Formation of Nanoscale Intermetallic Phases in Ni Surface Layer at High Intensity Implantation of Al Ions

The results of experimental study of nanoscale intermetallic formation in surface layer of a metal target at ion implantation are presented. To increase the thickness of the ion implanted surface layer the high intensive ion implantation is used. Compared with the ordinary ion implantation, the high intensive ion implantation allows a much thicker modified surface layer. Pure polycrystalline nickel was chosen as a target. Nickel samples were irradiated with Al ions on the vacuum-arc ion beam and plasma flow source 'Raduga-5'. It was shown that at the high intensity ion implantation the fine dispersed particles of Ni3AI, NiAl intermetallic compounds and solid solution Al in Ni are formed in the nickel surface layer of 200 nm and thicker. The formation of phases takes place in complete correspondence with the Ni-AI phase diagram.

Mykert-Sanzheevka Field of Polycomponent Ores (Pb, Zn, Ag, Au, PGE): Geologic-Substance Characteristics and Formation Features of Ore-Forming System

The new results of geologic-structural, petrographic and mineralogic-geochemical researches of Mykert-Sanzheevka ore field—the Uda-Vitim mineragenic zone South-West ending of West Transbaikalia are given. Its main ore-controlling structure, represented by losange, consisting of rhombohedral and tetrahedral blocks-duplexes mosaic clusters, which are separated by narrow tectonic sutures, is specified. It is clarified that polycomponent ores clusters are confined with these small-block sutures, made by subvolcanic dykes of shoshonite-latite volcano-plutonic association (233 - 188 million years), apodyke dynamometamorphites (breccias, cataclasite, mylonites) and also mechanometasomatites. Four stages of the dynamometamorphites formation characterized by different species compositions of ore minerals appeared as a result of mechanochemical reactions are determined. A carbonyl model of mineral microaggregates formation with films containing noble metal nanoparticles is proposed. Ore-forming system features of Mykert-Sanzheevka field are considered.

Synthesis and Sintering Character of Nanophase Calcium-deficient Apatite

Nanophase culcium-deficient hydroxyapatite（ CDHA ） with a Ca/P ratio about 1.5 synthesized by chemical wet method was sintered at different temperatures, and then its chemical composition, phase structure arut morphology were analyzed with methods of FT-IR spectrascopy, X-ray diffraction （XRD） and field emission scanning microscopy （FESEM）, respectively. Results show that when the sintering temperature is below 500℃ , apatite crystal keeps a stable size with a diameter of 12- 26 nm and a length of 30-66 run. After being sintered at 600℃ for 2 h, apatite crystal grows much larger with a diameter of 25-40 nm and a length of 75- 100 nm. At the temperature of 700-800 ℃ , this powder decomposes into, Ca3 （ PO4）2, The crystal size of the Ca3 （ PO4）2 surpasses 200nm in diameter and length. NH4^＋ ion can be removed at temperature beyond 300℃ .

Electron Microscopic In－situ Observation for Preparation of Ultrafine La_2O_3 Nanophase Powder

In-situ observation in high voltage electron microscope(HVEM) was used to investigate transformation from amorphous La(OH)3 to nanophase La2O3. Electron diffraction pattern indicates that the transition temperature from La(OH)3 to nanophase La2O3 is 400 ℃. Particle sizes for nanophase La2O3 are from 20 to 50 nm.

Nanophase Decomposition of a Zn-Al Based Alloy Zn_(68)Al_(10)Cu_(22)

The nanostructural evolution and phase transformation of the films of a Zn-Al based alloy (Zn68Al10Cu22 in wt pct) have been studied by using X-ray diffraction and scanning electron microscopy. Nanostructural thin films of the Zn-AI based alloy were produced by using an electron beam deposition technique. It was found that a nanocrystalline phase η'n had a strong preferred crystal orientation at (0002) crystal planes in the as-deposited films. During ageing at 220℃, the decomposition of nanophase η'n started with clustering to form Z-zones, and transitionai phase, which was accompanied by an eutectoid decomposition of the η'n phase: η'n β'eut T'. Decomposition, such as clustering and the formation of the Z-zones, and the transitionai phase etc. were observed in the nanophase β'eut. The formation and the decomposition of the transitionai phase of micrometers in size were involved in the decomposition of the main nanophase η'n. The mechanism of the Z-zones formation and the stability of nanophases were discussed.

Effect of Nanophase on the Nucleation of Intragranular Ferrite in Microalloyed Steel

MnS, MnS＋V（C, N） complex precipitates in micro-alloyed ultra-fine grained steels were precisely analyzed to investigate the grain refining mechanism. The experimental results shows that MnS, MnS＋V（C, N） precipitates provide nucleation center for Intra-granular ferrite （IGF）, so that refined grain remarkably. Moreover, substructures such as grain boundary, sub-boundary, distortion band, dislocation and dislocation cell in austenite increased as the deformation energy led by heavy deformation at low temperature （deformation temperature≤800 ℃, deformation quantity≥50%）. As a result, V（C, N） nanophase precipitated at these substructures, which pinned and stabilized substructures. The substructures rotated and transformed into ultra-fine ferrite. 20 nm-50 nm were the best grain size range of V（C, N） as it provided nucleating center for intragranular ferrite. The grain size of V（C, N） were less than 30 nm in the microalloyed steels that with volume ratio of ultra-fine ferrite more than 80% and grain size less than 4 μm.

Microstructure Study on Nano-phase Powder of Indium Tin Oxide

hemical co-precipitation method was used to prepare indium tin hydroxide. Indium tin hydroxide has the structure of cubic crystal. The cubic crystal structure transformed to amorphous after heat treatment at 250℃ for 1 h. When the heat treatment temperature was higher than 280℃, the amorphous transformed to cubic crystal structure. After heat treatment at 600℃ for 1 h, the particle size of indium tin oxide is 8～20 nm. The weight ratio of In∶Sn is near 9∶1. Its granule has spherical shape. The dispersity is good.

Infrared quantum cutting conversion luminescence of Tb(0.7)Yb(3):FOV

The infrared quantum cutting of oxyfluoride nanophase vitroceramics Tb（0.7）Yb（3）：FOV has been studied in the present paper. The actual quantum cutting efficiency formula calculated from integral fluorescence intensity is extended to the case of Tb（0.7）Yb（3）：FOV. The visible and the infrared fluorescence spectra and their integral fluorescence intensities are measured from static fluorescence experiment. Lifetime curve is measured from dynamic fluorescence experiment. It is found that the total actual quantum cutting efficiency n of the excited 5D4 level is about 93.7%, and that of excited （5D3, 5G6） levels is 93.5%. It is also found that the total theoretical quantum cutting efficiency upper limit ？~x^Yb of the 485.5 nm excited 5D4 level is about 121.7%, and that of 378.5 nm excited （5D3, 5G6） levels is 137.2%.

Preparation and Improvation of Nanophase Artificial Bone Composite Scaffold and Relevant Study on Properties

Objective:To prepare nanophase artificial bone composite scaffold based on bionics theory,and probe into how different content ratio between collagen and inorganic part as well as different molecular weight of conglutinant agent influence microstructure and properties of the scaffold.Methods:Lead calcic inorganic molecules to deposite onto self-assembled collagen template during coprecipitation under certain reactive conditions such as content ratio and pH value of environment,and then nanophase collagen/calcic salt is obtained.In order to improve the mechanical properties,poly lactic acid (PLLA) which has stable equal properties and controllable biodegradable activities is chosen as conglutinant agent,and then the aimed artificial bone scaffold (nanophase collagen/calcic salt/PLLA composite) is accomplished.After preparation liquid displacement method with isoproanol alcohol,scanning electron microscopic (SEM),transmission electron microscope (TEM),fourier transform infrared spectrometry (FTIR),mechanical testing system are performed to test porosity and density,morphology,conformation,composition and mechanical property,respectively.Results:The artificial synthesized bone composite scaffold is mainly composed of collagen and calcium phosphate partly displaced with B-type carbonate.The crystallinity is low,and the crystal size reaches nanometer which is similar to natural bone.PLLA used effectively improves the mechanical property which can reach at the floor level of cancellous standard,and develops three-dimensional-porous structure with high porosity of 80%.According to the comparison it can be seen that content ratio between collagen and calcic inorganic salt as well as addition of conglutinant PLLA all have an effect on microstructure of the synthesized scaffold,additionally molecular weight of PLLA has an effect on mechanical properties.Conclusion:The nanophase artificial bone composite scaffold synthesized by biomimetic process is one of the most promising optimal materials for clinical application no matter how judged from structure,composition and property.The various factors influencing the scaffold discussed in this article may indicate some useful modification ways according to the actual utility in the near future.

Nanophase separated,grafted alternate copolymer styrene-maleic anhydride as an efficient room temperature solid state lithium ion conductor

All solid-state lithium metal batteries(ASSLMBs)based on polymer solid electrolyte and lithium metal anode have attracted much attention due to their high energy density and intrinsic safety.However,the low ionic conductivity at room temperature and poor mechanical properties of the solid polymer electrolyte result in increased polarization and poor cycling stability of the Li metal batteries.In order to improve the ionic conductivity at room temperature while maintaining mechanical strength,we combine the conductivity of short chain polyethylene oxide(PEO)and strength of styrene-maleic anhydride copolymer(SMA)to obtain a grafted block copolymer with nanophase separation structure,which has room temperature ionic conductivity up to 1.14×10^(-4)S/cm and tensile strength up to 1.4 MPa.Li||Li symmetric cell can work stably for more than 1500 h under the condition of 0.1 mA/cm^(2).Li||LiFePO_(4)full cells can deliver a high capacity of 151.4 mAh/g at 25℃and 0.2 C/0.2 C charge/discharge conditions,showing 85.6%capacity retention after 400 cycles.Importantly,the all solid state Li||LiFePO_(4)pouch cell shows excellent safety performance under different abuse conditions.These results demonstrate that the nanophase separated,grafted alternate copolymer electrolyte has huge potential for application in Li metal batteries.

Open-cell mullite ceramic foams derived from porous geopolymer precursors with tailored porosity

Porous geopolymer precursors were firstly prepared by the direct foaming method using bauxite,fly ash(FA),and metakaolin(MK)as raw materials,and porous mullite ceramics were prepared after ammonium ion exchange and then high-temperature sintering.The effects of chemical foaming agent concentration,ion-exchange time,and sintering temperature on porous geopolymerderived mullite ceramics were studied,and the optimal preparation parameters were found.Studies have shown that the concentration of blowing agent had great influence on open porosity(q)and porosity and cell size distributions of geopolymer samples,which in turn affected their compressive strength(σ).Duration of the ion exchange had no obvious effect on the sintered samples,and the amount of mullite phase increased with the increase in the sintering temperature.Mullite foams,possessing an open-celled porous structure,closely resembling that of the starting porous geopolymers produced by directly foaming,were obtained by firing at high temperatures.Stable mullite(3Al_(2)O_(3)·2SiO_(2))ceramic foams with total porosity(ε)of 83.52 vol%,high open porosity of 83.23 vol%,and compressive strength of 1.72 MPa were produced after sintering at 1400 for 2 h in℃ air without adding any sintering additives using commercial MK,bauxite,and FA as raw materials.

Metal matrix nanocomposites in tribology: Manufacturing, performance, and mechanisms

Metal matrix nanocomposites(MMNCs)become irreplaceable in tribology industries,due to their supreme mechanical properties and satisfactory tribological behavior.However,due to the dual complexity of MMNC systems and tribological process,the anti-friction and anti-wear mechanisms are unclear,and the subsequent tribological performance prediction and design of MMNCs are not easily possible:A critical up-to-date review is needed for MMNCs in tribology.This review systematically summarized the fabrication,manufacturing,and processing techniques for high-quality MMNC bulk and surface coating materials in tribology.Then,important factors determining the tribological performance(mainly anti-friction evaluation by the coefficient of friction(CoF)and anti-wear assessment with wear rate)in MMNCs have been investigated thoroughly,and the correlations have been analyzed to reveal their potential coupling/synergetic roles of tuning tribological behavior of MMNCs.Most importantly,this review combined the classical metal/alloy friction and wear theories and adapted them to give a(semi-)quantitative description of the detailed mechanisms of improved anti-friction and anti-wear performance in MMNCs.To guarantee the universal applications of these mechanisms,their links with the analyzed influencing factors(e.g.,loading forces)and characteristic features like tribo-film have been clarified.This approach forms a solid basis for understanding,predicting,and engineering MMNCs’tribological behavior,instead of pure phenomenology and experimental observation.Later,the pathway to achieve a broader application for MMNCs in tribo-related fields like smart materials,biomedical devices,energy storage,and electronics has been concisely discussed,with the focus on the potential development of modeling,experimental,and theoretical techniques in MMNCs’tribological processes.In general,this review tries to elucidate the complex tribo-performances of MMNCs in a fundamentally universal yet straightforward way,and the discussion and summary in this review for the tribological performance in MMNCs could become a useful supplementary to and an insightful guidance for the current MMNC tribology study,research,and engineering innovations.

Improved osteoblast proliferation, differentiation and mineralization on nanophase Ti6Al4V

Background Previous studies have demonstrated increased functions of osteoblasts on nanophase materials compared to conventional ceramics or composites.Nanophase materials are unique materials that simulate dimensions of constituent components of bone as they possess particle or grain sizes less than 100 nm.However,to date,interactions of osteoblasts on nanophase materials compared to conventional metals remain to be elucidated.The objective of the present in vitro study was to synthesize nanophase metals （Ti6Al4V）,characterize,and evaluate osteoblast functions on Ti6Al4V.Such metals in conventional form are widely used in orthopedic applications.Methods In this work,nanophase Ti6Al4V surfaces were processed by the severe plastic deformation （SPD） principle and used to investigate osteoblast long-term functions.Primary cultured osteoblasts from neonatal rat calvaria were cultured on both nanophase and conventional Ti6Al4V substrates.Cell proliferation,total protein content,and alkaline phosphatase （ALP） activity were evaluated after 1,3,7,10 and 14 days.Calcium deposition,gene expression of type Ⅰ collagen （Col-Ⅰ）,osteocalcin （OC）,osteopontin （OP） and the production of insulin-like growth factor-Ⅰ （IGF-Ⅰ） and transforming growth factor-beta 1 （TGF-β1） were also investigated after 14 days of culture.Results Functions of osteoblasts including proliferation,synthesis of protein,and ALP activity were improved on the nanophase compared to the conventional Ti6Al4V.The expression of Col-Ⅰ,OC and OP mRNA was also increased on nanophase Ti6Al4V after 14 days of culture.Calcium deposition was the same;the average number of the calcified nodules on the two Ti6Al4V surfaces was similar after 14 days of culture;however,highly significant size calcified nodules on the nanophase Ti6Al4V was observed,Of the growth factors examined,only TGF-β1 showed a difference in production on the nanophase surface.Conclusion Nanophase Ti6Al4V surfaces improve proliferation,differentiation and mineralization of osteoblast cells and should be further considered for orthopedic implant applications.

Ultraviolet and visible upconversion luminescence of Tm(0.1)Yb(5):FOV oxyfluoride nanophase vitroceramics

The ultraviolet upconversion luminescence of Tm3+ ions sensitized by Yb3+ ions in oxyfluoride nanophase vitroceramics when excited by a 975 nm diode laser was studied. An ultraviolet upconversion luminescence line positioned at 363.6 nm was found. It was attributed to the fluorescence transition of 1D2→3H6 of Tm3+ ion. Sev- eral visible upconversion luminescence lines at 450.7 nm, (477.0 nm, 462.5 nm), 648.5 nm, (680.5 nm, 699.5 nm) and (777.2 nm, 800.7 nm) were also found, which result respectively from the fluorescence transitions of 1D2→3F4, 1G4→3H6, 1G4→3F4, 3F3→3H6 and 3H4→3H6 of Tm3+ ion. The careful measurement and analysis of the variation of upconversion luminescence intensity F as a function of the 975 nm pumping laser power P prove that the upconversion luminescence of 1D2 state is partly a five-photon upconversion luminescence, and the upconversion lumines- cence of 1G4 state and 3H4 state are respectively the three-photon and two-photon upconversion luminescence. The theoretical analysis suggested that the upcon- version mechanism of the 363.6 nm 1D2→3H6 upconversion luminescence is partly the cross energy transfer of {3H4(Tm3+)→3F4(Tm3+), 1G4(Tm3+)→1D2(Tm3+)} and {1G4(Tm3+)→3F4(Tm3+), 3H4(Tm3+)→1D2(Tm3+)} between Tm3+ ions. In addition, the upconversion luminescence of 1G4 and 3H4 state results respectively from the se- quential energy transfer {2F5/2(Yb3+)→2F7/2(Yb3+), 3H4(Tm3+)→1G4(Tm3+)} and {2F5/2(Yb3+) →2F7/2(Yb3+), 3F4(Tm3+)→3F2(Tm3+)} from Yb3+ ions to Tm3+ ions.

Ionic Conduction of Nanophase Solid Ca_((1-x))La_xF_(2+x)

People are very interested in the research into fluorine ionic conductor, because F^- is the smallest negative ion, and it has only one charge which is in favour of migration; fluoride has quite a large change of free energy when forming, so it can be used as spacer material to get a battery with high voltage and high energy density; in addition, structure of fluoride is simple, its electron-conductivity is very low, so its theoretical model for ion-moving becomes simplified. Usually people apply the method of mingling with fluoride having higher valence in order to enhance ionic conductivity. For example, Insti-

Manipulating the ionic nanophase of Nafion by in-situ precise hybridization with polymer quantum dot towards highly enhanced fuel cell performances

Hierarchical-structure materials hold great promise for numerous applied domains such as fuel cell,sensor,and optic.However,the developments are significantly impeded by the lack of efficient strategy permitting precise and efficient decoration of specific confined space.Here,an in-situ precise hybridization strategy is proposed to efficiently manipulate the nanostructure of membrane nanochannels.Typically,Nafion ionic nanochannels are impregnated with precursors via heat swelling,followed by microwave-assisted condensation to form polymer quantum dot network.The formation of polymer quantum dot network significantly improves the stability and functionality of ionic nanophase(i.e.,ionic nanochannel).This helps hybrid membrane achieving enhanced proton conduction and methanol barrier properties,resulting in over ten times increase in proton/methanol selectivity.These then impart prominent device performances for both hydrogen and methanol fuel cells with the elevation of~100%.Importantly,such function manipulation of ionic nanochannels is achieved with fully maintaining function of backbone nanophase.Besides,the regulation of physical topology and chemical environment of ionic nanochannel also brings optimization of gas and ion separation properties.This facile and versatile strategy may open up a new avenue for decorating confined space of many hierarchical-structure materials.

Atom Vibration of One-dimensional Nanophase Materials

1 Introduction In studying nanophase materials, it has been found that many mechanical, physicaland chemical properties of nanophase materials are obviously different from those ofconventional materials, and this may accelerate the development of high technologies andopen new applications for materials.

Phase transition of nanophase ferroelectric PbTiO_3 ultrafine powder

With the development of optoelectronics, nanometer materials play a more and moreimportant role. Recent theoretical researches indicate that the nanosized semiconductorcrystallites demonstrate a high nonlinear optical susceptibility and a fast response speed.Studies on nanometer-sized particles are very active. Because of the multielements of chemi-cal composition and higher crystallization temperature, it is very difficult to preparenanosized ferroelectric particles through conventional ceramic method.

Synergistic optimization of electrical and thermal transport in n-type Bi-doped PbTe by introducing coherent nanophase Cu1-75Te

Based on the calculated results of band structures and density of states,Bi doping is used to adjust its carrier concentration in order to obtain n-type PbTe materials with high power factor.Then,coherent nanophase Cu1.75Te is in situ formed in the n-type PbTe matrix,which can simultaneously optimize the thermal and electrical properties.As a result,at a relative lower temperature than other reports,the highest ZT value of 1.4 is obtained at 623 K for the nominal Pb0995Bi0005Te+0.86 wt%Cu175Te sample.More importantly,the ZT hold a higher value in the broad temperature;especially,ZT value is about 1.2-1.4 in the temperature range of 573-773 K,which is beneficial to the significant average ZT value ZTave~0.9 in the temperature range of 300-773 K.These results indicate that it is an effective and feasible method to enhance the thermoelectric properties via synergistic modulation of electrical and thermal transport properties by element doping and in situ coherent nanophase.