The wetting of tungsten and polycrystalline alumina by a liquid-phase-sintering model-glass in controlled atmospheres

Author

Jerold E. Lazaroff

Abstract

"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.

Advisor(s)

Ownby, P. D.

Committee Member(s)

Anderson, H. U. (Harlan U.)
Roach, D. Vincent

Department(s)

Materials Science and Engineering

Degree Name

M.S. in Ceramic Engineering

Publisher

University of Missouri--Rolla

Publication Date

Fall 1993

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

Pagination

xv, 139 pages

Note about bibliography

Includes bibliographical references.

Rights

© 1993 Jerold Earl Lazaroff, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Thesis Number

T 6645

Print OCLC #

30000873

Link to Catalog Record

Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.

Recommended Citation

Lazaroff, Jerold E., "The wetting of tungsten and polycrystalline alumina by a liquid-phase-sintering model-glass in controlled atmospheres" (1993). Masters Theses. 1190.
https://scholarsmine.mst.edu/masters_theses/1190