About Titanates

Aluminum Titanate

Titanates are compounds containing titanium, oxygen, and at least one additional metallic element. Some of the most common titanates are strontium titanate, barium titanate, calcium titanate, and dysprosium titanate.

Strontium titanate, at room temperature, is a centrosymmetric paraelectric material with a perovskite structure. However, at low temperatures it nears a ferroelectric phase transition with a very large dielectric constant, but remains paraelectric down to the lowest temperatures measured. It was long thought to be an entirely artificial material until 1982 when its natural counterpart tausonite was recognized. Tausonite remains an extremely rare mineral in nature, occurring as extremely small crystals. Strontium titanate’s most important application has been in its synthesized form; it is occasionally used as a diamond alternative, in precision optics, in varistors, and in advanced ceramics. Strontium titanate is both much denser and much softer than diamond. Its crystal system is cubic and its refractive index is nearly identical to that of diamond, but the dispersion (the optical property responsible for the "fire" of cut gem stones) of strontium titanate is over four times higher, resulting in an excess of fire when compared to diamond.

Synthetic strontium titanate is usually transparent and colorless, but it can be doped with certain rare earth or transition metals to produce red, yellow, brown, and blue hues. Natural tausonite is usually translucent to opaque, in shades of reddish brown, dark red, or grey. Both have an diamond-like luster. Synthetic strontium titanate has a very large dielectric constant and is used in high-voltage capacitors. At 0.35 K strontium titanate is superconductive and was the first insulator and oxide in which this property was studied. At temperatures lower than 105 K, its cubic structure transforms to tetragonal, making it an excellent substrate for epitaxial growth of high-temperature superconductors and many oxide-based thin films. Strontium titanate can be used as optical windows and high-quality sputtering targets.

Strontium titanate is also periodically manufactured for use in jewelry. It is one of the most costly of diamond alternatives, and due to its rarity collectors may pay a premium for large specimens. As a diamond substitute, strontium titanate is most deceptive when mingled with melée and when it is used as the base material for a composite or doublet stone. Under the microscope, gemologists distinguish strontium titanate from diamond by the former's softness and excess dispersion, and occasional gas bubbles which are remnants of synthesis. Doublets can be detected by a join line at the girdle and flattened air bubbles or glue visible within the stone at the point of bonding.

Barium titanate is an oxide composed of barium and titanium. Barium titanate appears as white powder or transparent crystals. It is insoluble in water, but will dissolve in concentrated sulfuric acid. It is a ferroelectric ceramic material, with a photorefractive effect and piezoelectric properties. Solid barium titanate has five phases: hexagonal, cubic, tetragonal, orthorhombic, and rhombohedral crystal structure. All of the crystal structures with the exception of the cubic exhibit the ferroelectric effect. Barioperovskite is a very rare natural analogue of barium titanate, found as micro-inclusions in benitoite. Adding of inclusions of barium titanate to tin has been shown to create material with a higher visco-elastic stiffness than that of diamonds.

Barium titanate can be manufactured by liquid phase sintering of barium carbonate and titanium dioxide, sometimes with other materials for doping. Barium titanate is often mixed with strontium titanate and is used as a dielectric material for ceramic capacitors and as a piezoelectric material for microphones and other transducers. Polycrystalline barium titanate displays positive temperature coefficient, making it a useful material for thermostats and self-regulating electric heating systems. High purity barium titanate powder is reported to be a key component of new barium titanate capacitor-based alternative energy storage systems for use in electric vehicles.

Barium titanate crystals can be used in nonlinear optics. The material has high beam-coupling gain, and can be operated at visible and near-infrared wavelengths. It has the highest reflectivity of the materials used for self-pumped phase conjugation applications. Thin films of barium titanate display electro-optic modulation to frequencies over 40 GHz. The pyro-electric and ferroelectric properties of barium titanate are exploited in some types of uncooled sensors for thermal cameras.

Calcium titanate is a chemical compound and a mineral known as perovskite, named after Russian mineralogist, L. A. Perovski (1792-1856). Calcium titanate can aid in the integration of biomaterials such as bone implants in hip replacement surgery. It has low dielectric loss, especially at microwave frequencies and is therefore used as dielectric material in ceramic capacitors.

Dysprosium titanate is a ceramic titanate with pyrochlore structure and is a "spin ice" material. In 2009, dysprosium titanate was observed to have quasi-particles resembling magnetic monopoles at low temperature and high magnetic field. Dysprosium titanate is also being investigated as a new material for nuclear reactor control rods.

Recent Research & Development for Titanates

Titanium dioxide nanoparticles-based colorimetric sensors for determination of hydrogen peroxide and triacetone triperoxide (TATP)., Gökdere, Bahar, Üzer Ayşem, Durmazel Selen, Erçağ Erol, and Apak Reşat , Talanta, 2019 Sep 01, Volume 202, p.402-410, (2019)

Piezoelectric barium titanate nanostimulators for the treatment of glioblastoma multiforme., Marino, Attilio, Almici Enrico, Migliorin Simone, Tapeinos Christos, Battaglini Matteo, Cappello Valentina, Marchetti Marco, de Vito Giuseppe, Cicchi Riccardo, Pavone Francesco Saverio, et al. , J Colloid Interface Sci, 2019 Mar 07, Volume 538, p.449-461, (2019)

Polyarylene Ether Nitrile and Barium Titanate Nanocomposite Plasticized by Carboxylated Zinc Phthalocyanine Buffer., Liu, Shuning, Liu Chenchen, Liu Changyu, Tu Ling, You Yong, Wei Renbo, and Liu Xiaobo , Polymers (Basel), 2019 Mar 04, Volume 11, Issue 3, (2019)

Electrical and Magnetic Properties of Barium Hexaferrite Modified Barium Zirconium Titanate Lead-Free Ceramics., Jarupoom, Pakpoom, Jaita Pharatree, Manotham Supalak, Phatungthane Thanatep, Chokethawai Komsanti, Randorn Chamnan, and Rujijanagul Gobwute , J Nanosci Nanotechnol, 2019 Mar 01, Volume 19, Issue 3, p.1276-1282, (2019)

Preparation, characterization and evaluation of the zinc titanate and silver nitrate incorporated wipes for topical chemical and biological decontamination., Sharma, Navneet, Chaudhary Mamta, Butola Bhupendra Singh, Jeyabalaji Joseph Kingston, Pathak Dharm Pal, and Sharma Rakesh Kumar , Mater Sci Eng C Mater Biol Appl, 2019 Mar, Volume 96, p.183-196, (2019)

Morphology-controlled synthesis of calcium titanate particles and adsorption kinetics, isotherms, and thermodynamics of Cd(II), Pb(II), and Cu(II) cations., Hang, Ying, Si Yang, Zhou Qin, Yin Hengbo, Wang Aili, and Cao Amei , J Hazard Mater, 2019 Jun 28, Volume 380, p.120789, (2019)

Atomic-scale investigation on the ultra-large bending behaviours of layered sodium titanate nanowires., Liu, Qiong, Zhan Haifei, Zhu Huaiyong, Sun Ziqi, Bell John, Bo Arixin, and Gu YuanTong , Nanoscale, 2019 Jun 20, Volume 11, Issue 24, p.11847-11855, (2019)

Ethanol-Quenching Introduced Oxygen Vacancies in Strontium Titanate Surface and the Enhanced Photocatalytic Activity., Xiao, Yang, Chen Shihao, Wang Yinhai, Hu Zhengfa, Zhao Hui, and Xie Wei , Nanomaterials (Basel), 2019 Jun 14, Volume 9, Issue 6, (2019)

Titanate Nanowires as One-Dimensional Hot Spot Generators for Broadband Au-TiO Photocatalysis., Negrín-Montecelo, Yoel, Testa-Anta Martín, Marín-Caba Laura, Pérez-Lorenzo Moisés, Salgueiriño Verónica, Correa-Duarte Miguel A., and Comesaña-Hermo Miguel , Nanomaterials (Basel), 2019 Jul 09, Volume 9, Issue 7, (2019)

Barium Titanate-Based Porous Ceramic Flexible Membrane as a Separator for Room-Temperature Sodium-Ion Battery., R, Arunkumar, Saroja Ajay Piriya Vij, and Sundara Ramaprabhu , ACS Appl Mater Interfaces, 2019 Jan 30, Volume 11, Issue 4, p.3889-3896, (2019)

Gold Size Effect in the Thermal-Induced Reaction of CO₂ and H₂ on Titania- and Titanate Nanotube-Supported Gold Catalysts., László, Balázs, Baán Kornélia, Ferencz Zsuzsa, Galbács Gábor, Oszkó Albert, Kónya Zoltán, Kiss János, and Erdőohelyi András , J Nanosci Nanotechnol, 2019 Jan 01, Volume 19, Issue 1, p.470-477, (2019)

Preparation, characterization and investigation of sonophotocatalytic activity of thulium titanate/polyaniline nanocomposites in degradation of dyes., Sobhani-Nasab, Ali, Behpour Mohsen, Rahimi-Nasrabadi Mehdi, Ahmadi Farhad, Pourmasoud Saeid, and Sedighi Farideh , Ultrason Sonochem, 2019 Jan, Volume 50, p.46-58, (2019)

Large Pockels effect in micro- and nanostructured barium titanate integrated on silicon., Abel, Stefan, Eltes Felix, J Ortmann Elliott, Messner Andreas, Castera Pau, Wagner Tino, Urbonas Darius, Rosa Alvaro, Gutierrez Ana M., Tulli Domenico, et al. , Nat Mater, 2019 Jan, Volume 18, Issue 1, p.42-47, (2019)