Application of NDE methods to green ceramics: initial results

Abstract

Calculation of Geometric Unsharpness, U_ 4 LIST OF FIGURES (continued) No. Title Page 5. Prints of a Microfocus Radiograph (Top) and a Conventional Radiograph (Bottom) of Green Ceramic Sample NB10, Showing Small Inclusions (Black Dots) 11 6. Echoes from a 3.8-mm-Thick YCrO., Sample Insonified with (Top) Longitudinal Waves and (Bottom) Shear Waves at 2.25 MHz 13 7. Sample Density vs Longitudinal Velocity of Sound for MgO + 20% Carbowax 14 8. Theoretical Upper and Lower Bounds for Longitudinal Velocity vs Carbowax Volume Fraction 15 9. Frequency Spectra for Longitudinal Waves Propagating in (A) Plexiglass and (B-D) Spinel Disks with Agglomerate Contents of (B) 0%, (C) 2%, and (D) 20% 17 10. Shear-Wave Velocity vs Applied Transducer Pressure for Silicon Nitride Greenware 18 11. Longitudinal-Wave Velocity vs Transducer Pressure for Spinel (Upper Curve) and Silicon Nitride Greenware 19 12. Phase Velocities (Dashed Curves) and Group Velocities (Solid Curves) of Longitudinal and Shear Waves as a Function of Frequency 20 13. Reference Transmission through Plexiglass 20 14. Variation of Received Longitudinal-Wave Specfum with Transducer Pressure 21 15. Comparison of Received Shear-Wave Spectra Obtained.with Transducer Pressures of 200 and 1400 kPa 21 16. Shear-Wave Spectrum for Spinel Sample NB2 21 17. NMR Image of Slices through a Water-doped SiC Disk (Axial View). . 23 18. NMR Image of Same Sample as Fig. 17 (Side View) 24 LIST OF TABLES I. Green Ceramic Specimens Used in the Present Investigation 3 II. Availability of Microfocus X-Ray Units 7 III. Sound Velocity in YCrO 3 Sample with PVA Binder 12

Review and Statistical Analysis of the use of Ultrasonic Velocity for Estimating the Porosity Fraction in Polycrystalline Materials

“…REVIE~ AND ANALYSIS V versus %P data were obtained for Al203 [20][21][22][23], MgO [24], porcelain-based ceramics [7,25] Tables 1 and 2 Table 1 presents the linear regression statistics corresponding to the scatter plots. The 95 percent confidence interval for the predicted slope and intercept values are presented in the table while the 95 percent confidence interval for mean predicted velocity values is shown by dashed lines on the scatter plots.…”

O efeito do ultra-som em reações químicas

“…A partir de 1980 a sonoquímica sofreu grande avanço e muitos trabalhos foram publicados em diferentes sistemas 2 . O ultra-som é usado na indústria 1,2 para limpeza de materiais, solda de plásticos, processos químicos, preparação de emulsão e suspensão, desgaseificação de solventes e avaliação não-destrutiva 4 em materiais, isto é, a obtenção de informações sobre defeitos, fraturas, aglomerados, inclusão e anisotropia; em hospitais para análise de imagem 2 e estimulação do calo ósseo 5,6 .…”

Proton NMR Imaging of Green State Ceramics

“…This paper explores the applicability of proton NMR imaging to the QNDE of ceramic materials. While proton NMR imaging is clearly well developed in the area of medical applications (1), onlya few experiments have been performed to determine the applicability of this technique to the analysis of ceramic bodies (2). Compared to the NMR imaging of soft tissues for medical applications, the magnetic interactions of protons in solids or semi-solids make high resolution image generat ion more difficult.…”