Ruoyu Wanga, Tong Zhou, Liu Jie, Xinwen Zhang, Jianfei Yang, Wenbin Hu, L. Lei
Abstract Biofouling originated from ubiquitous bacteria has affected quantities of practical applications, such as biomedical devices, biosensors and marine industry, thus the design for anti-biofouling coatings has aroused great concern in the scientific community. However, current anti-biofouling strategies based on either the release of biocidal compounds or surface textured/chemical design (superhydrophobic grille) cannot satisfy the practical demands when encountering real-world complex conditions. Here we, inspired by the ferroelectric/piezoelectric effect, report a refreshing strategy to prepare anti-biofouling coatings. The BaTiO3 particles are embedded in TiO2 coatings by micro-arc oxidation of pure titanium, and the obtained coatings have marvellous antifouling performance against Gram-negative E. coli. The contact potential differences (CPD) and reactive oxygen species (ROS) are successfully induced by the spontaneous polarization of micro/nano BaTiO3, and then the BaTiO3-incorporated TiO2 coatings (BaTiO3/TiO2) can effectively resist fouling organisms. Our experiments demonstrate that the ferroelectric effect of coatings plays a crucial role in the antimicrobial mechanism. It is therefore believed that our design strategy could also guide the development of other anti-biofouling materials and bring a new era to the marine antifouling.
{"title":"Designing Novel Anti-biofouling Coatings on Titanium based on the Ferroelectric-Induced Strategy","authors":"Ruoyu Wanga, Tong Zhou, Liu Jie, Xinwen Zhang, Jianfei Yang, Wenbin Hu, L. Lei","doi":"10.2139/ssrn.3805223","DOIUrl":"https://doi.org/10.2139/ssrn.3805223","url":null,"abstract":"Abstract Biofouling originated from ubiquitous bacteria has affected quantities of practical applications, such as biomedical devices, biosensors and marine industry, thus the design for anti-biofouling coatings has aroused great concern in the scientific community. However, current anti-biofouling strategies based on either the release of biocidal compounds or surface textured/chemical design (superhydrophobic grille) cannot satisfy the practical demands when encountering real-world complex conditions. Here we, inspired by the ferroelectric/piezoelectric effect, report a refreshing strategy to prepare anti-biofouling coatings. The BaTiO3 particles are embedded in TiO2 coatings by micro-arc oxidation of pure titanium, and the obtained coatings have marvellous antifouling performance against Gram-negative E. coli. The contact potential differences (CPD) and reactive oxygen species (ROS) are successfully induced by the spontaneous polarization of micro/nano BaTiO3, and then the BaTiO3-incorporated TiO2 coatings (BaTiO3/TiO2) can effectively resist fouling organisms. Our experiments demonstrate that the ferroelectric effect of coatings plays a crucial role in the antimicrobial mechanism. It is therefore believed that our design strategy could also guide the development of other anti-biofouling materials and bring a new era to the marine antifouling.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83235677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Geng, Yijie Ban, Xu Li, Yi Zhang, K. Song, Yanlin Jia, B. Tian, Meng Zhou, Yong Liu, A. Volinsky
High performance copper alloys are widely used in electrical, electronic, aerospace fields welcomed due to their high electrical conductivity and excellent mechanical properties. At present work, we proposed a new class of Cu-Co-Si-Ti alloy by incorporating the multiple alloying elements, resulting in the multiple strengthening during heat treatment. The achievement of solution strengthening, deformation strengthening and dual-nanoprecipitation strengthening leaded to the Cu-Co-Si-Ti alloy with excellent tensile strength (617.9 MPa) and high electrical conductivity (41.7% IACS) by the optimum process of 50% cold rolling and aging at 500 °C for 30 min. EBSD was used to analyze the microstructure and texture evolution during the aging process. Moreover, it was found that the volume fraction of Goss, Brass, copper and S texture had close connections with the mechanical properties. By comparing with the contributions of multiple strengthening mechanisms, dual-nanoprecipitation strengthening contributed quite a lot due to the nanoprecipitation of Co2Si and Cu4Ti.
{"title":"Excellent Mechanical Properties and High Electrical Conductivity of Cu-Co-Si-Ti Alloy Due to Multiple Strengthening","authors":"Y. Geng, Yijie Ban, Xu Li, Yi Zhang, K. Song, Yanlin Jia, B. Tian, Meng Zhou, Yong Liu, A. Volinsky","doi":"10.2139/ssrn.3782845","DOIUrl":"https://doi.org/10.2139/ssrn.3782845","url":null,"abstract":"High performance copper alloys are widely used in electrical, electronic, aerospace fields welcomed due to their high electrical conductivity and excellent mechanical properties. At present work, we proposed a new class of Cu-Co-Si-Ti alloy by incorporating the multiple alloying elements, resulting in the multiple strengthening during heat treatment. The achievement of solution strengthening, deformation strengthening and dual-nanoprecipitation strengthening leaded to the Cu-Co-Si-Ti alloy with excellent tensile strength (617.9 MPa) and high electrical conductivity (41.7% IACS) by the optimum process of 50% cold rolling and aging at 500 °C for 30 min. EBSD was used to analyze the microstructure and texture evolution during the aging process. Moreover, it was found that the volume fraction of Goss, Brass, copper and S texture had close connections with the mechanical properties. By comparing with the contributions of multiple strengthening mechanisms, dual-nanoprecipitation strengthening contributed quite a lot due to the nanoprecipitation of Co2Si and Cu4Ti.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81976075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lingxiang Zhu, Liang Huang, Surendar R. Venna, Adrienne K. Blevins, Yifu Ding, David P. Hopkinson, M. Swihart, Haiqing Lin
Nanoporous silica membranes exhibit excellent H2/CO2 separation properties for sustainable H2 production and CO2 capture but are prepared via complicated thermal processes above 400 oC, which prevent their scalable production at low cost. Here, we demonstrate the rapid fabrication (within 6 minutes) of ultrathin silica membranes (≈6 nm) via oxygen plasma treatment of polydimethylsiloxane based thin-film composite membranes at 20 oC. The resulting organosilica membranes exhibit H2 permeance of 280 - 930 GPU (1 GPU = 3.347×10-10 mol m-2 s-1 Pa-1) and H2/CO2 selectivity of 93 - 32 at 200 °C, far surpassing state-of-the-art membranes and Robeson’s upper bound for H2/CO2 separation. When challenged with a 3-day simulated syngas test containing water vapor and a 340-day stability test at 200 °C, the membrane shows stable separation performance. The robust H2/CO2 separation properties coupled with excellent scalability demonstrate the great potential of these organosilica membranes for economic H2 production with minimal carbon emissions.
{"title":"Scalable Polymeric Few-Nanometer Organosilica Membranes for Pre-Combustion CO 2 Capture","authors":"Lingxiang Zhu, Liang Huang, Surendar R. Venna, Adrienne K. Blevins, Yifu Ding, David P. Hopkinson, M. Swihart, Haiqing Lin","doi":"10.2139/ssrn.3778364","DOIUrl":"https://doi.org/10.2139/ssrn.3778364","url":null,"abstract":"Nanoporous silica membranes exhibit excellent H2/CO2 separation properties for sustainable H2 production and CO2 capture but are prepared via complicated thermal processes above 400 oC, which prevent their scalable production at low cost. Here, we demonstrate the rapid fabrication (within 6 minutes) of ultrathin silica membranes (≈6 nm) via oxygen plasma treatment of polydimethylsiloxane based thin-film composite membranes at 20 oC. The resulting organosilica membranes exhibit H2 permeance of 280 - 930 GPU (1 GPU = 3.347×10-10 mol m-2 s-1 Pa-1) and H2/CO2 selectivity of 93 - 32 at 200 °C, far surpassing state-of-the-art membranes and Robeson’s upper bound for H2/CO2 separation. When challenged with a 3-day simulated syngas test containing water vapor and a 340-day stability test at 200 °C, the membrane shows stable separation performance. The robust H2/CO2 separation properties coupled with excellent scalability demonstrate the great potential of these organosilica membranes for economic H2 production with minimal carbon emissions.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83542288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Real bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) should be the ones that exhibit an immortal behavior during catalysis without structural transformation or surface reconstruction. Otherwise, they could be only termed as “pre-catalysts” rather than the real catalysts. Herein, single-atom dispersed catalysts (SACs) embedding atomically dispersed Ru onto nickel-vanadium layered double hydroxide matrix (termed as Ru/Ni3V-LDH) not only exhibit excellent HER activity (~ 54.3 fold mass activity vs. the commercial Pt/C) and OER activity, but also possess decent full-cell performance for overall water splitting (1.5 V@10 mA cm-2). Most importantly, in-situ XAS and Raman spectroscopic studies clarified that, unlike numerous bifunctional catalysts that have suffered from the structural reconstruction/transformation for adapting the HER/OER cycles, Ru/Ni3V-LDH is characteristic of immortally dual reactive sites (i.e., Ru and Ni sites) for individual catalysis of electrochemical water splitting and could be termed as the real bifunctional electrocatalyst.
真正用于析氢反应和析氧反应的双官能团电催化剂应该是在催化过程中不发生结构转变或表面重构而表现出不朽行为的电催化剂。否则，它们只能被称为“预催化剂”，而不是真正的催化剂。本研究中，单原子分散催化剂(SACs)将原子分散的Ru嵌入镍钒层状双氢氧化物基体(称为Ru/Ni3V-LDH)上，不仅表现出优异的HER活性(质量活性是商业Pt/C的54.3倍)和OER活性，而且还具有良好的全电池整体水分解性能(1.5 V@10 mA cm-2)。最重要的是，原位XAS和拉曼光谱研究表明，与许多双功能催化剂不同，为了适应HER/OER循环而遭受结构重构/转变，Ru/Ni3V-LDH具有永久的双活性位点(即Ru和Ni位点)，用于单独催化电化学水分解，可以被称为真正的双功能电催化剂。
{"title":"Immortally Dual Sites on Single-Atom Dispersed Electrocatalyst for High-Efficient Hydrogen/Oxygen Evolution Reaction","authors":"Huachuan Sun, Chine-Wei Tung, Yang Qiu, Wei Zhang, Qi Wang, Zhishan Li, Jiang Tang, Hsiao‐Chien Chen, Chundong Wang, Hao Ming Chen","doi":"10.2139/SSRN.3770933","DOIUrl":"https://doi.org/10.2139/SSRN.3770933","url":null,"abstract":"Real bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) should be the ones that exhibit an immortal behavior during catalysis without structural transformation or surface reconstruction. Otherwise, they could be only termed as “pre-catalysts” rather than the real catalysts. Herein, single-atom dispersed catalysts (SACs) embedding atomically dispersed Ru onto nickel-vanadium layered double hydroxide matrix (termed as Ru/Ni3V-LDH) not only exhibit excellent HER activity (~ 54.3 fold mass activity vs. the commercial Pt/C) and OER activity, but also possess decent full-cell performance for overall water splitting (1.5 V@10 mA cm-2). Most importantly, in-situ XAS and Raman spectroscopic studies clarified that, unlike numerous bifunctional catalysts that have suffered from the structural reconstruction/transformation for adapting the HER/OER cycles, Ru/Ni3V-LDH is characteristic of immortally dual reactive sites (i.e., Ru and Ni sites) for individual catalysis of electrochemical water splitting and could be termed as the real bifunctional electrocatalyst.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88749561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, an attempt has been made to investigate the specific wear rate of the GFRP composite filled with graphite and fly-ash as filler material fabricated by hand lay-up process. Here the wt% of glass fiber is kept constant with 50% and matrix and filler are varied. Three different weight percentages such as 2wt%, 4wt% and 6wt% of filler materials added with 48wt%, 46wt% and 44wt% of epoxy resin respectively. The unlubricated pin-on-disc wear tests are conducted to examine the wear behavior of the GFRP composites. The testing parameters considered are wt% of filler material (%), applied load (N) and sliding distance (S). Specific wear rate is calculated in terms of weight loss of the sample. An orthogonal array and analysis of variance (ANOVA) are applied to investigate the influence of process parameters on the sliding wear behavior of the composites. The result shows that addition of graphite in the epoxy based hybrid composite enhances the capability of material to withstand against sliding wear. It is observed from the range of load and sliding distance in the study that the load has stronger effect on the specific wear rate than wt% of filler material and sliding distance. The weight loss of developed composite increases with an increase in normal applied load keeping the wt% of filler and sliding distance as constant.
{"title":"Study of Tribological Behavior of GFRP Hybrid Composite Using Fly-Ash and Graphite as Filler Material","authors":"A. Parida, A. Nayak, S. K. Pattnaik, R. Bhuyan","doi":"10.2139/ssrn.3768678","DOIUrl":"https://doi.org/10.2139/ssrn.3768678","url":null,"abstract":"In this paper, an attempt has been made to investigate the specific wear rate of the GFRP composite filled with graphite and fly-ash as filler material fabricated by hand lay-up process. Here the wt% of glass fiber is kept constant with 50% and matrix and filler are varied. Three different weight percentages such as 2wt%, 4wt% and 6wt% of filler materials added with 48wt%, 46wt% and 44wt% of epoxy resin respectively. The unlubricated pin-on-disc wear tests are conducted to examine the wear behavior of the GFRP composites. The testing parameters considered are wt% of filler material (%), applied load (N) and sliding distance (S). Specific wear rate is calculated in terms of weight loss of the sample. An orthogonal array and analysis of variance (ANOVA) are applied to investigate the influence of process parameters on the sliding wear behavior of the composites. The result shows that addition of graphite in the epoxy based hybrid composite enhances the capability of material to withstand against sliding wear. It is observed from the range of load and sliding distance in the study that the load has stronger effect on the specific wear rate than wt% of filler material and sliding distance. The weight loss of developed composite increases with an increase in normal applied load keeping the wt% of filler and sliding distance as constant.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86742348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Dirba, H. Sepehri-Amin, K. Skokov, Y. Skourski, K. Hono, O. Gutfleisch
We have investigated synthesis, magnetic properties and microstructure of Sm5Fe17-based hard magnetic phase with a Sm20Fe70Ti10 composition. Ultrahigh coercivities, μ0Hc=7.18 T at room temperature and μ0Hc=8.86 T at 10 K, have been achieved. The room-temperature coercivity, determined from high-field pulse measurements, reaches 35% of the anisotropy field μ0Ha=20.7±0.8 T. Further, it is demonstrated that a coercivity of 2.18 T is maintained even at 500 K. The Curie temperature TC of Sm20Fe70Ti10 is 577 K and the calculated exchange stiffness parameter A is 7.72 pJ/m. Detailed transmission electron microscopy investigations show a two-phase microstructure consisting of the Sm5Fe17-based hard magnetic matrix phase with grain size below 200 nm and finer, below 100 nm, Fe2Ti grains. Majority of the Fe2Ti phase is located at the grain boundaries with some finer inclusions found also inside the 5:17 grains. Despite the high fraction of the Fe2Ti grains, nearly single-phase demagnetization loops are observed. In order to enhance Ms, the effect of Ti content on phase constitution, magnetic properties and microstructure was studied in detail. Ms increases and Hc decreases for the Ti-lean compositions.
{"title":"Magnetic Properties and Microstructure of Sm 5Fe 17-Based Composite Magnets","authors":"I. Dirba, H. Sepehri-Amin, K. Skokov, Y. Skourski, K. Hono, O. Gutfleisch","doi":"10.2139/ssrn.3765774","DOIUrl":"https://doi.org/10.2139/ssrn.3765774","url":null,"abstract":"We have investigated synthesis, magnetic properties and microstructure of Sm5Fe17-based hard magnetic phase with a Sm20Fe70Ti10 composition. Ultrahigh coercivities, μ0Hc=7.18 T at room temperature and μ0Hc=8.86 T at 10 K, have been achieved. The room-temperature coercivity, determined from high-field pulse measurements, reaches 35% of the anisotropy field μ0Ha=20.7±0.8 T. Further, it is demonstrated that a coercivity of 2.18 T is maintained even at 500 K. The Curie temperature TC of Sm20Fe70Ti10 is 577 K and the calculated exchange stiffness parameter A is 7.72 pJ/m. Detailed transmission electron microscopy investigations show a two-phase microstructure consisting of the Sm5Fe17-based hard magnetic matrix phase with grain size below 200 nm and finer, below 100 nm, Fe2Ti grains. Majority of the Fe2Ti phase is located at the grain boundaries with some finer inclusions found also inside the 5:17 grains. Despite the high fraction of the Fe2Ti grains, nearly single-phase demagnetization loops are observed. In order to enhance Ms, the effect of Ti content on phase constitution, magnetic properties and microstructure was studied in detail. Ms increases and Hc decreases for the Ti-lean compositions.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86167833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have investigated post-annealing induced microscopic structural change of kink boundaries (KBs), which have been initially introduced by a hot-extrusion of an Mg-Zn-Y alloy containing long period stacking/order (LPSO) phase, based on scanning transmission electron microscopy (STEM) and atom-probe tomography (APT). STEM observations show that the KBs appear to be segmented into several submicron-scale, each of which is composed of arrays of extended basal (a-) dislocations that are geometrically necessary to account for the LPSO crystal rotations. Atomic-scale STEM/APT observations reveal significant reconstructions of these extended dislocation-core structures, which occur at the solute-enriched face-centered cubic (fcc) layers in the LPSO structures and forms local hexagonal close-packed (hcp) Mg region with distinct solute depletions. These recovery features indeed enhance the thermal stability of the KBs, and the corresponding driving force can be reasonably described according to disclinations, whose elastic energy is defined by crystal rotations and the relevant dipole distances.
{"title":"Recovery of Kink Boundaries During Post-Annealing of a Hot-Extruded Mg-Zn-Y Alloy","authors":"D. Egusa, K. Inoue, Y. Nagai, E. Abe","doi":"10.2139/ssrn.3762197","DOIUrl":"https://doi.org/10.2139/ssrn.3762197","url":null,"abstract":"We have investigated post-annealing induced microscopic structural change of kink boundaries (KBs), which have been initially introduced by a hot-extrusion of an Mg-Zn-Y alloy containing long period stacking/order (LPSO) phase, based on scanning transmission electron microscopy (STEM) and atom-probe tomography (APT). STEM observations show that the KBs appear to be segmented into several submicron-scale, each of which is composed of arrays of extended basal (a-) dislocations that are geometrically necessary to account for the LPSO crystal rotations. Atomic-scale STEM/APT observations reveal significant reconstructions of these extended dislocation-core structures, which occur at the solute-enriched face-centered cubic (fcc) layers in the LPSO structures and forms local hexagonal close-packed (hcp) Mg region with distinct solute depletions. These recovery features indeed enhance the thermal stability of the KBs, and the corresponding driving force can be reasonably described according to disclinations, whose elastic energy is defined by crystal rotations and the relevant dipole distances.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74868694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal oxide-based Resistive Random-Access Memories (RRAM) exhibit multiple intermediate resistive states, due to the formation/rupture of a conductive filament (CF) inside a switching layer. While there have been extensive studies on the resistive switching behavior caused by a pre-existing CF, the initial stage of the formation and growth of a CF, i.e., the electroforming process has been less understood. In this work, we developed a physical model to fundamentally understand the formation and growth behavior of a CF in a metal oxide layer constrained by the top/bottom electrodes. It is revealed that the CF formation is assisted by the supply of oxygen vacancies at the anode and the oxygen vacancies transport in the oxide layer. The effects of the external conditions (the oxygen exchange rate j 0 and the applied voltage) and the physical properties of the oxides (the electrical σ and thermal conductivity k th ) on the CF morphology evolution, current density evolution, and local temperature and electrical potential distribution have been systematically explored. It is found that larger oxygen vacancy exchange rate and relatively small voltage sweep rate result in a more uniform CF. Furthermore, by choosing oxides with lower Lorenz number (ratio of k th and σ ), CF with more homogeneous morphology can be realized. This work provides a fundamental understanding of the kinetic behaviors of the CF formation and growth during the electroforming process, and could potentially guide the oxide and electrode materials selection, synthesis and working conditions for switching to achieve improved RRAM stability and functionality.
{"title":"Modulation of the Conductive Filament Growth During the Electroforming Process in Metal Oxide-Based RRAM","authors":"Kena Zhang, Yao Ren","doi":"10.2139/ssrn.3855723","DOIUrl":"https://doi.org/10.2139/ssrn.3855723","url":null,"abstract":"Metal oxide-based Resistive Random-Access Memories (RRAM) exhibit multiple intermediate resistive states, due to the formation/rupture of a conductive filament (CF) inside a switching layer. While there have been extensive studies on the resistive switching behavior caused by a pre-existing CF, the initial stage of the formation and growth of a CF, i.e., the electroforming process has been less understood. In this work, we developed a physical model to fundamentally understand the formation and growth behavior of a CF in a metal oxide layer constrained by the top/bottom electrodes. It is revealed that the CF formation is assisted by the supply of oxygen vacancies at the anode and the oxygen vacancies transport in the oxide layer. The effects of the external conditions (the oxygen exchange rate j 0 and the applied voltage) and the physical properties of the oxides (the electrical σ and thermal conductivity k th ) on the CF morphology evolution, current density evolution, and local temperature and electrical potential distribution have been systematically explored. It is found that larger oxygen vacancy exchange rate and relatively small voltage sweep rate result in a more uniform CF. Furthermore, by choosing oxides with lower Lorenz number (ratio of k th and σ ), CF with more homogeneous morphology can be realized. This work provides a fundamental understanding of the kinetic behaviors of the CF formation and growth during the electroforming process, and could potentially guide the oxide and electrode materials selection, synthesis and working conditions for switching to achieve improved RRAM stability and functionality.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74923794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yun Zhang, Ming Yan, Wanting Niu, Jian Fang, Hongjiao Mao, Yonghong Sun
Wear particles-induced inflammatory osteolysis, a major contributing factor of aseptic loosening, affects long-term survival of orthopedic prostheses. Increasing observations have demonstrated that osteocytes death is involved in wear particles-induced periprosthetic osteolysis, but the underling molecular mechanisms remain unclear. We chose micro-sized tricalcium phosphate (TCP) particles to simulate TCP wear debris from loosened TCP implants, which have been widely used as bone substitute biomaterials in orthopedic and dental surgery for almost 40 years, and investigated the direct biological effects of the particles on calvaria osteocytes in vivo . Results showed that TCP wear particles triggered nod-like receptor protein 3 (NLRP3) inflammasome activation and pyroptosis in calvaria osteocytes, as indicated by increased osteocytes death, up-regulation of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), cleaved Caspase-1 and interleukin (IL)-1β, elevation of IL-1β, IL-18 and lactic dehydrogenase (LDH), which were all inhibited by the Caspase-1 inhibitor VX765. Moreover, the NLRP3 inhibitor MCC950 reduced TCP particles-induced Caspase-1 cleavage, production of IL-18, IL-1β and LDH, and pyroptotic death in calvaria osteocytes. Further experiments revealed that the NLRP3-mediated pyroptosis pathway was mediated by reactive oxygen species (ROS) in TCP particles-induced cell death of calvaria osteocytes, since a ROS scavenger (N-acetyl-cysteine, NAC) efficiently prevented NLRP3 inflammasome activation and pyroptosis. Taken together, TCP wear particles induce pyroptosis of calvaria osteocytes through activation of ROS/NLRP3/Caspase-1 pathway, which is involved in osteoclastogenesis and periprosthetic osteolysis. Our findings strongly suggest that pyroptosis may play a significant role in wear particles-induced cell death of osteocytes and periprosthetic osteolysis, and will provide a novel evidence for elucidating its pathophysiology.
{"title":"ROS/NLRP3/Caspase-1 Pathway Contributes to TCP Particles-Induced Pyroptosis of Calvaria Osteocytes in the Mouse Osteolysis Model","authors":"Yun Zhang, Ming Yan, Wanting Niu, Jian Fang, Hongjiao Mao, Yonghong Sun","doi":"10.2139/ssrn.3799707","DOIUrl":"https://doi.org/10.2139/ssrn.3799707","url":null,"abstract":"Wear particles-induced inflammatory osteolysis, a major contributing factor of aseptic loosening, affects long-term survival of orthopedic prostheses. Increasing observations have demonstrated that osteocytes death is involved in wear particles-induced periprosthetic osteolysis, but the underling molecular mechanisms remain unclear. We chose micro-sized tricalcium phosphate (TCP) particles to simulate TCP wear debris from loosened TCP implants, which have been widely used as bone substitute biomaterials in orthopedic and dental surgery for almost 40 years, and investigated the direct biological effects of the particles on calvaria osteocytes in vivo . Results showed that TCP wear particles triggered nod-like receptor protein 3 (NLRP3) inflammasome activation and pyroptosis in calvaria osteocytes, as indicated by increased osteocytes death, up-regulation of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), cleaved Caspase-1 and interleukin (IL)-1β, elevation of IL-1β, IL-18 and lactic dehydrogenase (LDH), which were all inhibited by the Caspase-1 inhibitor VX765. Moreover, the NLRP3 inhibitor MCC950 reduced TCP particles-induced Caspase-1 cleavage, production of IL-18, IL-1β and LDH, and pyroptotic death in calvaria osteocytes. Further experiments revealed that the NLRP3-mediated pyroptosis pathway was mediated by reactive oxygen species (ROS) in TCP particles-induced cell death of calvaria osteocytes, since a ROS scavenger (N-acetyl-cysteine, NAC) efficiently prevented NLRP3 inflammasome activation and pyroptosis. Taken together, TCP wear particles induce pyroptosis of calvaria osteocytes through activation of ROS/NLRP3/Caspase-1 pathway, which is involved in osteoclastogenesis and periprosthetic osteolysis. Our findings strongly suggest that pyroptosis may play a significant role in wear particles-induced cell death of osteocytes and periprosthetic osteolysis, and will provide a novel evidence for elucidating its pathophysiology.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84820853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Vorotilo, K. Sidnov, A. Sedegov, D. Moskovskikh
The phase stability and mechanical properties of N-metallic carbides are assessed using entropy forming ability (EFA), mixing enthalpy, and Mazhnik-Oganov ab initio model of mechanical properties. EFA quantifies configurational disorder of solid solutions and is currently used to predict the phase stability and assess the hardness of high-entropy carbides with 5 transitional metals on the metallic sublattice. In this work, we use the concept of EFA for the 13 N-metallic carbides (N=2-5), four of which are investigated for the first time. Additionally, we propose a semi-empiric version of the Mazhnik-Oganov model and perform micro-indentation testing of the investigated compositions to verify the model’s capabilities. The proposed approach allows for a fast modeling and nanoindentation-based screening of the most promising carbide solid solutions for more detailed characterization.
{"title":"Phase Stability and Mechanical Properties of N-Metallic Carbides","authors":"S. Vorotilo, K. Sidnov, A. Sedegov, D. Moskovskikh","doi":"10.2139/ssrn.3821951","DOIUrl":"https://doi.org/10.2139/ssrn.3821951","url":null,"abstract":"The phase stability and mechanical properties of N-metallic carbides are assessed using entropy forming ability (EFA), mixing enthalpy, and Mazhnik-Oganov ab initio model of mechanical properties. EFA quantifies configurational disorder of solid solutions and is currently used to predict the phase stability and assess the hardness of high-entropy carbides with 5 transitional metals on the metallic sublattice. In this work, we use the concept of EFA for the 13 N-metallic carbides (N=2-5), four of which are investigated for the first time. Additionally, we propose a semi-empiric version of the Mazhnik-Oganov model and perform micro-indentation testing of the investigated compositions to verify the model’s capabilities. The proposed approach allows for a fast modeling and nanoindentation-based screening of the most promising carbide solid solutions for more detailed characterization.","PeriodicalId":18341,"journal":{"name":"Materials Science eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86494960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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