Pyroelectric material and preparation method thereof

Abstract

The invention relates to pyroelectric materials, and especially relates to a pyroelectric material and a preparation method thereof. The preparation method prepares a PMNT ceramic through part of an oxalate process route, in this method, the formation of pyrochlore phase is prohibited, the ceramic density is increased, and the comprehensive electric properties of the piezoelectric material are improved; the low-cost PMNT ceramic has a comparative or even better pyroelectric property than that of pyroelectric monocrystal PMNT or PZNT, overcomes the shortages of difficult growth, high cost, and long period of piezoelectric monocrystal; is suitable for manufacturing a pyroelectric detector, because of the excellent dielectric property, thermophysical property, pyroelectric property and mechanical property of the PMNT ceramic, is capable of improving the comprehensive properties of the pyroelectric detector, improves the manufacturing technology of the pyroelectric detector, and is advantageously be used in fields of uncooled infrared detection and imaging devices.

Description

technical field [0001] The invention relates to pyroelectric materials, in particular to a pyroelectric material and a preparation method thereof, wherein Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -PbTiO 3 (PMNT) ceramics, PMNT ceramics prepared at low cost exhibit equivalent or better pyroelectric properties than pyroelectric single crystals, overcoming the problems of difficult piezoelectric single crystal growth, high cost, and long cycle; using low-cost preparation Pyroelectric detectors made of PMNT ceramics can improve the comprehensive performance of pyroelectric detectors and are expected to be applied in uncooled infrared detection and imaging devices. Background technique [0002] Since the Gulf War, the night vision (imaging) function of infrared focal plane array devices used by the US military has shocked the international infrared science community and triggered the rapid development of infrared detection devices around the world; pyroelectric devices used at room temperature ...

AI Technical Summary

Problems solved by technology

Currently used pyroelectric materials, lithium tantalate (LT) has a small pyroelectric coefficient and low permittivity, which is not suitable for small-area detectors in detector arrays, and the thermal diffusivity is too large, making it difficult to improve pyroelectric detectors. Transverse thermal time constant; triglycine sulfate (TGS) single crystal is easy to hydrolyze, needs to be sealed, and has a large dielectric loss, low detection value, low Curie temperature (about 49°C), and inconvenient processing and use; niobium The detection merit of various ceramic materials such as lead iron zirconate (PZ-FN) and modified lead titanate (PT) is not high

[0004] Large-size, high-quality relaxor ferroelectric single-crystal PMNT and Pb(Zn 1 / 3 Nb 2 / 3 )O 3 -PbTiO 3 The successful growth of (PZNT) is an "exciting breakthrough" in the field of ferroelectricity in the past 50 years; the successful growth of PMNT and PZNT single crystals has laid a solid foundation for the development of new physical properties of materials, expansion and promotion of the application of single crystals In recent years, Luo Haosu and Fang Bijun have found that PMNT and PZNT single crystals have large pyroelectric coefficients and high pyroelectric detection merits, small dielectric loss, small thermal diffusivity, and stable chemical properties. However, due to the complex composition of the relaxor ferroelectric single crystal, there is competition between the two phases of perovskite and pyrochlore during the crystallization of the melt, and the high temperature melt of PbO will have serious damage to the Pt crucible. Corrosion, composition segregation, phase change and domain change near the quasi-isomorphic phase boundary with the best performance of PMNT and PZNT single crystals are more sensitive, which makes it difficult to prepare large-sized single crystals; the performance limitations of pyroelectric materials limit pyroelectricity. Therefore, it is necessary to develop new ideas and prepare new pyroelectric materials with excellent comprehensive performance at low cost.

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