ZrC coatings were deposited on graphite substrates by low pressure chemical vapor deposition（LPCVD） with the Br2-Zr-C3H6-H2-Ar system. The effects of deposition time on the microstructures and growth behavior of ZrC...ZrC coatings were deposited on graphite substrates by low pressure chemical vapor deposition（LPCVD） with the Br2-Zr-C3H6-H2-Ar system. The effects of deposition time on the microstructures and growth behavior of ZrC coatings were investigated. ZrC coating grew in an island-layer mode. The formation of coating was dominated by the nucleation of ZrC in the initial 20 minutes, and the rapid nucleation generated a fine-grained structure of ZrC coating. When the deposition time was over 30 min, the growth of coating was dominated by that of crystals, giving a column-arranged structure. Energy dispersive X-ray spectroscopy showed that the molar ratio of carbon to zirconium was near 1：1 in ZrC coating, and X-ray photoelectron spectroscopy showed that ZrC was the main phase in coatings, accompanied by about 2.5mol% ZrO2 minor phase.展开更多
IN the process of forecasts, analyses and numerical treatments of the ground water resource, we often meet with various chemical reaction models. One type of them is three kinds of chemical substance M<sub>1<...IN the process of forecasts, analyses and numerical treatments of the ground water resource, we often meet with various chemical reaction models. One type of them is three kinds of chemical substance M<sub>1</sub>, M<sub>2</sub> and M<sub>3</sub> which can react with each other to produce two new kinds of other chemical compounds: （M<sub>2</sub>）<sub>n</sub> （M<sub>1</sub>）<sub>m</sub> and （M<sub>3</sub>）<sub>r</sub> （M<sub>1</sub>）<sub>κ</sub> at the same time. Usually, these reactions are irreversible and they have the following forms:展开更多
基金Founded by the National Natural Science Foundation of China(No.91216302)the National Program on Key Basic Research Project of the People's Republic of China(No.2015CB655200)
文摘ZrC coatings were deposited on graphite substrates by low pressure chemical vapor deposition（LPCVD） with the Br2-Zr-C3H6-H2-Ar system. The effects of deposition time on the microstructures and growth behavior of ZrC coatings were investigated. ZrC coating grew in an island-layer mode. The formation of coating was dominated by the nucleation of ZrC in the initial 20 minutes, and the rapid nucleation generated a fine-grained structure of ZrC coating. When the deposition time was over 30 min, the growth of coating was dominated by that of crystals, giving a column-arranged structure. Energy dispersive X-ray spectroscopy showed that the molar ratio of carbon to zirconium was near 1：1 in ZrC coating, and X-ray photoelectron spectroscopy showed that ZrC was the main phase in coatings, accompanied by about 2.5mol% ZrO2 minor phase.
文摘IN the process of forecasts, analyses and numerical treatments of the ground water resource, we often meet with various chemical reaction models. One type of them is three kinds of chemical substance M<sub>1</sub>, M<sub>2</sub> and M<sub>3</sub> which can react with each other to produce two new kinds of other chemical compounds: （M<sub>2</sub>）<sub>n</sub> （M<sub>1</sub>）<sub>m</sub> and （M<sub>3</sub>）<sub>r</sub> （M<sub>1</sub>）<sub>κ</sub> at the same time. Usually, these reactions are irreversible and they have the following forms:
