Sputtering targets of CIGS quaternary ceramic were fabricated by hot-press sintering the milled powder mixture of Cu2Se, In2Se3 and Ga2Se3. When the milling time of the powders less than 4 h, the sintered targets delaminated, while the delamination disappeared with the prolonging milling time. Therefore the physico-chemical changes of the powder mixture during the milling process and their influence on the delamination of the targets were investigated. The results indicate that with the progress of the milling process, mechanical alloying (MA) occurred, and chalcopyrite Cu(In, Ga)Se2 (CIGS) formed from Cu2Se, In2Se3 and Ga2Se3; With the increasing milling time, CuInSe2 (CIS) formed on the surface of binary copper selenide firstly and CIGS was subsequently generated due to the inward diffusion of Ga; Thus the original blend powders became a mixture of CIGS and residual Ga2Se3 after milling for 48 h. Since CIGS and Cu2-xSe have a similar crystallographic structure, therefore this epitaxial relation may facilitate the formation of CIGS. The disappearance of Cu-Se binary compound and the formation of CIGS restrained the delamination of the CIGS targets in the sintering process.
The effect of nanocrystallization on the adsorption of Cl- on Fe20Cr alloy in [Cl-] =0.1 mol/L borate buffer solution was investigated by means of X-ray photoelectron spectrum(XPS) and calculations per the first-principles. The results show that the influence of Cr on Cl- adsorption behavior could be described as the following two aspects : the one, in view of the calculation per the first-principles, is that the adsorption energy decrease with the increasing Cr content at the interface of passive film/alloy, which is conducive to the adsorption of Cl-; the other is that the Cr enrichment may also facilitate the formation of passivation film, which inhibit the Cl- adsorption. Nanocrystallization may enhance the diffusivity of Cr, which leads to the enrichment of Cr within the passive film as well as at the interface of passive film/alloy. Thus, nanocrystallization can inhibit the adsorption and the inward migration of Cl-, and finally enhance the corrosion resistance of the alloy.
A gradient and nanostructured (GNS) surface layer was formed on a 316L stainless steel sample by using surface mechanical rolling treatment (SMRT). The effect of SMRT on the evolution of phase composition and microstructure was studied of the GNS surface layer. The results show that deformation-induced martensite transformation occurs in the surface layer after SMRT, and the martensite amount increases with the increasing penetration depth of SMRT. The microstructural refinement mechanism includes subsequently the formation and interaction of various dislocations, deformation twinning, deformation-induced martensite transformation, and martensite refinement. Finally, nanostructure with mostly martensite and a mean grain size of ca. 55 nm was achieved in the topmost surface layer of the 316L sample.
Pre-alloyed powders of T55 have been hot-isostatic-pressed (HIPed) at different HIPing temperatures, and the powder compacts were solution- and aging- treated. Thereafter the powder compacts were carefully examined to establish the relationship between their microstructure and mechanical property. Powder compacts HIPed at 940℃ and 970℃ showed no significant difference on the microstructure and tensile properties. Due to the densification wave effect caused by a non-uniformity of temperature/pressure field during HIPing, the recommended HIPing temperature is 940℃ in this work. The tensile property of powder compact at 600℃ was improved obviously after solution- and aging- treatment. The tensile property of the heat-treated powder compact is close to that of the wrought alloy but better than those of the cast ones. Finite element analysis was used to predict the final dimensions of the small casing component after HIPing, which is well consonant with the experimental data, thus, the FEM analysis is an efficient method for the design and manufacture of powder components. Based on the optimal container design and FEM analysis, a large thin-wall cylindrical structure of Ti55 alloys was manufactured successfully.
N-succinyl-O-hydroxypropyl sulfonated chitosan (SA-HPSCS) was prepared and then characterized by FT-IR and 1HNMR. The role of SA-HPSCS in the biomimetic synthesis of CaCO3 was studied, while the CaCO3 crystal produced in a pure water system was used as a reference. The influence of pH value on the morphology and crystallographic structure of CaCO3 crystal in the SA-HPSCS system was investigated and the relevant mechanism was proposed. The results show that the calcite is the only phase of CaCO3 crystal prepared in the pure water system, while the vaterite is dominant phase of those prepared in the SA-HPSCS system. By pH=6 the vaterite content in the prepared CaCO3 reached 95.8%, but both the size and the content of the vaterite dropped with the increase of pH value. The results also indicate that SA-HPSCS could regulate effectively the synthesis process of the CaCO3 crystal in terms of morphology, polymorph and dimension, and the pH value could strongly affect its regulation effect.
The effect of transition metal elements, such as Zr, Nb, Mo and Cu on the amorphous forming ability, thermal stability and magnetic propertywere investigated for the Fe78Si9B13 alloy.By varying the Fe content of the Fe74Cu1Si13B9Nb3amorphous alloy, two series alloys, i.e. Fe(76+x)Cu1Nb3Si(11-x)B9(x=0, 2, 4) and Fe(79+x)Cu1Nb2Si(6-x)B12(x=0, 2, 4) amorphous- and nanocrystalline-alloyswere prepared and finally their ribbons were producedby melt-spinning.The microstructures and magnetic properties of the prepared ribbonswere investigated by XRD, DSC, TEM and VSM etc. and the soft magnetic properties ofthe high Fe content alloyswere optimized by increasing the content of Nb.The results showed that theelements of Zr and Nb can effectively improve the amorphous forming ability and thermal stability of Fe78Si9B13 alloys; A seriesFe-Cu-Nb-Si-B amorphous- and nanocrystalline-alloys with Fe content >80% (atomic fraction) were successfully prepared, themicrostructures of which are typically composed of dual amorphous- and nanocrystalline-phase. Their saturation magnetizations Bs are larger than 180emu/g and coercivitiesHcare between 2Oe and 9Oe, which means the alloys exhibit a good soft magnetic property. Thecoercivity would be reducedsince the grain size would be refined and thus the soft magnetic properties would be significantly improved as the Nbcontent increases. When the Fe content is between 80% (atomic fraction) and 83% (atomic fraction), the alloyswould exhibit an excellent soft magnetic property but when the Fe content comes to 85% (atomic fraction), phases of Fe2B and Fe3B would be precipitated that would furiouslydeterioratethe soft magnetic properties of the alloys.
Anti-static zirconia ceramic with perfect mechanical properties was prepared by carburization treatment method. The influence of carburization temperature and time on the surface resistivity and Vickers hardness was investigated. It shows that after carburization the surface resistivity was decreased, while Vickers hardness was enhanced for the ZrO2 ceramics. After carburization at 1450℃ for 3 h, the surface resistivity of ZrO2 ceramic could be reduced to 107 Ω/□ and Vickers hardness could be enhanced slightly to 14 GPa; the surface modification layer was about 3 μm in thickness; and of which the carbon content deceased from the surface towards the inner. It was verified by XPS that carbon in the inner portion of carburization layer existed as elemental status, while on the surface layer as element C and carbide ZrC0.85, which might facilitate the anti-static property of the ZrO2 ceramics.
To simulate the ordered texture of the collagen in natural bone tissue, membranes of collagen with hierarchically ordered texture were fabricated. The effect of templates made of collagen with and without ordered texture on the biomineralization process of calcium phosphate was comparatively studied in vitro. The morphology and structure of the deposited calcium phosphate on the collagen templates were characterized by using polarizing microscope (POM), scanning electron microscope (SEM), atomic force microscope (AFM) and X-ray diffraction (XRD). The results show that the collagen with hierarchically ordered texture has obvious effect on the biomimetic mineralization process; on which the deposited calcium phosphate is much more orderly and compact either in micro- or in macro scales. This result indicates that the collagen with hierarchically ordered texture is beneficial to the building of biomimetic bone tissues as materials for repair of human bone etc.
The friction and wear properties of graphene (GP) as a lubricant additives were investigated by means of a UTM-2 tribometer via a ball on plate contact reciprocating sliding. The molecular structure and morphology of graphene nano sheets were characterized by TEM, SEM, XRD, IR and Raman spectroscopy. The friction and wear test was performed with lubricant of PAO4 oil without and with addition of 0.01% graphene (GP) respectively at different temperatures for the textured bronze with different ratio of textured area. The results show that GP can effectively reduce the friction and wear, especially at 60℃ and 100℃. For the simple PAO4 oil, the bronze with untextured surface exhibits the lowest friction coefficient and wear rate at 60℃ and 100℃; whilst, with the increasing ratio of the textured area, the friction coefficient and wear rate increase. For graphene-containing PAO4 lubricating oil, the friction coefficient is lower for the bronze with 5% textured area, while higher for those with 20%; the wear rate is lower for the bronze with 10% textured area.
Flower-like nanostructured SnS2 was synthesized by polyethylene glycol octylphenol ether(Triton X-100)-assisted hydrothermal method, the effect of the amount of surfactant Triton X-100 on the ingredient, morphology and electrochemical properties of the synthesized product was studied. Results show that the product is single-phase SnS2 with crystal structure of hexagonal CdI2. The Triton X-100 plays a dominative role in controlling the morphology of SnS2. With a dosage of 0.5 mL Triton X-100 the synthesized SnS2 possesses the highest degree of crystallinity with a fully flower-like morphology . A rechargeable Li-ion batteries with the as-prepared flowerlike nanostructured SnS2 as anode exhibits excellent electrochemical performance with high initial discharge specific capacity 1598 mAhg-1 and reversible capacity 656 mAhg-1 respectively, in a voltage range of 0.01-1.2 V and a rate of 0.15C. After 50 cycles with a rate of 0.15C, the specific capacities retain 572 mAhg-1 and capacity retention rate can reach 87.2%.
Polyethylene glycol (PEG)/ polyacrylonitrile (PAN) shape-stabilized phase-change materials were prepared by blending acrylonitrile (AN) with copolymer P (AN-co-IA) as compatibilizer, which was copolymerized with itaconic acid (IA) and acrylonitrile/itaconic acid. First the compatibilizing mechanism of P (AN-co-IA) was analyzed and discussed, then the chemical composition, thermal insulation properties, thermal properties and crystallinity of the blend materials were investigated by FT-IR, cooling curve, differential scanning calorimetry (DSC), XRD and polarizing microscope (POM). The results show that the blends exhibit excellent insulation properties and have a large enthalpy; the solid- solid phase transition temperature and enthalpy increased with the increasing content of PEG; after cyclic heating for a limited cycles, the phase transition temperature and enthalpy had no significant changes which implies a good durability of heat storage of the blends.
Effect of surface treatment on tensile property of a near lamellar gamma-based TiAl-alloy Ti-45Al-5Nb-1W-1B (atom fraction, %) has been investigated. The results show that the highest tensile strength of the alloy at room temperature and high temperature can be achieved by shot peening. The alloy processed by turning possesses a tensile strength close to that of shot penned one at room temperature, however a dramatic decline at high temperature. Electro polishing leads to the lowest tensile strength at room temperature, but a tensile strength at high temperature as high as that of shot penned one. Although the residual compressive stress can be introduced by shot peening and turning, besides a surface layer of deformation can also be caused by the former, therefore the compressive residual stress induced by shot penning is higher than that by turning. Meanwhile, crack initiation has been transferred from surface to subsurface because of the existence of the residual compressive stress.
