The development of the conductive phase in some thick-film resistors during firing

The development of the conductive phase in some thick-film resistors with both low and with high temperature coefficients of resistivity was studied using X-ray diffraction analysis and electron microscopy. After long-term high-temperature firing the conductive phase in thick-film resistors based on RuO₂ remains unchanged, while the ruthenates decompose. This is presumably due to interactions of the ruthenate with the silica-rich glass phase in the resistors. The reaction kinetics is faster for higher concentrations of SiO₂