Catalytic Properties of ZrB2-Based Ultra-High Temperature Ceramics Based on the Wall Temperature Response Method

2013 ◽  
Vol 745-746 ◽  
pp. 636-641 ◽  
Author(s):  
Ning Li ◽  
Ping Hu ◽  
Xing Hong Zhang ◽  
Wen Bo Han
Keyword(s):  
High Temperature ◽  
Wall Temperature ◽  
Surface Composition ◽  
Catalytic Properties ◽  
Temperature Response ◽  
Ultra High Temperature Ceramics ◽  
Balance Principle ◽  
Sic Composites ◽  
Response Method ◽  
Ultra High Temperature

This paper presented the application of microwave-discharge plasma apparatus which was used to evaluate the catalytic properties of ZrB2-based ultra-high temperature ceramics in the simulated real service environment by the wall temperature response method based on the heat balance principle. The results showed that the material composition had a significant influence on the catalytic properties of ZrB2-based ultra-high temperature ceramics, and the catalytic activity of ZrB2-SiC composites with Cr addition had been increased significantly. The relationship between catalytic properties of ZrB2-based ultra-high temperature ceramics and surface composition was discussed in detail. The composition optimization was considered to be a very effective way to inhibit the recombination reactions of dissociated atoms on the surface of ultra-high temperature ceramics.

High-Entropy Ultra-High-Temperature Borides and Carbides: A New Class of Materials for Extreme Environments

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Lun Feng ◽  
William G. Fahrenholtz ◽  
Donald W. Brenner
Keyword(s):  
High Temperature ◽  
Extreme Environments ◽  
Experimental Studies ◽  
Heat Fluxes ◽  
Annual Review ◽  
Publication Date ◽  
Structure Property ◽  
High Entropy ◽  
Ultra High Temperature Ceramics ◽  
Ultra High Temperature

Herein, we critically evaluate computational and experimental studies in the emerging field of high-entropy ultra-high-temperature ceramics. High-entropy ultra-high-temperature ceramics are candidates for use in extreme environments that include temperatures over 2,000°C, heat fluxes of hundreds of watts per square centimeter, or irradiation from neutrons with energies of several megaelectron volts. Computational studies have been used to predict the ability to synthesize stable high-entropy materials as well as the resulting properties but face challenges such asthe number and complexity of unique bonding environments that are possible for these compositionally complex compounds. Experimental studies have synthesized and densified a large number of different high-entropy borides and carbides, but no systematic studies of composition-structure-property relationships have been completed. Overall, this emerging field presents a number of exciting research challenges and numerous opportunities for future studies. Expected final online publication date for the Annual Review of Materials Science, Volume 51 is July 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Sign in / Sign up

Export Citation Format

Share Document