Meenakshi Choudhary

Preparation of nanosized tin oxide powder by sol-gel method

Nanosized SnO2 particles have been synthesized by a simple sol-gel method. The obtained tin oxide powder has been characterized using X-ray powder diffraction, scanning electron microscope, TG-DTA and fourier transform infrared spectroscopy. The result shows that there is the formation rutile type (tetragonal) structure in nanometric range (14.68 nm). Thermogravimetric analysis was executed to confirm that at 400°C (the calcination temperature) no further structural changes due to mass loss occur. It is recommended that the thermal analysis should be done in argon gas because nitrogen gas is more reactive. The IR bands are due to different Sn-O or Sn=O stretching modes and its lattice modes at 615 and 494 cm-1.

Gas Sensing Properties of Tin Oxide Nano-Powder Synthesized via Sol–Gel Route

In the present work SnO2 nano-powder has been synthesized by a sol–gel method. Thick film pastes are then developed by using as-synthesized SnO2 nano-powder with two different concentrations (0.5 and 1 wt %) of palladium (Pd). After that, the thick film sensor has been fabricated for the detection of various concentrations (1–5 vol %) of Liquefied Petroleum Gas (LPG). The investigations depict that sensing response of Pd-doped SnO2 is size dependent and small particles are found to be enhance the sensitivity of the sensor. The mechanism for LPG sensing has been also described.

Synthesis, characterization and gas sensing properties of tin oxide nanopowder

In the present work, tin oxide nanopowder has been synthesized by solid-state reaction technique. The as-prepared pure and palladium doped (0.5 and 1%) powders have been used for the fabrication of thick film sensors. The influence of particle size of powders and morphology of the thick films has been studied on the sensing performance of thick film sensor. It is observed that the sensors produced from the SnO2 doped with 1% palladium have an excellent ability for the detection of hydrogen gas.

Experimental Study on LTCC Glass-Ceramic Based Dual Segment Cylindrical Dielectric Resonator Antenna

The measured characteristics in C/X bands, including material properties of a dual segment cylindrical dielectric resonator antenna (CDRA) fabricated from glass-ceramic material based on B2O3–La2O3–MgO glass and La(Mg0.5Ti0.5)O3 ceramic, are reported. The sintering characteristic of the ceramic in presence of glass is determined from contact angle measurement and DTA. The return loss and input impedance versus frequency characteristics and radiation patterns of CDRA at its resonant frequency of 6.31 GHz are studied. The measured results for resonant frequency and return loss bandwidth of the CDRA are also compared with corresponding theoretical ones.

Platinum and palladium doped tin oxide thick film sensors for sensing methane and hydrogen

In this work, platinum (Pt) and palladium (Pd) doped SnO2 thick film sensors have been developed using solid state derived tin oxide powder. Thick film sensors were fabricated on a 1˝x1˝ alumina substrate. The crystal structure and particle size are confirmed by X-ray diffraction (XRD) pattern. The fabricated sensors are tested for varying concentration (1–5%) of hydrogen and methane gas at different operating temperatures (200–350 °C). The effect of Pt and Pd doping have been analysed on different operating temperature, sensitivity and response/recovery time. The doping effects are also very important from view point of the gas selectivity. Based on the experimental results, we have observed the formation of tetragonal structure and particle size of the powders is drastically decreases from 26 to 19 nm after replacing the platinum dopant with palladium. Both the doped sensors have been found to be sensitive for hydrogen as compare to methane however, Pd-doped SnO2 sensor are most selective for hydrogen with very fast response and recovery time (20 s, 101 s) due to the small size effect.