Influence of platinum foil impurities on sintering of functional ceramics

Impurities in ceramic powders or in the sintering atmosphere can have a strong influence on the densification and microstructure development during sintering. Our sintering studies have shown that the presence of bulk platinum and adsorbed minor amounts of adsorbed impurities during the sintering process can affect the microstructural and property development of materials via the gas phase. Four different oxide powders were shaped into green bodies and sintered in presence and absence of bulk platinum. Analyses of the materials after sintering show clear differences in the microstructure and the electronic properties between samples sintered in a furnace environment and those sintered in contact or in the close vicinity of platinum foil. When Pt foil had been present in the sintering set-up, trace chemical analysis detected accumulations of the platinum metal and other trace impurities at crucible surfaces which had not been in direct physical contact with Pt foil.