Severe erosion by hard particles is a crucial problem to engine blades when aircraft take off and land in harsh environments, especially for the developed lightweight titanium alloy components. Here, we deposited the ...Severe erosion by hard particles is a crucial problem to engine blades when aircraft take off and land in harsh environments, especially for the developed lightweight titanium alloy components. Here, we deposited the Ti/TiAlN multilayer coatings with various cycles on Ti–6 Al–4 V substrates by a home-made hybrid multisource cathodic arc system. The effects of the silica sand and glass beads on erosion behavior of the coatings were focused. Results showed that the Ti/TiAlN multilayer coatings eroded by the silica sand exhibited the predominant "layer by layer" failure mechanism. In particular, increasing the number of cycles led to the dramatic increase in erosion rate for Ti/TiAlN multilayer coatings, due to the deterioration of their mechanical properties. Different from the silica sand case, however, the erosion rate of the coatings treated by glass beads indicated faint dependence upon the number of cycles, where the coating failure was dominated by the "piece by piece" failure mechanism. Noted that the Ti layers along with the formed interfaces enhanced the erosion resistance of the coatings, although the failure mechanisms were differently eroded by silica sand and glass beads. Meanwhile, the Ti layers and interfaces hindered the propagation of radial cracks and restrained the lateral cracks within one single TiAlN layer.展开更多
Ni-rich cathode materials show great potential of applying in high-energy lithium ion batteries,but their inferior cycling stability hinders this process.Study on the electrode/electrolyte interfacial reaction is indi...Ni-rich cathode materials show great potential of applying in high-energy lithium ion batteries,but their inferior cycling stability hinders this process.Study on the electrode/electrolyte interfacial reaction is indispensable to understand the capacity failure mechanism of Ni-rich cathode materials and further address this issue.This work demonstrates the domain size effects on interfacial side reactions firstly,and further analyzes the inherent mechanism of side reaction induced capacity decay through comparing the interfacial behaviors before and after MgO coating.It has been determined that LiF deposition caused thicker SEI films may not increase the surface film resistance,while HF erosion induced surface phase transition will increase the charge transfer resistance,and the later plays the dominant factor to declined capacity of Ni-rich cathode materials.This work suggests strategies to suppress the capacity decay of layered cathode materials and provides a guidance for the domain size control to match the various applications under different current rates.展开更多
基金financially supported by the National Science and Technology Major Project(No.2017-VII-0012-0108)CAS Interdisciplinary Innovation Team(No.292020000008)K.C.Wong Education Foundation(No.GJTD-2019-13)。
文摘Severe erosion by hard particles is a crucial problem to engine blades when aircraft take off and land in harsh environments, especially for the developed lightweight titanium alloy components. Here, we deposited the Ti/TiAlN multilayer coatings with various cycles on Ti–6 Al–4 V substrates by a home-made hybrid multisource cathodic arc system. The effects of the silica sand and glass beads on erosion behavior of the coatings were focused. Results showed that the Ti/TiAlN multilayer coatings eroded by the silica sand exhibited the predominant "layer by layer" failure mechanism. In particular, increasing the number of cycles led to the dramatic increase in erosion rate for Ti/TiAlN multilayer coatings, due to the deterioration of their mechanical properties. Different from the silica sand case, however, the erosion rate of the coatings treated by glass beads indicated faint dependence upon the number of cycles, where the coating failure was dominated by the "piece by piece" failure mechanism. Noted that the Ti layers along with the formed interfaces enhanced the erosion resistance of the coatings, although the failure mechanisms were differently eroded by silica sand and glass beads. Meanwhile, the Ti layers and interfaces hindered the propagation of radial cracks and restrained the lateral cracks within one single TiAlN layer.
基金supported by the National Key R&D Program of China(2016YFB0100301)the National Natural Science Foundation of China(21875022,51802020,U1664255)+2 种基金the Science and Technology Innovation Foundation of Beijing Institute of Technology Chongqing Innovation Center(2020CX5100006)the Young Elite Scientists Sponsorship Program by CAST(2018QNRC001)the support from the Beijing Institute of Technology Research Fund Program for Young Scholars。
文摘Ni-rich cathode materials show great potential of applying in high-energy lithium ion batteries,but their inferior cycling stability hinders this process.Study on the electrode/electrolyte interfacial reaction is indispensable to understand the capacity failure mechanism of Ni-rich cathode materials and further address this issue.This work demonstrates the domain size effects on interfacial side reactions firstly,and further analyzes the inherent mechanism of side reaction induced capacity decay through comparing the interfacial behaviors before and after MgO coating.It has been determined that LiF deposition caused thicker SEI films may not increase the surface film resistance,while HF erosion induced surface phase transition will increase the charge transfer resistance,and the later plays the dominant factor to declined capacity of Ni-rich cathode materials.This work suggests strategies to suppress the capacity decay of layered cathode materials and provides a guidance for the domain size control to match the various applications under different current rates.
