“Bakor” Research Center for Special Ceramics, Shcherbinka, Russia:

B. L. Krasnyi, General Director, Doctor of Technical Sciences
K. I. Ikonnikov, Head of the Research Center for Special Ceramics, Candidate of Technical Sciences, e-mail: konst@ntcbakor.ru
A. L. Galganova, Deputy Head of the Research Center for Special Ceramics
O. I. Rodimov, Research Associate of the Research Center for Special Ceramics

The publication provides general information about CaZrCh, discusses synthesis methods and main application areas. Based on the analysis of sources, it was found that the least expensive and easiest technique is solid-phase synthesis from natural carbonate powder and zirconium dioxide. The morphology of powders of micromarble brand KM-2, monoclinic zirconium dioxide brand CrO-1 and calcium metazirconate of domestic production is investigated. To determine the temperature of calcium zirconate synthesis from the initial powders of zirconium dioxide and calcium carbonate, a differential thermal analysis was used. The temperature of the chemical compound formation is approximately 1230 ^oC. Calcination of a mixture of initial powders was carried out at temperatures of 1100, 1200, 1300 and 1400 ^oC. X-ray phase and microscopic analysis of the obtained powders was conducted. It is established that at a temperature of 1100 ^oC solid-phase synthesis does not occur, at 1200 ^oC it does not pass completely, at 1300 ^oC and 1400 ^oC it is fully completed. However, the powder synthesized at 1400 ^oC is dense aggregated, the destruction of which requires mechanical action. And the powder synthesized at 1300 ^oC consists of friable particles that can be easily desegregated and is sinter active. A comparison between cera mics obtained from synthesized powder and from calcium meta zirconate of domestic production was carried out. The material made of the synthesized powder has a denser structure and greater strength. The crucible from the synthesized powder was successfully tested under vacuum heating conditions to a temperature of 1600 ^oC in contact with of Ti – Ni – Hf and Ti – Zr – Nb preforms.

1. Kim S. K., Kim T. K., Kim M. G., Hong T. W. et al. Investment casting of titanium alloys with CaO crucible and CaZrO₃ mold. Lightweight Alloys for Aerospace Applications. 2001. pp. 251–260. DOI: 10.1002/9781118787922.ch.23.
2. Schaffoner S., Aneziris C. G., Berek H., Rotmann B. et al. Investigating the corrosion resistance of calcium zirconate in contact with titanium alloy melts. Journal of the European Ceramic Society. 2015. Vol. 35, No. 1. pp. 259–266.
3. Schaffоner S., Qin T., Fruhstorfer J., Jahn C. et al. Refractory castables for titanium metallurgy based on calcium zirconate. Materials & Design. 2018. Vol. 148. pp. 78–86.
4. Klotz U. E., Legner C., Bulling F. et al. Investment casting of titanium alloys with calcium zirconate moulds and crucibles. International Journal of Advanced Manufacturing Technology. 2019. Vol. 103. pp. 343–353.
5. Schaffоner S., Fruhstorfer J., Faauer C., Freitag L., Jahn C. et al. Advanced refractories for titanium metallurgy based on calcium zirconate with improved thermomechanical properties. Journal of the European Ceramic Society. 2019. Vol. 39, No. 14. pp. 4394–4403.
6. Schaffоner S. Reactions of alkaline earth zirconate refractories with titanium alloys. MATEC Web of Conferences. 2020. Vol. 321, No. 10012. pp. 1–11.
7. Nadler M. R., Fitzsimmons E. Preparation and properties of calcium zirconate. Journal of the American Ceramic Society. 1955. Vol. 38, No. 6. pp. 214–217.
8. Reznitskiy L. A., Guzey A. S. Thermodynamic properties of alkaline earth titanates, zirconates and hafnates. Uspekhi khimii. 1978. Vol. XLVII, Iss. 2. pp. 177–211.
9. Du Y., Jin Z., Huang P. Thermodynamic calculation of the zirconiacalcia system. Journal of the American Ceramic Society. 2005. Vol. 75, No. 11. pp. 3040–3048.
10. Phase Equilibria Diagrams. Electronic Data and Programmes. ACerS-NIST. CD-ROM Database. Version 3.1.0
11. Iano R. G. Temperature and atmosphere influence during combustion synthesis of metal oxide (nano) powders: Habilitation Thesis. Politehinca University of Timisoara, Faculty of Industrial Chemistry and Environmental Engineering, 2015. p. 105.
12. Koopmans H. J. A., Van de Velde G. M. H., Gellings P. J. Powder neutron diffraction study of the perovskites CaTiO₃ and CaZrO₃. Acta Crystallographica Section C. 1983. Vol. 39. pp. 1323–1325.
13. Hou T. I., Kriven W. M. Mechanical properties and microstructure of Ca₂SiO₄–CaZrO₃ composites. Journal of the American Ceramic Society. 1994. Vol. 77, No. 1. pp. 65–72.
14. Rog G., Dudek M., Kozlowska-Rog A., Bucko M. Calcium zirconate: preparation, properties and application to the solid oxide galvanic cells. Electrochimica Acta. 2002. Vol. 47, No. 28. pp. 4523–4529.
15. Serena S., Sainz M. A., Caballero A. Corrosion behavior of MgO/CaZrO₃ refractory matrix by clinker. Journal of the European Ceramic Society. 2004. Vol. 24, No. 8. pp. 2399–2406.
16. Suzuki Y., Morgan P. E. D., Ohji T. New uniformly porous CaZrO₃/MgO composites with three-dimensional network structure from natural dolomite. Journal of the American Ceramic Society. 2000. Vol. 83, No. 8. pp. 2091–2093.
17. Janke D. Oxygen probes based on calcia-doped hafnia or calcium zirconate for use in metallic melts. Metallurgical and Materials Transactions A. 1982. Vol. B 13, No. 2. pp. 227–235.
18. Yajima T., Kazcoka H., Yogo T., Iwahara H. Proton conduction in sintered oxides based on CaZrO₃. Solid State Ionics. 1991. Vol. 47, No. 3–4. pp. 271–275.
19. Gonenli I. E., Tas A. C. Chemical synthesis of pure and Gd-doped CaZrO₃ powders. Journal of the European Ceramic Society. 1999. Vol. 19, No. 13–14. pp. 2563–2567.
20. Pollet M., Daturi M., Marinel S. Vibrational spectroscopy study of the lattice defects in CaZrO₃ ceramics. Journal of the European Ceramic Society. 2004. Vol. 24, No. 6. pp. 1805–1809.
21. Prasanth C. S., Kumar H. P., Pazhani R., Solomon S. et al. Synthesis, characterization and microwave dielectric properties of nanocrystalline CaZrO₃ ceramics. Journal of Alloys and Compounds. 2008. Vol. 464, No. 1–2. pp. 306–309.
22. Yu T., Zhu W., Chen C., Chen X. et al. Preparation and characterization of sol–gel derived CaZrO₃ dielectric thin films for high-k applications. Physica B. 2004. Vol. 348, No. 1–4. pp. 440–445.
23. Qiu X. Y., Liu H. W., Fang F. F., Ha M. J. Thermal stability and dielectric properties of ultrathin CaZrO_x films prepared by pulsed laser deposi- tion. Applied Physics A. 2005. Vol. 81, No. 7. pp. 1431–1434.
24. Qiu X. Y., Liu H. W., Fang F., Ha M. J. et al. Interfacial properties of high-k dielectric CaZrO_x films deposited by pulsed laser deposition. Applied Physics Letters. 2006. Vol. 88, Iss. 18. p. 182907. 25. Schafföner S., Aneziris C. G., Berek H., Hubálková J. et al. Fused calcium zirconate for refractory applications. Journal of the European Ceramic Society. 2013. Vol. 33, No. 15–16. pp. 3411–3418.
26. Baudín C., Pena P., Obregón Á., Rodríguez-Galicia J. L. Mechanical behaviour of MgO – CaZrO₃-based refractories for cement kilns. Advances in Science and Technology. 2010. Vol. 70. pp. 47–52.
27. Schafföner S., Fruhstorfer J., Faauer C., Freitag L. et al. Influence of in situ phase formation on properties of calcium zirconate refractories. Journal of the European Ceramic Society. 2017. Vol. 37, No. 1. pp. 305–313.
28. Freitag L., Schafföner S., Lippert N., Faauer C. et al. Silica-free investment casting molds based on calcium zirconate. Ceramics International. 2017. Vol. 43, No. 9. pp. 6807–6814.
29. Lu M.-W., Lin K.-L., Lin C.-C. Investigation of the interactions between titanium and calcium zirconium oxide (CaZrO₃) ceramics modified with alumina. Processing and Application of Ceramics. 2019. Vol. 13, No. 1. pp. 79–88.
30. Vassen R., Cao X., Tietz F., Basu D. et al. Zirconates as new materials for thermal barrier coatings. Journal of the American Ceramic Society. 2000. Vol. 83, No. 8. pp. 2023–2028.
31. Jahn C., Schafföner S., Ode C., Jansen H. et al. Investigation of calcium zirconate formation by sintering zirconium dioxide with calcium hydroxide. Ceramics International. 2018. Vol. 44, No. 10. pp. 11274–11281.

32. Nadler M. R., Fitzsimmons E. S. Preparation and Properties of Calcium Zirconate. Journal of the American Ceramic Society. 1955. Vol. 38, No. 6. pp. 214–217.
33. Iwahara H., Yajima T., Hibino T., Ozaki K. et al. Protonic conduction in calcium, strontium and barium zirconates. Solid State Ionics. 1993. Vol. 61, No. 1–3. pp. 65–69.
34. Shumenko V. N., Kolenkova V. A., Dorokhina M. N. Interaction of brazilite with calcium oxide and carbonate. Izvestiya vuzov. Tsvetnaya metallurgiya. 1974. No. 3. pp. 96–100.
35. Keler E. K., Godina N. A. On solid phase reactions between zirconium dioxide and magnesium, calcium and barium oxides. Ogneupory. 1953. No. 9. pp. 416–426.
36. Boys G. V., Gindin E. I., Mikhaylova N. A., Prodavtsova E. I. Interaction of ZrO₂ with carbonates of alkaline earth metals. Neorganicheskie materialy. 1976. Vol. 12, No. 3. pp. 456–460.
37. Rog G., Dudek M., Kozlowska-Rog A., Bucko M. Calcium zirconate: preparation, properties and application to the solid oxide galvanic cells. Electrochimica Acta. 2002. Vol. 47, No. 28. pp. 4523–4529.
38. Song Z., Li Q., Ma D., Wen J. et al. Method for producing electric smelting calcium zirconate. Patent 1420103 CN. Applied: 27.12.2001. Published: 28.05.2003.
39. Belyaev I. N., Lupeyko V. I., Nalbandyan I., Efremova T. I. Synthesis of titanates and zirconates of alkaline earth metals from carbonates and dioxides in the presence of ionic melts. Zhurnal neorganicheskoy khimii. 1979. Vol. 24, No. 4. pp. 881–884.
40. Li Z., Lee W. E., Zhang S. Low-temperature synthesis of CaZrO₃ powder from molten salts. Journal of the American Ceramic Society. 2007. Vol. 90, No. 2. pp. 364–368.
41. Fazli R., Fazli M., Golestani-fard F., Mirhabibi A. The effects of raw materials particle size and salt type on formation of nano-CaZrO₃ from molten salts. Ceramics International. 2013. Vol. 38, No. 7. pp. 5775–5781.
42. Lee W. J., Wakahara A., Kim B. H. Decreasing of CaZrO₃ sintering temperature with glass frit addition. Ceramics International. 2005. Vol. 31, No. 4. pp. 521–524.
43. Yu T., Zhua W. G., Chen C. H., Chen X. F. et al. Preparation and characterization of sol–gel derived CaZrO₃ dielectric thin films for high-k applications. Physics B. 2004. Vol. 348, No. 1–4. pp. 440–445.
44. Brzezinska-Miecznik J., Haberko K., Bucko M. M. Barium zirconate ceramic powder synthesis by the coprecipitation–calcination technique. Materials Letters. 2002. Vol. 56, No. 3. pp. 273–278.
45. Gonenli E., Tas A. C. Chemical synthesis of pure and Gd-doped CaZrO₃ powders. Journal of the European Ceramic Society. 1999. Vol. 19, No. 13–14. pp. 2563–2567.
46. Ianos R., Barvinschi P. Solution combustions synthesis of calcium zirconate, CaZrO₃, powders. Journal of Solid State Chemistry. 2010. Vol. 183, No. 3. pp. 491–496.
47. GOST 2409–2014. Refractories. Method for determination of bulk density, apparent and true porosity, water absorption. Introduced: 01.09.2015.
48. GOST 4071.1–94. Refractory products with a true porosity of less than 45%. Determination of cold compressive strength. Introduced: 01.01.1996.
49. GOST 8691–2018. Refractory products of general use. Form and size. Introduced: 01.02.2019.
50. Technical conditions 5716-001-32524584–2014. Conditioned ground marble and crushed marble. Introduced: 01.11.2014.
51. GOST 21907–76. Zirconium dioxide. Specifications. Introduced: 01.01.1977.
52. Technical conditions 6-09-2214–77. Calcium metazirconate (calcium zirconate meta). Chandes 1-3. Introduced: 01.10.1977.