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Method of using low melting point fusant as sealing material to prevent evaporation of lead oxide

A sealing material, low melting point technology, applied in chemical instruments and methods, chemical/physical/physical chemical process, chemical/physical process, etc., can solve the problems of large dust removal system, high cost, volatile lead oxide, etc. Simple and low cost effect

Inactive Publication Date: 2004-12-22
SHANGHAI JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] In the preparation process of lead-based ferroelectric materials, high temperature is often required, and lead oxide is easy to volatilize at high temperature, which causes harm to the health of experimenters and the surrounding environment
At the same time, the volatilization of lead oxide will also cause the system to deviate from the stoichiometric ratio, which will bring a lot of inconvenience to the experimental work. Therefore, it is usually necessary to use a closed system to prevent the volatilization of lead.
At present, in the preparation process of lead-based ferroelectric materials, the main methods to solve the volatilization of lead oxide are: (1) the method of simply adding a cover and sealing, the sealing effect is not very good like this, can not fundamentally prevent the volatilization of lead; 2) Improve the experimental process (such as adopting a multi-step synthesis process), reduce the calcination temperature of the system, and reduce the residence time at high temperature. This method complicates the process and cannot fundamentally solve the problem of lead volatilization; (3) adopt Although the airtight dust removal system can well solve the harm to the human body and the environment caused by the volatilization of some harmful components, due to the huge negative pressure of the dust removal system, the volatilization of components is strengthened, making it more deviated from the stoichiometric ratio. At the same time, the dust removal system is generally more Huge, serious power consumption, cost is also more expensive; (4) adopt the completely closed system, for example the method of airtight crucible, it can effectively control the volatilization of lead, but because the system is completely closed, it is not conducive to monitoring and control in the experimental process, giving Experimental operation brings inconvenience

Method used

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  • Method of using low melting point fusant as sealing material to prevent evaporation of lead oxide
  • Method of using low melting point fusant as sealing material to prevent evaporation of lead oxide
  • Method of using low melting point fusant as sealing material to prevent evaporation of lead oxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Control of lead oxide volatilization during calcination of lead-based ferroelectric ceramic materials. The experiment adopts as attached figure 1 The device shown, the specific operation steps are as follows:

[0021] 1. Choose sodium chloride NaCl powder as the sealing material.

[0022] 2. Add pre-prepared lead-containing powder 4 in the small crucible 1, put NaCl powder 5 in the shallow large crucible 2, and cover the crucible 1 with the sealing cover 6 and the sealing crucible 3.

[0023] 3. Raise the temperature to 800°C, which is slightly higher than the melting point of NaCl, and keep it warm for 1 hour. After the NaCl powder is completely melted to form a seal, continue to raise the temperature to 900°C, keep it warm for 4 hours, and cool down to room temperature with the furnace.

[0024] 4. Add distilled water to the crucible 2 to dissolve the sealed substance NaCl, and uncover the sealed crucible 3 and the sealed cover 6 to take out the calcined lead-contai...

Embodiment 2

[0027] Control of lead oxide volatilization during preparation of lead-based ferroelectric thick film materials by liquid phase epitaxy. The experiment adopts as attached figure 2 The device shown, the specific operation steps are as follows:

[0028] 1. Choose NaCl powder as the sealing material.

[0029] 2. Add pre-prepared lead-containing powder 4 into the small crucible 1, put NaCl powder 5 into the perforated shallow crucible 2, and cover the sealing cover 6 and the sealing crucible 3 to form a double-layer sealing system.

[0030] 3. Raise the temperature to 800°C, which is slightly higher than the melting point of NaCl, and keep it warm for 1 hour. After the NaCl powder is completely melted to form a seal, continue to raise the temperature to 1150°C, and keep it warm for 12 hours to completely melt the lead-containing powder.

[0031] 4. Cool down to 1060°C, uncover the sealed crucible 3 and the sealed cover 6, and carry out feeding or liquid phase epitaxial thick fi...

Embodiment 3

[0035] Control of lead oxide volatilization during preparation of lead-based ferroelectric crystal materials by liquid phase epitaxy. The experiment adopts as attached figure 2 The device shown, the specific operation steps are as follows:

[0036] 1. Choose BaCO3:CuO powder with a ratio of 1:1, and Ba-Cu-O powder formed after calcination at 900°C for 24 hours as the sealing material.

[0037] 2. Add pre-prepared lead-containing powder 4 in the small crucible 1, load the Ba-Cu-O powder obtained after calcining in step 1 in the shallow crucible with holes, and cover the sealing cover 6 and the sealing crucible 3. Form a double-layer sealing system.

[0038] 3. Raise the temperature to 980°C, which is slightly higher than the melting point of Ba-Cu-O, and keep it warm for 1 hour. After the Ba-Cu-O powder is completely melted to form a seal, continue to raise the temperature to 1150°C, and keep it warm for 12 hours, so that the lead-containing powder Melt completely.

[0039...

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Abstract

A method for preventing volatilization of lead oxide by using the low-smelting-point molten substance as sealing features that the sealing material with low smelting point and different to volatilize is loaded in the big crucible surrounding the small crucible to be sintered and a sealing crucible and a sealing cover is put on said small crucible to form a dual-layr sealing system. After the sealing material is molten to form a seal, the temp. is continuously raised to prepare the Pb-base ferroelectric material.

Description

Technical field: [0001] The invention relates to a method for preventing the volatilization of lead oxide by using a low-melting-point melt as a sealing substance. It is a method for preventing the volatilization of lead at high temperature by using a low-melting-point melt that is difficult to volatilize as a sealing substance, and can effectively control lead-based ferroelectric materials. The problem of lead volatilization during the preparation process. Background technique: [0002] In the preparation process of lead-based ferroelectric materials, high temperature is often required, and lead oxide is easy to volatilize at high temperature, which causes harm to the health of experimenters and the surrounding environment. At the same time, the volatilization of lead oxide will also cause the system to deviate from the stoichiometric ratio, which will bring a lot of inconvenience to the experimental work. Therefore, a closed system is usually required to prevent the volati...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01J19/16C04B35/497C04B35/653H10N30/095
Inventor 曾新华姚忻
Owner SHANGHAI JIAOTONG UNIV