Controlled release NPK compound fertilizers were prepared by means of in situ polymerization of monomers on the surface of fertilizer granules at room temperature. Methacrylate, α-methyl acrylic acid, and ethylene di...Controlled release NPK compound fertilizers were prepared by means of in situ polymerization of monomers on the surface of fertilizer granules at room temperature. Methacrylate, α-methyl acrylic acid, and ethylene dimethylacrylate were used as monomers, Dibenzoyl peroxide as initiator, and cobalt naphthenate, and triethyl amine as promoters. The structures of coating materials were characterized by IR spectra. The thermogravimetric analysis result indicated that the coating materials were of good thermal stability. The mean thickness of single coating measured with screw gauge was ca. 140 μm. The morphologies of uncoated and coated fertilizer granules analyzed by using scanning electron microscopy were changed from porosities and gullies to hills and plain. The release rate of coated compound fertilizers in water could be controlled by the hydrophicity and thickness of coating. The increase in coating hydrophicity caused the increase in release rate of fertilizer. The increase in thickness of coating slowed the release rate.展开更多
A single Si_(1−x)C_(x)coating and compound coatings were deposited on Mg-3Sn matrix alloy by magnetron sputtering method.Compound coatings included Mg or Mg/AlTi intermediates between Mg-3Sn substrate and Si_(1−x)C_(x...A single Si_(1−x)C_(x)coating and compound coatings were deposited on Mg-3Sn matrix alloy by magnetron sputtering method.Compound coatings included Mg or Mg/AlTi intermediates between Mg-3Sn substrate and Si_(1−x)C_(x)coating.The thermal conductivity of the Mg-3Sn alloy after coating was enhanced at room temperature.The results showed that the Mg-3Sn alloy coated with Mg/AlTi/Si_(1−x)C_(x)displayed higher thermal conductivity,its thermal conductivity after corrosion was 90.1 W/(m K)and 108.4 W/(m K)at 25℃and 100℃,respectively.Meanwhile,it was revealed that the Mg/Si_(1−x)C_(x)and Mg/AlTi/Si_(1−x)C_(x)compound coatings had nobler Ecorr and much lower i_(corr),higher Rp,compared with the bare Mg-3Sn and Mg-3Sn/Si_(1−x)C_(x)system,and improved the corrosion resistance of the magnesium substrate.展开更多
In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel substrate.Before the coating process, the substrate is heated to temperature ranging from room...In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel substrate.Before the coating process, the substrate is heated to temperature ranging from room temperature to 400℃. The microstructure, porosity, microhardness, adhesion strength, and corrosion behavior of the coating are investigated at different substrate temperatures. Results show that coating porosity is lower on high temperature surface. Microhardness and adhesion strength of the deposition layer on the substrate without preheating have lower values than with preheating. The polarization test result shows that corrosion performance of the coating is dependent on micro cracks and porosities and the increasing of substrate temperature can improve the quality of coating and corrosion performance.展开更多
Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt bath.In this study,the microhardness,the phase constitution and the compositional di...Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt bath.In this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions were systematically characterized.The results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound layers.The mechanism for the formation of compound layer as well as the growth kinetics of the layer was also discussed.Upon the duplex treatment,the wear and corrosion resistances of steel surface were significantly improved.It was found that the growth kinetics of compound layer obeyed the parabolic law,with the activation energy of 122.82 kJ·moL^(-1).展开更多
Lithium-rich manganese-based oxides have the advantages of high discharge specific capacity, so they are potential candidates for advanced lithium battery cathode materials. However, they also have drawbacks to be sol...Lithium-rich manganese-based oxides have the advantages of high discharge specific capacity, so they are potential candidates for advanced lithium battery cathode materials. However, they also have drawbacks to be solved such as serious irreversible loss of capacity and voltage decay in the cycling process. Surface coating method was used in this paper to modify the lithium-rich manganese-based oxide(LRMO,Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)) to improve its electrochemical properties. Zirconium-based compounds coated LRMO materials(ZBC@LRMO) were obtained via the reaction of lithium hydroxide with zirconium n-butanol and subsequent thermal treatment at different temperatures. The results of X-ray diffraction and transmission electron microscopy confirm that the crystal structure and composition of the ZBC coating layer vary with the calcination temperature. The coating layer obtained at 600 ℃ is composed of tetragonal ZrO_(2) and Li_(2)ZrO_(3). The ZBC@LRMO sample with tetragonal ZrO =2 and Li_(2)ZrO_(3) composite exhibits the best electrochemical performance: the discharge capacity of ZBC@LRMO can reach 296 mAh g^(-1) at 0.1 C and 120 mAh g^(-1) at high rate of 5 C.展开更多
基金Supported by Natural Science Foundation of China(30571086)
文摘Controlled release NPK compound fertilizers were prepared by means of in situ polymerization of monomers on the surface of fertilizer granules at room temperature. Methacrylate, α-methyl acrylic acid, and ethylene dimethylacrylate were used as monomers, Dibenzoyl peroxide as initiator, and cobalt naphthenate, and triethyl amine as promoters. The structures of coating materials were characterized by IR spectra. The thermogravimetric analysis result indicated that the coating materials were of good thermal stability. The mean thickness of single coating measured with screw gauge was ca. 140 μm. The morphologies of uncoated and coated fertilizer granules analyzed by using scanning electron microscopy were changed from porosities and gullies to hills and plain. The release rate of coated compound fertilizers in water could be controlled by the hydrophicity and thickness of coating. The increase in coating hydrophicity caused the increase in release rate of fertilizer. The increase in thickness of coating slowed the release rate.
文摘A single Si_(1−x)C_(x)coating and compound coatings were deposited on Mg-3Sn matrix alloy by magnetron sputtering method.Compound coatings included Mg or Mg/AlTi intermediates between Mg-3Sn substrate and Si_(1−x)C_(x)coating.The thermal conductivity of the Mg-3Sn alloy after coating was enhanced at room temperature.The results showed that the Mg-3Sn alloy coated with Mg/AlTi/Si_(1−x)C_(x)displayed higher thermal conductivity,its thermal conductivity after corrosion was 90.1 W/(m K)and 108.4 W/(m K)at 25℃and 100℃,respectively.Meanwhile,it was revealed that the Mg/Si_(1−x)C_(x)and Mg/AlTi/Si_(1−x)C_(x)compound coatings had nobler Ecorr and much lower i_(corr),higher Rp,compared with the bare Mg-3Sn and Mg-3Sn/Si_(1−x)C_(x)system,and improved the corrosion resistance of the magnesium substrate.
文摘In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel substrate.Before the coating process, the substrate is heated to temperature ranging from room temperature to 400℃. The microstructure, porosity, microhardness, adhesion strength, and corrosion behavior of the coating are investigated at different substrate temperatures. Results show that coating porosity is lower on high temperature surface. Microhardness and adhesion strength of the deposition layer on the substrate without preheating have lower values than with preheating. The polarization test result shows that corrosion performance of the coating is dependent on micro cracks and porosities and the increasing of substrate temperature can improve the quality of coating and corrosion performance.
基金financially supported by the National Natural Science Foundation of China(No.51372009)。
文摘Superior compound coatings were prepared on CK45 steel surface by vanadium-nitrocarburizing duplex treatment in low-temperature salt bath.In this study,the microhardness,the phase constitution and the compositional distribution in the coatings prepared under different conditions were systematically characterized.The results indicated that the reactions among activated vanadium,carbon and nitrogen atoms occurred on the steel surface,leading to the formation of compound coatings composed of outermost and compound layers.The mechanism for the formation of compound layer as well as the growth kinetics of the layer was also discussed.Upon the duplex treatment,the wear and corrosion resistances of steel surface were significantly improved.It was found that the growth kinetics of compound layer obeyed the parabolic law,with the activation energy of 122.82 kJ·moL^(-1).
基金supported by the National Natural Science Foundation of China(No.21776051)the Research Fund Program of Key Laboratory of Fuel Cell Technology of Guangdong Province。
文摘Lithium-rich manganese-based oxides have the advantages of high discharge specific capacity, so they are potential candidates for advanced lithium battery cathode materials. However, they also have drawbacks to be solved such as serious irreversible loss of capacity and voltage decay in the cycling process. Surface coating method was used in this paper to modify the lithium-rich manganese-based oxide(LRMO,Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)) to improve its electrochemical properties. Zirconium-based compounds coated LRMO materials(ZBC@LRMO) were obtained via the reaction of lithium hydroxide with zirconium n-butanol and subsequent thermal treatment at different temperatures. The results of X-ray diffraction and transmission electron microscopy confirm that the crystal structure and composition of the ZBC coating layer vary with the calcination temperature. The coating layer obtained at 600 ℃ is composed of tetragonal ZrO_(2) and Li_(2)ZrO_(3). The ZBC@LRMO sample with tetragonal ZrO =2 and Li_(2)ZrO_(3) composite exhibits the best electrochemical performance: the discharge capacity of ZBC@LRMO can reach 296 mAh g^(-1) at 0.1 C and 120 mAh g^(-1) at high rate of 5 C.
