Effect of surface properties of silver powder on the sintering of its thick-film conductor

The effect of the surface properties of silver powder on the sintering of its thick film has been investigated in this study. The variations in the sintering structure have been observed to depend upon the kind of surfactant treatment of the powders and their surface area (SA). Silver powders treated with both caprylic acid and triethanolamine show a better densification in both dried prints as well as fired films as compared with those treated with single surfactant or none. For the powders treated with both surfactants, the surface area primarily determines the densification of fired films. Powders with SA greater than 7 X 10(3) m(2) kg(-1) have thus been observed to be appropriate for thick-film applications, even at firing temperatures (450 degrees C) considerably lower than usual (800 degrees C). Structural evolution during firing has been studied by inspecting the morphology (as shown by scanning electron microscope) and sheet resistivity of the films.