Zeolite Sensor for Nitrogen Monoxide Detection at High Temperature

1996 ◽  
Vol 454 ◽  
Author(s):  
Hiroshi Tsuchiya ◽  
Isao Sasaki ◽  
Azuchi Harano ◽  
Tatsuya Okubo ◽  
Masayoshi Sadakata
Keyword(s):  
High Temperature ◽  
Gold Electrode ◽  
Gas Sensing ◽  
Nitrogen Monoxide ◽  
X Ray Diffraction ◽  
Zeolite Film ◽  
And Performance ◽  
Flowing Stream ◽  
No Sensor ◽  
Thermal Stability Of

ABSTRACTDevelopment of new NOx sensors, which would be sensitive, selective, inexpensive and stable at elevated temperature, will greatly contribute to the reduction of the air pollution. In this paper, synthesis and performance of zeolite film applied for gas sensing are reported.Zeolite thin films (Cu ion-exchanged ZSM-5) were synthesized on the gold electrode of AT-cut quartz platelet by hydrothermal synthesis. In order to probe the target molecule (NO) selectively, Na in as synthesized ZSM-5 film was ion-exchanged with Cu. The films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The synthesis condition for orientation to (0×0) face, on which the straight pores of ZSM-5 are opening, was optimized.The bulk type quartz oscillator coated with Cu-ZSM-5 thin layer was tested as NO sensor in a flowing stream of He. This sensing system could be operated at high temperature because of the thermal stability of the ZSM-5 film and the gold electrode. As a result, NO was successfully detected at 348 K.

Investigation on the Thermal Stability of the Compounds Y3Fe29-xCrx

2013 ◽  
Vol 820 ◽  
pp. 71-74
Author(s):  
Xiao Hua Wang ◽  
Wei He ◽  
Ling Min Zeng
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Single Phase ◽  
Binary Compound ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Transition Elements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

Binary compound Y3Fe29cannot be directly formed by rare earth Y and Fe and the third element M (non-iron transition elements) must be introduced to form ternary compound Y3(Fe,M)29. In this work, six alloys with compositions of the Y3Fe29-xCrx(x=1,2,3,4,5,6) were prepared and investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and differential thermal analysis (DTA). The study on the thermal stability of these compounds points to that the compoundY3(Fe,Cr)29is a high temperature phase and exists above 1100K. The alloys with single-phase of Y3(Fe,Cr)29was decomposed into Y2(Fe,Cr)17and Y(Fe,Cr)12annealed at high temperature 1100K.

Synthesis and performance of a photocatalytic titania-hydroxyapatite composite

2008 ◽  
Vol 23 (9) ◽  
pp. 2398-2405 ◽  
Author(s):  
N. Phonthammachai ◽  
J. Kim ◽  
T.J. White
Keyword(s):  
Calcination Temperature ◽  
X Ray Diffraction ◽  
Titanium Butoxide ◽  
X Ray ◽  
Hydroxyapatite Composite ◽  
Porous Titania ◽  
And Performance ◽  
Optimal Material ◽  
Tricalcium Phosphates ◽  
Thermal Stability Of

The photocatalytic degradation of methylene blue (MB) over a porous titania-hydroxyapatite (HAp) composite under ultraviolet radiation was studied. The catalyst was prepared by coating porous HAp with a titanium butoxide [Ti(OBu)4] sol at titania loadings of 17–49 wt%. Quantitative powder x-ray diffraction showed higher proportions of anatase as the calcination temperature increased from 500 to 800 °C due to crystallization of an amorphous precursor. The transformation of anatase to rutile was delayed until 900 °C, demonstrating the high thermal stability of the composite. Decomposition of HAp to α- and β- tricalcium phosphates takes place at 900 °C and is accompanied by the formation of perovskite at 1000 °C. A systematic study of the influence of calcination temperature and titania:HAp ratios demonstrated that for the optimal material, a surface area of 100 m2 g−1 was obtained at a titania loading of 49 wt% and calcination temperature of 600 °C. A highly dispersed suspension of finely ground titania-HAp enhanced the photodegradation of MB, allowed a high percentage recovery of catalyst, and was shown to be recyclable.

Improvement of Thermal Stability of ZrB2/Si3N4 Coatings as High-Temperature Solar Selective Absorbers

2014 ◽  
Vol 521 ◽  
pp. 581-585
Author(s):  
Yao Ming Sun ◽  
Xiu Di Xiao ◽  
Guan Qi Chai ◽  
Gang Xu ◽  
Bin Xiong ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
High Temperature ◽  
Substrate Temperature ◽  
Bias Voltage ◽  
X Ray Diffraction ◽  
Substrate Bias Voltage ◽  
X Ray ◽  
Deposition Parameters ◽  
Thermal Stability Of

ZrB2 thin films were prepared by DC magnetron sputtering technique. The microstructure, thermal stability and optical properties of thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and spectrophotometer. The compactness of ZrB2 thin films was studied to improve the thermal stability by optimizing the deposition parameters. The compactness and thermal stability of the coatings were improved with the increase of substrate temperature. However, these properties of the coatings were enhanced firstly and then weakened with the increase of substrate bias voltage. The selectivity of sample deposited at high substrate temperature and suitable bias voltage degraded slightly after annealing at 500 °C/100 h in air. This provided a new way to improve the thermal stability of high-temperature solar selective absorber.

scholarly journals Microstructure evolution and phase transformation of ZrB2-45MoSi2-10Al coating at high temperature

2021 ◽  
Vol 2124 (1) ◽  
pp. 012010
Author(s):  
M G Kovaleva ◽  
V Yu Novikov ◽  
O N Vagina ◽  
V V Sirota
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Carbon Composites ◽  
X Ray Diffraction ◽  
Detonation Spraying ◽  
X Ray ◽  
Dense Microstructure ◽  
Composite Substrate ◽  
Oxidation Resistant ◽  
Thermal Stability Of

Abstract The ZrB2-45MoSi2-10Al coating was prepared by a Robotic complex for detonation spraying of coatings equipped with a multi-chamber detonation accelerator on surface of carbon/carbon composites without adhesion sublayer. The coating has a lamella-type structure typical for gas-thermal coatings, well connected with C/C composite substrate without sublayer, and composed of m-ZrO2, t-ZrO2, t-MoSi2, some h-ZrB2, and c-Al phases. Heat treatment of the samples at 1500 °C for 1, 3 and 6 h was carried out in air. The effect of heat treatment on the microstructure and phase composition of the ZrB2-45MoSi2-10Al coating was investigated by X-ray diffraction and scanning electron microscopy. The c-ZrO2 and h-(α-Al2O3) were formed after oxidation at 1500 °C for 6 h. The uniform distribution of ZrO2 ceramic particles and the formation of a-Al2O3 enhanced the thermal stability of the coating. The coating after heat treatment (1, 3 and 6 h) exhibited structure without cracks and low porosity. The dense microstructure of the coating contributed to its good oxidation-resistant property at high temperature.

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