Synthesis by coprecipitation of india-stabilized zirconia and codoping with MoO3, WO3, TaO2.5, or NbO2.5 for application as thermal barrier coatings

Author(s)

Roger Honorato Piva ^[1] ; Diógenes Honorato Piva ^[2] ; Márcio Raymundo Morelli ^[3]

Affiliation

^[1] Federal University of São Carlos. Materials Engineering Department - Brasil

^[2] Federal University of São Carlos. Materials Engineering Department - Brasil

^[3] Federal University of São Carlos. Materials Engineering Department - Brasil

• Document type: Journal article
• Source: MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS; v. 19, n. 1, p. 31-39, 2016-02-05.

Abstract

Coprecipitation synthesis of nanocrystalline india-stabilized zirconia with high surface area and codoping with MoO3, WO3, TaO2.5, or NbO2.5 is reported. The concentration of codopants was defined by the charge-compensating mechanism. Ethanol washing followed by azeotropic distillation and freeze drying were compared as dehydration techniques for the gels. As determined by XRD and Raman scattering, 9 mol% of InO1.5 plus charge-compensating dopants is sufficient to completely stabilize the high-temperature tetragonal phase of zirconia. The effect of alloying hexavalent and pentavalent oxides was secondary compared to the InO1.5 concentration in the retention of the tetragonal structure. Improved specific surface area of 106.1 m2 g‒1 and crystallite size between 8 and 9 nm were achieved through ethanol washing and subsequent azeotropic distillation even after calcination at 600 ºC. This result is attributed to the effect of the incorporation of ethoxy and butoxy groups after the treatment of the gels in organic medium, as detected by FT-IR spectroscopy and DSC/TG. (AU)

• FAPESP's process: 13/14189-8 - Nb2O5/Ta2O5 + Sc2O3 codoped zirconia as a thermal barrier coating for turbines application
• Grantee: Roger Honorato Piva
• Support Opportunities: Scholarships in Brazil - Doctorate