Method for preparing lanthanum titanate crystal by vertical zone melting descent method

Abstract

The invention relates to the technical field of C30B crystal growth, in particular to a method for preparing lanthanum titanate crystals through a vertical zone melting descent method. According to the method, TiO2 and La2O3 are used as initial raw materials, the lanthanum titanate crystal is prepared through zone heating and strict control of the heat preservation time in the crystallization process, the temperature gradient of crystal production and the gradual descending speed of a crucible, the purity and yield of the prepared lanthanum titanate crystal are excellent, most importantly, the scheme provides a technology for locally heating lanthanum titanate, and the method is suitable for industrial production. On the basis of ensuring that the lanthanum titanate crystal has excellent yield and purity, the energy consumption is obviously reduced, and the method is green and environment-friendly, conforms to the modern industrial research and development concept of energy conservation and emission reduction, is suitable for industrial-grade large-scale production and popularization, and has potential application value in the field of optical evaporation materials.

Description

technical field [0001] The invention relates to the technical field of C30B crystal growth, and more specifically, the invention provides a method for preparing lanthanum titanate crystals by a vertical zone melting descent method. Background technique [0002] As an important basic raw material for the preparation of optical devices, optical evaporation materials play an important role in the quality of precision optical devices. They have potential application value in the fields of reflective coatings, anti-reflection coatings, and interference filters. The lanthanum titanate crystal has a wide range of applications in the field of preparing various high-performance optoelectronic devices due to its stable high refractive index, high homogeneity and high transmittance. At present, the preparation methods of lanthanum titanate crystals mainly include high-vacuum high-frequency cold crucible slow sedimentation method, seed crystal solution method, vertical temperature gradi...

AI Technical Summary

Problems solved by technology

At present, the preparation methods of lanthanum titanate crystals mainly include high-vacuum high-frequency cold crucible slow sedimentation method, seed crystal solution method, vertical temperature gradient method and crucible drop method, but the preparation methods of lanthanum titanate crystals in the prior art have crystal purity that needs to be improved. , Bubbles need to be excluded during the preparation process, high energy consumption and low yield

[0003] The Chinese invention patent with the published patent number CN109879308A discloses a method for preparing lanthanum titanate. In this disclosed patent, submicron solid spheres of pyridine-2,5-dicarboxylic acid rare earth coordination polymers are synthesized by microwave method, and then Preparation of Nano-TiO(OH) by Uniform Precipitation 2 , and then the lanthanum-based coordination polymer and nano-TiO(OH) 2 Grind evenly at a certain mass ratio, and calcinate in a muffle furnace to obtain lanthanum titanate crystals, but the crystals prepared by this method have the disadvantages of low purity and low yield

[0004] The Chinese invention patent with the published patent No. CN101200794A discloses a method for preparing a pre-melted lanthanum titanate crystalline evaporation material. In this disclosed patent, La 2 o 3 and TiO 2 As a raw material, it is heated by a high-frequency source to form a lanthanum titanate melt, and then slowly settles and cools to form a crystal material. This method has a simple process, but impurities in the raw material and bubbles formed during the melting process will be included in the crystal, and the quality of the crystal is not good. question

[0005] The Chinese invention patent with the patent publication number CN101701357A discloses a growth method of lanthanum titanate crystal coating material. In this disclosed patent, the method of vacuum induction heating and top seeding is used to grow lanthanum titanate crystals, and the process is similar to the pulling technology , the advantage is that the equipment is easy to operate, safe and reliable in operation, but it has the disadvantage of huge energy consumption, which is not conducive to large-scale industrial production

[0006] The Chinese invention patent with the patent publication number CN104389021A and the patent publication number CN101063232A discloses the method for preparing lanthanum titanate crystals by the vertical temperature gradient method and the crucible descending method, emphatically improving the purity of lanthanum titanate crystals, but the above-mentioned schemes require all titanium The raw material of lanthanum acid is melted, the energy consumption is serious, and the production cost is too high

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