Engineering Commons^™

Oxidation Of Uc: An In-Situ High Temperature Environmental Scanning Electron Microscopy Study, Claudia Gasparrini, Michael J.D. Rushton, William E. Lee, Renaud Podor, Denis Horlait, Olivier Fiquet

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

Uranium carbide (UC) has the potential to be used as fuel in Generation IV nuclear reactors thanks to its higher metal atom density and better thermal conductivity when compared to the most commonly used fuel: uranium dioxide (UO₂) [1]. Although UC offers improved properties during operation, it needs to be converted into an oxide form after usage as it is reactive and potentially pyrophoric [2] in oxidising environments. Previous oxidation studies on UC, performed over a range of oxygen atmospheres and temperatures, suggest different mechanisms lead to the formation of either a protective or a pulverised non-protective oxide …

Introduction To H2020 Project C3harme: Next Generation Ceramic Composites For Combustion Harsh Environments And Space, Diletta Sciti, Laura Silvestroni, Luca Zoli, Antonio Vinci, Frederic Monteverde

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

Materials for aeronautical and space applications largely involve ceramic matrix composites, CMCs, made of carbon or silicon carbide. However, C/C composites suffer from poor erosion resistance while silicon-based ceramics, SiC/SiC or C/SiC composites, may undergo strong ablation due to the formation and volatilization of silica. In recent years, Ultra-High Temperature Ceramics, UHTCs, have shown outstanding erosion resistance at temperatures up to 2000°C or even higher but they still cannot resist to thermal shocks and damage. Therefore, there is an increasing demand for advanced materials with temperature capability in highly corrosive environments to enable space vehicles to resist several launches and …

Feasibility Research Of Gaining “Refractory High Entropy Carbides” Through In Situ Carburization Of Refractory High Entropy Alloys, Yuanlin Ai, Shuxin Bai, Li’An Zhu, Yicong Ye

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

Abstract: High entropy alloys (HEAs) refer to solid solution alloys which contain five or more principal elements in equal or near equal atomic percent. Due to their unique structures, HEAs have superior comprehensive properties compared with the conventional alloys based on only one element. The property improvement based on the effect of high entropy may works on the refractory carbides used in ultra-high temperature ceramics. Therefore, a solid carburization method was employed on a refractory high entropy alloy of HfZrTiTa to prepare in situ the possible “Refractory High Entropy Carbides”. The microstructure, micro-hardness and oxidation resistance of the carburized layer …

Ultra High Temperature Ceramics For Hypersonic Space Vehicles: Opportunities And Challenges, Bikramjit Basu

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

Among ultrahigh temperature ceramics (UHTC), ZrB₂-based ceramics have received the most attention for applications in the leading edge of hypersonic space vehicles. Despite significant research efforts, the development of ZrB₂-SiC based ceramics in reference to performance-qualifying property assessment (shock resistance, ablation, etc.) together with the design of thermal protection system (TPS) has not been extensively reported in literature. While briefly presenting our recent research in this direction, I shall discuss myriad of opportunities and challenges ahead in TPS design for hypersonic space vehicles.

To begin with, results of the carefully designed experiments using innovative multi-stage spark …

Testing Ultra-High Temperature Ceramics For Thermal Protection And Rocket Applications, Raffaele Savino

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

The work is focused on experimental aerothermodynamic characterization of Ultra-High-Temperature Ceramic materials for aerospace applications. These materials are assuming an increasing importance in aerospace research because their high temperature resistance makes them interesting to develop components for extreme applications, such as thermal protection systems for hypersonic or atmospheric reusable re-entry vehicles, specific components for propulsion, combustion chambers, engines intakes or rocket nozzles. In order to test the materials behavior in extreme relevant environments, different facilities are available, including supersonic arc-jet wind tunnels and lab-scaled rocket motors.

Typical activities include the design of prototypes for the experimental campaigns, tests on material …

Phase Transformations In Oxides Above 2000°C: Experimental Technique Development, Sergey V. Ushakov, Alexandra Navrotsky

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

Oxidation of carbides-based ultra-high temperature ceramics is the main limiting factor for its use for aerodynamic surfaces. Experimental thermodynamic and structural data for refractory oxides above 2000 °C are mostly absent. The following techniques applied to fill this gap will be discussed: i) Commercial ultra-high temperature differential thermal analyzers (DTA) allow investigation of phase transformations and melting in inert environment to the temperatures up to 2500 °C; ii) Combination of laser heating with splittable nozzle aerodynamic levitator allow splat quenching and drop calorimetry from temperatures limited only by sample evaporation; iii) Synchrotron X-ray and neutron diffraction on laser heated aerodynamically …

Extended Potentials Of Uhtcmcs In Space Vehicle Extreme Environment Applications - Large System Intergrator View And Expectations, Wolfgang Fischer

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

Research and development performed in recent years in the field of UHTC revealed promising properties of these new materials in the field of extreme environments.

Particularly in applications where high thermal loadings are expected these materials offer high potentials of extended performance for various applications.

However, the combination of high thermal loadings together with high mechanical loadings requires a new class of UHTC. By creating UHTCs with fiber reinforcement an improvement of characteristic properties is anticipated.

Research in this very specific area has been initiated and is currently ongoing based on promising ideas.

This class of UHTCMCs is expected to …

Novel Ir-X Thermal Protection Coatings Designed For Extreme Aerodynamic Heating Environment, Kaili Zhang, Yicong Ye, Li`An Zhu, Shuxin Bai

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

Due to the rapid evaporation of SiO₂ protective layer, most Si-containing oxidation resistant coatings could not withstand a temperature above 1800℃, which is not enough for hypersonic voyage in upper atmosphere. With a higher melting point (2440℃) and lower oxygen permeability（10^-20g·m^-1·s^-1）, iridium is supposed to be a promising coating material for ultra-high temperature applications. However, Iridium has a low emissivity ε(0.017 for 2.5-25μm) and high recombination coefficient γ(0.64 at 1200℃) of atomic oxygen, resulting in a much higher thermal response compared with the ceramic materials under the same aerodynamic environment. To solve this …

Conference Program, Jon Binner, Bill Lee

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

No abstract provided.