Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781721270675
Total Pages : 34 pages
Book Rating : 4.2/5 (76 download)
Book Synopsis Thermal Conductivity of Ceramic Thermal Barrier and Environmental Barrier Coating Materials by : National Aeronautics and Space Administration (NASA)
Download or read book Thermal Conductivity of Ceramic Thermal Barrier and Environmental Barrier Coating Materials written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal barrier and environmental barrier coatings (TBC's and EBC's) have been developed to protect metallic and Si-based ceramic components in gas turbine engines from high temperature attack. Zirconia-yttria based oxides and (Ba,Sr)Al2Si2O8(BSAS)/mullite based silicates have been used as the coating materials. In this study, thermal conductivity values of zirconia-yttria- and BSAS/mullite-based coating materials were determined at high temperatures using a steady-state laser heat flux technique. During the laser conductivity test, the specimen surface was heated by delivering uniformly distributed heat flux from a high power laser. One-dimensional steady-state heating was achieved by using thin disk specimen configuration (25.4 mm diam and 2 to 4 mm thickness) and the appropriate backside air-cooling. The temperature gradient across the specimen thickness was carefully measured by two surface and backside pyrometers. The thermal conductivity values were thus determined as a function of temperature based on the 1-D heat transfer equation. The radiation heat loss and laser absorption corrections of the materials were considered in the conductivity measurements. The effects of specimen porosity and sintering on measured conductivity values were also evaluated. Zhu, Dong-Ming and Bansal, Narottam P. and Lee, Kang N. and Miller, Robert A. Glenn Research Center NASA/TM-2001-211122, E-12971, NAS 1.15:211122