface. The morphology difference is caused by the larger gas supersaturation and accommodation coefficient of the pore channels on the block surface. In addition, defects of the carbon matrix are cumulated to the highest at 1500 °C and the structure-ordered carbon is obtained after heat treated at 1900 °C.