Browsing by Author "Lynch, Matthew"

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    Deposition and Single-Step Processing of YBCO Thick Films for Multilayered Electronics
    Langman, Jonathan; Lynch, Matthew (Virginia Tech Department of Materials Science and Engineering, 2005-09-22)
    The goal of this project was to successfully cofire a screen-printed yttrium bar ium copper oxide (YBCO) superconductor onto a low-temperature cofired ceramic (LTCC) substrate. The purpose was to investigate the compatibility of thick-film, high-temperature superconductors with multilayered ceramic (MLC) packages for cryogenic applications. Paste consisting of standard organics and YBCO powder of -325 mesh particle size was screen-printed onto Dupont 951 Green Tape. The system was cofired at temperatures ranging from 925°C to 975°C. The quality of the cofired system was characterized in several ways: Meissner diamagnetism, scanning electron microscopy, x-ray diffraction, and AC susceptibility tests were performed to determine the superconducting capability of the system. Samples cofired at 950°C retained some superconductivity after firing and showed the best compromise be­tween sintering and degradation.
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    The Effect of Microwaves on Aqueous Corrosion of Glass
    Lynch, Matthew (Virginia Tech, 2006-07-24)
    Glass corrodes in aqueous environments. The corrosion process is well-understood for many circumstances involving long periods of time at room temperature as well as processes that involve conventional heating, but the effect of microwave energy on glass corrosion has never been fully investigated. It was suspected that microwaves may alter or accelerate the aqueous corrosion processes that occur in glass which contribute to migration into foods or other materials. Lithium disilicate (Li2O-2SiO2) and commercial soda-lime glass were corroded using both conventional and microwave heating in this study. The results did not clearly show substantial differences in corrosion under the test conditions, but leave open the possibility of an altered mechanism in some circumstances. These findings suggest the need for testing at a lower microwave frequency, specifically 2.45 GHz.