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Humidity sensing properties of TiO2-Sb2O5 nanocomposite

Srivastava A. K., Yadav B. C.

Materials Science Poland

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2010

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Vol. 28, No. 2

491--502

EN

The syntheses of TiO2-Sb2O5 (AT) composites were investigated by the conventional precipitation method and their use as humidity sensors. 2-50 wt. % of Sb2O5 was added to TiO2 and pellets were made under the pressure of 616 MPa a room temperature of 30°C. The pellets were annealed at various temperatures (200, 500, 700 and 800 °C) for 3 h and the humidity sensing properties of each pellet were studied. A saturated aqueous solution of potassium sulphate was used as the humidifier and a saturated solution of potassium hydroxide was used as the dehumidifier. Upon increasing relative humidity (RH) inside the test chamber, the resistance of each pellet decreased for the RH range from 10% to 95%. Samples of the sensor material, differing in the percentage of the additive, were subject to SEM and XRD analysis. The minimum grain size, estimated from SEM, was 30 nm and the minimum crystallite size from XRD data was 20 nm. The material was found to have suitable properties to be applied as a resistive humidity sensor operating over the entire humidity range.

2

Optical humidity sensing behaviour of sol-gel processed nanostructured ZnO films

Yadav B. C., Yadav R. C., Dubey G. C.

Optica Applicata

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2009

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Vol. 39, nr 3

617-627

EN

This paper reports the humidity sensing behaviour of sol-gel processed ZnO films deposited on U-shaped borosilicate rods as substitute of optical fiber having the same radius of curvature. The films prepared on each sensing element were dried for 15 minutes using a 100 watt electric bulb. Both ends of the U-shaped borosilicate rod were coupled to optical fibers. Light from a He-Ne laser is fed into the sensing element through one of the ends. Light is received from the other end of fiber coupled into an optical power meter. Variations in the intensity of light with changes in humidity from 10% to 95% have been recorded. Characterization of sensing material has been done using SEM.

3

Fibre optic pressure sensor and monitoring of structural defects

Pandey N. K., Yadav B. C.

Optica Applicata

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2007

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Vol. 37, nr 1-2

57-63

EN

Pressure induced microbends have been created in a 50 mm graded index multimode optical fibre with spatial periodicity L = 4.5 mm, embedded in the sample of araldite. If high pressure is applied directly to optical fibre having microbends, it may break, and if pressure is applied to embedded fibre in a solid structure without microbends, the sensitivity is lower. In this paper, a combination of the embedded sensor and microbend sensor is presented. It has the advantage of sensing high pressure on a structure with the sensitivity of a microbend sensor without breaking the optical fibre. It measures pressure up to 1.6 MPa with reproducibility within ą 5% of the measurand. The average sensitivity of the sensor is 5.3/ MPa on an arbitrary scale.