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in creator/contributor: "Steckenrider, J.S."  
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Automated laser scatter detection of surface and subsurface defects in Si{sub 3}N{sub 4} components

Description: Silicon Nitride (Si{sub 3}N{sub 4}) ceramics are currently a primary material of choice to replace conventional materials in many structural applications because of their oxidation resistance and desirable mechanical and thermal properties at elevated temperatures. However, surface or near-subsurface defects, such as cracks, voids, or inclusions, significantly affect component lifetimes. These defects are currently difficult to detect, so a technique is desired for the rapid automated detection… more
Date: June 1995
Creator: Steckenrider, J. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Application of laser scattering for detection of surface and subsurface defects in Si{sub 3}N{sub 4} components

Description: Si{sub 3}N{sub 4} ceramics are currently primary materials of choice in structural applications because of their mechanical and thermal properties. However, the lifetimes of these ceramic components -- especially those that experience contact fatigue (e.g., bearings) -- are most affected by defects such as voids, inclusions, or microstructural variations in the surface or near-surface (< 200{mu}m) region. Thus, a technique is desired for the rapid detection and quantification of both surface an… more
Date: January 1, 1994
Creator: Steckenrider, J. S. & Ellingson, W. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Surface and subsurface defect detection in Si{sub 3}N{sub 4} components by laser scattering

Description: Lifetimes of Si{sub 3}N{sub 4} components that experience contact fatigue (e.g., bearings) are affected by defects (voids, inclusions, etc.) at or near the surface (<200 {mu}m). An optical technique was developed for rapid detection and quantification of defects in both surface and subsurfaces, as well as characterization of subsurface microstructure. This laser scattering technique was applied to various Si{sub 3}N{sub 4} component shapes. Polarization techniques were used to independently ana… more
Date: September 1, 1993
Creator: Steckenrider, J. S. & Ellingson, W. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Full-field characterization of thermal diffusivity in continuous- fiber ceramic composite materials and components

Description: Continuous-fiber ceramic matrix composites (CFCCs) are currently being developed for various high-temperature applications, including use in advanced heat engines. Among the material classes of interest for such applications are silicon carbide (SiC)-fiber-reinforced SiC (SiC{sub (f)}/SiC), SiC-fiber-reinforced silicon nitride (SiC {sub (f)}/Si{sub 3}N{sub 4}), aluminum oxide (Al{sub 2}O{sub 3})-fiber-reinforced Al{sub 2}O{sub 3} (Al{sub 2}O{sub 3}{sub (f)}/Al{sub 2}O{sub 3}), and others. In su… more
Date: May 1, 1995
Creator: Steckenrider, J.S.; Ellingson, W.A. & Rothermel, S.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Infrared-based NDE methods for determining thermal properties and defects in ceramic composites

Description: Continuous-fiber ceramic matrix composites are currently being developed for various high temperature applications, including use in advanced heat engines. In the material classes of interest for such applications, i.e., silicon carbide (SiC)-fiber-reinforced SiC (SiC{sub (f)}/SiC), SiC-fiber-reinforced silicon nitride (SiC{sub (f)}/Si{sub 3}N{sub 4}), Al{sub 2}O{sub 3 (f)}/Al{sub 2}O{sub 3}, etc., the condition of the interface between the fibers and matrix is critical to the mechanical and th… more
Date: August 1, 1996
Creator: Ahuja, S.; Ellingson, W.A.; Steckenrider, J.S. & Koch, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Nondestructive characterization of structural ceramic components

Description: Advanced structural ceramic components under development for heat-engine applications include both monolithic and continuous fiber composites (CFC). Nondestructive characterization (NDC) methods being developed differ for each material system. For monolithic materials, characterization during processing steps is important. For many CFC, only post process characterization is possible. Many different NDC systems have been designed and built A 3D x-ray micro computed tomographic (3DXCT) imaging sy… more
Date: June 1, 1994
Creator: Ellingson, W. A.; Steckenrider, J. S.; Sivers, E. A. & Ling, J. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermal diffusivity imaging of continuous fiber ceramic composite materials and components

Description: Continuous-fiber ceramic matrix composites (CFCCs) are currently being developed for various high-temperature applications, including use in advanced turbine engines. In such composites, the condition of the interfaces between the fibers and matrix or between laminae in a two-dimensional weave lay-up are critical to the mechanical and thermal behavior of the component. A nondestructive evaluation method that could be used to assess the interface condition and/or detect other `defects` has been … more
Date: December 31, 1995
Creator: Ahuja, S.; Ellingson, W.A.; Steckenrider, J.S. & King, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Recognition of subsurface defects in machined ceramics by application of neural networks to laser scatter patterns

Description: Laser scatter has shown promise as a method to characterize damage microstructural variations as well as a method to characterize surfaces in optical translucent ceramics. Because large volumes of data need to be handled (and sorted) quickly, automated pattern recognition methods using neural networks have been implemented to recognize differences in patterns. A He-Ne laser ({lambda}=0.632{mu}) has been used to obtain scatter patterns from hot pressed Si{sub 3}N{sub 4} with various microstructu… more
Date: September 1, 1994
Creator: Stinson, M. C.; Lee, O. W.; Steckenrider, J. S. & Ellingson, W. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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