Sol-Gel-Syntheses and Structural as well as Electrical Characterizations of Anatase- and Rutile-Type Solid Solutions...

Area of Science:

• Materials Science
• Solid-state Chemistry
• Crystallography

Background:

• The iridium-titanium oxide system (IrO2-TiO2) is crucial for understanding mixed oxide properties.
• Investigating solid solutions is key to tailoring material characteristics.

Purpose of the Study:

• To characterize solid solutions in the quasibinary iridium-titanium oxide system.
• To determine the solubility limits and structural behavior of iridium in titanium dioxide (TiO2) lattices.
• To examine the effect of iridium on the phase transformation between anatase and rutile TiO2.

Main Methods:

• X-ray diffraction (XRD) with Rietveld refinement for lattice parameter analysis.
• Compositional series (0-100 mol% iridium) and calcination temperature series.
• Two-point conductivity measurements under varying pressure.

Main Results:

• A complete solid solution series was confirmed for the rutile crystal structure.
• The solubility limit of iridium in the anatase lattice was determined to be 6.0(8) mol% via sol-gel processing.
• Iridium acts as a promoter for the anatase to rutile phase transition.
• XRD and conductivity data provide insights into phase segregation and conductivity mechanisms.

Conclusions:

• The iridium-titanium oxide system exhibits extensive solid solubility, particularly in the rutile phase.
• The sol-gel method has a defined limit for iridium incorporation into anatase TiO2.
• Iridium doping influences the phase stability and electrical properties of TiO2 materials.