Synthesis and oxidation behavior of polymer-derived SiCN and SiAlCN amorphous ceramics

Keywords

Ceramic materials -- Corrosion

Abstract

Polymer-derived ceramics are a new class of materials synthesized by thermal decomposition of polymeric precursors. Previous studies have shown that these materials are stable and exhibit excellent thermo-mechanical properties at temperatures up to 1800°C. Furthermore, the novel chemical-to-ceramic route enables the manipulation of compositions and structures, thereby the properties, of the resultant materials at atomic/nano level by designing the chemistry of precursors. In this paper we present the results on the synthesis of polymer derived SiCN and SiAlCN and their oxidation behavior. ·The oxidation kinetics is obtained by measuring the thickness of the oxide scale as a function of annealing time. The results revealed that the oxidation of SiCN exhibit parabolic behavior, and both, the rate constant and activation energy of SiCN are close to those for silicon, indicating that the oxidation mechanism of SiCN is by oxygen diffusion through silicon dioxide layer. While the oxidation of SiAlCN follows parabolic behavior at earlier stage, the increase in the thickness of the oxide layer stops after a certain time. The X-ray elemental mapping indicated that the oxide layer of SiAlCN had a uniform distribution of Si, Al and 0. The mechanism of the high oxidation resistance exhibited by SiAlCN is not fully clear yet, the possible explanation being the low diffusion rate of oxygen through the Si-Al-O network. The high oxidation resistance of SiAlCN material suggests that it is a promising material for many high temperature applications, e.g. environmental barrier coatings and matrixes for composites.

Notes

This item is only available in print in the UCF Libraries. If this is your thesis or dissertation, you can help us make it available online for use by researchers around the world by STARS for more information.

Graduation Date

2003

Advisor

An, Linan

Degree

Master of Science (M.S.)

College

College of Engineering

Department

Mechanical, Materials, and Aerospace Engineering

Format

PDF

Pages

82 p.

Language

English

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

Identifier

DP0029098

Subjects

Dissertations, Academic -- Engineering; Engineering -- Dissertations, Academic

This document is currently not available here.

Share

COinS