Оксид титана висмута (Bi4Ti3O12)

Description

Bismuth titanium oxide Bi4Ti3O12 (bismuth titanate) is a complex oxide with a layered perovskite-like Aurivillius structure, consisting of alternating layers of [Bi2O2]2+ and perovskite blocks [Bi2Ti3O10]2-. CAS number 12010-77-4, EC number 234-564-6. Belongs to the class of ferroelectric ceramic materials.

Basic Attributes

• CAS No.: 12010-77-4
• Chemical formula: Bi4Ti3O12 (Bi, O, Ti)
• Molecular Weight: 1171.52
• Exact weight: 1171.70000
• EU number: 234-564-6
• PSA Specifications: 202

Physico-chemical characteristics

• Melting point: 1203 °C

Synonyms

Bismuth titanium oxide (Bi4Ti3O12); bismuth titanate (IV) (Bi4(TiO4)3); bismuth titanate (Bi4(TiO4)3); additional CAS numbers 872131-38-9, 251346-58-4, 1032194-14-1.

Substance class and mechanism of action

Bi4Ti3O12 is a ferroelectric of the Aurivillius family with a high Curie temperature of about 675 °C and high spontaneous polarization of the order of 50 µC/cm2. Below the Curie point, the crystal structure loses its center of symmetry, the domains receive stable electric polarization, the direction of which is switched by an external field - the operation of ferroelectric and piezoelectric devices based on it is based on this principle.

Scope of application

The material is used in the electronics industry in the production of capacitors, piezoelectric transducers, sensors and non-volatile memory elements. Due to its high Curie temperature, bismuth titanate is considered one of the most promising lead-free piezomaterials for high-temperature applications - ultrasonic motors, transducers and pyroelectric sensors, where Bi4Ti3O12-based ceramics, synthesized by the sol-gel method or solid-phase reaction, maintain performance characteristics at elevated temperatures.

Features and Limitations

The practical application of the material is limited by the increased leakage conductivity, which complicates the polarization process of the ceramics. To increase piezoelectric characteristics and reduce conductivity, alloying additives are introduced into the structure and the content of oxygen vacancies is regulated. Research is underway to improve the dielectric and pyroelectric properties of Bi4Ti3O12 ceramics by varying the sintering temperature and synthesis method.

Storage and handling

Store in a dry place in a tightly closed container, avoiding contact with moisture and dust formation. When working with powder, use respiratory protection and gloves.

Receipt methods

Bi4Ti3O12 ceramics are produced by the solid-phase reaction of bismuth oxide Bi2O3 and titanium oxide TiO2 during high-temperature sintering, as well as the sol-gel method from alkoxide or nitrate precursors, which makes it possible to obtain a more uniform microstructure and fine-grained films for thin-film devices. The PSA 202 indicator reflects the high polarity of the oxygen framework of the structure, which determines the dielectric properties of the material.

Comparison with other phases of Aurivillius

In the family of layered perovskite-like Aurivillius oxides, Bi4Ti3O12 has one of the highest Curie temperatures, which distinguishes it from related compounds such as SrBi2Ta2O9 or Bi3TiNbO9, which are used mainly at more moderate operating temperatures.