检索结果-南通市图书馆

In-situ fabrication of Al(Zn)-Al_2O_3 graded composite using the aluminothermic reaction during hot pressing

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2018年第7期25卷 832-839页

作者： s.m.a.haghi s.a.sajjadi a.babakhani Department of Materials science and Engineering Engineering facultyFerdowsi University of MashhadMashhadIra

In INs study, the fabrication of multilayer AI（Zn）-A1203 with different volume fractions of A1203 was investigated. A1 and ZnO powders were milled by a plaaetaxy ball mill, after which five-layer functionally graded samples were produced flarough hot pressing at 580~C and 90 MPa pressure for 30 min. Formation of reinforcing A1203 particles occurred in the aluminum matrix via the aluminolkermic reaction. Determination of the ignition temperature of the aluminolkennic reaction was accomplished using differential lkermal and lkermo- gravimelric amlyses. scaaming electron microscopy, energy dispersive spectroscopy, and X-ray diffractometery amlyses were utilized to characterize the specimens. The lkermal amlysis results showed that the ignition temperatures for the aluminolkennic reaction of layers with the highest and lowest ZnO contents were 667 and 670~C, respectively. Microslxuctural observation and chemical amlysis confirmed the fa- brication of AI（Zn）-A1203 functionally graded materials composites with precipitation of additional Zn in the matrix. Moreover, nearly dense functionally graded samples demonstrated minimum and maximum hacdness values of HV 75 and HV 130, respectively.

关键词： metal-matrix composites functionally graded composites fllermogravimet^ic analysis powder processing sintering

smart composite antibacterial coatings with active corrosion protection of magnesium alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2022年第12期10卷 3589-3611页

作者： A.s.Gnedenkov s.L.sinebryukhov V.s.Filonina N.G.Plekhova s.V.Gnedenkov Institute of Chemistry of FEB RAs 159 Pr.100-letiya VladivostokaVladivostok690022Russia

A new method of the formation of composite coatings with the function of active corrosion protection of magnesium alloys was developed using the plasma electrolytic oxidation(PEO) method. susceptibility of PEO-layers to pitting formation was evaluated using localized electrochemical methods(sVET/sIET). The morphological features and electrochemical properties of composite coatings were studied using sEM/EDX, XRD, micro-Raman spectroscopy and EIs/PDP measurements, respectively. The effect of surface layers impregnation with corrosion inhibitor on their protective properties in a corrosive environment was established. Additional protection was achieved using controllable coating pore sealing with polymer. It was found that the polymer treatment of the PEO-layer does not reduce the inhibitor’s efficiency. The formed protective composite inhibitor-and-polymer-containing layers decrease the corrosion current density of a magnesium alloy in a 3 wt.% Na Cl solution to three orders of magnitude. This predetermines the prospect of new smart coatings formation that significantly expand the field of application of electrochemically active materials. The mechanism of smart composite coating corrosion degradation was established. The antibacterial activity of the inhibitor-containing coatings against s. aureus methicillin-resistant strain was proved using the in vitro model. These protective layers are promising for reducing the incidence of implant-associated infections.

关键词： Magnesium alloy Plasma electrolytic oxidation Corrosion inhibitor self-healing Protective coatings

Tm^(3+) interactions in LiYF_4 studied by high-resolution spectroscopy

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2009年第4期27卷 633-636页

作者： s.A.Klimin D.s.Pytalev Institute of spectroscopy Russian Academy of Sciences 5 Fizicheskaya Str. 142190 Troitsk Moscow region 142190 Russia

We used the high-resolution spectroscopy to study the interactions that Tm3＋ ion in a LiYF4 crystal is subjected to. several crystal field transitions with low integral intensity were found not registered before by means of ordinary spectroscopy. spectral evidences for interionic, hyperfine, isotopic interactions, and for a resonant broadening of the ground state are presented.

关键词： high-resolution Fourier-transform speclroscopy hyperfme structure isotopic structure pair centers rare earths

MgO-attached graphene nanosheet(MgO@GNs)reinforced magnesium matrix nanocomposite with superior mechanical,corrosion and biological performance

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第9期31卷 2062-2076页

作者： s.Abazari A.shamsipur H.R.Bakhsheshi-Rad M.s.soheilirad F.Khorashadizade s.s.Mirhosseini Department of Materials and Metallurgical Engineering Amirkabir University of TechnologyTehran ***Iran Iranian National standards Organization of Hormozgan HormozganIran Advanced Materials Research Center Department of Materials EngineeringNajafabad BranchIslamic Azad UniversityNajafabadIran Department of Materials and Metallurgical Engineering Iran University of Science and TechnologyTehranIran

Magnesium(Mg)alloys are gaining great consideration as body implant materials due to their high biodegradability and ***,they suffer from low corrosion resistance and antibacterial *** this research,semi-powder metallurgy followed by hot extrusion was utilized to produce the magnesium oxide@graphene nanosheets/magnesium(MgO@GNs/Mg)composite to improve mechanical,corrosion and cytocompatibility *** have revealed that the incorporation of MgO@GNs nanohybrids into Mg-based composite enhanced microhardness and compressive *** vitro,osteoblast cell culture tests show that using MgO@GNs nanohybrid fillers enhances osteoblast adhesion and apatite *** presence of MgO@GNs nanoparticles in the composites decreased the opening defects,micro-cracks and micro-pores of the composites thus preventing the penetration of the corrosive solution into the *** demonstrated that the MgO@GNs/Mg composite possesses excellent antibacterial properties because of the combination of the release of MgO and physical damage to bacterium membranes caused by the sharp edges of graphene nanosheets that can effectively damage the cell wall thereby facilitating penetration into the bacterial lipid ***,the MgO@GNs/Mg composite with high mechanical strength,antibacterial activity and corrosion resistance is considered to be a promising material for load-bearing implant applications.

关键词： metal matrix composites MgO@GNs nanohybrid strengthening mechanisms antibacterial activity biocompatibility

Low cycle fatigue properties and cyclic deformation behavior of as-extruded AZ31 magnesium alloy

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals society of China 2010年第B07期20卷 533-539页

作者： s.KWON K.sONG K.s.sHIN s.I.KWUN Department of Materials science and Engineering Korea University school of Materials science and Engineering Seoul National University

The low cycle fatigue(LCF)properties of as-extruded AZ31 Mg alloy were investigated under total strain amplitudes in the range of 0.4%-1.2%with strain rate of 1×10- 2s -*** to the twinning effect in compression during loading and the detwinning effect during unloading,the alloy showed an asymmetric hysteresis *** cyclic stress response exhibited cyclic hardening at high total strain *** cyclic deformation behaviors were discussed using the Coffin-Manson plot,which divided the plastic strain amplitudes into the tension side and the compression *** the LCF tests that were started from either tension or compression under a total strain amplitude of 1.0%,the interaction between the twinning effect and dislocation was *** twinning effect during the LCF test and the variation of the dislocation density were investigated using optical microscopy and transmission electron microscopy,respectively.

关键词： AZ31 magnesium alloy low cycle fatigue twinning dislocation

Bianchi Type-I Massive string Magnetized Barotropic Perfect Fluid Cosmological Model in the Bimetric Theory of Gravitation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第8期28卷 368-371页

作者： N.P.Gaikwad M.s.Borkar s.s.Charjan Department of Mathematics Dharampeth M.P.Deo Memorial Science CollegeNagpur 440033India Post Graduate Department of Mathematics Mahatma Jyotiba Phule Educational CampusAmravati RoadR.T.M.Nagpur UniversityNagpur 440033India Department of Mathematics Late K.Z.S.Science CollegeBramhniKalmeshwar 441501 Dist.NagpurIndia

We investigate the Bianchi type-I massive string magnetized barotropic perfect fluid cosmological model in Rosen's bimetric theory of gravitation with and without a magnetic field by applying the techniques used by Latelier(1979,1980)and stachel(1983).To obtain a deterministic model of the universe,it is assumed that the universe is filled with barotropic perfect fluid *** physical and geometrical significance of the model are *** comparing our model with the model of Bali et al.(2007),it is realized that there are no big-bang and big-crunch singularities in our model and T=0 is not the time of the big bang,whereas the model of Bali et *** with a big bang at T=***,our model is in agreement with Bali et al.(2007)as time increases in the presence,as well as in the absence,of a magnetic field.

关键词： universe massive Perfect

Carboxylates as green corrosion inhibitors of magnesium alloy for biomedical application

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第7期12卷 2909-2936页

作者： A.s.Gnedenkov s.L.sinebryukhov A.D.Nomerovskii V.s.Marchenko A.Yu.Ustinov s.V.Gnedenkov Institute of Chemistry of FEB RAs 159 Pr.100-letiya VladivostokaVladivostok 690022Russia

The efficiency of the green inhibitors(sodium salts of fumarate,glycolate and gluconate)in suppressing corrosion of the structural MA8 magnesium alloy(Mg–Mn–Ce)and the biomedical Mg–0.8Ca alloy was studied using the hydrogen evolution measurements,mass loss test,EIs,PDP,sVET/*** analysis of the morphology,chemical composition,and growth kinetic of corrosion films formed in 0.9 wt%NaCl solution with and without corrosion inhibitors was carried *** most compact surface film with the smallest thickness was formed in a saline solution with sodium *** Mg alloy samples exhibited the highest polarization resistance,the lowest localized electrochemical activity,and the lowest corrosion rate in saline with the addition of sodium fumarate and sodium *** efficiency of the applied inhibitors was up to 81%.The model of the corrosion mechanism based on the sorption of molecules of organic inhibitors is *** results show the high compatibility of the used inhibitors with the calcium-phosphate PEO-matrix,indicating the possibility of forming a self-healing coating by means of these active substances.

关键词： Magnesium and its alloys Organic inhibitor Electrochemical behavior PEO-coatin Bioresorbable implant Degradation mechanism

spin synthesis of monolayer of siO_2 thin films

在线全文

学校读者我要写书评

暂无评论

Journal of semiconductors 2015年第4期36卷 16-25页

作者： s.s.shinde s.Park J.shin Korea Research Institute of standards and science

The highly ordered monolayer of submicron size silica （siO2） particles （235 nm） is developed on p-silicon by using three-step spin-coating in colloidal suspension, which has significant potential in various applications. The influence of three-step spin speeds, spinning time, acceleration time between different steps, concentration of siO2 particles in the solution, solution quantity, and the ambient humidity （relative humidity） on the properties ofmonolayer siO2 are studied in order to achieve a large area monolayer film. A relatively high surface coverage and uniform monolayer film of siO2 particles in the range of 85%-90% are achieved by appropriate control of the preparative parameters. We conclude that this method can be useful in industrial applications, because of the fabrication speed, surface coverage and cost of the process.

关键词： thin films spin synthesis electron microscopy

Workability Behaviour of Fe-C-Mo steel Preforms During Cold Forging

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and steel Research International 2013年第9期20卷 126-130页

作者： s Narayan A Rajeshkannan K s Pandey s shanmugam school of Engineering and Physics Faculty of ScienceTechnology and EnvironmentUniversity of South Pacific Department Metallurgical and Materials Engineering National Institute of Technology Department of Mechanical Engineering National Institute of Technology

A systematic method to construct the workability diagram for powder metallurgy （P/M） materials has been proposed. Preforms of Fe-0.8 %C, Fe-0.8% C-1% Mo and Fe-0.8 % C 2 % Mo were prepared to the relative den-sity of 0.86 with two different geometries through primary operations of P/M processes. Each sintered preform was cold upset forged with incremental compressive loading of 0.04 MN under three different lubricant conditions till a visible crack appeared at the free surface. Oyane＇s fracture criterion was used to develop a theory to study P/M prod-ucts. The least square method was used to determine the constants in fracture criteria and these equations were even- tually used to construct workability diagram. It is found that the proposed method was well in agreement with the experimental results.

关键词： workability diagram yield criterion formability