Applied Mechanics and Materials Vols. 217-219

Abstract: Abstract：The shaped-wire drawing dies are used more and more popularly in the metal product industry for several advantages of locked structure. In present investigation, a layer of CVD diamond film is deposited on the interior-hole surface of shaped-wire drawing die using a hot filament chemical vapor deposition (HFCVD) method, followed by a surface polishing process, aiming at further prolonging its working lifetime of shaped-wire drawing dies and improving the surface quality of produced wires. The scanning electron microscopy (SEM), surface profiler and Raman spectroscopy are adopted to present the characterization of both as-deposited CVD diamond films before and after polishing. Furthermore, the performance of as-fabricated CVD diamond coated drawing dies is examined in the practical production process. The results show that as-deposited CVD diamond films are homogeneous and the working surface is smoother after polishing. Comparing with the conventional shaped drawing dies, the working lifetime of the diamond coated shaped-wire drawing dies can be increased by a factor of above 10, and the shaped wires with higher surface quality can be obtained.

Abstract: Ce0.5Ti0.5O2 ion storage films were prepared by using sol–gel routes employed butyltitanate（Ti(OC4H9)4） and cerium nitrate（Ce(NO3)3•6H2O） as main initial materials. Structural, optical and electrochemical properties were investigated by XRD, SEM, cyclic voltammetry curves and utraviolet visible spectroscopy in this work. Ce0.5Ti0.5O2 ion films contained crystallization CeO2 and amorphous TiO2, and had large ion storage capacity. Its injection of charge density was high to 12.01 mC•cm-2 and K value was 0.75. It had better cyclic reversibility and high transparency, which kept colorless and transparent during the whole injection and extraction process of Li+. Light insert ion storage films of Ce0.5Ti0.5O2 has important significance in the preparation of electrochromic device.

Abstract: Zirconia optical films have been facilely deposited based on a modified sol-gel route, which involved solvothermal-treating a mixture of zirconyl nitrate, water, and methanol at 80 °C to produce zirconia-based sols, spin-coating the sols on K9 glass substrates, and then calcining the films at moderate temperatures. The experiments show that, at the proper volume ratio of methanol to water V_M/V_W (from 40/35 to 70/5), the high deprotonation-condensation reaction rate of the precursor zirconium salt, along with the moderate critical supersaturation level of the reaction medium, give rise to stable and uniform sols comprising particles with mean hydrodynamic diameter of 10-40 nm. This enables rapid deposition of zirconia-based films with a comparatively high refractive index of 1.62 (at 1064 nm). After calcination at 400 °C, the purification and crystallization of film material endow the film with a high refractive index of 1.91 (at 1064 nm).

Abstract: When both SnO2 film and a-Si film with infinite square resistance are deposited on an ITO film, the square resistance of the ITO film notably decreases. This phenomenon is more remarkable, when an ITO film has large square resistance. We believe that the films are composed of spaced crystalline grains. The film resistance is due to crystal boundary scattering carriers. Smaller crystalline grain and greater distance to the crystal boundary lead to fiercer scattering. The crystalline grains of the SnO2 film and a-Si film short-circuit the spaced ITO grains to form bridges so interface electrons can flow trough.

Abstract: It is difficult to keep the precise conveyance in film discontinuous winding system, while there are no etch or print marks on the transparent film. Based on dark field illumination theory, a micro-indentation detection method is proposed for multilayer structured transparent film roll-to-roll processing. Two parallel strip lights are involved in the vision system to illuminate the indentation at a low angle, which ensures that the distinct image of the cutting indentation can be obtained in reflection and diffuse homogeneous lights. The measurement of micro-indentations can be used to evaluate the film conveying positioning accuracy and calculate the compensation of film feeding position control. An experiment platform was established to show the efficiency and feasibility of proposed scheme. Experimental results showed that the micro-indentation detection method, based on dark field illumination, is successful to increase the feeding precision of multilayer structured transparent film discontinuous winding system.

Abstract: Synthesis of metallic lithium thin film was investigated from two ionic liquid of [EMIM]Tf2N and PP13Tf2N with LiTFSI as a lithium source. Cyclic voltammograms on Au electrode showed the possibility of the electrodeposition of metallic lithium, the reduction current in [EMIM]Tf2N was higher than the value in PP13Tf2N. The metallic lithium thin film could be synthesized on the Au electrode by the potentiostatic condition, which was confirmed by various analytical techniques including x-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. The lithium surface electrodeposited was uniformly without dendrite, any impurity was not detected except trace oxygen contaminated during handling for analyses.

Abstract: TiO2 films were deposited on AZ31 magnesium alloy substrates by r.f. magnetron sputtering. The corrosion behaviors in simulated body fluid (SBF) of the film samples were investigated and compared to the bare AZ31 magnesium alloy. After 3 days’ corrosion in SBF, only part of the TiO2 layer suffered from corrosion and the substrate was prevented from corrosion. In contrast, the bare magnesium alloy suffered from severe corrosion. After 10 days’ corrosion, the TiO2 layer was penetrated and the substrates still did not suffer from corrosion. After 15 days’ corrosion, besides TiO2 layer, the substrate suffered from corrosion to some degree. The depth of the corrosion layer is about 6 m, which is far lower than that of bare magnesium alloy, 40 m. The results show that TiO2 films effectively improve the corrosion properties of magnesium alloys.

Abstract: According to the Sentmanat Extensional Rheometer (SER) and its Universal Testing Platform, a uniaxial tensile method and its device design scheme based on single rotary drum applied for polymer films is proposed in the paper, which will be used to characterize mechanical properties of various types of plastic films under wider temperatures and constant Hencky strain rates. Basic principal and device design ideas are discussed with formula derivation and figures, which provides references to develop the related fixture and carry out some relevant experiments for future.

Abstract: In the present investigation, titanium (Ti), silicon carbide (SiC), silicon (Si) and tantalum (Ta) samples with the same geometry are selected as substrates to deposite HFCVD boron-doped diamond films with the same deposition parameters, using trimethyl borate as the dopant. FESEM, EDS, Raman spectroscopy and Rockwell hardness tester are used to characterize as-deposited boron-doped diamond (BDD) films. The FESEM micrographs exhibit that the film deposited on Si substrate presents the best uniformity and that on Ti substrate has smallest grain size and film thickness, with titanium element detected in the EDS spectra. Moreover, it’s speculated by indentation test that the adhesive strength between the BDD films and different substrates can be order as SiC>Ta>Ti for the different thermal expansion coefficient gaps between the substrate and diamond, and the hardness of the BDD coated samples measured using Rockwell hardness tester can also be order as SiC>Ta>Ti due to the different hardness of substrate materials. Finally, similar and representative characterization for BDD films is obtained from the Raman spectra for all the BDD films on different substrates.

Abstract: Ag thin films were prepared on the float-glass substrate by DC magnetron sputtering method. The relationship of surface morphology/electrical properties with technical conditions was investigated. The experimental results showed that sputtering power, sputtering pressure and substrate temperature had effects on the morphology and electrical properties of Ag thin films. The optimum parameters were obtained with sputtering power of 100 W，sputtering pressure of 0.4 Pa and substrate temperature of 130 °C. Under the optimum parameters, the deposited Ag thin film was smooth and its resistivity was as low as 1.96×10^-8 Ω•m.