Effect of Rare Earth Element Cerium on Mechanical Properties and Morphology of TiN Coating Prepared by Arc Ion Plating

TiN coatings were deposited on polished substrates of W18Cr4V high speed steel by means of vacuum arc ion plating. The effect of cerium on adhesion between TiN coating and substrate was studied. The microstructures and composition of TiN coatings were also investigated by means of scanning electron microscope (SEM), Auger electron spectroscopy (AES), and X ray diffraction (XRD) technique. It was found that cerium is an effective modifying agent and the addition of suitable amount of cerium to TiN coatings can produce relatively excellent properties such as micro hardness, wear resistance, oxidation resistance and porosity. The experimental results show that the added cerium in TiN coatings makes a contribution to form the preferred direction along with a (111) or (222) close packed face, which may be one of the reasons that improves some properties mentioned above.

Preparation of Sn nano-film by direct current magnetron sputtering and its performance as anode of lithium ion battery

Sn thin film on Cu foil substrate as the anode of lithium ion battery was prepared by direct current magnetron sputtering(DCMS). The surface morphology,composition and thickness and the electrochemical behaviors of the prepared Sn thin film were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),inductively coupled plasma atomic emission spectrometry(ICP),cyclic voltammetry(CV) and galvanostatic charge/ discharge(GC) measurements. It is found that the Sn film is consists of pure Sn with an average particle diameter of 100 nm. The thickness of the film is about 320 nm. The initial lithium insertion capacity of the Sn film is 771 mA·h/g. The reversible capacity of the film is 570 mA·h/g and kept at 270 mA·h/g after 20 cycles.

Effects of rare-earth elements on the glass-forming ability and mechanical properties of Cu_(46)Zr_(47-x)Al_7M_x(M = Ce,Pr,Tb,and Gd) bulk metallic glasses

Cu46Zr47-xA17Mx （M = Ce, Pr, Tb, and Gd） bulk metallic glassy （BMG） alloys were prepared by copper-mold vacuum suction casting. The effects of rare-earth elements on the glass-forming ability （GFA）, thermal stability, and mechanical properties of Cu46Zr47-xA17Mx were investigated. The GFA of Cu46Zr47-xA17Mx （M = Ce, Pr） alloys is dependent on the content of Ce and Pr, and the optimal content is 4 at.%. Cu46Zr47-xA17Thx（X = 2, 4, and 5） amorphous alloys with a diameter of 5 mm can be prepared. The GFA of Cu46Zr47-xA17Gdx（x = 2, 4, and 5） increases with increasing Gd. Tx and Tp of all decrease. Tg is dependent on the rare-earth element and its content. ATx for most of these alloys decreases except the Cu46Zra2Al7Gd5 alloy. The activation energies △Eg, △Ex, and △Ep for the Cu46Zr42A17Gd5 BMG alloy with Kissinger equations are 340.7, 211.3, and 211.3 kJ/mol, respectively. These values with Ozawa equations are 334.8, 210.3, and 210.3 kJ/mol, respec- tively. The Cu46Zr45Al7Tb2 alloy presents the highest microhardness, Hv 590, while the Cu46Zr43A17Pr4 alloy presents the least, Hv 479. The compressive strength （at.f.） of the Cu46Zra3A17Gd4 BMG alloy is higher than that of the Cu46Zr43Al7Tb4 BMG alloy.

Effects of yttrium on the formation and magnetic properties of bulk metallic glassy(Fe,Co)-B-Si-Nb alloys

The bulk metallic glassy （BMG） rods of [（Fe0.5Co0.5）0.72B0.192Si0.048Nb0.04]100-xYx （x=0-6） and [（FexCO1-x）0.72B0.192Si0.048Nb0.04]96Y4 （x=0.5-0.8） were prepared by copper mold casting. The structure, thermal stability, and magnetic properties of the samples were studied by X-ray diffraction （XRD）, differential scanning calorimetry （DSC）, and vibrating sample magnetometer （VSM）. Adding 1 at% to 6at% of yttrium, the bulk glassy alloy rods of [（Fe0.5Co0.5）0.72B0.192Si0.048Nb0.04]100-xYx （x=0-6） with the diameter of 3 mm were not formed, and the sample with 4at% of yttrium showed less crystalline phase than others. When the Fe/Co atomic ratio was between 5：5 and 7：3, the bulk glassy alloy rods of [（Fe1-xCox）0.72B0.192Si0.048Nb0.04]96Y4 （x=0.5-0.8） with the diameter of 2 mm were fabricated. In the （Fe, Co）-B-Si-Nb-Y BMGs, when the Fe content increased, the thermal stability, the supercooled liquid region, and the glass-forming ability （GFA） decreased, but the saturation magnetization （Ms） increased.

Lithium intercalation/de-intercalation behavior of a composite Sn/C thin film fabricated by magnetron sputtering

A tin film of 320 nm in thickness on Cu foil and its composite film with graphite of-50 nm in thickness on it were fabricated by magnetron sputtering. The surface morphology, composition, surface distributions of alloy elements, and lithium intercalation/de-intercalation behaviors of the fabricated films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, electron probe microanalyzer （EPMA）, X-ray photoelectron spectroscopy （XPS）, inductively coupled plasma atomic emission spectrometry （ICP）, cyclic voltammetry （CV）, and galvanostatic charge/discharge （GC） measurements. It is found that the lithium intercalation/de-intercalation behavior of the Sn film can be significantly improved by its composite with graphite. With cycling, the discharge capacity of the Sn film without composite changes from 570 mAh/g of the 2nd cycle to 270 mAh/g of the 20th cycle, and its efficiency for the discharge and charge is between 90% and 95%. Nevertheless, the discharge capacity of the composite Sn/C film changes from 575 mAh/g of the 2nd cycle to 515 mAh/g of the 20th cycle, and its efficiency for the discharge and charge is between 95% and 100%. The performance improvement of tin by its composite with graphite is ascribed to the retardation of the bulk tin cracking from volume change during lithium intercalation and de-intercalation, which leads to the pulverization of tin.

Tribological characteristics of new series of Al-Sn-Si alloys

Tribological characteristics of new series of Al Sn Si alloys were investigated by means of pin disk types of wear testing machines, OM, SEM and EDAX. Rules about the influence of Sn, Si content and load on the friction and wear characteristics of the alloys were ascertained. The friction factor and wear rate of the alloys decrease with increasing Sn content, the wear rate decreases but the friction factor varies hardly with increasing Si content. The friction factor of the alloys increases slightly and the wear rate increases observably with increasing load in the range of 1080 N. The wear mechanism of Al Sn Si alloys consists of ‘plough’ action and abrasive wear below 30 N; the adhesive and delamination mechanism are shown in the range of 3080 N. The tribological characteristics of Al Sn Si system are superior to those of Al Sn or Al Si systems due to their “peritectic type” island shape microstructure of Si surrounded with Sn.

MECHANISM RESEARCH FOR 3D NON-AXISYMMETRIC THIN-WALL TUBE OFFSET SPINNING

Difference of offset spinning with conventional symmetric spinning is analyzed. A 3D FEM model for offset tube neck-spinning is established and the spinning process is simulated by means of ANSYS software. Dynamic boundary and contact problems in simulation are solved. Transient stress distribution of contact area, transient strain distribution of nodes in typical section and strain distribution of the workpiece at last are attained, the place and the cause of crack are analyzed. Strain variation curves with time of offset spinning and conventional spinning are compared. It shows the mechanism difference between offset spinning and conventional spinning. In addition, simulation results show how strain distribution of typical section, thickness of some typical nodes, axial extension in left section and force of three rollers change with time. According to the study of the variation curve, material flow law along radial, tangential and axial direction is attained and the whole spinning process is studied. The simulation results discover that offset distance is the key to manufacture offset non-symmetric tube, and process parameters change with spinning angle. Experiment data really reflect different process parameters＇ influence on conventional symmetric and offset spinning force. Experiments accord well with simulation.

Ultrasonic-electrodeposited Sn-CNTs composite used as anode material for lithium ion battery

Tin carbon nanotube(Sn-CNTs) composite was prepared by ultrasonic-electrodepositing tin on the substrate of copper foil in a sulfate bath containing carbon nanotubes(CNTs). The composites were characterized by scanning electron microscopy(SEM),cyclic voltammetry(CV) and charge-discharge cycling test. The results show that Sn-CNTs have a better electrochemical performance than Sn. The capacity of Sn-CNTs is 843 mA·h/g during the first discharge and the efficiency of charge-discharge reaches 85%. After 50 cycles,the capacity of Sn-CNTs keeps at 380 mA·h/g. The CNTs in tin act as a structure supporter and play a role of an elastomer and conductive network,alleviating the electrode dilapidation resulted from volume change during the lithium insertion and deinsertion.

A new kind of magnetic targeting induction heating drug carrier and its physical and biological properties

Nano-carbon and iron composite—carbon-coated iron nanoparticles (CCINs) produced by carbon arc method can be used as a new kind of magnetic targeting induction heating drug carrier for cancer therapy. The structure and morphology of CCINs are studied by X-ray diffraction (XRD) and transmission electron microscope (TEM). Mossbauer spectra of these nanoparticles show that they contain only iron and carbon, without ferric carbide and ferric oxide. CCINs can be used as the magnetic drug carrier, with the effect of targeting magnetic induction heating in its inner core and higher drug adsorption in its nano-carbon shell outside because of its high specific surface area. CCINs can absorb Epirubicin (EPI) of 160 μg/mg measured by an optical spectrometer. In acute toxicity experiment with mice, the median lethal dose (LD50) of EPI is 16.9 mg/kg, while that of EPI-CCINs mixture is 20.7 mg/kg and none of the mice died after pure CCINs medication. The results show that pure CCINs belong to non-toxic grade and EPI delivery in mixture with CCINs can reduce its acute toxicity in mice. The magnetic properties of CCINs and their magnetic induction heating are investigated. The iron nanoparticle in its inner core has better magnetism with a good effect on targeting magnetic induction heating. When the CCINs are mixed with physiological salt water and are injected uniformly in pig’s liver, the temperature goes up to 48°C. While in the case that CCINs are filled in a certain section of pig’s liver, the temperature goes up to 52°C. In both cases the temperature is high enough to kill the cancer cell. CCINs have potential applications in cancer therapy.