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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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It can be seen that ZrO containing Ce 2 The main problems of binary shape

Method used

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  • Shape memory ceramic and its prepn
  • Shape memory ceramic and its prepn

Examples

Experimental program
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Effect test

Example Embodiment

[0015] Example 1

[0016] To prepare 8mol% CeO 2 , 0.5mol% Y 2 O 3 And the balance is ZrO 2 The shape memory ceramics are 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] Using this method, the average grain size can be 1.06μm and the density is 6.03g / cm 3 Tetragonal zirconia polycrystalline bulk material, such as figure 1 Shown. The test data of the recoverable strain and shape recovery rate of the polycrystalline ceramic 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 measured length before compression of the sample l 1 =6.974mm, length l after compression 0 =6.892, warm up to 600℃ and then cool to room tempe...

Example Embodiment

[0020] Example 2

[0021] Use the same preparation and sintering method as in Example 1 to obtain a composition of 7.5 mol% CeO 2 , 0.45mol% Y 2 O 3 And the balance is ZrO 2 The obtained tetragonal zirconia block was tested by the same test method as in Example 1, and the recoverable strain was 1.2%, and the shape recovery rate was 100%.

Example Embodiment

[0022] Example 3

[0023] Use the same preparation and sintering method as in Example 1 to obtain a composition of 8.5 mol% CeO 2 , 0.55mol% Y 2 O 3 And the balance is ZrO 2 The prepared tetragonal zirconia block was tested by the same test method as in Example 1, and the recoverable strain was 1.1%, and the shape recovery rate was 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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