Tailoring and Processing of Defect Free Barium Titanate Stannate Functionally Graded Ceramics: BTS2.5/BTS5/BTS7/BTS10 FGMs
Four-component barium titanate stannate (BaTi1−x Sn x O3, BTS) functionally graded materials (FGMs) were designed, processed and examined. BTS powders with different tin content (x = 0.025, 0.05, 0.07 and 0.10, abbreviated as BTS2.5, BTS5, BTS7 and BTS10, respectively) were used as ingredient materials. Four-layered samples, produced by powder-stacking method and uniaxial pressing, were consolidated in BTS2.5/BTS5/BTS7/BTS10 FGMs by sintering at 1420 °C with dwell time of 2 h. To achieve high-quality FGMs, without structural or microstructural damages, the master sintering curve (MSC) approach were used. In this study, the MSC was constructed for four-layered FGMs using shrinkage data obtained by a heating microscope during non-isothermal part of the sintering up to 1420 °C with heating rates of 2, 5, 10 and 30°/min. To prepare FGMs with desired final density the corresponding Θ value was estimated from the abscissa of the master sintering curve. Estimated Θ value was used in Φ(ρ) = logΘ(t,T(t)) equation, which correlate density (ρ) and the time and temperature dependent parameter Θ(t,T(t)). This calculation allowed us to determine experimental parameters which should be applied in sintering procedure to obtain FGMs with projected density. According to constructed MSC, four different sintering schedules were designed and applied where four BTS2.5/BTS5/BTS7/BTS10 FGMs were prepared. To validate the constructed MSC, the microstructure and chemical (Ti/Sn) gradient in the prepared FGMs were examined by SEM–EDS methods.
KeywordsBarium titanate stannate Functionally graded materials Master sintering curve Microstructure
This study was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia under grant no III45004. Part of the results was obtained at Jožef Stefan Institute in Ljubljana, Slovenia, owing the bilateral cooperation program between the Republic of Serbia and the Republic of Slovenia. The authors are grateful to Prof. Dr. Danilo Suvorov and Prof. Dr. Srečo Škapin for their precious and selfless help during the period 2009-2016.
- 2.M. Koizumi, M. Nino, Overview of FGM research in Japan, MRS Bull. 20(1), 19–21 (1995). (Special Issue, Functionally Gradient Materials, ed. by E.L. Fleischer)Google Scholar
- 5.B.H. Rabin, I. Shiota (Guest Editors), Functionally gradient materials. MRS Bull. 20(1), 14–18 (1995). (Special Issue, Functionally Gradient Materials, ed. by E.L. Fleischer)Google Scholar
- 6.S. Amada, Hierarchical functionally gradient structures of bamboo, barley, and corn. MRS Bull. 20(1), 35–36 (1995). (Special Issue, Functionally Gradient Materials, ed. by E.L. Fleischer)Google Scholar
- 7.M. Koizumi, Recent progress of functionally gradient materials in Japan, Ceram. Eng. Sci. Proc. 13, 337–347 (1992)Google Scholar
- 10.S. Marković, D. Uskoković, Sintering of defect-free BaTi0.975Sn0.025O3/BaTi0.85Sn0.15O3 functionally graded materials, in Advances and Applications in Electroceramics: Ceramic Transactions, vol. 226, ed. by K.M. Nair, S. Priya, Q. Jia (Wiley, New York, 2011), pp. 97–106. ISBN: 978-1-1180-5999-9Google Scholar
- 11.S. Marković, D. Uskoković, Barium titanate stannate functionally graded materials: choosing of the Ti/Sn concentration gradient and the influence of the gradient on electrical properties, in Advances in Electroceramic Materials II: Ceramic Transactions, vol. 221, ed. by K.M. Nair, S. Priya (Wiley, New York, 2010), pp. 3–17. ISBN: 978-0-470-92716-8Google Scholar
- 12.S. Marković, Č. Jovalekic, Lj. Veselinović, S. Mentus, D. Uskoković, Electrical properties of barium titanate stannate functionally graded materials. J. Eur. Ceram. Soc. 30, 1427–1435 (2010)Google Scholar
- 19.L.J. Veselinović, M. Mitrić, L. Mančić, M. Vukomanović, B. Hadžić, S. Marković, D. Uskoković, The effect of Sn for Ti substitution on the average and local crystal structure of BaTi1-xSnxO3 (0 ≤ x ≤ 0.20). J. Appl. Crystallogr. 47, 999–1007 (2014)Google Scholar