Effect of ion bombardment on the optical properties of LDPE/EPDM polymer blends

Ion bombardment is a suitable tool to improve the physical properties of polymers. In the present study, the effect of ion bombardment on the optical properties of low density polyethylene (LDPE)/Ethylene propylene diene monomer (EPDM) blend (LDPE/EPDM) was studied. Polymer samples was bombarded with 130 keV He and 320 keV Ar ions at fluencies levels ranging from 1 × 10¹³ to 2 × 10¹⁶ ions/cm². The untreated and ion beam bombarded samples were investigated using ultraviolet-visible (UV-Vis) spectrophotometry. The optical band gap (E_g), was decreased from ∼2.9 eV for the pristine sample down to 1.7 eV for the samples bombarded with He and Ar ions at the highest fluences. Change in the optical gap indicates the presence of a gradual phase transition for the polymer blends. Activation energy has been investigated as a function of the ion fluences. With increasing ion fluence, a decrease in both the energy gap and the activation energy was observed. The number of carbon atoms (N) in a formed cluster is determined according to the modified Tauc's equation.     

Surface modification of polymers by ion-assisted reaction

This paper deals with a new surface modification technique of polymers, the so-called ion-assisted reaction (IAR) to improve the surface properties of polymers and provides outstanding experimental results regarding wettability and adhesion of various polymers. In the IAR, polymer surfaces were subjected to low energy ion irradiation at different dosage in reactive gas environment. Dramatic improvements in wettability and surface energy are observed for the IAR-treated polymer surfaces and can be explained by the addition of functional groups, responsible for the increase of polar component in surface energy. The formation of functional groups results from the interaction among ion, reactive gas and polymer chain involved in IAR treatment, depending on the reactive ion species, the flow rate of the reactive gas and the irradiating ion fluence. The improvement in adhesion between the IAR-treated polymers and coating materials was explained in terms of the increased surface energy as well as surface roughness in the polymers modified by the IAR and possible adhesion enhancement mechanism is to be discussed.     

铝型材挤压模具离子注入表面强化

铝型材热挤压模具的磨损、润滑和使用寿命短等问题直接影响着铝加工行业中铝产品的质量和厂家的经济效益。我院与广东兴发铝型材厂合作，将离子注入技术应用于铝型材生产，对铝型材挤压模具进行了表面改性处理。51只离子注入改性后的模具在线实验表明：模具总的中间使用寿命平均提高了140%，同时改善了铝型材的表面光洁度，减少了模具的拆卸、修整次数和降低了生产工人的劳动强度。     

Surface modification of PET membrane by ion implantation

Semicrystalline poly(ethylene terephtalate) (PET) foils were irradiated with N⁵⁺, O⁷⁺ and C³⁺ ions. Ions beams of 50 keV N⁵⁺, 70 keV O⁷⁺ and 30 keV C³⁺ were produced from the ECR ion source. The induced effects and wettability of ion-implanted membranes were investigated by means of the Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and by the contact-angle methods. FTIR measurements of the virgin and irradiated samples show the scission processes of main chains at the ethylene glycol residue. Various degradation processes known from photochemical degradation were also observed. The AFM observation revealed that the surface topography changes after irradiation. The contact-angle measurements showed that the PET membranes became significantly more hydrophilic after the ion irradiation.     

蛋白质生物降解塑料的研究

概括了蛋白质生物降解塑料的研究 ,包括蛋白质塑料的降解原理 ,研究用蛋白种类 ,蛋白塑料的改性方法 ,以及蛋白塑料制样方式等 ,并对其发展前景进行了展望。     

Surface modification of electric hair clipper blade for increasing its lifetime

Making the angle of a hair clipper blade edge acute improves its cutting ability but causes the edge to be susceptible to wear, resulting in decreased cutting service life. An enhancement of blade edge hardness of hair clippers by various surface modifications has been studied to increase their wear resistance. Ion nitriding method formed a thick nitrided layer on the mother material surface. PVD and CVD methods formed a fine and thin hard coating at relatively low temperatures. In this study, surface modification by ion plating and plasma CVD methods was carried out to improve the cutting edge qualities of 45° angle blades, material which is used is hardened SUS420J2Mo. The effectiveness was verified by cutting performance lifetime test using artificial hair. It enhanced the cutting performance lifetime of clipper blades more than four times.     

炭纤维阳极氧化法表面改性

采用阳极氧化法对聚丙烯腈（PAN）基炭纤维进行表面改性，利用原子力显微镜（AFM）、X射线光电子能谱（XPS）、扫描电子显微镜（SEM）和动态力学热分析（DMTA）对炭纤维表面改性效果进行了研究。研究结果表明，炭纤维经适当的阳极氧化表面改性后，表面的粗糙度和比表面积增大，表面羟基含量提高31％，羰基含量提高61％。表面改性炭纤维增强树脂基复合材料（CFRP）较未改性炭纤维CFRP，玻璃化温度（Tg）升高，损耗角正切峰值（tanδmax）降低，定量计算出的界面黏结参数A和a与CFRP的层间剪切强度（ILSS）所反映的炭纤维与树脂间界面黏结效果一致。采用适当的改性条件可使CFRP的ILSS提高25％，纤维抗拉强度仅损失5％。     

Surface modification and chemical sputtering of graphite induced by low-energy atomic and molecular deuterium ions

The surface morphology, and chemical/structural modifications induced during chemical sputtering of ATJ graphite by low-energy (<200 eV/D) deuterium atomic and molecular ions are explored by Scanning Electron Microscopy (SEM), Raman and Auger Electron Spectroscopy (AES) diagnostics. At the lowest impact energies, the ion range may become less than the probe depth of Raman and AES spectroscopy diagnostics. We show that such diagnostics are still useful probes at these energies. As demonstration, we used these surface diagnostics to confirm the characteristic changes of surface texture, increased amorphization, enhanced surface reactivity to impurity species, and increased sp³ content that low-energy deuterium ion bombardment to steady-state chemical sputtering conditions produces. To put these studies into proper context, we also present new chemical sputtering yields for methane production of ATJ graphite at room temperature by impact of D₂⁺ in the energy range 10-250 eV/D, and by impact of D⁺ and D₃⁺ at 30 eV/D and 125 eV/D, obtained using a Quadrupole Mass Spectroscopy (QMS) approach. Below 100 eV/D, the methane production in ATJ graphite is larger than that in HOPG by a factor of ∼2. In the energy range 10-60 eV/D, the methane production yield is almost independent of energy and then decreases with increasing ion energies. The results are in good agreement with recent molecular dynamics simulations.     

Surface modification processes by hypervelocity plasma pulses

The Institute of Astronautics of the Technische Universität München works in the field of electrothermal and electromagnetic particle launchers. Capacitor-driven arc discharges generated within these accelerators eject very fast and dense plasma pulses that can be used to modify surfaces of metals and alloys. During the last years, a completely new facility for surface modification purposes was designed, built, and put into operation. In preparation for the industrial application of the plasma-pulse-technique, further modifications and optimizations of the facility were performed. Fast and reliable feeding of seeding and/or reaction products to the plasma was realized with a specially designed and built gas injection system. Very short opening times for the injection valves could be realized. It is now possible to supply a substantial amount of gas to the process. The pressure pulse from the gas injection allows uniformly and finely distributed feeding of pulverized additives to the plasma as well. For the first time, we generated a carbon–nickel plasma that was used for steel-hardening. In contrast to our former experiments, a hard surface but largely free of fissures could be generated. This is a necessary and important step towards an industrial application of the plasma-pulse-technique. A different application is the surface doping of titanium aluminides (TiAl) with chlorine atoms. This modification leads to a substantial reduction of the oxidation of such materials. This is essential for the high temperature regime of turbine blades in jet engines. After the modification of the gas injection system for chlorine, TiAl samples were impacted with chlorine doped plasma pulses and the oxidation was tested. A reduced oxidation was observed which proves the principle applicability of the plasma pulse process for this special application.     

Surface segregation studied by low-energy ion scattering: experiment and numerical simulation

The changes in surface composition of metallic alloys caused by segregation can be very efficiently studied by low-energy ion scattering (LEIS) due to the specific surface sensitivity of this technique. Investigations of single-crystal surfaces of ordered alloys are of particular interest because they provide the possibility to investigate the interplay between segregation effects and the order-disorder phase transition when passing through the transition temperature. Exemplifying these effects for bimetallic alloys we consider in particular the CuAu-system.For the quantitative interpretation of energy and angle resolved LEIS intensity distributions we compare experimental results with those from numerical simulations using the MARLOWE code which we extended with a detailed trajectory analysis. This allows us to apply various discrimination criteria, such as number of collisions, distance of closest approach, identification of the scattering crystal layer, total path length, etc. On this basis structural effects, ion survival probabilities and the influence of thermal vibrations can be studied.We demonstrate this potential by using CuAu(1 0 0) as a special example. The scattering potential parameters were calibrated with elemental single crystals of known structures and the anisotropic Debye temperatures taken from the literature showed good agreement, neutralization was of minor importance in this case. Our procedure could be successfully used for the quantitative analysis of the composition of the first and second layer as a function of temperature. These results are in good agreement with theoretical predictions.     

Surface modification of medical metals by ion implantation of silver and copper

Implant related infections remain a concern in modern surgery. Surface modification is an effective way to reduce the occurrence of these complications. Of various techniques, ion implantation shows promise. In the present work, silver and copper were ion implanted separately, into three typical medical metals, namely 317L stainless steel, titanium, and Ti-Al-Nb by a MEVVA ion source machine at various ion doses. The objective of this study was to determine the influence of silver and copper ion implantation on antibacterial performance and wear and corrosion resistance of the three materials. Antibacterial activity of silver- and copper-implanted samples against Staphylococcus aureus were assessed by the plate-counting method. The results show that silver and copper implantation improves the antibacterial rate and wear performance of all the three metals studied. It is also found that silver ion implantation does not change the corrosion resistance while the corrosion resistance of copper-implanted samples shows a significant decline. In conclusion, silver ion implantation is favorable to copper ion implantation for increasing the antibacterial nature of these three metals.     

Relation between the plasma characteristics and physical properties of functional zinc oxide thin film prepared by radio frequency magnetron sputtering process

The ZnO thin film was deposited on a glass substrate by a RF reactive magnetron sputtering method. Results showed that plasma density, electron temperature, deposition rate and estimated ion bombardment energy increase with increasing applied RF power. Three distinct power regimes were observed, which are strongly correlated with plasma properties. In the low-power regime, the largest grain size was observed due to slow deposition rate. In the medium-power regime, the smallest grain size was found, which is attributed to insufficient time for the adatoms to migrate on substrate surface. In the high-power regime, relatively larger grain size was found due to very large ion bombardment energy which enhances the thermal migration of adatoms. Regardless of pure ZnO thin film or ZnO on glass, high transmittance (> 80%) in the visible region can be generally observed. However, the film thickness plays a more important role for controlling optical properties, especially in the UV region, than the applied RF power. In general, with properly coated ZnO thin film, we can obtain a glass substrate which is highly transparent in the visible region, is of good anti-UV characteristics, and is highly hydrophobic, which is highly suitable for applications in the glass industry.     

Ion bombardment of Poly-Allyl-Diglycol-Carbonate (CR-39)

Ion bombardment is thought to have great potential for improving the optical properties of polymeric materials. In this paper, Poly-Allyl-Diglycol-Carbonate (CR-39) polymer samples were bombarded with 320 keV Ar and 130 keV He ions, at different ion fluences. Effects of ion bombardment on the optical properties of CR-39 have been investigated using UV-vis spectrophotometer and photoluminescence (PL) spectroscopy. UV-vis spectra of irradiated samples reveal that the optical band gap decreases with increasing the ion fluence for both Ar and He ions. The width of the tail of localized states in the band gap (E_u) was evaluated using the Urbach edge method. The decrease in the PL intensity with the increase in the ion fluence was observed. This decrease is attributed to ion bombardment induced defects and clusters in the CR-39 which serves as non-radiative centers.     

电子回旋共振等离子体用于聚四氟乙烯材料表面改性

在电子回旋共振 (ECR)等离子体装置中 ,使用Ar气 ,N2 气 ,H2 气和普通空气放电 ,对聚四氟乙烯 (PTFE)材料进行表面处理以提高其表面粘结性能。详细研究了在不同的放电气压 ,微波功率 ,处理时间 ,气体种类的情况下 ,样品表面的接触角的变化。同时也讨论了样品导电性能和外观等的变化。使用红外吸收谱对样品结构处理前后的变化进行了测量 ,对等离子体处理的机理进行了初步的讨论。使用Langmuir探针测量了Ar气和N2 气等离子体中的离子密度 ,用能量分析器测量了离子的能量。发现在对样品的处理中 ,ECR等离子体的离子密度是影响表面性能的主要因素 ,离子能量的作用不明显     

Surface modification of carbon electrodes using an argon plasma

In this work, an activated carbon sheet was modified, to improve capacitance and energy density of electric double layer capacitors (EDLCs). Surfaces were treated with plasma for selected times of 1, 5, 10, 20, and 30 min. The plasma source was a DC glow discharge in argon gas. The pressure was 20 Pa and the distance between positive and negative electrodes was 20 mm. DC power was 70 W. The activated carbon sheets were set up so that the sheets were covered with the DC glow discharge. The results showed that plasma treatment led to roughening of the surface of the activated carbon sheets which became more pronounced for increased time. This was attributed to an increased surface area caused by argon plasma etching. For discharge times greater than 10 min, contamination from sputtered PTEE in the chamber appeared to have a smoothing effect and led to a reduction of the measured surface area. Capacitance of the EDLCs cells with the activated carbon sheets after 1 min plasma surface treatment was increased by 2% compared to EDLCs cells with the original activated carbon sheet. The results have shown that the modification by plasma treatment of activated carbon sheets is a suitable technique for EDLCs used in high current applications.     

Enhanced exchange field of NiO/NiFe biyer by dual ion beam sputtering process control

Dual IBS (Ion Beam Sputtering) technique was used to fabricate NiO/NiFe bilayers. Various process conditions were examined to enhance the exchange field of the bilayer. Ion beam sputtering with an ion beam voltage above the threshold voltage and with the optimum ion beam current produced a fine-grained and smooth NiO film. This fine-grained surface followed by optimum etching exhibited an enhanced exchange field of 100 Oe. Growing NiO films were ion bombarded with a secondary ion-beam source having various beam voltages. The texture, surface roughness and grain size of the NiO films changed due to the ion bombardment; however, the grain size and/or surface roughness rather than texture was found to be responsible for controlling the exchange coupling. Furthermore, it was demonstrated that an optimum etching time of the NiO film prior to the depositing of NiFe for a large exchange field exists. With this optimum etching of the NiO film, surface segregated impurities could be eliminated without deteriorating the surface unnecessarily. Exchange fields and coercivities of the NiO/NiFe bilayers were measured with a MOKE (Magneto–Optic Kerr Effect) hysteresis looper and the surface properties of NiO films were examined with an AFM (Atomic Force Microscope) and an AES (Auger Electron Spectroscope).     

Surface modification of basic copper carbonate by mechanochemical processing with sulfur and ammonium sulfate

Mechanochemical phenomena including mechanical activation and direct reaction have been widely observed particularly from dry grinding operation and various applications of the phenomena have been reported in many fields of chemistry. A new approach was introduced here to trigger partial reaction by co-grinding samples with small addition of water/liquid to achieve the purpose of surface modification with new phase formed. As one example, basic copper carbonate was wet ground with elemental sulfur and appropriate additives such as ammonium sulfate to transform the surface chemical composition from oxide to sulfide. Physicochemical characterizations of the prepared samples were conducted by a set of analytical methods, including X-ray diffraction analysis, Fourier Transform infrared spectroscopy, Raman spectroscopic analysis, SEM morphology analysis, Zeta potential and the dissolved copper concentration measurement. The beneficiation efficiency of the modified copper carbonate by a conventional froth flotation used usually for sulfide minerals was examined as a quantitative evaluation to optimize the experimental conditions for the modification operation. A metal yield over 80% was obtained easily after one step concentrating of the flotation operation, indicating that mechanochemically surface controlling concept may serve as a novel pathway to enrich and recycle carbonate-style nonferrous resources by applying the traditional mineral processing technology on the modified samples.     

Low emittance ion beams by laser interaction

Laser ion sources offer the possibility to get ion beam utilizable to improve particle accelerators. Pulsed lasers at intensities of the order of 10⁸ W/cm² and of ns pulse duration interact with solid matter in vacuum to produce plasma of high temperature and density. The charge state distribution of the plasma generates high electric fields which accelerate ions along the normal to the target surface. The energy of emitted ions has a Maxwell Boltzmann distribution, which depends on the ion charge state. To increase the ion energy, a post-acceleration system can be employed by means of high voltage power supplies of about 100 kV. The post-acceleration system results in a good method to obtain high ion currents by an inexpensive system and the final ion beams find interesting applications in the field of the ion implantations, scientific applications and industrial use. In this work we compare the electromagnetic and geometric properties, like the emittance, of the beams delivered by a Cu and Y target. The characterization of the plasma was performed by a Faraday cup for the electromagnetic characteristics and a pepper pot system for the geometric ones. At 60 kV accelerating voltage and 5.5 mA output current the normalized beam emittance resulted in 0.22 π mm mrad for the Cu target, while under the same accelerating voltage but with 7.4 mA output current, a lower normalized beam emittance value was reached for the Y target. It resulted in 0.14 π mm mrad. The brightness of the beams was of 114 and 378 mA (π mm mrad)⁻² for the Cu and Y targets, respectively.     

Controllable fabrication of amorphous Si layer by energetic cluster ion bombardment

We report on the fabrication of an amorphous Si (a-Si) thin layer by means of bombardment of a Si(100) surface using monoenergetic C₆₀ cluster ions with energies from 50 keV to 400 keV. The C₆₀ cluster implantation produces nanogranules on the surface of a-Si layer detected by atomic force microscopy. The structural disorder and thickness of the modified layer were identified using Raman spectrometry, ion channelling, spectroscopic ellipsometry (SE) and transmission electron microscopy (TEM). According to SE and TEM data the thickness of a-Si layer gradually increases with cluster ion energy reaching to about 30 nm in the 200 keV C₆₀-bombarded Si sample. There is also thin layer of nanocrystalline Si found between the a-Si layer and pristine Si crystal. The obtained results represent an attractive method for creation of the a-Si layer as a functional material for opto- and nano-electronics. The study describes nanostructure created by cluster ion implantation as well as demonstrates the structural consequences of fast cluster energy dissipation in solids such as local heating and shock waves.     

Surface morphology analysis of natural single crystal diamond chips bombarded with Ar ion beam

We have studied the surface morphology of natural single crystal diamond chips machined by 0.5-3.0 keV Ar⁺ ion beam irradiation at ion incidence angles of 0°, 30°, 45°, 60°, and 80° with ion doses from 3.4 × 10¹⁸ ions/cm² to 6.8 × 10¹⁸ ions/cm². The surface of diamond chips machined with 0.5 and 1.0 keV Ar⁺ ion beam, at angles of ion incidence from 0° to 45° can be made smooth. Results show that the machined surface at ion dose of 6.8 × 10¹⁸ ions/cm² and beam energy of 0.5 and 1.0 keV become ultra-smooth (surface roughness SR = 0.1 nm rms) compared with unprocessed surface (SR = 0.15-2.1 nm rms). Results also confirm the ripple formation on diamond surface at ion incidence angles of 60°-80° by 0.5-3.0 keV Ar⁺ ion beam. Therefore, the technique of smoothing by choosing ion beam irradiation parameter can be applicable to nano-finishing of diamond tools without ripple formation. This technique can also be applicable in mass production if the diamond surface is mechanically pre-finished.