Method for preparing bismuth sodium titanate base leadless piezoelectricity thick film

Abstract

The invention discloses a process for preparing natrium bismuthate titanate based lead-free piezoelectric thick films, the steps are that (1) ceramic powder materials, constitutional formula of which is (Na0.5Bi0.5)(1-x)BaxTiO30 C04B 35 / 64 C04B 35 / 468 C04B 35 / 475 C04B 35 / 462 2 11 3 2008 / 1 / 9 101215172 2008 / 7 / 9 000000000 Huazhong University of Science & Technology Wuhan 430074 Jiang Shenglin Zhang Haibo Zeng Yike Zhong Nanhai Liu Yaoping caobao jing 42201 The Patent Agency of Huazhong University of Science and Engineering No.151 Louyu Road, Wuchang, the City of Wuhan, Hubei Province 430074

Description

technical field [0001] The invention belongs to the technical field of preparation of functional ceramic thick films, in particular, it relates to a method for preparing bismuth sodium titanate-based lead-free piezoelectric thick films. Filling improves the density of bismuth and sodium titanate-based lead-free piezoelectric thick films. Background technique [0002] Piezoelectric thick film usually refers to a piezoelectric film with a thickness of 10-100 μm. Compared with thin films, its piezoelectric and ferroelectric properties are less affected by interfaces and surfaces, and larger thicknesses can also generate greater driving force. , and has higher sensitivity and wider operating frequency; compared with bulk materials, piezoelectric thick film has low operating voltage (<5V), high frequency of use, and is compatible with semiconductor processes. Therefore, piezoelectric thick films are widely used in microactuators, piezoelectric micromotors, microfluidic pumps,...

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Problems solved by technology

Among them: the basic principle of the composite sol-gel method is to mix the 0-dimensional piezoelectric functional ultrafine powder into the 3-dimensional precursor liquid to form a uniform and stable slurry, and then deposit it by spin coating, pulling or spraying. film, but because the powder content added to the sol is not high, about 10Vo.%, its organic matter is more likely to produce pores, the shrinkage rate is large, resulting in a high probability of cracking, and the maximum single-layer thickness is small; tape-casting method prepared The solid content of the thick film is not high, and the thickness of the film is too large (above 20 μm), it is difficult to obtain a piezoelectric thick film of 1-20 μm; the electrophoretic deposition method is too low because the electric field strength is too low, the deposition rate is too low, the film thickness is small, and the electric field is too high. The film layer is rough and easy to crack, and other electrochemical reactions are prone to occur on the electrode, which affects the electrical properties of the ceramic thick film, so it is very immature; the inkjet printing molding technology is to prepare the piezoelectric ceramic powder to be formed with various organic substances to form a ceramic Ink, the ceramic ink is printed on the molding plane by the printer, and its solid content is low, the shrinkage rate is large, and the density is not high; the biggest advantage of the aerosol method is that the deposition rate is high and no organic matter is added, but the quality of the deposited film is affected. The performance of functional powder particles and the stability of aerosol are very sensitive, and the process is relatively complicated and immature

[0005] In comparison, the screen printing method is fully compatible with MEMS technology, the thickness can be controlled and the thickness is suitable, especially suitable for the preparation of piezoelectric thick films of 10-100 μm, the equipment is simple, the raw materials are cheap, the cost is low, and no complicated procedures are required. Photolithography has the advantages of various printed thick film graphics, but compared with piezoelectric ceramic body materials, the density of printed piezoelectric thick films is not high, which reduces the electrical properties. This is because the thick film blank contains about 20% The organic binders, solvents and dispersants, etc. during the sintering process will produce pores

[0006] In the existing research, the method of adding sintering aids to the powder is often used to increase the density, but the added low melting point or glass phase material can reduce the sintering temperature and improve the density of the piezoelectric thick film, because it is a non-functional phase. Therefore, the electrical performance of the thick film is also reduced.

There are a few foreign reports that use sol infiltration filling to improve the density of piezoelectric thick films, but the pure sol has less active ingredients and difficult penetration of pores, so the filling efficiency is low, the effect is poor, and the density of piezoelectric thick films is not improved much.

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