Degradation of Silicon Carbide in Combustion Gas Flow at High Temperature and High Speed

Melt growth composites (MGCs) have a unique microstructure, in which continuous networks of single-crystal phases interpenetrate without grain boundaries. Therefore, the MGCs have excellent high-temperature strength characteristics, creep resistance, oxidation resistance and thermal stability in an air atmosphere at very high temperature. To achieve ultra-high thermal efficiency and low NOx emission for gas turbine systems, non-cooled turbine nozzle vanes and heat shield panels of combustor liners has been fabricated on an experimental basis. These components are thermally stable after heat treatment at 1700°C for 1000 hours in an air atmosphere. In addition, we have just started the exposure tests to evaluate the influence of combustion gas flow environment on MGCs.

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Attritious Wear of Silicon Carbide

Journal of Engineering for Industry ◽

10.1115/1.3439065 ◽

1976 ◽

Vol 98 (4) ◽

pp. 1125-1134 ◽

Cited By ~ 10

Author(s):

R. Komanduri ◽

M. C. Shaw

Keyword(s):

Silicon Carbide ◽

Electron Microscope ◽

High Temperature ◽

High Speed ◽

Layer By Layer ◽

Wear Area ◽

Work Material ◽

Transmission Electron ◽

Metal Silicides ◽

Boundary Fracture

Attritious wear of silicon carbide in simulated grinding tests against a cobalt base superalloy at high speed and extremely small feed rate was studied using a scanning electron microscope (SEM) and an auger electron spectroscope (AES). In many cases the wear area of silicon carbide was found to be concave rather than planar in shape. Several microcracks and grain boundary fracture were also observed. No evidence of metal build-up was observed on silicon carbide which was not the case with aluminum oxide. AES study of the rubbed surface on the work material and transmission electron microscope (TEM) investigation of the wear debris suggest that attritious wear of silicon carbide is due to one or more of the following mechanisms: 1 – Preferential removal of surface atoms on the abrasive, layer by layer, by oxidation under high temperature and a favorably directed shear stress; 2 – disassociation of silicon carbide at high temperature and (a) diffusion of silicon into the work material and formation of metal silicides and (b) diffusion of carbon into the work material and formation of unstable metal carbides (in the present case Ni3C and Co3C) which decompose during cooling to metal and carbon atoms; 3 – pinocoidal cleavage fracture of silicon carbide on basal planes c(0001) resulting in the removal of many micron-sized crystallites.

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Uniform silicon carbide doped Sb2Te nanomaterial for high temperature and high speed PCM applications

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2016.01.036 ◽

2016 ◽

Vol 664 ◽

pp. 591-594 ◽

Cited By ~ 1

Author(s):

Yun Meng ◽

Qiuming She ◽

Liangliang Cao ◽

Yan Chen ◽

Peigao Han ◽

...

Keyword(s):

Silicon Carbide ◽

High Temperature ◽

High Speed

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Model Combustor to Assess the Oxidation Behavior of Ceramic Materials Under Real Engine Conditions

Volume 4: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education; IGTI Scholar Award; General ◽

10.1115/99-gt-349 ◽

1999 ◽

Cited By ~ 4

Author(s):

D. Filsinger ◽

A. Schulz ◽

S. Wittig ◽

C. Taut ◽

H. Klemm ◽

...

Keyword(s):

High Temperature ◽

International Development ◽

Gas Turbines ◽

Gas Flow ◽

Oxidation Behavior ◽

Elevated Temperatures ◽

Ceramic Materials ◽

Test Rig ◽

Combustion Gas ◽

Wide Range

A further increase of thermal efficiency and a reduction of the exhaust emissions of ground based gas turbines can be achieved by introducing new high temperature resistant materials. Therfore, ceramics are under international development. They offer excellent strengths at room and elevated temperatures. For gas turbine combustor applications, however, these materials have to maintain their advantageous properties under hostile environment. For the assessment and comparison of the oxidation behavior of different nonoxide ceramic materials a test rig was developed at the Institute for Thermal Turbomachinery (ITS), University of Karlsruhe, Germany. The test rig was integrated into the high temperature/ high pressure laboratory. A ceramic model combustion chamber was designed which allowed the exposure of standard four-point flexure specimens to the hot combustion gas flow. Gas temperatures and pressures could be varied in a wide range. Additionally, the partial steam pressure could be adjusted to real combustor conditions. The present paper gives a detailed description of the test rig and presents results of 100 hours endurance tests of ceramic materials at 1400°C. The initial strengths and the strengths after oxidation tests are compared. In addition to this, photographs illustrating the changes of the material’s microstructure are presented.

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

10.1115/gt2021-59125 ◽

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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Characterization of Electric Discharge Machining for Silicon Carbide Single Crystal

Materials Science Forum ◽

10.4028/www.scientific.net/msf.600-603.855 ◽

2008 ◽

Vol 600-603 ◽

pp. 855-858 ◽

Cited By ~ 22

Author(s):

Tomohisa Kato ◽

Toshiya Noro ◽

Hideaki Takahashi ◽

Satarou Yamaguchi ◽

Kazuo Arai

Keyword(s):

Silicon Carbide ◽

High Temperature ◽

Electric Discharge ◽

High Voltage ◽

High Speed ◽

Surface Damage ◽

Lower Surface ◽

Etch Pits ◽

Electric Discharge Machining

In this study, we report electric discharge machining (EDM) as a new cutting method for silicon carbide (SiC) single crystals. Moreover, we discuss characteristics and usefulness of the EDM for the SiC. The EDM realized not only high speed and smooth cutting but also lower surface damage. Defect propagation in the EDM SiCs have been also estimated by etch pits observation using molten KOH, however, we confirmed the EDM has caused no damage inside the SiCs in spite of high voltage and high temperature during the machining.

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