Characterization of hydroxyapatite film with mixed interface by Ar+ ion beam enhanced deposition

Ar+ ion beam enhanced deposition (IBED) was used to produce a hydroxyapatite (HA) film on polished titanium substrates. In this study, the HA ceramic target was sputtered by an argon-ion beam with an energy of 1.5 KeV, and the sputtered film was intermittently bombarded by energetic argon-ions at 60 KeV. An effective Ca-Ti mixed layer produced by the energetic argon-ion bombardment was confirmed by using Auger electron spectroscopy. The characteristics of the deposited films were evaluated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. XRD analysis revealed that the as-deposited film was amorphous, and a hydroxyapatite-type structure was obtained from the post-heat treatment of the deposited films. SEM observations showed that no distinct difference in surface morphology was found between the as-deposited and heat-treated samples for Ar+ IBED films, suggesting a strongly bonded HA film on the titanium substrate. In comparison with the HA target, some chemistry alterations were brought about in the deposited films, such as the incorporation of CO3, the loss of the OH groups and some distortion of the phosphate lattice.     

Hard amorphous silicon carbonitride coatings produced by plasma enhanced chemical vapour deposition

Hard amorphous silicon carbonitride coatings for wear resistance have been produced by d.c. plasma‐enhanced chemical vapour deposition on pure iron at 573 K. Compared with most plasma assisted processes work was conducted under a relatively high pressure of 130 Pa. The advantages of this technique are an amorphous film structure, high deposition rates (up to 2 μm/min), high hardness and simple equipment. Hexamethyldisilazan (HMDSN) was used as precursor and argon, hydrogen, nitrogen and ammonia as process gases. The dependence of the coatings on the process parameters (process gas and d.c. power) was investigated. The characterization of the samples was carried out mainly by Fourier transform infrared spectrometry (FTIR), electron probe microanalysis (EPMA) and hardness measurement. Samples show clearly the infrared spectra absorption bands characteristic of SiC and Si₃N₄, with traces of hydrogen bonding. The material structure shows a strong dependence on the process gas and the d.c. power. However, for argon and hydrogen were deposited carbon‐rich SiC films with low nitrogen content. Nitridic films with low carbon content were deposited using nitrogen and especially ammonia. The hardness of the produced coatings was about 10 ‐ 55 GPa.     

Optical characterization of tin oxide thin films synthesized by DC sputtering

Tin Oxide thin films have a large transmittance in the visible region of the electromagnetic spectrum, owing to the large bandgap, which varies from 3.6 eV to about 4.2 eV. In general, the films are transparent from a wavelength of 400nm to about 2000nm. The transparency decreases with increasing carrier concentration due to the larger absorbance by the electrons. The Tin Oxide films were deposited under a vacuum of 0.1 mbar on glass substrate by DC sputtering. The structural characterization was done using XRD spectral analysis which was followed by UV-VIS-NIR Spectroscopy. Optical properties of these films are investigated in the entire UV-Visible-IR region. The observed absorption edge lies at 3.8 eV for undoped tin oxide.     

Synthesis of gadolinium aluminate thin film by ion beam sputtering sequential deposition

Sequentially deposited by thin film synthesis consisted of multilayer precursor film deposition and thermal treatment. It is especially useful in complex-ingredient or precise stoichoimetric controlling thin film synthesis. Gadolinium aluminate, a new good candidate system for many luminescence usages other than laser crystals, scintillation crystals, phosphors, contains many phases, such as Gd₄Al₂O₉(GAM), GdAlO₃(GAP), Gd₃Al₅O₁₂(GAG), so precise stoichoimetry of the amorphous ingredient layers is very important to the final single phase film synthesis. In our work, Gd₂O₃ and Al amorphous layers (ingredients for gadolinium aluminate film) were deposited in a certain sequence on MgO (100) and Si (100) substrate by IM100 (an ion beam sputtering instrument). The multi-amorphous-layered precursor was annealed with two-step thermal treatment (diffusion at a low temperature and then crystallization at a high temperature). The XRD (X-ray diffraction pattern), SEM (scanning electron microscope second electron image) and AES (Auger electron spectroscopy depth profiles) analyses were used to detect the film microstructures and properties. The analyses results showed that ion beam sputtering deposition could control ingredient stoichoimetric ratio by an in site depositing thickness measurement. During the two-step thermal treatment, diffusion at a low temperature would cost a rather long time to make the amorphous precursor film uniform (more than 120 h), and the suitable diffusion temperature should be around 400 °C. The crystallization temperature should be decided by the gadolinium aluminate phase types and cost rather less time (about 4 h). The stable phases GAP and GAM should be annealed at 1300 °C or higher temperatures, but the metastable phase GAG should just be annealed at around 1100 °C.     

Synthesis of gadolinium aluminate thin film by ion beam sputtering sequential deposition

Sequentially deposited by thin film synthesis consisted of multilayer precursor film deposition and thermal treatment. It is especially useful in complex-ingredient or precise stoichoimetric controlling thin film synthesis. Gadolinium aluminate,a new good candidate system for many luminescence usages other than laser crystals,scintillation crystals,phosphors,contains many phases,such as Gd4Al2O9(GAM) ,GdAlO3(GAP) ,Gd3Al5O12(GAG) ,so precise stoichoimetry of the amorphous ingredient layers is very important to the final single phase film synthesis. In our work,Gd2O3 and Al amorphous layers(ingredients for gadolinium aluminate film) were deposited in a certain sequence on MgO(100) and Si(100) substrate by IM100(an ion beam sputtering instrument) . The multi-amorphous-layered precursor was annealed with two-step thermal treatment(diffusion at a low temperature and then crystallization at a high temperature) . The XRD(X-ray diffraction pattern) ,SEM(scanning electron microscope second electron image) and AES(Auger electron spectroscopy depth profiles) analyses were used to detect the film microstructures and properties. The analyses results showed that ion beam sputtering deposition could control ingredient stoichoimetric ratio by an in site depositing thickness measurement. During the two-step thermal treatment,diffusion at a low temperature would cost a rather long time to make the amorphous precursor film uniform(more than 120 h) ,and the suitable diffusion temperature should be around 400 oC. The crystallization temperature should be decided by the gadolinium aluminate phase types and cost rather less time(about 4 h) . The stable phases GAP and GAM should be annealed at 1300 oC or higher temperatures,but the metastable phase GAG should just be annealed at around 1100 °C.     

An analytical model for the oxide size in Al alloys synthesized by reactive atomization and deposition

This article presents the formulation of an analytical model to predict the size scale of oxide dispersoids in as-deposited Al alloys synthesized by reactive atomization and deposition (RAD). The proposed model formulation is primarily based on the assumption that all of the strain energy in the oxides is used to create interfaces between the oxide dispersoids and the matrix. It is also assumed that oxides are fragmented into plate-shaped dispersoids. Assuming three types of cross-sectional geometries for the oxide plates, i.e., circular (corresponding to disc-shaped oxide dispersoids), rectangular, and equilateral polygon, the following predictions are made on the basis of the analytical model. First, the curves for calculated effective cross-sectional diameters of plate-shaped oxide dispersoids vs droplet size and calculated effective volumetric diameter of plate-shaped oxide dispersoids vs droplet size can be divided into three distinct regions. These three regions are identified on the basis of two characteristic droplet sizes corresponding to the solid fraction equal to that on the deposited material’s surface ( ) and to solid fraction of 0.6 (D _0.6), respectively, at impact. Second, the velocity of individual droplets at impact has a limited effect on the calculated effective cross-sectional diameter and effective volumetric diameter. With an increase in solid fraction on the deposited material’s surface, the calculated effective cross-sectional diameter and effective volumetric diameter decrease significantly when droplet sizes are smaller than , whereas they remain almost unchanged when droplet sizes are higher than D _0.6. Third, when plate-shaped oxide dispersoids with rectangular or equilateral polygon cross-sectional geometries are chosen, the calculated effective cross-sectional diameter and effective volumetric diameter are larger than the corresponding calculated diameter and effective volumetric diameter of disc-shaped oxide dispersoids. The calculated effective cross-sectional diameters, based on different cross-sectional geometries (e.g., circular, rectangular with up to 10 of the length/width ratio, and equilateral polygon), are all in reasonable agreement with the experimentally observed effective cross-sectional diameter of oxides.     

质量分离的双离子束沉积法生长CeO2(111)/Si薄膜

利用一种全新的薄膜生长技术-质量分离的双离子束沉积技术,在较低温度(400℃)下对CeO2(111)/Si(100)薄膜的生长进行了研究.两束离子的比例以及离子束的能量对薄膜的成分和晶体质量有很大影响,较高能量(300eV)的离子束对薄膜有轰击作用,并有助于薄膜的择优取向生长.在400℃时,制备了CeO2(111)/Si(100)单晶薄膜.     

Preliminary evaluation of an SF5+ polyatomic primary ion beam for analysis of organic thin films by secondary ion mass spectrometry

Organic vapor deposited thin films of pure biomolecules, polymer films and biomolecules dispersed in gelatin and biological tissue have been analyzed in a magnetic sector secondary ion mass spectrometer using an SF5+ primary ion beam at keV impact energies. In comparison to Ar+ bombardment under identical conditions, bombardment with SF5+ gives a 10 to 50 fold enhancement in the secondary ion yields for characteristic molecular ions. The SF5+ primary ion beam can be focussed to a small spot allowing molecular ion images to be obtained at micrometer spatial resolution with enhanced sensitivity. More importantly, the decay in molecular ion signal as a function of primary ion dose commonly observed in SIMS using monoatomic primary ions is either eliminated or greatly reduced, allowing molecular depth profiles to be obtained of organic thin films. By continuing to sample intact molecules as sputtering proceeds into the sample, the total number of detected characteristic secondary ions is increased by as much as a factor of approximately 700 for SF5+ bombardment as compared to Ar+ bombardment under identical analytical conditions. This effect is thought to be a result of the high erosion rate and the low penetration depth inherent in the use of a polyatomic primary projectile.     

Tonoko pneumoconiosis with deposition of titanium

A 56-year-old man had worked as a furniture painter and had been exposed to tonoko polishing powder for 30 years. He had complained of dyspnea on exertion for 7 years, and was admitted to our hospital in 1991. A chest X-ray film revealed large opacities and emphysematous changes in both lung fields. Tonoko pneumoconiosis was diagnosed after transbronchial lung biopsy. Home oxygen therapy was given because of progressive hypoxemia, but the patient died of respiratory failure. At autopsy, examination of the lungs showed severe emphysematous changes, and collapse of alveoli. Many gray masses resembling coating cement were seen especially in the upper lobes. Microscopical examination showed that the large opacities were composed of hyaline nodules, similar to silicotic nodules, with anthracosis. Scanning electron microscopy with X-ray microanalysis revealed a high concentration of titanium in the gray mass. A low dose of titanium would not be expected to induce fibrotic changes in the lung, but a high dose and long-term exposure might have that effect. Titanium contained in paint might have exacerbated tonoko pneumoconiosis in this patient.     

Microstructure of amorphous electrodeposited Co-Ni-W films

The phase composition of electrodeposited films of (Co_{100 ? x} -Ni _x )_{100 ? y} W _y alloys (x = 0–100 at % Ni, y = 0–30 at % W), the microstructures of amorphous films of this system on the submicrometer and nanometer scales, and the mechanism of their nucleation and growth are studied. X-ray diffraction analysis demonstrates that, as the tungsten concentration increases, the transition from a crystalline into an amorphous state in the films based on Co-W alloys occurs through a supersaturated hcp solid solution, whereas this transition in the films based on Ni-W alloys occurs through an fcc structure. Heterophase states consisting of a mixture of hcp and fcc structures are observed in the composition range x = 30–80 at % Ni, and, at concentrations higher than 12–14 at % W, an amorphous phase is also observed. A homogeneous amorphous phase forms at a refractory-metal content of 19–20 at % or more. Transmission and scanning electron microscopies show that the amorphous Co-W, Ni-W, and Co-Ni-W films have a network structure. The laws of the variation of the network microstructure with the chemical composition of the amorphous films are established and explained in the framework of the island model of thin film nucleation and growth.