Barium strontium titanate pyroelectric ceramic prepared from uniform fine grains and preparation method thereof

A technology of pyroelectric ceramics and barium strontium titanate, which is applied in the field of uniform fine-grain barium strontium titanate pyroelectric ceramics and its preparation, can solve problems such as difficulty in obtaining uniform fine-grain BST pyroelectric ceramics, and achieve Solve the effect of large and uneven grain size, uniform grain size and high performance

Inactive Publication Date: 2015-06-17

SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI

2 Cites 0 Cited by

AI-Extracted Technical Summary

Problems solved by technology

[0005] The present invention aims to overcome the problem that it is difficult to obtain uniform fine-grained BST pyroelectric ceramics...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Abstract

The invention relates to barium strontium titanate pyroelectric ceramic prepared from uniform fine grains and a preparation method thereof. The composition chemical formula of the barium strontium titanate pyroelectric ceramic is (Ba(1-x)Srx) (1-a-b)A(a+b)Ti(1-a-b)FeaMnbO3, wherein x is greater than or equal to 0.20 and smaller than or equal to 0.35, a is greater than 0 and smaller than or equal to 0.01. b is greater than 0 and smaller than or equal to 0.005, and A is selected from Y, Sm and/or La.

Technology Topic

CeramicFine grain +3

Image

Examples

Experimental program(2)
Comparison scheme(1)

Example Embodiment

[0035] More specifically, the preparation method of the uniform fine-grained barium strontium titanate pyroelectric ceramics includes:

[0036] (1) Weigh the raw material BaCO according to the stoichiometric ratio 3 , SrCO 3 , TiO 2 , Fe 2 O 3 , MnCO 3 and the oxides of A, mixed uniformly by wet ball milling process, after drying, adding 4-10wt% deionized water according to the weight of the raw materials for briquetting, and keeping the temperature at 1000-1200 ℃ for 1- The barium strontium titanate was obtained in 3 hours; then the obtained barium strontium titanate was pulverized and sieved to obtain (Ba 1-x Sr x ) 1-a-b A a+b Ti 1-a-b Fe a Mn b O 3 powder;

[0037] (2) Income (Ba 1-x Sr x ) 1-a-b A a+b Ti 1-a-b Fe a Mn b O 3 The powder is uniformly mixed by wet ball milling process, dried and added with a specified amount of binder, and then pre-pressed, isostatically pressed, and molded to obtain a green body of barium strontium titanate after granulation, ageing, and sieving. ;

[0038] (3) The obtained barium strontium titanate body is sintered at 1350-1500° C. in an oxygen atmosphere to obtain the uniform fine-grained barium strontium titanate ceramic.

[0039]In step (1), the wet ball milling process conditions are: the mass ratio of raw material, ball milling medium and deionized water is 1:(1.0~2.0):(1.0~1.5), and the ball milling time is 12~26 hours. The ball milling medium is agate balls.

[0040] In step (1), pass 40 mesh sieves to obtain (Ba 1-x Sr x ) 1-a-b A a+b Ti 1-a-b Fe a Mn b O 3 powder.

[0041] In step (2), the wet ball milling process conditions are: (Ba 1-x Sr x ) 1-a-b A a+b Ti 1-a-b Fe a Mn b O 3 The mass ratio of powder, ball milling medium and deionized water is 1:(1.5-2.0):(0.5-1.0), the ball-milling time is 24-48 hours, and the ball-milling medium is agate balls.

[0042] In step (2), the binder is a polyvinyl alcohol solution with a mass concentration of 3-10%, and the addition amount of the binder is (Ba 1-x Sr x ) 1-a-b A a+b Ti 1-a-b Fe a Mn b O 3 3 to 10% of the mass of the powder.

[0043] In step (2), the aging time is 22-26 hours, and the temperature of the plastic-removing is 750-850°C.

[0044] In step (3), the process conditions of the sintering are: heating at a rate of 1-4°C/min, oxygen is supplied during the sintering process, and the oxygen flow rate is 1-3L/min, when the temperature is raised to 1350-1500°C, Incubate for 5 to 20 hours, then cool to room temperature with the furnace, and turn off the oxygen.

[0045] It is known through experiments that the present invention has the following beneficial effects compared with the prior art:

[0046] 1) The grain size of the BST pyroelectric ceramic of the present invention is small and uniform, the average grain size d≤3μm, and the proportion of grains with grain size between d±0.5dμm is ≥70%. And the sample has high density and high performance, which can meet the requirements of making uncooled infrared focal plane devices, and effectively solve the problem of large and uneven grain size of BST ceramics;

[0047] 2) The preparation method of the present invention has the advantages of simple process, no need for special equipment, low cost, etc., is suitable for large-scale production, and can meet the needs of industrialization.

Example Embodiment

[0049] Example 1 (preparation of 6 mol, 1313.87 g)

[0050] Weigh the raw powder BaCO 3 (849.14g), SrCO 3 (249.09g) and TiO 2 (475.55g), and Fe 2 O 3 (4.45g), MnCO 3 (1.66g) and Y 2 O 3 (7.86) grams of powder, all powders are mixed evenly by wet ball milling process; the mass ratio of material, ball milling medium and deionized water is 1:1.5:1.2, the ball milling time is 24 hours, and the ball milling medium is agate balls;

[0051] Dry the abrasive, add 4% of the total powder mass in deionized water, briquette, and synthesize in the air at a synthesis temperature of 1150° C. and a holding time of 2 hours to obtain BST blocks; pulverize, pass through a 40-mesh sieve, use a The ball milling process makes the powder evenly mixed; the mass ratio of material, ball milling medium and deionized water is 1:2.0:0.8, the ball milling time is 48 hours, and the ball milling medium is agate balls;

[0052] Drying, adding PVA solution as a binder, granulating, aging for 24 hours, sieving, pre-pressing and then isostatic pressing, the green body was discharged at 800 ℃, and the BST green body was obtained; Sintering in oxygen, the sintering conditions are: heating at a rate of 2.0 °C/min; and oxygen flow at a flow rate of 2 L/min; when the temperature rises to 1500 °C, hold for 20 hours; cool to room temperature, and turn off oxygen;

[0053] The sintered samples were ground, polished, cleaned and thermally etched to observe the microstructure. The other part was processed into the required size, ultrasonically cleaned, screen-printed silver paste, dried, and kept at 700°C for 30 minutes to test the dielectric and pyroelectric properties of the samples.

[0054] figure 1 Scanning electron microscope photos of the BST pyroelectric ceramics prepared in this example after surface polishing and hot corrosion. Depend on figure 1 It can be seen that the grain size of ceramics is small and uniform, the average grain size d≤3μm, and the proportion of grains with grain size between d±0.5dμm is ≥70%. And less pores, high density.

[0055] figure 2 The graph of the change of dielectric constant and dielectric loss with temperature of the BST pyroelectric ceramics prepared in this example without a DC electric field is shown by figure 2 It can be seen that the Curie temperature of the ceramic is around room temperature, and the dielectric constant is 10 3 order of magnitude, the dielectric loss at the Curie temperature is 1.68%.

[0056] image 3 The change curve of the pyroelectric coefficient of the BST pyroelectric ceramics prepared in this example under an external DC electric field (500V/mm) with temperature, as shown by image 3 It can be seen that the pyroelectric coefficient reaches the maximum value at 12.8°C, which is 12.54×10 - 8 C/cm 2 K, the pyroelectric coefficient is high, which meets the application requirements.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Login to view more

PUM

Property	Measurement	Unit
Average grain size	3.0	µm
Average grain size	<= 3.0	µm
Pyroelectric coefficient	1.25E-7	c·k/cm²
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

We can also present the details of the Description, Claims and Application information to help users get a comprehensive understanding of the technical details of the patent, such as background art, summary of invention, brief description of drawings, description of embodiments, and other original content. On the other hand, users can also determine the specific scope of protection of the technology through the list of claims; as well as understand the changes in the life cycle of the technology with the presentation of the patent timeline. Login to view more.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine

Login to view more

Classification and recommendation of technical efficacy words

Uniform grain size
Small grain size

Barium strontium titanate pyroelectric ceramic prepared from uniform fine grains and preparation method thereof

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

Similar technology patents

Production method of high-strength wear-resistant complex-phase poly-crystal engineering plate

Catalyst for preparing propylene by methyl alcohol and/or dimethyl ether and preparation method thereof

Fe-ni alloy metal foil having excellent heat resilience and method for manufacturing same

Preparation method for nano nickel oxide

High-performance hard alloy with cobalt-based alloy as binding phase

Classification and recommendation of technical efficacy words

Tantalum and niobium billets and methods of producing the same

Preparation method of photoassisted sol-gel of yttrium doped zinc oxide transparent conductive film

High magnetic conductive low temperature sintered NiCuZn ferrite material

Multi-element microalloyed titanium alloy processing method

Environment-friendly heat-resistant polylactic acid and preparation method thereof

Cold spray formation of thin metal coatings

Target of intermetallic compound with B2-ordered lattice structure, production method thereof and magnetic recording medium having B2-structured underlayer

Nano zeolitic imidazolate frameworks crystal preparation method through dynamic crystallization

Method for preparing ultra-fine crystal WC-Co hard alloy

Coated body with nanocrystalline CVD coating for enhanced edge toughness and reduced friction