Alfred University Research and Archive (AURA)

Photo-Induced Outgassing of Hollow Glass Microspheres

Show simple item record

dc.contributor.advisor Shelby, James Raszewski, Fabienne 2017-02-07T15:24:32Z 2017-02-07T15:24:32Z 2007-04
dc.description Advisory committee members: William Carlson, Alexis Clare, Matthew Hall. Dissertation completed in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in Glass Science at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University en_US
dc.description.abstract All as – received microsphere compositions exhibit large variations in microsphere diameter (10 – 280 μm) and wall thickness (0.90 – 2.78 μm) . The amber and undoped microspheres have true densities around 0.65 g/cm3, whereas the Fe, Ni and Co –doped microspheres have true densities between 0.29 – 0.4 g/cm3. An increase in the amount of gas released from microspheres is observed with a decrease in density for samples of the same mass. Activation energies for permeation of helium lie in the range of 17 – 30 kJ/g–atom, which is consistent with previous values for microspheres, but low compared to bulk glasses of similar composition (49 kJ/g–atom). Compared to thermal outgassing, photo outgassing of doped microspheres is immediate and requires less time to occur. The undoped microspheres do not demonstrate a photo – induced response and release gas only by heating from the infrared source. Photo – outgassing is characterized by switch – like behavior and is maximized at full lamp intensity. Wavelengths in the range of 1500 – 2200 nm are most responsible for the photo – response. Microspheres of all sizes have been successfully filled to pressures as high as 340 atm. The initial rate of photo and thermal outgassing increases significantly as the fill pressure is increased to 340 atm. All compositions exhibit minimal hydrogen losses when stored at room temperature for 5 weeks, with higher losses occurring at 50°C. Photo – ingassing has been demonstrated for doped microspheres and is more efficient than thermal ingassing up to ~300°C. Extended treatments in hydrogen up to 360 hours, results in formation of metallic particles in the nickel and cobalt doped microspheres. Considerably more nickel ions are reduced than cobalt ions during treatment, as metallic nickel can be detected by X – ray diffraction and the Curie temperature of nickel occurring at 352°C can be measured using thermogravimetric analysis under a magnetic field. Photo – outgassing is slightly increased after 335 hours of hydrogen treatment in the nickel and cobalt – doped samples, whereas there is no change in the iron – doped microspheres. en_US
dc.format.extent 195 pages en_US
dc.language.iso en_US en_US
dc.publisher New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering. en_US
dc.relation.ispartof Scholes Library en_US
dc.rights.uri en_US
dc.title Photo-Induced Outgassing of Hollow Glass Microspheres en_US
dc.type Thesis en_US

Files in this item

This item appears in the following Collection(s)

Show simple item record



My Account