Structure, properties and oxidation resistance of prospective HfB2–SiC based ceramics

2020 ◽  
pp. 41-54
Author(s):  
Yu. S. Pogozhev ◽  
A. Yu. Potanin ◽  
S. I. Rupasov ◽  
E. A. Levashov ◽  
V. A. Volkova ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Hot Pressing ◽  
Plasma Torch ◽  
Gas Flow ◽  
Operating Conditions ◽  
Average Particle ◽  
Hafnium Diboride ◽  
Protective Oxide

The paper focuses on obtaining a heterophase powdered and sintered ceramics based on hafnium diboride and silicon carbide by combined self-propagating high-temperature synthesis (SHS) and hot pressing (HP). The structure of the synthesized SHS powder consists of hafnium diboride grains and agglomerated polyhedral 2–6 μm silicon carbide grains. The powders obtained had an average particle size of ~10 μm with a maximum value of 30 μm. Phase compositions were identical for the ceramics sintered by hot pressing and the synthesized powder. The resulting compact featured by a high degree of structural and chemical uniformity, porosity of 3.8 %, hardness of 19.8±0.4 GPa, strength of 597±59 MPa, and fracture toughness of 8.8±0.4 MPa·m1/2. Plasma torch testing (PTT) was carried out to determine the oxidation resistance under the influence of a high-enthalpy gas flow. The phase composition and surface microstructure of the compact after testing were investigated. The HP compact demonstrated an outstanding resistance to the high-temperature gas flow at 2150 °С and heat flow density of 5.6 MW/m2 for 300 s. A dense protective oxide layer 30–40 μm thick was formed on the surface of HfB2–SiC ceramics during the plasma torch testing. The layer consisted of a scaffold formed by HfO2 oxide grains with a space between them filled with SiO2–B2O3 amorphous borosilicate glass. The HfB2–SiC SHS composite powder was hot pressed to produce experimental samples of model bushings for the combustion chamber of a low thrust liquid rocket engine designed for PTT in the environment close to actual operating conditions.

Hot Pressing and Characterization of ZrB2-SiC-MoSi2 Composite

2015 ◽  
Vol 830-831 ◽  
pp. 421-424
Author(s):  
T. Venkateswaran ◽  
M. Agilan ◽  
D. Sivakumar ◽  
Bhanu Pant
Keyword(s):  
High Temperature ◽  
Melting Point ◽  
Oxidation Resistance ◽  
Hot Pressing ◽  
Mechanical And Thermal Properties ◽  
High Melting ◽  
Hafnium Diboride ◽  
High Melting Point ◽  
Microstructural Investigation ◽  
Ultra High Temperature

Transition metal diborides, especially zirconium and hafnium diboride are potential ceramic material for ultra high temperature applications above 1800°C. These borides are characterized by high melting point, formation of high melting point oxides, good oxidation resistance and excellent thermo-mechanical properties. In this present exploration, zirconium diboride (ZrB2) has been selected for its moderate density (6.09 gm/cc) and better oxidation resistance compared to high density hafnium diboride (11.2 gm/cc). The developed ZrB2 composite in the present study contains 10 wt. % SiC and 10 wt. % MoSi2 as sintering additives. SiC and MoSi2 were added to improve the thermal shock resistance and sinterability of the ultra high temperature ceramics (UHTCs). Vacuum hot pressing was carried out at 1800°C for a holding period of 30 minutes and applied pressure of 30 MPa. Attractive feature of this ZrB2 composite is good machinability due to better electrical conductivity and complicated shapes can be realized easily through electro discharge machining (EDM) process. Detailed XRD phase analysis and microstructural investigation of the polished and fractured composites was carried out using SEM. Mechanical and thermal properties tests have been carried out for the optimized ZrB2 composite material.

HASTELLOY ALLOY X

Alloy Digest ◽  
1954 ◽  
Vol 3 (12) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
High Temperatures ◽  
Heat Treating ◽  
Operating Conditions ◽  
Molybdenum Alloy ◽  
High Temperature Strength ◽  
Nickel Chromium

Abstract HASTELLOY Alloy X is a nickel-chromium-iron-molybdenum alloy recommended for high-temperature applications. It has outstanding oxidation resistance at high temperatures under most operating conditions, and good high-temperature strength. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on forming, heat treating, and machining. Filing Code: Ni-14. Producer or source: Haynes Stellite Company.

Fabrication and Strength Properties of LPS-SiC Ceramics

2005 ◽  
Vol 287 ◽  
pp. 183-188 ◽  
Author(s):  
Yi Hyun Park ◽  
Dong Hyun Kim ◽  
Han Ki Yoon ◽  
Akira Kohyama
Keyword(s):  
Elastic Modulus ◽  
High Temperature ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Average Particle Size ◽  
Process Temperature ◽  
Average Particle ◽  
Pressing Method ◽  
Temperature And Pressure ◽  
Sic Composites

SiC materials have been extensively studied for high temperature components in advanced energy system and advanced gas turbine. SiCf/SiC composites are promising for various structural materials. But, high temperature and pressure lead to the degradation of the reinforcing fiber during the hot pressing. Therefore, reduction of the process temperature and pressure is key requirements for the fabrication of SiCf/SiC composites by hot pressing method. In the present work, monolithic LPS-SiC was fabricated by hot pressing method at various temperatures. The starting powder was high purity β-SiC nano-powder with an average particle size of 30nm. Compositions of sintering additives were Al2O3 / Y2O3 = 0.7 and 1.5 (wt.%). Monolithic LPS-SiC was evaluated in terms of sintering density, micro-structure, flexural strength, elastic modulus and so on. Sintered density, flexural strength and elastic modulus of fabricated LPS-SiC increased with increasing the process temperature. Particularly, relative density of LPS-SiC fabricated at 1820oC with additive composition of Al2O3/Y2O3=1.5(wt.%) was 95%. Also, flexural strength and elastic modulus were 900MPa and 220GPa, respectively. In the fracture surface of this specimen, the size and shape of SiC grains grew up and changed. Also, tortuous crack paths and occurrence of interfacial debonding were observed.

ADVANCER NITRIDE BONDED SILICON CARBIDE

Alloy Digest ◽  
1992 ◽  
Vol 41 (4) ◽  
Keyword(s):  
Silicon Carbide ◽  
Shear Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Oxidation Resistance ◽  
High Temperature Strength ◽  
Kiln Furniture ◽  
Low Mass ◽  
Long Life

Abstract ADVANCER NITRIDE BONDED SILICON CARBIDE has exceptional high-temperature strength. Its oxidation resistance assures long life. It is a low-mass ceramic that is ideally suited to kiln furniture. This datasheet provides information on composition, physical properties, elasticity, and shear strength. Filing Code: Cer-11. Producer or source: Norton Company.

CROLOY 5Si

Alloy Digest ◽  
1958 ◽  
Vol 7 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Operating Conditions ◽  
Temperature Performance

Abstract CROLOY 5 Si is a chromium-silicon-molybdenum heat resisting steel recommended for operating conditions at elevated temperatures where oxidation resistance is a primary requirement. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-78. Producer or source: Babcock & Wilcox Company.

High Temperature Solid Particle Erosion in a Melt-Infiltrated SiC/SiC Ceramic Matrix Composite

2021 ◽  
Author(s):  
Michael J. Presby
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Gas Turbines ◽  
Material Removal ◽  
Gas Flow ◽  
Ceramic Matrix Composite ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Solid Particles ◽  
Material System

Abstract Ceramic matrix composites (CMCs) are an enabling propulsion material system that offer weight benefits over current Ni-based superalloys, and have higher temperature capabilities that can reduce cooling requirements. Incorporating CMCs into the hot section of gas-turbine engines therefore leads to an increase in engine efficiency. While significant advancements have been made, challenges still remain for current and next-generation gas-turbines; particularly when operating in dust-laden or erosive environments. Solid particles entrained in the gas flow can impact engine hardware resulting in localized damage and material removal due to repeated, cumulative impacts. In this study, the erosion behavior of a melt-infiltrated (MI) silicon carbide fiber-reinforced silicon carbide (SiC/SiC) CMC is investigated at high temperature (1,200 °C) in a simulated combustion environment using 150 μm alumina particles as erodent. Particle impact velocities ranged from 100 to 200 m/s and the angle of impingement varied from 30° to 90°. Erosion testing was also performed on α-SiC to elucidate similarities and differences in the erosion response of the composite compared to that of a monolithic ceramic. Scanning electron microscopy (SEM) was used to study the post-erosion damage morphology and the governing mechanisms of material removal.

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