Atmospheric pressure chemical vapour deposition

Ashraf, S., Blackman, C. S., Naisbitt, S. C. and Parkin, I. P. (2008) The gas-sensing properties ofW03-x thin films deposited via the atmospheric pressure chemical vapour deposition (APCVD) of WC16 with ethanol. Measurement Science and Technology 19,025203. 

Binions, R. (2007) A comparison of the gas sensing prop>erties of solid state metal oxide semiconductor gas sensors produced by atmospheric pressure chemical vapour deposition and screen printing. Measurement Science and Technology 18. 

Shaw, G. A., Parkin, I. P. and WiUiams, D. E. (2003) Atmospheric pressure chemical vapour deposition of Cr2-xTix03 (CTO) thin films on to gas sensing substrates. Journal of Materials Chemistry 13,2957-62. 

Lengtenberg et al. [328] used an atmospheric pressure chemical vapour deposition to deposit boron oxide as an intermediate layer for anodic bonding. 

The application of NIR laser diode spectroscopy to the on-line analysis of atmospheric pressure chemical vapour decomposition has been reported. In the process of depositing a thin layer of tin on a glass surface the monitoring of methane in the presence of oxygen, water and dichloromethyl tin dichloride in the reactor is important. Laser diode spectroscopy has been used at high sensitivity (detection limit of 0.01%) and at high frequency (5 Hz) for this purpose [40]. 

III-V nitride films were grown by the two-flow metalorganic chemical vapour deposition (MOCVD) method, details of which are described elsewhere [1]. The growth was conducted at atmospheric pressure. Sapphire with (0001) orientation (C-face), of two-inch diameter, was used as a substrate. 

Only a small amount of liquid, about a hundred molecule thick layer, is sufficient for the adhesion contact of sub-micron diameter particles ( 8). In the case of a volatile liquid, the equilibrium thickness of the film, and thus the adhesion, varies with partial pressure of the vapour in the surrounding atmosphere. When evaporation from a liquid film occurs, as a result of increased temperature, the adhesion first rises to a maximum value due to the meniscus effect but it breaks down as the film thickness is reduced to molecular dimensions. However, before the break-down of the surface tension chemical and mechanical bonds may develop between the deposited ash and boiler tube surface. 

Atmospheric conditions such as wind speed, temperature and relative air humidity are some environmental conditions that influence the volatilization rate. Increased wind speed tends to reduce the resistance to gas phase transport. This has the effect of increasing the dry gaseous deposition flux to the soil, but can also clearly increase the revolatihzation of the chemical from the soil [5, 30]. Temperature has a profound effect on the vapour/soil partitioning. Volatilization rates are influenced by soil and ambient air temperature mainly through its effect on vapour pressure, i.e. increase of temperature increases vapour pressure. If the relative humidity of the air is not 100%, increases in airspeed wiU hasten the drying of soil. This indirect effect alters the soil water content, which as it was previously mentioned has an effect on volatilization [30, 31]. 

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