Key Engineering Materials Vols. 609-610

Abstract: This paper reports a novel and facile activation process for electroless copper plating on Acrylonitrile Butadiene Styrene (ABS) plastic substrate using gold nanoparticles as catalyst. Gold nanoparticles were prepared by chemical reduction method and characterized by UVvisible adsorption spectrum and transmission electron microscope (TEM). The gold nanoparticles were sphere-like with a size of less than 50 nm. Gold nanoparticles were adsorbed on ABS surface and acted as nucleation centers in activating process of the electroless copper plating. The uniform and dense film was obtained at the optimal technological parameters which were achieved by the orthogonal experiment. The scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffractometer (XRD) and X-ray photoelectron spectroscopy (XPS) were used to detect the morphology, structure and elemental composition of the coating, respectively. The results indicated that copper coating contained only Cu (0) without any other elements.

Abstract: Anodic spark deposition (ASD) is a novel technique to deposit bioceramic films on the surface of titanium (Ti) and its alloys, and the films prepared with nano/micro scale pores are characterized by high-quality performance for dental implant. Among the process parameters, electrolyte provides a leading role owing to its vital influence not only on the films chemistry but also on the electrical conductivity of the circuit, which affects the film properties. In this study, titania porous films were synthesized by ASD and the effect of electrolytic temperature on microstructure and chemical composition of the films was studied. The results show that the electrolytic temperature could significantly influence the surface topography, thickness and chemical composition of the oxidation films produced by ASD and, therefore, determined the layered hydroapatite (HA) deposition as the other process parameters were fixed.

Abstract: Plasma electrolytic oxidation (PEO) has been one of the most applicable methods to deposit bioceramic coating on an implant and can provide the possibility for incorporating Ca and P ions. In this study, the titanium substrates were oxidized by optimized electric parameters for 5, 10, 15 and 20 mins respectively during PEO process, to analyze the effect of varied oxidation intensity on the microstructure, phase and element composition of the treated coatings. The results show that the PEO coating of 15 min exhibited excellent advantages of creating favorable microstructure, phase and element composition, and could promote the formation of nanoHA on the treated coating, as a result of some HA nanorods deposited on the surface after 7 days immersion in SBF. The PEO technique proved to be another choice to enhance the bioactivity of titanium and the coating could facilitate the precipitation of nanoHA to functionalize the biomedical materials.

Abstract: To obtain nanofibriled cellulose (NFC) with uniform diameter and high aspect ratio, chemical pretreatment was employer to remove the hemicellulose and lignin of cornstalks with further ultrasonic treatment. The prepared samples were characterized by SEM, TEM, FTIR, XRD, and TG. Results showed: The obtained NFC possessed the uniform diameter of about 25 nm and high aspect ratio (>300). The crystalline type of NFC was cellulose I type. The NFC with high crystallinity, high aspect ratio, and nanoscale is a newly great potential nanomaterial in different fields.

Abstract: ZnO/graphene composites has been synthesized using a one-pot hydrothermal method at moderate temperature of 90°C. Hydrothermal growth was done in an aqueous solution consisting of 20 mL graphene oxide (GO) solution (0.25 mg/mL) with equimolar of zinc acetate [ZAc, Zn (CH₃COO)₂·2H₂ and hexamethylenetetramine (HMTA, C₆H₁₂N₄). The as-synthesized composites was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The results of the characterization indicate that GO was reduced to graphene in the growth process, while ZnO in the form of quantum dots (QDs) or nanoparticles embedded in the graphene sheet. The composites synthesized by this method will have potential applications in bioimaging, gas sensing, optoelectrical materials and devices. The photoluminescence (PL) of the conposites was also investigated.

Abstract: In this paper, SiC films were deposited on the surface of 316L stainless steel by magnetron sputtering with sintering SiC target to improve its wear resistance. The structure and morphologies of the SiC films were characterized by XRD and SEM. The impacts of sputtering way, deposition time, and substrate temperature on the deposition rate and mechanical properties of SiC films were further investigated by the performance parameters of hardness, elastic modulus, friction and wear properties, coating adhesion, etc. The results show that coating adhesion is higher when the films are deposited by mid-frequency magnetron sputtering than that of which by direct current sputtering; Hardness and elastic modulus of the films increased gradually with the deposition time changing from 1 to 5h or the substrate temperature changing from room temperature to 200°C; However, the friction coefficient initially decreases, but turns to increase with the deposition time prolonging or the substrate temperature rising. The wear resistance of the films is the best when deposition time is 2h and substrate temperature is 100°C.

Abstract: In the paper, the surface modification of nanotitanium and its effect on the antibacterial properties of waterborne wood coating were studied. The effect of the type and amount of surfactant (system) and the ultrasonic treatment time on the property of nanotitanium and the effect of the dosage and adding method of nanoslurry on the properties of water-based wood coating were both investigated. The nanotitanium slurry made in the optimum conditions was also characterized. The results showed that nanotitanium slurry with excellent performance was obtained when 0.5wt% polyoxyethylene octylphenol ether and 3wt% sodium polyacrylate were used and ultrasonic treated 5h. It also showed that the waterborne wood coating with excellent drying performance and antibacterial property was got when 1.5wt % nanoslurry was mixed to water-based emulsion to hybrid. Under the conditions, the antibacterial rate against Escherichia coil and Staphlococcus aureus reaches to 95%.

Abstract: The infrared antireflection protection film is designed and deposited on magnesium fluoride substrate for 3~5 μm. The multilayer antireflection film is designed and prepared by ion beam assisted electron-beam deposition. After repeated experiments, the absorption peak of SiO₂ is found at 3000nm,using MgF₂ and SiO₂ as the low-index materials to reduce the absorption. The coating structure is Sub|1.46H1.37L2.19H1.45L2.49M|Air. DLC (diamond-like carbon) protection coating is deposited by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD). Through contrast tests, the best deposition process is obtained (the butane flow rate is 5sccm/s, deposition temperature is 80°C) by setting deposition time as invariant, the reaction gas flow rate and deposition temperature as variables. Meanwhile the problem of associativity between antireflection film and DLC protection coating is solved by adding a Si transition layer. The result shows that the average transmittance of this film in 3~5μm is 95.5%, and this film can withstands harsh environment tests. Key words: Magnesium fluoride substrate; Antireflection protection film; 3~5 μm infrared band Document Code: A Article ID: DIO

Abstract: In recent years, yellow laser has the broad application in military, civil use, health care and so on, so it is important to study the cavity facet film in yellow laser. In this paper, the substrate is Nd:YVO₄，Ta₂O₅ and SiO₂ are chosen as the film materials. A accurate film is designed and prepared with the specific refractive at the band of 589nm, 1064nm, 1178nm, 1342nm. The influence of thickness monitoring error on the measured spectral curve is analyzed. The film thickness control accuracy is improved by optimizing the parameters (for example: temperature, oxygen filling etc.) and adjusting the correction coefficient of sensitive layer. Finally，the influence of error on filter spectral characteristics is reduced. The result shows that the prepared film satisfies the using requirement standard.

Abstract: Inspection and measurement for the sheet resistance and resistivity play a pivotal role in the semiconductor industry. In this study, a high-accuracy measurement system for sheet resistance of thin films was designed based on dual-measurement with four-point probe method. The measurement system was composed of a special switching circuit, a digital output module, Keithley 2400 SourceMeter, and a computer running LabVIEW. The special switching circuit designed based on the multiplexer played an important role in current probes and voltage probes automatic switching under the control of virtual instrumentation software LabVIEW and National instruments digital output module hardware NI 9401. Keithley 2400 SourceMeter controlled by LabVIEW was used for two-times high-precision voltage measurement. Van der Pauw correction factor were calculated based on the results of the two-times voltage measurement. Then the sheet resistance of thin films was calculated by LabVIEW softwares powerful computing. The experimental results show that the designed and developed system can meet the needs of fast on-line measurement of thin films sheet resistance with a wide range, and moreover, the accuracy of measurements and the level of automatization have been dramatically improved compared to the conventional measurement system.