WETTING IN AN ELECTRONIC PACKAGING CERAMIC SYSTEM .2. WETTING OF ALUMINA BY A SILICATE GLASS MELT UNDER CONTROLLED P(O2) CONDITIONS

The wetting of polycrystalline alumina by a colored, calcia-magnesia aluminosilicate glass was found to be dependent on temperature between 1300 degrees and 1500 degrees C, but independent of gas atmosphere effects, Neither the oxygen partial pressure, over the range of 10(-6) to 10(-10) Pa, the gas buffer system (CO/CO2 or H-2/H2O), nor pre-equilibration of the substrate surface with the atmosphere at the experimental temperature before solid-liquid interface formation affected the stable contact angle, An initial drop in contact angle occurring within the first hour is attributed to rapid dissolution of alumina and the formation of a stable glass/alumina interface, The contact angle after an 8-h isothermal hold decreased linearly from 29 degrees to 14 degrees as the temperature was increased from 1300 degrees to 1500 degrees C, The solid-liquid interfacial energy, gamma(sl), controls the wetting behavior, Changes in gamma(sl) are attributed to the breakup of the silica network as temperature increases.