Brake friction materials with different zinc powder contents(0,2,4,6,8 wt.%)were fabricated via powder metallurgy method.The results indicate that with the increasing zinc powder content,the density and thermal conduc...Brake friction materials with different zinc powder contents(0,2,4,6,8 wt.%)were fabricated via powder metallurgy method.The results indicate that with the increasing zinc powder content,the density and thermal conductivity of the materials gradually increase,while the hardness decreases monotonously.With increasing zinc powder content,the curve of the nominal friction coefficient shows fluctuating trend but the lowest friction coefficient also shows an increase.However,the wear rate and braking noise of the friction material monotonously decrease with increasing zinc content.This effect may be attributed to the transformation of the tribological mechanism from adhesive wear and abrasive wear to adhesive wear.The brake friction material with 4 wt.%zinc powder exhibits both the best tribological and noise performance.展开更多
A new kind of polyesteramide based on 3-morpholinone and e caprolactone was synthesized by ring opening polymerization with zinc powder as catalyst.The polymer was characterized by^(1)H NMR,GPC and FT-IR.The effect of...A new kind of polyesteramide based on 3-morpholinone and e caprolactone was synthesized by ring opening polymerization with zinc powder as catalyst.The polymer was characterized by^(1)H NMR,GPC and FT-IR.The effect of time,temperature and ratio of m(M)/m(1),n(M)/n(CL)on the reaction was studied.The results show that the optimal reaction temperature is 120℃;the optimal duration of reaction is 24 h;the optimal ratio of m(M)/m(CL)is 50:1;the optimal ratio of n(M)/n(CL)is 1:2.Under the optimal condition the polymer whose M_(n)was 13509 could be obtained while the weight yield was 79%.展开更多
The density of zinc powder for alkaline battery was determined using a pyknometer.The results showed that powders made before the end of 2003 could reach relative densities above 99% of the theoretical density.Investi...The density of zinc powder for alkaline battery was determined using a pyknometer.The results showed that powders made before the end of 2003 could reach relative densities above 99% of the theoretical density.Investigating the relative volume swelling of electrolysed gels of zinc powders,no evident relation between swelling and pyknometer density was found.展开更多
A convenient and environmentally benign method for reducing the carbonyl group in hydroxy- and amino- 9,10-anthracenediones, ortho （or para） acyl phenols and acyl anilines to a methylene group by zinc powder in an a...A convenient and environmentally benign method for reducing the carbonyl group in hydroxy- and amino- 9,10-anthracenediones, ortho （or para） acyl phenols and acyl anilines to a methylene group by zinc powder in an aqueous sodium hydroxide solution was reported. Based on theoretical calculations using the density functional theory （DFT）, the mechanism of these reduction reactions was postulated. This mechanism can be applied to help predicting the reduced products of aryl ketones （or aldehydes） in an alkaline solution.展开更多
Zinc powder electrodeposited from suspension bath has higher corrosion resistance than that from conventional bath. The results of X ray, SEM and EIS (Electrochem. Impedance Spectrum) indicated that the microstructur...Zinc powder electrodeposited from suspension bath has higher corrosion resistance than that from conventional bath. The results of X ray, SEM and EIS (Electrochem. Impedance Spectrum) indicated that the microstructures of zinc powder could be modified according to the kinds of suspension species. Suspension of TiO 2, SiO 2, In 2O 3, PbO 2 and SnO 2 could obviously improve the polarization resistance of zinc powder anodes in 5 mol/L KOH solution.展开更多
Mercury free zinc alloy powder were electrodeposited from alkaline solution. Additives containing lead, indium or bismuth were added in the electrolyte and zinc powders with corresponding compositions were obtained....Mercury free zinc alloy powder were electrodeposited from alkaline solution. Additives containing lead, indium or bismuth were added in the electrolyte and zinc powders with corresponding compositions were obtained. The relations between adding amounts of additives and the contents of corresponding compositions in zinc powder are not linear. Aluminum and calcium cannot be co deposited with zinc. Electrodeposition effectively reduced the contents of harmful impurities. Gas evolution of electrodeposited Zn Pb In Bi alloy powder was less than that of atomized mercury free alloy powder.展开更多
This work focused on the zinc powder coated with Y(OH)3 microparticles by means of ultrasonic immersion for performance improvement of zinc electrodes in alkaline battery systems.Scanning electron microscopy and other...This work focused on the zinc powder coated with Y(OH)3 microparticles by means of ultrasonic immersion for performance improvement of zinc electrodes in alkaline battery systems.Scanning electron microscopy and other characterization techniques were applied to examine the influence of the ultrasonic power on the sonochemical growth of Y(OH)3 microparticles in direct contact with zinc powder.Electrochemical properties of zinc electrodes containing Y(OH)3 microparticles were discussed through the measurement...展开更多
Zn-doped TiO_2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis,BET, XRD in this study.Under the irradiation of simulant sunlight,the photocatalytic activity for the degradation of p-nitr...Zn-doped TiO_2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis,BET, XRD in this study.Under the irradiation of simulant sunlight,the photocatalytic activity for the degradation of p-nitrophenol was studied too.After irradiation for 2.5 h,the degradation percentage of p-nitrophenol could rise to more than 80%.The results showed that the spectrum absorption band edge of Zn/TiO_2 powder does not broaden obviously comparing with pure TiO_2 powder.Zinc exists as Zn (Ⅱ).When calcined at 973 K,there is a new phase as ZnTiO_3 in Zn/TiO_2 catalyst.The order of photocatalytic activity of Zn/TiO_2 catalysts calcined at different temperatures for p-nitrophenol is 773 K＞673 K＞873 K＞573 K＞973 K and the photocatalytic activity of Zn/TiO_2 catalyst cal- cined at 773 K is better than TiO_2 catalysts heated at the same temperature,and outclasses that of commercial TiO_2 catalyst.It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irra- diation of simulant sunlight.展开更多
Zinc oxide, which has photocatalytic activity, is used as white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by ultraviolet radiation in sunlight. In this work, zinc oxide was shaken with...Zinc oxide, which has photocatalytic activity, is used as white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by ultraviolet radiation in sunlight. In this work, zinc oxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Zinc oxide was set with 0.1 mol/L of phosphoric acid at P/Zn = 1/1 and 1/2, and then shaking in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, color phase, and smoothness of the obtained powder were studied. The P/Zn ratio in preparation had an effect on the reaction between phosphoric acid and zinc oxide. The photocatalytic activity of zinc oxide was inhibited by phosphoric acid treatment. The obtained samples had enough high reflectance at the visible light region.展开更多
基金Project(2016YFB1100103)supported by the National Key Research and Development Program of ChinaProject(KC1703004)supported by the Science and Technology Planning Project of Changsha City,ChinaProject(2018ZZTS127)supported by the Fundamental Research Funds for the Central Universities of Central South University,China。
文摘Brake friction materials with different zinc powder contents(0,2,4,6,8 wt.%)were fabricated via powder metallurgy method.The results indicate that with the increasing zinc powder content,the density and thermal conductivity of the materials gradually increase,while the hardness decreases monotonously.With increasing zinc powder content,the curve of the nominal friction coefficient shows fluctuating trend but the lowest friction coefficient also shows an increase.However,the wear rate and braking noise of the friction material monotonously decrease with increasing zinc content.This effect may be attributed to the transformation of the tribological mechanism from adhesive wear and abrasive wear to adhesive wear.The brake friction material with 4 wt.%zinc powder exhibits both the best tribological and noise performance.
文摘A new kind of polyesteramide based on 3-morpholinone and e caprolactone was synthesized by ring opening polymerization with zinc powder as catalyst.The polymer was characterized by^(1)H NMR,GPC and FT-IR.The effect of time,temperature and ratio of m(M)/m(1),n(M)/n(CL)on the reaction was studied.The results show that the optimal reaction temperature is 120℃;the optimal duration of reaction is 24 h;the optimal ratio of m(M)/m(CL)is 50:1;the optimal ratio of n(M)/n(CL)is 1:2.Under the optimal condition the polymer whose M_(n)was 13509 could be obtained while the weight yield was 79%.
文摘The density of zinc powder for alkaline battery was determined using a pyknometer.The results showed that powders made before the end of 2003 could reach relative densities above 99% of the theoretical density.Investigating the relative volume swelling of electrolysed gels of zinc powders,no evident relation between swelling and pyknometer density was found.
基金Project supported by the Science Foundation of Jiangsu Province of China （No. BK2004085） and the National Natural Science Foundation of China （No. 20372032）.
文摘A convenient and environmentally benign method for reducing the carbonyl group in hydroxy- and amino- 9,10-anthracenediones, ortho （or para） acyl phenols and acyl anilines to a methylene group by zinc powder in an aqueous sodium hydroxide solution was reported. Based on theoretical calculations using the density functional theory （DFT）, the mechanism of these reduction reactions was postulated. This mechanism can be applied to help predicting the reduced products of aryl ketones （or aldehydes） in an alkaline solution.
文摘Zinc powder electrodeposited from suspension bath has higher corrosion resistance than that from conventional bath. The results of X ray, SEM and EIS (Electrochem. Impedance Spectrum) indicated that the microstructures of zinc powder could be modified according to the kinds of suspension species. Suspension of TiO 2, SiO 2, In 2O 3, PbO 2 and SnO 2 could obviously improve the polarization resistance of zinc powder anodes in 5 mol/L KOH solution.
文摘Mercury free zinc alloy powder were electrodeposited from alkaline solution. Additives containing lead, indium or bismuth were added in the electrolyte and zinc powders with corresponding compositions were obtained. The relations between adding amounts of additives and the contents of corresponding compositions in zinc powder are not linear. Aluminum and calcium cannot be co deposited with zinc. Electrodeposition effectively reduced the contents of harmful impurities. Gas evolution of electrodeposited Zn Pb In Bi alloy powder was less than that of atomized mercury free alloy powder.
基金supported by the Innovation Foundation of BUAA for Ph. D Graduates Provided by Beihang University in China
文摘This work focused on the zinc powder coated with Y(OH)3 microparticles by means of ultrasonic immersion for performance improvement of zinc electrodes in alkaline battery systems.Scanning electron microscopy and other characterization techniques were applied to examine the influence of the ultrasonic power on the sonochemical growth of Y(OH)3 microparticles in direct contact with zinc powder.Electrochemical properties of zinc electrodes containing Y(OH)3 microparticles were discussed through the measurement...
文摘Zn-doped TiO_2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis,BET, XRD in this study.Under the irradiation of simulant sunlight,the photocatalytic activity for the degradation of p-nitrophenol was studied too.After irradiation for 2.5 h,the degradation percentage of p-nitrophenol could rise to more than 80%.The results showed that the spectrum absorption band edge of Zn/TiO_2 powder does not broaden obviously comparing with pure TiO_2 powder.Zinc exists as Zn (Ⅱ).When calcined at 973 K,there is a new phase as ZnTiO_3 in Zn/TiO_2 catalyst.The order of photocatalytic activity of Zn/TiO_2 catalysts calcined at different temperatures for p-nitrophenol is 773 K＞673 K＞873 K＞573 K＞973 K and the photocatalytic activity of Zn/TiO_2 catalyst cal- cined at 773 K is better than TiO_2 catalysts heated at the same temperature,and outclasses that of commercial TiO_2 catalyst.It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irra- diation of simulant sunlight.
文摘Zinc oxide, which has photocatalytic activity, is used as white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by ultraviolet radiation in sunlight. In this work, zinc oxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Zinc oxide was set with 0.1 mol/L of phosphoric acid at P/Zn = 1/1 and 1/2, and then shaking in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, color phase, and smoothness of the obtained powder were studied. The P/Zn ratio in preparation had an effect on the reaction between phosphoric acid and zinc oxide. The photocatalytic activity of zinc oxide was inhibited by phosphoric acid treatment. The obtained samples had enough high reflectance at the visible light region.
