Effect of TiO₂ addition on zirconia-mullite composites fabricated by in-situ controlled crystallization of Si-Al-Zr-O amorphous bulk

Abstract

Zirconia-mullite composite ceramics were fabricated by in-situ controlled crystallization of Si-Al-Zr-O amorphous bulk. The effects of TiO₂ addition on the fabrication of zirconia-mullite composites were investigated. The ultra-fine zirconia-mullite composite ceramics were prepared from the amorphous bulk treated at 980 °C for nucleation and 1 140 °C for crystallization. The phase transformation of the ceramics was examined using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). The microstructural features of the samples were evaluated with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX) and transmission electron microscopy (TEM). The mechanical properties were also determined using Vickers indentation. The results show that the TiO₂ additives with mass fraction of 1%–7% reduce the formation temperature of t-ZrO₂ and mullite. When the mass fraction of TiO₂ additives is less than 5%, the phases do not change, and most of TiO₂ dissolves in ZrO₂. When the mass fraction of TiO₂ additives is over 5%, the excessive TiO₂ forms a new phase, ZrTiO₄. Meanwhile, the results also show that TiO₂ additives have a great impact on the microstructure and mechanical properties of zirconia-mullite composites. As the TiO₂ content increases from 1% to 7% (mass fraction), the grain size and the Vickers hardness of zirconia-mullite composites increase. The composite with 3% (mass fraction) TiO₂ additives attains relatively higher fracture toughness.

Keywords

TiO₂ / ZrO₂ / mullite / comoposites

References

[1] SchineiderH., SchreuerJ., HildmannB.. Structure and properties of mullite—A review [J]. Am Ceram Soc, 2008, 28(2): 329-344

[2] MedvedovskiE.. Alumina-mullite ceramics for structural applications [J]. Ceramics International, 2006, 32(4): 369-375

[3] LanF. T., LiK. Z., LiH. J., FuQ. G.. A cordierite mullite anti-oxidation coating for carbon composite [J]. Carbon, 2007, 45(13): 2692-2716

[4] ZhangH. Y., MaljkovicN., MitchellB. S.. Structure and interfacial properties of nanocrystalline alumina/mullite composites [J]. Mater Sci Eng A, 2002, 326(2): 317-323

[5] GarridoL. B., AgliettiE. F.. Reaction-sintered mullite-zirconia composites by colloidal processing of alumina-zircon-CeO₂ mixtures [J]. Mater Sci Eng A, 2004, 369(1/2): 250-257

[6] GarridoL. B., AgliettiE. F., MartorelloL., CamerucciM. A., CavalieriA. L.. Hardness and fracture toughness of mullite-zirconia composites obtained by slip casting [J]. Mater Sci Eng A, 2006, 419(1/2): 290-296

[7] AnanthakumarS., JayasankarM., WarrierK. G. K.. Microstructural, mechanical and thermal characterization of sol-gel derived aluminium titanate-mullite ceramic composites [J]. Acta Materialia, 2006, 54(11): 2965-2973

[8] KhorK. A., YuL. G., LiY.. Spark plasma reaction sintering of ZrO₂-mullite composites from plasma spheroidized zircon/alumina powers [J]. Mater Sci Eng A, 2003, 339(1/2): 286-296

[9] EbadzadehT., GhasemiE.. Effect of TiO₂ addition on the stability of t-ZrO₂ in mullite-ZrO₂ composites prepared from various starting materials [J]. Ceram int, 2002, 28(4): 447-450

[10] HongJ. S., HuangX. X., GuoJ. K., LiB. S., GuiL. H.. Strengthening and toughening of mullite ceramics by SiC particles and Y-TZP [J]. J Inorg Mater, 1990, 5(4): 340-345

[11] WangJ., KouH. M., KouL. X. J., PanY. B., GuoJ. K.. Reinforcement of mullite matrix with multi-walled carbon nanotubes [J]. Ceram int, 2007, 33(5): 719-722

[12] JinX. H., GaoL., KanY. M., ChenY. R., YuanQ. M.. Influence of Nb₂O₅ on the mechanical performances and toughening mechanism of ZrO₂ in ZTM-Al₂O₃ [J]. J Inorg Mater, 2000, 15(6): 1009-1014

[13] HuangY. F., XieG. S., XiaoH. N.. The influence of CeO₂ in ZTM ceramics prepared by in-situ sintering [J]. Ceramics, 2006, 6: 9-11

[14] LiangS. Q., LiS., TanX. P.. Crystallization behavior of Si-Al-Zr-O amorphous bulk with higher zirconium [J]. Chin J Nonferrous Met, 2005, 15(8): 1189-1194

[15] PontonC. B., RawlingsR. D.. Mechanical properties of siliceramic glass-ceramics [J]. Mater Sci Tech, 1989, 5(9): 865-872

[16] SchullerK. H.. Reaction between mullite and glassy phase in porcelains [J]. Br Ceram Soc, 1964, 63(2): 103-117

[17] ComerJ. J.. Electron microscopy studies of mullite development in fired kaolinites [J]. Am Ceram Soc, 1960, 43(7): 378-384

[18] HongS. H., MessingG. L.. Mullite transformation kinetics in P₂O₅₋, TiO₂₋ and B₂O₃-doped aluminosilicate gels [J]. Am Ceram Soc, 1997, 80(6): 1551-1559

[19] HongS. H., MessingG. L.. Anisotropic grain growth in diphasic-gel-derived titania-doped mullite [J]. Am Ceram Soc, 1998, 81(5): 1269-1277