Palladium nickel alloy hydrogen sensor

Principle of palladium nickel alloy Hydrogen sensor

Palladium nickel alloy Hydrogen sensor It is a sensor specially used to detect the concentration of hydrogen. Its principle is mainly based on the special adsorption performance of palladium nickel alloy for hydrogen and the change of electrical performance. Solid palladium nickel alloy hydrogen sensor includes palladium alloy resistance, nickel film resistance and gold film resistance, among which palladium alloy film resistance is used for hydrogen detection, nickel film resistance is used for chip temperature measurement, and gold film resistance is used for chip heating. The principle and working process of palladium nickel alloy hydrogen sensor will be introduced in detail below.

Pd Ni alloy is a kind of metal material with excellent hydrogen adsorption performance. In Pd Ni alloys, Pd atoms have a strong adsorption capacity for hydrogen, while Ni atoms play a role in adjusting the spacing of Pd atoms and enhancing the mechanical strength of the alloy. When palladium nickel alloy is exposed to the environment containing hydrogen, hydrogen molecules will be adsorbed on the surface of palladium atoms and form palladium hydrogen (Pd-H) compounds with it. In this process, the hydrogen molecule decomposes into hydrogen atoms and enters the lattice gap of Pd Ni alloy, resulting in a small expansion of the alloy volume.

With the increase of hydrogen concentration, the number of hydrogen atoms in Pd Ni alloy will also increase, thus changing the electrical properties of the alloy. Specifically, the introduction of hydrogen atoms will affect the concentration and mobility of free electrons in Pd Ni alloys, which will lead to changes in the resistivity of the alloys. There is a functional relationship between the change of resistivity and hydrogen concentration, so the hydrogen concentration can be inferred by measuring the resistivity of Pd Ni alloy.

In order to achieve accurate measurement of hydrogen concentration, Pd Ni alloy hydrogen sensors usually use the combination of thin film technology and microelectronic processing technology. First, a Pd Ni alloy film was deposited on the sensor substrate, which has excellent hydrogen adsorption and electrical properties. Then, electrodes and leads are made on the film surface to connect with the external measuring circuit. In the working process, when hydrogen molecules pass through the sensor film, they will be adsorbed by Pd Ni alloy and decomposed into hydrogen atoms. The resistivity of Pd Ni alloy films changes with the increase of the number of hydrogen atoms. This change will be captured by the external measuring circuit and converted into an electrical signal for output. The accurate value of hydrogen concentration can be obtained by processing and analyzing the electrical signal.

Pd Ni alloy principle Advantages of hydrogen sensor:

• The sensor can measure pure hydrogen from ppm to 99.9%;
• Based on the detection technology of hydrogen partial pressure, the sensor does not need O2 to work, and can work under different background gases such as air, N2, inert gas (He, etc.); No cross response, including CxHy, CO, H2S, ethanol and other combustible gases; The detection accuracy is not affected by humidity;
• The sensor chip can withstand γ - ray irradiation, and the irradiation will not affect the chip life and detection accuracy;
• The detection gas temperature can reach 80 ℃, providing high measurement accuracy and fast response;
• It can be inserted into transformer oil to directly measure dissolved hydrogen in oil without oil gas separation;

Palladium nickel alloy hydrogen sensor Palladium nickel alloy hydrogen sensor Application field:

• The application fields of hydrogen sensors mainly include power, nuclear energy, petrochemical and other industries and national defense fields.
• Dissolved hydrogen concentration in oil of oil filled electrical equipment
• Hydrogen concentration monitoring of hydrogen cooled generator
• Leakage monitoring of water tank in power station
• Petrochemical: catalytic reforming, hydrocracking