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 a luminosilicate glass was found to be dependent on temperature between 1300 degrees and 1500 degrees C, but independent of gas atmosphere eff ects, 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-equili bration of the substrate surface with the atmosphere at the experiment al temperature before solid-liquid interface formation affected the st able contact angle, An initial drop in contact angle occurring within the first hour is attributed to rapid dissolution of alumina and the f ormation of a stable glass/alumina interface, The contact angle after an 8-h isothermal hold decreased linearly from 29 degrees to 14 degree s 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 s ilica network as temperature increases.