Confocal fluorescence microscopy in alumina-based ceramics: Where does the signal come from?

Guo, Sheng; Todd, Richard I.

doi:10.1016/j.jeurceramsoc.2009.08.020

Cited by 20 publications

(21 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We use an approach developed previously. 17 When the laser is focused at a distance z 0 (z 0 = n z, where n is the effective refractive index 17,33 ) below the surface of a translucent material such as polycrystalline alumina, the signal generated in a finite volume of material is collected, as indicated in Fig. 6.…”

Section: Probe Response Function (Prf)mentioning

confidence: 99%

“…A model for the residual stresses simulating the displacement of material in the ground or polished condition by an array of continuously distributed edge dislocations is proposed. It is then convoluted with a PRF established previously 16,17 to compare with the experimental results. The actual residual stresses are then estimated by fitting the parameters in the stress model to the experimental results.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cr3+ microspectroscopy measurements and modelling of local variations in surface grinding stresses in polycrystalline alumina

Guo

Todd

2010

Journal of the European Ceramic Society

Self Cite

View full text Add to dashboard Cite

Section: Probe Response Function (Prf)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cr3+ microspectroscopy measurements and modelling of local variations in surface grinding stresses in polycrystalline alumina

Guo

Todd

2010

Journal of the European Ceramic Society

Self Cite

View full text Add to dashboard Cite

“…At least part of the motivation for the polycrystalline research was to investigate the stress fields arising in polycrystalline alumina responsible for microcracking-the spontaneous localized cracking that occurs in polycrystalline alumina on cooling as a consequence of the anisotropic structure and thermal expansion of corundum [39][40][41]. From the 1990s onward, although there were many notable fundamental studies of the phenomenon [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58], the shift in energy of R lines with stress was largely confined to the applied domain, detailed in numerous works, such as: measurement of stress in bulk Al2O3 polycrystals [42,[58][59][60][61][62][63][64][65][66][67]; in bulk Al2O3-ZrO2 composites [68][69][70][71][72][73][74][75][76][77][78]; in sapphire or composite fibers, free or in matrices [79][80]…”

mentioning

confidence: 99%

Review: Coefficients for Stress, Temperature, and Composition Effects in Fluorescence Measurements of Alumina

Cook

Michaels

2017

J. RES. NATL. INST. STAN.

View full text Add to dashboard Cite

The numerical coefficients linearly relating the effects of stress (including pressure), temperature, and composition to shifts in the energies of the Cr-related fluorescence in alumina (Al2O3) are reviewed. The primary focus is the shift of the R1 and R2 “ruby” fluorescence lines under conditions typical for stress determination in polycrystalline Al2O3. No significant experimental difference in the R1 and R2 responses is observed for hydrostatic stress (or pressure) conditions (average shift coefficient of about 7.6 cm−1/GPa), changes in temperature (about 0.140 cm−1/K), or variations in composition (about 120 cm−1/mass fraction of Cr). There are significant differences in the R1 and R2 responses for nonhydrostatic stress conditions. In particular, for uniaxial stress along the a and c directions in the Al2O3 crystal, the R1 piezospectroscopic tensor coefficients (about 3.0 cm−1/GPa and 1.6 GPa cm−1/GPa, respectively) differ considerably, whereas the R2 coefficients (about 2.6 cm−1/GPa and 2.3 GPa cm−1/GPa, respectively) do not. Measurements of the piezospectroscopic tensor coefficients are shown to have interlaboratory relative consistency of about 4 % extending over 30 years, and are consistent with the scalar high-pressure measurements. Measurements of the temperature coefficients are shown to have interlaboratory relative consistency less than 1 % extending over 60 years. Fluorescence-based measurements of stress in polycrystalline Al2O3, although requiring temperature adjustment, are shown to have a relative uncertainty of about 2.5 %.

show abstract

“…For the laser with a wavelength of ~532 nm, the values of k are about 0.017 for amorphous carbon and 0.0013 for 3C-SiC [22]. Therefore, the effective penetration depth for the PyC layer and the SiC layer can be estimated to be ~1.25 μm and ~16.28 μm, respectively, which is also confirmed by the depth scan measurement [23]. Figure 4 shows the intensity as a function of defocus distance (the distance away from the focal plane (i.e.…”

Section: Raman Spectroscopy Of Triso Particle Layersmentioning

confidence: 65%

Evaluation of thermal conductivity of the constituent layers in TRISO particles using Raman spectroscopy

Cao

Liu

Wang

et al. 2017

Journal of the European Ceramic Society

View full text Add to dashboard Cite

The thermal conductivity of individual layer in the tristructural-isotropic fuel particle was evaluated using Raman spectroscopy. In this method, laser acted simultaneously as an excitation source and a heating source. A three-dimensional point-heating model was developed to estimate the local temperature rise in the probing volume of the laser. The thermal conductivity can be evaluated based on the dependences of the Raman peak position on the temperature and laser power. The calculated thermal conductivities were 8.9±0.2 W/m·°C, 13.9±1.5 W/m·°C and 11.9±0.9 W/m·°C for the buffer, the inner and the outer PyC layers, respectively. Contrastly, the thermal conductivity of the SiC layer was 4.1 W/m·°C, which is much lower than the reference value, e.g. 168 W/m·°C reported by López-Honorato et al. (J. Nucl. Mater. 378(1) 35-39, 2008). The uncertainty of employing Raman spectroscopy to determine thermal conducitvity was discussed.

show abstract

Confocal fluorescence microscopy in alumina-based ceramics: Where does the signal come from?

Cited by 20 publications

References 29 publications

Cr3+ microspectroscopy measurements and modelling of local variations in surface grinding stresses in polycrystalline alumina

Cr3+ microspectroscopy measurements and modelling of local variations in surface grinding stresses in polycrystalline alumina

Review: Coefficients for Stress, Temperature, and Composition Effects in Fluorescence Measurements of Alumina

Evaluation of thermal conductivity of the constituent layers in TRISO particles using Raman spectroscopy

Contact Info

Product

Resources

About