"Factors that effect the wetting of tungsten and polycrystalline alumina by a Cr- doped calcia-magnesia-aluminosilicate glass was investigated.
In part I, the wetting of tungsten by the glass was found to be dependent on oxygen partial pressure. The degree of wetting was also effected by whether or not the substrate was allowed to equilibrate with the atmosphere before the formation of the solid-liquid interface. The contact angle decreased with increasing pO2. The wetting was also found to be independent of temperature, over the range 1300 - 1500°C. .
Evidence of dissolution of tungsten in the glass was observed and sometimes resulted in a tungsten precipitate forming on the surface of the glass drop. The oxidation state of the chromium ion in the glass varied from Cr3+ to Cr2+ to Cr according to the pO2 over the range from 10-10.9 to 10-15.6 atm and could be observed from the color of the cooled sessile drop.
In part II, the wetting of polycrystalline alumina by the same glass composition was independent of oxygen partial pressure, buffer system, and equilibration between substrate and atmosphere before formation of sessile drop. It was only dependent on temperature, with contact angle decreasing with increasing temperature. In a few cases, devitrification of the glass was observed with the crystalline phase being identified as anorthite. Over the pO2 range from 10-11.7 to 10-14.1 atm, the dominant oxidation state of the chromium ion was Cr2+"--Abstract, page iv.
Ownby, P. D.
Anderson, H. U. (Harlan U.)
Roach, D. Vincent
Materials Science and Engineering
M.S. in Ceramic Engineering
University of Missouri--Rolla
Journal article titles appearing in thesis/dissertation
- Wetting in an Electronic Packaging Ceramic System, I: Wetting of Tungsten by a Liquid-Phase-Sintering Model-Glass
- Wetting in an Electronic Packaging Ceramic System, II: Wetting of Polycrystalline Alumina by a Liquid-Phase-Sintering Model-Glass
xv, 139 pages
© 1993 Jerold Earl Lazaroff, All rights reserved.
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Lazaroff, Jerold E., "The wetting of tungsten and polycrystalline alumina by a liquid-phase-sintering model-glass in controlled atmospheres" (1993). Masters Theses. 1190.
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