Laser Scattering Detection of Machining-Induced Damage in Si3N4 Components

Sun, Jie; Haselkorn, M.; Ellingson, W. A.

doi:10.1007/978-1-4615-4847-8_58

Cited by 2 publications

(2 citation statements)

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“…The backscatter intensity is recorded at every pixel during the scan of the 2D valve surface, and the resulting series data are composed into a 2D laser‐scatter‐intensity image according to the pixel positions on the surface. Because subsurface scattering becomes stronger at regions with subsurface defects and damage, the 2D scattering image can be used to identify the location, size, and relative severity of subsurface defects 36,38,39 . This system can therefore be used to inspect the quality of manufactured valves and to evaluate accumulated damage in rig/engine‐tested valves.…”

Section: Laser‐scatter Methods and Experimental Setup For Nde Of Cerammentioning

confidence: 99%

“…Figure 4 shows a typical laser‐scattering image of an NT551 valve; it exhibits no apparent large‐scale subsurface flaws. Most of the flaws, appearing as high scatter‐intensity spots in the image, were <50 μm in size, and they have been identified as high‐porosity pores or small voids within the subsurface 39 Figure 5. shows a detailed laser‐scatter image and photomicrograph of one such porous region (∼70 μm in size) in an NT551 valve surface, which also contains a small partially exposed void at its center.…”

Section: Laser‐scatter Characterization Of Ceramic Valvesmentioning

confidence: 99%

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Evaluation of Silicon‐Nitride Ceramic Valves

Sun

Zhang

Andrews

et al. 2008

Int J Applied Ceramic Tech

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Silicon‐nitride ceramic valves can improve the performance of both light‐ and heavy‐duty automotive engines because of the superior material properties of silicon nitrides over current metal alloys. However, ceramics are brittle materials that may introduce uncertainties in the reliability and durability of ceramic valves. As a result, the lifetime of ceramic valves are difficult to predict theoretically due to wide variations in the type and distribution of microstructural flaws in the material. Nondestructive evaluation (NDE) methods are therefore required to assess the quality and reliability of these valves. Because ceramic materials are optically translucent and the strength‐limiting flaws are normally located near the valve surface, a laser‐scatter method can be used for NDE evaluation of ceramic valves. This paper reviews the progress in the development of this NDE method and its application to inspect silicon‐nitride ceramic valves at various stages of manufacturing and bench and engine tests.

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Section: Laser‐scatter Methods and Experimental Setup For Nde Of Cerammentioning

confidence: 99%

Section: Laser‐scatter Characterization Of Ceramic Valvesmentioning

confidence: 99%