Effect of Glass Composition on the Thermal Expansion of Relict Crystals of RuO₂ in Doped Lead-Silicate Glasses (Thick Film Resistors)

Gulmurza Abdurakhmanov

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DOI: 10.4236/jmp.2011.27076                

Abstract

The thermal expansion coefficients (TEC) of RuO₂ crystallits in thick film resistor (TFR) composites, consisting of RuO₂ dispersed in lead-silicate glass of various compositions, were evaluated from X-ray diffraction patterns at temperatures 298; 773; 973 and 1123 K corresponding to characteristic temperatures of resistivity and thermopower anomalies of the TFRs. It has been found that TEC of free RuO₂ powder along a-axis has an anomaly at T > 973 K (expansion is replaced by constriction), whereas constriction along c-axes remains for all temperatures. This anomaly disappears in doped glass of simplest composition (2SiO₂.PbO) but occurs in glasses of some complex compositions. Symmetry of unit cell of RuO₂ is not changed in the temperature range investigated.

Keywords

Ruthenium Dioxide, Anomalous Thermal Expansion, High Temperature X-Ray Diffraction, Anomalies of Resistivity and Thermopowe

Conflicts of Interest

The authors declare no conflicts of interest.

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