In order to obtain ultrafine Nd-Fe-B powder, a spray-dried precursor was treated by reduction-diffusion (R/D) process. And, unlike the conventional R/D process, calcium reduction that is a crucial step for the formati...In order to obtain ultrafine Nd-Fe-B powder, a spray-dried precursor was treated by reduction-diffusion (R/D) process. And, unlike the conventional R/D process, calcium reduction that is a crucial step for the formation of Nd2Fe14B was performed without conglomerating the precursor with Ca powder. By adopting this modified process, it is possible to synthesize the hard magnetic Nd2Fe14B at the reaction temperature as low as 850 ℃. The average size of Nd2Fe14B particles that are uniformly distributed in the optimally treated powder was <<1 μm. Most Nd2Fe14B particles were enclosed with thin layers of Nd-rich phase. Typical magnetic properties of such powder without eliminating impurity CaO were iHc=～5.9 kOe, Br=～5.5 kG, and (BH)max=～6 MGOe.展开更多
In the quest to develop high-performance lubrication additives,a novel nanocomposite comprising biodiesel soot modified by silver(Ag/BDS)was synthesized.The tribological behavior of Ag/BDS nanocomposite as an additive...In the quest to develop high-performance lubrication additives,a novel nanocomposite comprising biodiesel soot modified by silver(Ag/BDS)was synthesized.The tribological behavior of Ag/BDS nanocomposite as an additive for liquid paraffin(LP)were systematically investigated using response surface methodology.To elucidate the friction and wear mechanisms associated with the Ag/BDS nanocomposite,various analytical techniques were employed,including scanning electron microscopy with energy-dispersive spectroscopy(SEM/EDS),Raman spectroscopy,and molecular dynamics simulations.The results show that the concentration of Ag/BDS has a significant impact on the tribological properties of LP under different applied loads and sliding speeds.Notably,LP containing 0.25%Ag/BDS shows the most favorable tribological performance and in comparison,to pure LP,the average friction coefficient and average wear volume have been reduced by 42.7%and 21.2%,respectively.The mechanisms underlying the reduction in friction and anti-wear mechanism of Ag/BDS have been attributed to the excellent synergies of Ag and BDS.Specifically,the Ag particles facilitate the incorporation of BDS particles in the formation of uniform boundary lubrication films.展开更多
文摘In order to obtain ultrafine Nd-Fe-B powder, a spray-dried precursor was treated by reduction-diffusion (R/D) process. And, unlike the conventional R/D process, calcium reduction that is a crucial step for the formation of Nd2Fe14B was performed without conglomerating the precursor with Ca powder. By adopting this modified process, it is possible to synthesize the hard magnetic Nd2Fe14B at the reaction temperature as low as 850 ℃. The average size of Nd2Fe14B particles that are uniformly distributed in the optimally treated powder was <<1 μm. Most Nd2Fe14B particles were enclosed with thin layers of Nd-rich phase. Typical magnetic properties of such powder without eliminating impurity CaO were iHc=～5.9 kOe, Br=～5.5 kG, and (BH)max=～6 MGOe.
基金funded by the National Natural Science Foundation of China(52075141)the Open Project of Anhui Province Key Laboratory of Critical Friction Pair for Advanced Equipment(LCFP-2408)+9 种基金Key Research&Development(R&D)Plan of Anhui Province under Grant(2022a05020019)Support Program for Outstanding Young Talents in Anhui Province Colleges and Universities(gxyq2022079)Excellent Research and Innovation Teams Project of Anhui Province's Universities(2022AH010092)Discipline Construction Quality Improvement Project of Chaohu University(kj22fdzy03,XLZ202307,XLZ202301)School-level Scientific Research Project of Chaohu University(XLY-202112)Scientific Research Planning Project of Anhui Provincial(2022AH051726)Anhui Province University Science and Engineering Teachers'Internship Program in Enterprises(2024jsqygz89)Anhui Province College Students'Innovation and Entrepreneurship Training Program(S202410380020)Anhui Province Postdoctoral Research Project(2024A773)Horizontal Research Project of Chaohu University(hxkt20230006).
文摘In the quest to develop high-performance lubrication additives,a novel nanocomposite comprising biodiesel soot modified by silver(Ag/BDS)was synthesized.The tribological behavior of Ag/BDS nanocomposite as an additive for liquid paraffin(LP)were systematically investigated using response surface methodology.To elucidate the friction and wear mechanisms associated with the Ag/BDS nanocomposite,various analytical techniques were employed,including scanning electron microscopy with energy-dispersive spectroscopy(SEM/EDS),Raman spectroscopy,and molecular dynamics simulations.The results show that the concentration of Ag/BDS has a significant impact on the tribological properties of LP under different applied loads and sliding speeds.Notably,LP containing 0.25%Ag/BDS shows the most favorable tribological performance and in comparison,to pure LP,the average friction coefficient and average wear volume have been reduced by 42.7%and 21.2%,respectively.The mechanisms underlying the reduction in friction and anti-wear mechanism of Ag/BDS have been attributed to the excellent synergies of Ag and BDS.Specifically,the Ag particles facilitate the incorporation of BDS particles in the formation of uniform boundary lubrication films.
