High energy ball milling(HEBM) method was applied to synthesize nickel hydroxide with and without partial substitution for Ni2+ sites by such metallic ions as Al3+, Al3+Zn2+ and Al3+Zn2+Co2+. The morphologies, structu...High energy ball milling(HEBM) method was applied to synthesize nickel hydroxide with and without partial substitution for Ni2+ sites by such metallic ions as Al3+, Al3+Zn2+ and Al3+Zn2+Co2+. The morphologies, structures, composition and thermal stability of the prepared powders were studied by SEM, XRD, FTIR and TG. The results reveal that all the synthesized Ni(OH)2 particles agglomerate in sub-micron sizes and the non-substituted Ni(OH)2 is composed of beta phase with a crystal interlayer distance of 4.64 , while the Al3+, Al3+Zn2+, Al3+Zn2+Co2+ substituted products are composed of alpha phase with 8.03 crystal interlayer space. Absorbed water molecule is found in all the synthesized Ni(OH)2 and the non-substituted particles are more thermally stable than substituted a-Ni(OH)2. The absorption peaks of inserted crystal anions of CO3 and SO24 are detected for metallic ion substituted a-Ni(OH)2. The specific capacity of Al3+substituted Ni(OH)2 is 325 mA·h/g, 5 mA·h/g higher than Al3+Zn2+ substituted and non-substituted Ni(OH)2, but 25 mA·h/g greater than Al3+Zn2+Co2+ substituted Ni(OH)2. The electrochemical mechanism of synthesized Ni(OH)2 electrodes is discussed by EIS spectrum and Al3+ substituted Ni(OH)2 electrode shows a high electrochemical cyclic stability.展开更多
Cu nanoparticles were fabricated by ball milling with the anhydrous alcohol as dispersant. The size and figure of Cu nanoparticles were characterized by X-ray diffractometry and transmission electron microscopy. The t...Cu nanoparticles were fabricated by ball milling with the anhydrous alcohol as dispersant. The size and figure of Cu nanoparticles were characterized by X-ray diffractometry and transmission electron microscopy. The tribological properties of adding Cu and MoS2 nanoparticles to the pure grease were measured on MM-200 tester, compared with the single additive and pure grease. The results show the size of Cu nanoparticles is about 50 nm. The surface with lubricant added nanopowder as additive possesses a remarkable decrease in wear volume. The friction coefficient and wear volume of lubricant mixed with 5% copper and 30% disulfide molybdenum nanoparticles are 0.09 and 1.80mm3, respectively. This mixed additive can not only increase the ability of supporting heavy load but repair the microscopic channels and cracks on the wear surface. Under higher load and long period of time, this lubricant has the characteristics of self-repairing, occluding resistance and ability of enduring higher temperature.展开更多
A new approach of ball-milled Mg_2Ni in tetrahydrofuran (THF) to improve thehydriding kinetics of Mg_2Ni alloy is suggested and studied. It is found that the modified alloydisplayed the improved activity for hydriding...A new approach of ball-milled Mg_2Ni in tetrahydrofuran (THF) to improve thehydriding kinetics of Mg_2Ni alloy is suggested and studied. It is found that the modified alloydisplayed the improved activity for hydriding even at relatively low temperature (e.g., 323-373 K).In the case of the sample milled in THF for 20 h, the hydrogen content (mass fraction) reaches 1.6 %at 323 K, 2.1% at 348 K and 3.4% at 448 K, respectively. The use of THF during grinding led to thechange of the structure, which is reflected by the broadening and weakening of the diffraction peaksin the XRD spectra. The XPS analysis shows that Mg (2s) binding energy peak of Mg_2Ni aftermodification shifted from a lower binding energy to a higher one, indicating the charge transferencebetween Mg and THF and the formation of catalytically active electron donor-acceptor (EDA)complexes on the surface of modified Mg_2Ni alloy.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
文摘High energy ball milling(HEBM) method was applied to synthesize nickel hydroxide with and without partial substitution for Ni2+ sites by such metallic ions as Al3+, Al3+Zn2+ and Al3+Zn2+Co2+. The morphologies, structures, composition and thermal stability of the prepared powders were studied by SEM, XRD, FTIR and TG. The results reveal that all the synthesized Ni(OH)2 particles agglomerate in sub-micron sizes and the non-substituted Ni(OH)2 is composed of beta phase with a crystal interlayer distance of 4.64 , while the Al3+, Al3+Zn2+, Al3+Zn2+Co2+ substituted products are composed of alpha phase with 8.03 crystal interlayer space. Absorbed water molecule is found in all the synthesized Ni(OH)2 and the non-substituted particles are more thermally stable than substituted a-Ni(OH)2. The absorption peaks of inserted crystal anions of CO3 and SO24 are detected for metallic ion substituted a-Ni(OH)2. The specific capacity of Al3+substituted Ni(OH)2 is 325 mA·h/g, 5 mA·h/g higher than Al3+Zn2+ substituted and non-substituted Ni(OH)2, but 25 mA·h/g greater than Al3+Zn2+Co2+ substituted Ni(OH)2. The electrochemical mechanism of synthesized Ni(OH)2 electrodes is discussed by EIS spectrum and Al3+ substituted Ni(OH)2 electrode shows a high electrochemical cyclic stability.
文摘Cu nanoparticles were fabricated by ball milling with the anhydrous alcohol as dispersant. The size and figure of Cu nanoparticles were characterized by X-ray diffractometry and transmission electron microscopy. The tribological properties of adding Cu and MoS2 nanoparticles to the pure grease were measured on MM-200 tester, compared with the single additive and pure grease. The results show the size of Cu nanoparticles is about 50 nm. The surface with lubricant added nanopowder as additive possesses a remarkable decrease in wear volume. The friction coefficient and wear volume of lubricant mixed with 5% copper and 30% disulfide molybdenum nanoparticles are 0.09 and 1.80mm3, respectively. This mixed additive can not only increase the ability of supporting heavy load but repair the microscopic channels and cracks on the wear surface. Under higher load and long period of time, this lubricant has the characteristics of self-repairing, occluding resistance and ability of enduring higher temperature.
基金This work is supported by the State Key Project for Fundamental Research (TG2000026406) and the National Natural Science Foundation of China (No. 50071053).
文摘A new approach of ball-milled Mg_2Ni in tetrahydrofuran (THF) to improve thehydriding kinetics of Mg_2Ni alloy is suggested and studied. It is found that the modified alloydisplayed the improved activity for hydriding even at relatively low temperature (e.g., 323-373 K).In the case of the sample milled in THF for 20 h, the hydrogen content (mass fraction) reaches 1.6 %at 323 K, 2.1% at 348 K and 3.4% at 448 K, respectively. The use of THF during grinding led to thechange of the structure, which is reflected by the broadening and weakening of the diffraction peaksin the XRD spectra. The XPS analysis shows that Mg (2s) binding energy peak of Mg_2Ni aftermodification shifted from a lower binding energy to a higher one, indicating the charge transferencebetween Mg and THF and the formation of catalytically active electron donor-acceptor (EDA)complexes on the surface of modified Mg_2Ni alloy.
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.
