Humidity sensitive lead titanate material doped with alkali metal and calcium and its prepn process

Abstract

The present invention belongs to the field of functional ceramic and humidity sensitive m technology, and is especially one kind of humidity sensitive lead titanate material doped with alkali metal and calcium. The present invention features that the humidity sensitive lead titanate material has doped alkali metal amount of 0.5-5 mol%, preferably 0.9-1.1 mol%, and calcium amount of 5-60 mol%, preferably 35-50 mol%, with the alkali metal being Li, Na, K, etc. The technological conditions include adopting water-alcohol mixture as solvent and glacial acetic acid for regulating the acidity of the precursor, adding butyl titanate to form gel after hydrolysis, controlling the viscosity, high speed rotary painting and homogenizing for several times, pre-treat at 300 deg.c for 0.3-0.6 hr, repeating for 3-5 times, and sintering to crystallize at 550-950 deg.c to form film. The alkali metal and calcium doped PbTiO3 modified film material has excellent humidity sensitive characteristic.

Description

technical field [0001] The invention belongs to the technical field of functional ceramics and moisture-sensitive materials, in particular to a lead titanate moisture-sensitive material doped with multiple elements of alkali metal and calcium. Background technique [0002] Lead titanate and its modified material system belong to the perovskite crystal structure and are typical ferroelectric materials. Compared with barium titanate, it has higher Curie temperature (Tc=490°C) and higher density (theoretical density is 7.78kg / m 3 ), and the dielectric constant is small (ε<200), C-axis oriented PbTiO 3 The dielectric constant ε r ≈100, there is a large anisotropy between the transverse and longitudinal piezoelectric coefficients Kp and Kr, and the hydrostatic piezoelectric constant (g h ) is very high, and the spontaneous polarization (Ps) and pyroelectric coefficient (λ) are large, so PbTiO 3 It is a good ferroelectric material. With photoelectric, pyroelectric, pyroele...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to find a modified lead titanate material as a material with moisture-sensitive characteristics, so as to overcome the problems of fine cracks and poor aging characteristics caused by phase transition in the cooling process of pure lead titanate after sintering

[0007] It was found that PbTiO doped with alkali metal and calcium 3 The modified thin-film moisture-sensitive material can solve the problems of micro-cracks and poor aging characteristics caused by phase transition during the cooling process after sintering

Images