Preparation method of potassium-sodium niobate-based nano fine-grain ceramic with average grain size of 160nm

An average grain size, potassium and sodium niobate based technology, applied in the field of functional materials, can solve the problems of low density of potassium and sodium niobate ceramics, narrow sintering temperature range, performance limitations, etc., to reduce the temperature and heat preservation time. , The grain size distribution is uniform, and the effect of grain refinement

CN112898020AInactive Publication Date: 2021-06-04NORTHWESTERN POLYTECHNICAL UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2021-06-04
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a preparation method of potassium-sodium niobate-based nano fine-grain ceramic with the average grain size of 160nm. 0.5 mol% of lanthanum oxide is added into raw materials, so that oxygen vacancies generated by volatilization of alkali metal elements can be reduced, meanwhile, growth of grains is hindered, and the purpose of refining the grains is achieved. The preparation method comprises the following steps: calcining dried powder subjected to ball milling for 12-18 hours at 800-900 DEG C for 2-4 hours, carrying out secondary ball milling for 12-18 hours, performing calcining at 800-900 DEG C again after drying for 2-4 hours, carrying out tertiary ball milling for 12-18 hours, performing drying, and carrying out multiple times of ball milling and calcining to enable raw materials to fully react and refine, so the sintering temperature and the heat preservation time can be reduced, and the purpose of grain refinement is achieved due to insufficient grain growth. Through doping modification of a rare earth element lanthanum and an improved traditional solid phase method, a scanning electron microscope diagram and a particle size distribution diagram of the finally obtained potassium-sodium niobate-based ceramic are shown in a figure 2, the average grain size of the potassium-sodium niobate-based ceramic is 160nm, and the grain size distribution is uniform and very fine.
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Description

technical field

[0001] The invention belongs to the field of functional materials and relates to a preparation method of potassium sodium niobate-based nano fine-grained ceramics with an average grain size of 160nm. Background technique

[0002] The performance of materials not only depends on the composition of materials, but also related to the microstructure of materials. In previous studies, it was also found that by changing the grain size of the ceramic material, the internal stress, squareness, grain boundary and phase transition temperature of the material are affected, and then the piezoelectric properties, optical properties, energy storage properties and dielectric properties of the material are affected. Electrical performance etc. will be affected. Refining the grains of ceramics can often greatly increase the breakdown field strength of the material, making the material have higher energy storage density and stability. In addition, the fine-grained ceramics h...

Examples

Embodiment 1

[0022] Weigh 3.433g K according to the ratio of raw materials 2 CO 3 , 2.637g Na 2 CO 3 , 13.234g Nb 2 o 5 , 0.163g La 2 o 3 .

[0023] Put the weighed raw material powder into a polytetrafluoroethylene ball mill jar equipped with zirconia balls, and use ethanol as a ball milling aid for ball milling at a rotational speed of 350r / min and a ball milling time of 12-18h.

[0024] The dried powder is sieved and pressed into large pieces with a diameter of 15mm and a height of about 28-32mm, placed on a corundum ceramic plate, and calcined at 800-900°C for 2-4h. Secondary ball milling is performed on the once calcined sample, and the ball milling time is 12-18h. After drying and sieving, it is calcined at 800-900°C for 2-4 hours, and then ball milled three times and dried and sieved. The ball milling time is 12-18 hours.

[0025] The powder is pre-pressed into small discs with a diameter of 10mm and a thickness of 0.9-1.1mm, and then formed by a cold isostatic press with a...

Embodiment 2

[0029] Weigh 3.45g K2CO3, 2.65g Na2CO3, 13.3g Nb2O5 according to the ratio of raw materials not doped with lanthanum oxide.

[0030] Put the weighed raw material powder into a polytetrafluoroethylene ball mill jar equipped with zirconia balls, and use ethanol as a ball milling aid for ball milling at a rotational speed of 350r / min and a ball milling time of 12-18h.

[0031] The dried powder is sieved and pressed into large pieces with a diameter of 15mm and a height of about 28-32mm, placed on a corundum ceramic plate, and calcined at 800-900°C for 2-4h. Secondary ball milling is performed on the once calcined sample, and the ball milling time is 12-18h. After drying and sieving, it is calcined at 800-900°C for 2-4 hours, and then ball milled three times and dried and sieved. The ball milling time is 12-18 hours.

[0032] The powder is pre-pressed into small discs with a diameter of 10mm and a thickness of 0.9-1.1mm, and then formed by a cold isostatic press with a forming pr...

Embodiment 3

[0036] Weigh 3.433g K2CO3, 2.637g Na2CO3, 13.234g Nb2O5, 0.163g La2O3 according to the ratio of raw materials doped with lanthanum 0.5%mol.

[0037] Put the weighed raw material powder into a polytetrafluoroethylene ball mill jar equipped with zirconia balls, and use ethanol as a ball milling aid for ball milling at a rotational speed of 350r / min and a ball milling time of 12-18h.

[0038] The dried powder is sieved and pressed into large pieces with a diameter of 15mm and a height of about 28-32mm, placed on a corundum ceramic plate, and calcined at 800-900°C for 2-4h. Then carry out secondary ball milling, the ball milling time is 12-18h, and then dry and sieve.

[0039] The powder is pre-pressed into small discs with a diameter of 10mm and a thickness of 0.9-1.1mm, and then formed by a cold isostatic press with a forming pressure of 200-300MPa.

[0040] The green body is placed on a ceramic plate sprinkled with powder of the same composition, and the surface is also covere...