|High Temperature Volatility and Oxidation Measurements of Titanium and Silicon Containing Ceramic Materials|
|Doctor of Philosophy in Clinical-Bioanalytical Chemistry, Cleveland State University, 2008, College of Science|
Titanium (Ti) and silicon (Si) containing materials are of high interest to the aerospace industry due to its high temperature capability, strength, and light weight. A continuous exterior oxide layer is desirable to reduce the oxidation rate of these two materials. At high temperatures, water vapor plays a key role in the volatility of materials including oxide surfaces. This study first evaluated several hot-pressed Ti and Si-containing compositions at high temperatures as a function of oxidation resistance. This study also evaluated cold pressed titanium dioxide (TiO2) powder pellets at a temperature range of 1400°C - 1200°C in water containing environments to determine the volatile hydoxyl species using the transpiration method. The water content ranged from 0-76 mole % and the oxygen content range was 0-100 mole % during the 20-250 hour exposure times. Results indicate that oxygen is not a key contributor at these temperatures and a volatile Ti-O-H species has been identified.
Committee: Lily M. Ng, PhD (Committee Chair); James L. Smialek, PhD (Advisor); Kang N. Lee, PhD (Committee Member); John F. Turner II, PhD (Committee Member); Mary V. Zeller, PhD (Committee Member)
Aerospace Materials; Chemistry; Materials Science
Keywords: aerospace; ceramic; combustion environment; high temperature; hydroxyl species; oxidation; materials; Si; silicon; titanium dioxide; TiO2; Ti-O-H; transpiration method; transpiration technique; volatility; water vapor