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Shape memory ceramic and its prepn

A technology of memory ceramics and polycrystalline ceramics, applied in the field of shape memory ceramics, can solve the problems of incomplete shape recovery, small recoverable strain, etc., and achieve the effect of high operating temperature

Inactive Publication Date: 2003-11-05
EMERSON ELECTRIC (CHINA) HLDG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It can be seen that ZrO containing Ce 2 The main problems of binary shape memory ceramics are small recoverable strain and incomplete shape recovery

Method used

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  • Shape memory ceramic and its prepn
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] In order to make the composition of 8mol% CeO 2 , 0.5mol% Y 2 o 3 and the balance is ZrO 2 The shape-memory ceramics were prepared by co-precipitation method to prepare ultra-fine powders of each component, sintered in air at 1500 ° C for 6 hours, and then gradually cooled.

[0017] This method can be used to obtain an average grain size of 1.06μm and a density of 6.03g / cm 3 Tetragonal zirconia polycrystalline blocks, such as figure 1 shown. The test data of the recoverable strain and shape recovery rate of the polycrystalline ceramics are listed in Table 1, and the corresponding temperature-strain and stress-strain relationship curves made according to the above test data are shown in figure 2 . It can be seen from the test results that when the recoverable strain is 1.18%, the shape recovery rate is still 100%.

[0018] During the test, the length before compression of the sample is measured l 1 =6.974mm, length l after compression 0 =6.892, heat up to 600°C...

Embodiment 2

[0021] Using the same preparation and sintering method as in Example 1 to produce a composition of 7.5mol% CeO 2 , 0.45mol%Y 2 o 3 and the balance is ZrO 2 Shape-memory ceramics, the prepared tetragonal zirconia bulk material is tested by the same test method as in Example 1, and the recoverable strain is 1.2%, and the shape recovery rate is 100%.

Embodiment 3

[0023] Using the same preparation and sintering method as in Example 1 to produce a composition of 8.5mol% CeO 2 , 0.55mol% Y 2 o 3 and the balance is ZrO 2 Shape-memory ceramics, the prepared tetragonal zirconia bulk material is tested by the same test method as in Example 1, and the recoverable strain is 1.1%, and the shape recovery rate is 100%.

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Abstract

The shape memory ceramic contains ZrO2 as base material, Ce and Y and consists of CeO2 7-10 mol%, preferably 7.5-8.5 mol%, Y2O3 0.2-0.8 mol%, preferably 0.45-0.55 mol%, and ZrO2 the rest. The preparation process includes the following steps: preparing superfine powder of the components via coprecipitation, sintering at 1500 deg.c for 4-6 hr, cooling gradually to obtain tetragonal crystal system of polycrystalline zirconia ceramic block with crystalline grain size 0.9-1.1 micron and density 5.9-6.1 g / cu cm. The shape memory ceramic has shape recovering rate of 95-100 % in strain up to 1.2 %,high action temperature and pseudo-elastic recovery of 3-4 %.

Description

technical field [0001] The invention relates to a shape memory ceramic, in particular to a shape memory ceramic based on zirconia containing cerium and yttrium. Background technique [0002] In recent years, zirconium dioxide (ZrO 2 )-based shape memory ceramics research and development are known: ZrO containing magnesium (Mg) 2 Shape memory ceramics, ZrO containing cerium (Ce) 2 Shape memory ceramics and ZrO containing yttrium (Y) 2 Binary ZrO such as shape memory ceramics 2 base shape memory ceramics. For ZrO 2 Based ceramics, which usually have high strength and toughness through stress-induced t→m martensitic transformation, and the above-mentioned added components can stabilize ZrO 2 Ceramic or crystal effect. The stress-induced martensitic phase exhibits the shape memory effect (SME) through reverse phase transformation by heating, that is, given a temperature change to the shape memory material, it can automatically work and recover its shape. For example, in ...

Claims

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Application Information

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IPC IPC(8): C04B35/486
CPCC04B35/486C04B2235/3225C04B2235/3229C04B2235/3244C04B2235/77C04B2235/785C04B2235/96
Inventor 徐祖耀金学军张玉龙
Owner EMERSON ELECTRIC (CHINA) HLDG CO LTD
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