A kind of preparation method of porous ceramic alumina type humidity sensor

A technology of humidity sensor and porous ceramics, which is applied in the direction of ceramic products, instruments, scientific instruments, etc., can solve the problems of sensitivity degradation, capacitive characteristic drift, etc., and achieve the effect of sufficient phase change, stable microstructure, and uniform pores

Inactive Publication Date: 2015-11-18
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Application Information

AI Technical Summary

Problems solved by technology

The nano-alumina film prepared by the low-field method will cause the drift of capacitance characteristics and the degradation of sensitivity after a period of time in a high-humidity environment, which is mainly attributed to the phenomenon of water infiltration in the pores.

Method used

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  • A kind of preparation method of porous ceramic alumina type humidity sensor
  • A kind of preparation method of porous ceramic alumina type humidity sensor
  • A kind of preparation method of porous ceramic alumina type humidity sensor

Examples

Experimental program
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Embodiment 1

[0029] The present embodiment porous ceramic Al 2 o 3 The preparation process of the type humidity sensor is as follows:

[0030] 1. Pretreatment of high-purity aluminum test pieces

[0031]The size of the high-purity aluminum sample in this embodiment is 50mm×50mm×0.5mm, and the purity is 99.99%. The pretreatment process is to use acetone to remove oil for 15-20 minutes under the action of ultrasonic waves. After degreasing, put it in 1mol / L NaOH solution for about 5 minutes to remove the natural oxide layer, and then use it.

[0032] 2. Preparation of porous ceramic Al by transient self-feedback micro-arc oxidation technology 2 o 3 Moisture Sensitive Film

[0033] The pretreated high-purity aluminum test piece is placed in a stainless steel tank containing electrolyte, the high-purity aluminum is used as the working electrode, and the stainless steel is used as the counter electrode to form a circuit. Utilize Durcourt IV high-power pulse power supply to apply double-p...

Embodiment 2

[0046] The difference from Example 1 is that step 2 adopts transient self-feedback micro-arc oxidation technology to prepare porous ceramic Al 2 o 3 For moisture sensitive films:

[0047] The main composition of the electrolyte is: sodium hydroxide 3~5g / L, sodium silicate 2~5g / L, sodium borate 5~8g / L, sodium molybdate 0.2~0.8g / L, sodium caprate 0.8~1.9g / L, sodium malate 0.7~1.2g / L, cerium nitrate 0.8~2.1g / L, electrolyte pH value 5~8 (use diluted NaOH, or dilute nitric acid solution to adjust). The double-pulse square-wave voltage with high-frequency carrier is applied to the electrolysis circuit by using Durcott Ⅳ high-power pulse power supply. The pulse frequency of the parent square-wave pulse voltage is 320-340Hz, and the forward pulse voltage amplitude is 330-350V. The pulse width is 0.6ms, the negative voltage amplitude is 540-620V, and the pulse width is 0.4ms; the high-frequency carrier frequency is 2500-2800Hz, and the high-frequency carrier voltage amplitude is 70-...

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Abstract

The invention discloses a porous ceramic alumina type humidity sensor and a making method thereof, and belongs o the technical field of components indicating the environment humidity. A transient self-feedback micro-arc oxidation technology is utilized to prepare a stable porous alpha-Al2O3 ceramic film on a highly pure aluminum slice as a humidity-sensitive dielectric layer, so the above obtained Al2O3 humidity sensor can improve or overcome the problems of long-term drift and unstable structure. The humidity sensor has the advantages of wide measuring range, high sensitivity, and good reappearance and stability, and can be widely applied in the industrial process control situation, the environment humidity detection situation and the like.

Description

technical field [0001] The invention relates to the technical field of components indicating the humidity of the environment, in particular to a porous ceramic alumina (Al 2 o 3 ) type humidity sensor and its preparation method. Background technique [0002] Humidity measurement is more and more widely used in the fields of metallurgy, electronics, and aerospace. At present, humidity sensors mainly include electrolyte type, polymer type and semiconductor type, but they all have certain limitations, which are mainly manifested in: electrolyte humidity sensor has shortcomings such as narrow measurement range, poor repeatability, and short service life; polymer type The compound humidity sensor has the advantages of good humidity sensing performance and high sensitivity, but under high temperature and high humidity conditions, the performance becomes poor, the stability is poor, and the corrosion resistance and stain resistance are poor; the semiconductor ceramic material hum...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N27/00C04B38/00C04B35/10
Inventor 杜克勤郭兴华郭泉忠王勇王福会
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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