Journal ArticleDOI
Processing, properties and arc jet oxidation of hafnium diboride/silicon carbide ultra high temperature ceramics
Reads0
Chats0
TLDR
In this article, the processing and properties of HfB2-20 vol%SiC ultra high temperature ceramics were examined and it was concluded that passive oxidation of SiC plays a role in determining the steady-state surface temperatures below 1700°C.Abstract:
The processing and properties of HfB2-20 vol%SiC ultra high temperature ceramics were examined. Dense billets were fabricated by hot-pressing raw powders in a graphite element furnace for 1 h at 2200°C. Specimens were then tested for hardness, mechanical strength, thermal properties and oxidation resistance in a simulated re-entry environment. Thermal conductivity of the current materials was found to be less than previous work had determined while the strength was greater. Oxidation testing of two flat-face models was conducted, at two conditions, for two 10-min durations each. It was concluded that passive oxidation of SiC plays a role in determining the steady-state surface temperatures below 1700°C. Above 1700°C, temperatures are controlled by the properties of a thick HfO2 layer and active oxidation of the SiC phase.read more
Citations
More filters
Journal ArticleDOI
Refractory Diborides of Zirconium and Hafnium
TL;DR: In this article, the crystal chemistry, synthesis, densification, microstructure, mechanical properties, and oxidation behavior of Zirconium diboride (ZrB2) and HfB2 ceramics are reviewed.
Journal ArticleDOI
Field-Assisted Sintering Technology/Spark Plasma Sintering: Mechanisms, Materials, and Technology Developments
Olivier Guillon,Jesus Gonzalez-Julian,Benjamin Dargatz,Tobias Kessel,Gabi Schierning,Jan Räthel,Mathias Herrmann +6 more
TL;DR: Field-assisted sintering is a low voltage, direct current (DC) pulsed current activated, pressure-assisted, and synthesis technique, which has been widely applied for materials processing in the recent years as mentioned in this paper.
Journal ArticleDOI
Thermodynamic Analysis of ZrB2–SiC Oxidation: Formation of a SiC-Depleted Region
TL;DR: In this article, a thermodynamic model was developed to explain the formation of a SiC-depleted layer during ZrB2-SiC oxidation in air at 1500°C.
Journal ArticleDOI
Evolution of structure during the oxidation of zirconium diboride–silicon carbide in air up to 1500 °C
TL;DR: In this paper, the structures that developed as dense ZrB2-SiC ceramics were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction.
Journal ArticleDOI
Material property requirements for analysis and design of UHTC components in hypersonic applications
TL;DR: In this paper, the authors analyze the thermal and mechanical properties of UH-Ceramic components, such as nose tips and wing leading edges for hypersonic applications, to predict component performance in particular flight environments.
References
More filters
Journal ArticleDOI
Mechanical, Thermal, and Oxidation Properties of Refractory Hafnium and zirconium Compounds
TL;DR: In this paper, the thermal conductivity, thermal expansion, Youngs Modulus, flexural strength, and brittle-plastic deformation transition temperature of ZrB2, HfC 0·98 and HfN 0·92 ceramics were determined.
Journal ArticleDOI
Evaluation of ultra-high temperature ceramics foraeropropulsion use
Stanley R. Levine,Elizabeth J. Opila,Michael C. Halbig,James D. Kiser,Mrityunjay Singh,Jonathan A. Salem +5 more
TL;DR: In this article, the authors examined three UHTC materials under conditions more representative of a propulsion environment, i.e., higher oxygen partial pressure and total pressure, and showed that these materials offer a good combination of properties that make them candidates for airframe leading edges on sharp-bodied reentry vehicles.
Journal ArticleDOI
High‐Temperature Vaporization Behavior of Oxides II. Oxides of Be, Mg, Ca, Sr, Ba, B, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Zn, Cd, and Hg
TL;DR: In this article, the Gibbs energy functions of condensed and vapor phases are given in the form of equations valid over wide temperature ranges, along with the standard entropies and enthalpies of formation.
Journal ArticleDOI
Processing and properties of zirconium diboride-based composites
TL;DR: In this article, two zirconium diboride base composites were produced and characterised, which were compared to those of a monolithic ZrB2+4 wt% Ni material.
Journal ArticleDOI
High‐Temperature Oxidation III . Zirconium and Hafnium Diborides
TL;DR: The parabolic rate constant for total oxygen consumption increases as the power of the oxygen partial pressure at 1630° and 1760°K as discussed by the authors, when the transition temperature for the monoclinic to tetragonal phase change in, there is a sharp increase in the rate of oxidation.