Fiber bragg grating hydrogen sensing system based on amorphous palladium-based alloy and sensor

A sensing system and fiber grating technology, applied in the field of hydrogen sensors, can solve the problems of fiber grating strain and temperature cross-sensitivity, large loss of coreless fiber, decreased accuracy, etc., to improve hydrogen embrittlement phenomenon, strong hydrogen permeability, The effect of low production cost

Inactive Publication Date: 2021-02-05
安徽伯华氢能源科技有限公司
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0005] However, fiber gratings have the problem of cross-sensitivity between strain and temperature. In order to achieve high-precision measurement, it is usually necessary to perform temperature compensation on the fiber grating sensing system.
Patent CN105841840A proposes an optical fiber sensor capable of simultaneously measuring hydrogen gas concentration and temperature. Its essence is to realize simultaneous measurement of hydrogen gas concentration and temperature by monitoring the interference spectrum generated by the coreless fiber and the reflection spectrum generated by the Bragg grating. High loss and poor stability
Patent CN105572054A proposes a fiber-optic hydrogen sensor with temperature compensation function, which uses two Bragg gratings with the same parameters in series to eliminate temperature cross-sensitivity through the difference in the center wavelength drift of the two gratings, but the design of the same grating is different in temperature or hydrogen When the concentration change is not obvious, there is wavelength confusion, which leads to the disadvantage of decreased accuracy

Method used

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  • Fiber bragg grating hydrogen sensing system based on amorphous palladium-based alloy and sensor
  • Fiber bragg grating hydrogen sensing system based on amorphous palladium-based alloy and sensor
  • Fiber bragg grating hydrogen sensing system based on amorphous palladium-based alloy and sensor

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Embodiment 1

[0034]See attachedfigure 1 , Use hydrofluoric acid to etch the fiber cladding (2) engraved with fiber Bragg grating (1) to reduce its thickness, thereby improving the sensitivity of the sensor. The corroded cladding is used as the substrate, and a certain thickness of polyimide film and Ni film are successively coated as the adhesion layer (3). The purpose is to increase the adhesion between the sensor layer and the optical fiber cladding and prevent hydrogen Sensitive material falls off. The amorphous palladium-based alloy film coated on the outside of the adhesion layer constitutes the outermost sensing layer (4) of the hydrogen sensitive probe. The Pd-Cu-Si amorphous alloy film is selected as the hydrogen sensitive material. The preparation method is as follows: The method uses vacuum magnetron sputtering method, the target materials are 99.99% purity Pd target and 99.9% CuSi alloy target, the atomic ratio of CuSi alloy target is Cu:Si=5:17; the Pd target is connected to the DC p...

Embodiment 2

[0037]In addition to etching or using ultra-fine Bragg gratings to improve the sensitivity of fiber gratings, the strategy of using long-period gratings instead of Bragg gratings has also received widespread attention. Because the long-period grating wavelength changes not only due to strain, but also due to changes in the refractive index of the cladding and coating. And if the coating thickness is small enough, the effect of strain on the wavelength shift can be ignored. Therefore, in this example, the second grating type is chosen to be long-period grating. Moreover, because LPG itself has a higher sensitivity than FBG, the thickness of the Pd-Cu-Si thin layer in this embodiment is selected as 15 nm to obtain a shorter response and recovery time. Except for the above two parameters, the preparation method of the sensing system (9) is the same as that of Example 1.

[0038]However, because LPG is the coupling between the core fundamental mode and the cladding mode transmitted in the ...

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Abstract

The invention discloses a fiber bragg grating hydrogen sensing system based on amorphous palladium-based alloy. The fiber bragg grating hydrogen sensing system is formed by welding a first fiber bragggrating and a second fiber bragg grating which have different central wavelengths in series, wherein the surface of the second fiber bragg grating is coated with a sensing film layer to form a hydrogen sensitive probe, and the sensing film layer is an amorphous palladium-based alloy film. Byutilizing the principle that the stress and the refractive index are changed after the sensing film layer absorbs hydrogen, the hydrogen concentration in the environment is converted into the offset of the central wavelength of a substrate, and the material has both the reversible hydrogen absorption performance of metal palladium and the excellent hydrogen permeability of amorphous alloy, so that the stability and sensitivity of a sensing system can be greatly improved. The surface of the first grating is exposed and used for temperature measurement and temperature compensation, and the inherent temperature cross sensitivity problem of the fiber grating sensor is eliminated. Aiming at the type ofthe second grating, the invention further provides two sensors loading the hydrogen sensing system based on reflection and transmission spectra respectively.

Description

Technical field[0001]The invention belongs to the technical field of hydrogen sensors, and specifically relates to a fiber grating hydrogen sensing system based on an amorphous palladium-based alloy. The invention also relates to a method for preparing a hydrogen sensor loaded with the sensing system.Background technique[0002]As one of the most promising clean energy sources, hydrogen has the characteristics of diverse sources, clean and low-carbon, flexible and efficient, and may become the ultimate form of energy use in the future. It has been used in many fields, such as reducing agents and heat sources in the metallurgical industry, and fuel for fuel cell vehicles. However, hydrogen is a colorless and odorless gas with a low ignition energy (only 0.02 mJ at the lowest) and a large flame propagation speed. When the hydrogen content in the air is between 4.0% and 75%, it will To open flame or electric current, it is easy to explode. At the same time, due to its small molecular vol...

Claims

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Application Information

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IPC IPC(8): G01D5/353G01D21/02G01N21/01G01N21/84
CPCG01D5/35316G01D21/02G01N21/01G01N21/84
Inventor 杨事成马凯成王广飞祝妍王广华
Owner 安徽伯华氢能源科技有限公司
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