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Method for Preparing Dense Diffusion Barrier Layer of Limiting Current Type Oxygen Sensor by Co-infiltration

A limiting current type, oxygen sensor technology, applied in the field of sensors, can solve problems such as unevenness, long cycle time, cumbersome preparation process, etc., and achieve the effects of low thermal expansion difference, short production cycle and high sensitivity

Active Publication Date: 2018-08-28
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Since LSM is easily reduced by C during the SPS sintering process, the thermal expansion coefficient mismatch between LSCM and YSZ causes cracking of the sintered body, so the oxygen measurement performance is not ideal
The so-called ceramic chip composite method is to use platinum paste to bond the sintered dense diffusion barrier layer and solid electrolyte, and then sinter the platinum paste to enhance the bonding performance of the two. This method avoids harmful chemical reactions between materials. And the crack phenomenon caused by the mismatch of thermal expansion coefficient, Liu Tao et al once used Sr 1–x Ho x CoO 3–δ is a dense diffusion barrier layer, with La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 o 2.815 (LSGM) is a solid electrolyte, and the oxygen sensor is prepared by the ceramic chip composite method, which has good oxygen measurement characteristics. However, the preparation process of this method is cumbersome and the cycle is long, and the dense diffusion barrier layer prepared by the conventional sintering method contains many pores.
The heating and cooling speed in the process of preparation by laser cladding technology is extremely fast, and the maximum speed can reach 1012°C / s. Due to the difference in temperature gradient and thermal expansion coefficient between the cladding layer and the base material, multiple thermal expansions may occur in the cladding layer. defects, mainly including pores, cracks, deformation and surface roughness, and the control method of crack sensitivity of laser cladding layer is not yet mature

Method used

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  • Method for Preparing Dense Diffusion Barrier Layer of Limiting Current Type Oxygen Sensor by Co-infiltration
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  • Method for Preparing Dense Diffusion Barrier Layer of Limiting Current Type Oxygen Sensor by Co-infiltration

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Embodiment 1

[0026] The method for preparing the dense diffusion barrier layer of the limiting current type oxygen sensor by the co-infiltration method in this embodiment is carried out according to the following steps:

[0027] (1) According to La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 o 2.815 (LSGM) stoichiometric ratio, weighed La 2 o 3 , SrCO 3 , Ga 2 o 3 and MgO, fully ground to a particle size of ≤100 μm and then pressed into tablets, kept at 1000°C for 20 hours, crushed after natural cooling, ground again and pressed into tablets, kept at 1200°C for 20 hours, and then crushed for the third time after natural cooling again. After grinding for the first time, press into tablets and keep warm at 1450°C for 20h;

[0028] (2) The prepared La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 o 2.815 The sheet is placed in the lower part of the forming mold, and the upper part of the forming mold is filled with Fe 2 o 3 The powder is kept under a pressure of 10 MPa for 10 minutes, and then sintered at 1450 °...

Embodiment 2

[0030] The method for preparing the dense diffusion barrier layer of the limiting current type oxygen sensor by the co-infiltration method in this embodiment is carried out according to the following steps:

[0031] (1) According to La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 o 2.815 (LSGM) stoichiometric ratio, weighed La 2 o 3 , SrCO 3 , Ga 2 o 3 and MgO, fully ground to a particle size of ≤100 μm and then pressed into tablets, kept at 1000°C for 20 hours, crushed after natural cooling, ground again and pressed into tablets, kept at 1200°C for 20 hours, and then crushed for the third time after natural cooling again. After grinding for the first time, press into tablets and keep warm at 1450°C for 20h;

[0032] (2) The prepared La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 o 2.815 The sheet is placed in the lower part of the forming mold, and the upper part of the forming mold is filled with Co 3 o 4 The powder was kept under a pressure of 10 MPa for 10 minutes, and then sintered at 1550 ...

Embodiment 3

[0035] The method for preparing the dense diffusion barrier layer of the limiting current type oxygen sensor by the co-infiltration method in this embodiment is carried out according to the following steps:

[0036] (1) According to La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 o 2.815 (LSGM) stoichiometric ratio, weighed La 2 o 3 , SrCO 3 , Ga 2 o 3 and MgO, fully ground to a particle size of ≤100 μm and then pressed into tablets, kept at 1000°C for 20 hours, crushed after natural cooling, ground again and pressed into tablets, kept at 1200°C for 20 hours, and then crushed for the third time after natural cooling again. After grinding for the first time, press into tablets and keep warm at 1450°C for 20h;

[0037] (2) The prepared La 0.8 Sr 0.2 Ga 0.83 Mg 0.17 o 2.815 The sheet is placed in the lower part of the forming mold, and the upper part of the forming mold is filled with NiO powder, held at a pressure of 6 MPa for 8 minutes, and then sintered at 1600 ° C for 30 hours. N...

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Abstract

The invention belongs to the field of sensor technology, and specifically relates to a method for preparing a dense diffusion barrier layer of a limiting current type oxygen sensor by co-infiltration method. The present invention uses La2O3, SrCO3, Ga2O3 and MgO as raw materials, adopts solid-phase synthesis method to prepare La0.8Sr0.2Ga0.83Mg0.17O2.815 tablets, and places the La0.8Sr0.2Ga0.83Mg0.17O2.815 tablets in a mold The lower part of the mold is filled with transition metal oxide powder and kept at a pressure of 6~10MPa for 5~10min, and then sintered at 1400℃~1600℃ for 5-50h. After natural cooling, a dense diffusion of the limiting current type oxygen sensor is obtained barrier layer. The dense diffusion barrier layer prepared by the method of the present invention has a dense, uniform and pore-free structure and is firmly bonded. The difference in thermal expansion between the matrix and the dense diffusion barrier layer is minimized. It has the advantages of short production cycle and high sensitivity.

Description

technical field [0001] The invention belongs to the technical field of sensors, and in particular relates to a method for preparing a dense diffusion barrier layer of a limiting current type oxygen sensor by co-infiltration. Background technique [0002] Furnaces in iron and steel metallurgical enterprises consume a lot of energy. In order to save energy and optimize the combustion of heating furnaces, it is necessary to strictly control the air-fuel ratio in the thermal system. Only when the air-fuel ratio is reasonable can a higher combustion temperature be achieved and energy utilization efficiency improved. It is a direct and effective method to detect the oxygen content in the furnace gas in real time and on-line by using the electrochemical oxygen sensor. [0003] Electrochemical oxygen sensors are divided into concentration battery type and limiting current type. Compared with concentration battery type oxygen sensors, limiting current type oxygen sensors have the adv...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/50C04B35/622C04B41/87G01N27/26
CPCC04B35/50C04B35/622C04B41/009C04B41/5027C04B41/5033C04B41/87C04B2235/3206C04B2235/3213C04B2235/3227C04B2235/3286G01N27/26C04B41/4545C04B41/4521C04B41/0072
Inventor 刘涛秦华杰王珊刘健
Owner NORTHEASTERN UNIV LIAONING