The adhesion strength of fluorine-containing rubber (a copolymer of CF2=CH2 and CF2=CF-CF3) to plasma treated aluminum was studied using X-ray photoelectron spectroscopy data and the water contact angle. Plasma treatments were as follows. (a) argon plasma treatment of aluminum at elevated temperatures in the presence of polytetrafluoroethylene (PTFE), sputtering PTFE onto the metal surface and (b) argon plasma treatments in the absence or in the presence of PTFE of plasma polymerized film (PPF) of cyclohexane previously formed on the aluminum surface. Adhesion was conducted by inserting rubber between two treated aluminum samples and adding compressive stress at high temperature. Adhesive strength was measured using Instron test equipment. Adhesive strength using treatment (a) was much greater than without treatment and slowly increased with increasing temperature, being due to the removal of carbon contaminants and the introduction of CF2 groups on the surface. Adhesive strength using treatment (b) increased several times compared to that without plasma treatments. The PPF surface after treatment (b) exhibited a hydrophihc nature, thought to play a significant role in adhesion.
Since needs for higher magnetic recording density have accelerated to prepare soft magnetic films with a higher saturation magnetic flux density, basic information on the magnetic properties of electrodeposited CoNiFe must be prepared, as must quenched CoNiFe ribbons. Electrodeposited CoNiFe films were prepared in a lower metal ion concentration permalloy bath, relatively independent of current density. When the NiSO4 concentration was fixed at 0.2mol dm-3 and the (CoSO4+FeSO4) concentration was varied, the Ni content was controlled. Co and Fe content were also controlled by changing the ratio of CoSO4 and FeSO4 concentration. The magnetic properties, coercivity, saturation magnetic flux density, and magnetostriction of ternary CoNiFe thin films were formed.
The purpose of this work is to confirm the proposition that the interaction between suspended particles and metal ions plays an important role in the composite coating of zinc and silica particles. To introduce functional groups onto the surface of silica particles, particles were pretreated with an amino silane coupling agent. The introduced amino groups are coordinated with zinc ions. Using potentiometric titration, the coordination reaction between zinc ions and amino groups on the particle surface was investigated. The relationship between zinc-silica codeposition behavior and the zinc-amino group interaction also investigated.
The codeposition mechanisms of silica particles with nickel from a Watts bath were investigated by analyzing the potentiometric titration curves and SEM photographs of the silica particles in codeposited films. Silica particles treated with a silane coupling agent was deposited with nickel from the Watts bath, while nickel ion forms the complex with the amino group on the particle surface, introduced by the above treatment. Silica particles could not be deposited without further treatment where no interaction was observed between the particles and nickel ion. The codeposition behavior is also discussed on the basis of the morphology of the deposited films.
A porous silicon layer (PSL) was prepared on single-crystal p-type Si (100) wafers with electrochemical etching in HF solutions at different current densities to explore the effect of current density on the PSL luminescence properties and microstructure. Luminesence was evaluated by measuring photoluminescence (PL) spectra. The microstructure was observed using FE-SEM, TEM, and CLSM. The surface composition was determined using FT-IR analysis. The PL intensity emitted by the PSL increased with increasing electrochemical etching current density. TEM images indicated that the PSL prepared on a Si specimen with a specific resistivity of 1kΩm consisted of dispersed ultrafine Si particles with a diameter of 2∼5nm. The structure of the PSL prepared on a Si specimen with a specifis resistivity of 0.1Ωm was coarse and columnar. The PSL microstructure (0.1Ωm) became fine and granular with increasing current density. FT-IR spectra showed that the surface SiHx concentration of PSL decreased with increasing current density. From these results, we concluded that the quantum confinement effect is operative on the visible luminescence from the PSL, and the surface compound consisting of SiHx forms surface states reducing the luminescence intensity. The electronic band models of the SiHx/PSL/p-Si substrate are proposed to explain the visible PL mechanism.
The effect of oxygen pressure during oxidation on the photo-anodic polarization behavior of TiO2 films formed by high-temperature oxidation was investigated in a Na2SO4 solution. Large photoanodic currents were observed for films formed by oxidation at low oxygen pressures. The donor concentration in films increased with the decrease in oxygen pressure during oxidation. This corresponded to the increase in the photoanodic current. The increase in photoanodic current with decreasing oxygen pressure during film formation was therefore explained by the photoanodic reaction model in which the reaction proceeded through the surface state corresponding to excessive titanium ions on the film surface.
Tantalum films were electrodeposited on the nickel substrate by a pulse potential in NaCl-KCl molten salt containing K2TaF7 at 1073K. The film morphology was investigated using SEM and film constituents using EPMA and X-ray diffraction analysis. Attention was focused particularly on the influence of the applied pulse potential on film morphology. Films consisted of an inner layer of metallic Ta and Ta-Ni intermetallic compounds and an outer layer of metallic Ta and tantalum oxide, and did not depend on the applied pulse potential. For film formed by polarization at pulse potentials of -11 and -0.6V, which generated a large cathodic and small anodic current, a thick, homogeneous inner layer was observed. Anodic polarization curves measured in a hot HNO3 solution showed that samples with deposition films became passive in the solution. For the sample with film formed at pulse potentials of -1.1 and -06V, spontaneous passivation behavior, in particular, was observed, the same as for pure tantalum.
In this paper, we attempt to explain the decohesion mechanism of Ti-C-N films by an approximate numerical analysis of the elastic-plastic stresses to which the material is subject in rolling contact. Compressive and tensile stresses were observed forward and backward in the rolling contact. The results were used to predict trends in film decohesion with the elastic properties of films deposited by ion plating on tool steel substrates. It is important to analyze the stresses at the interface between films and substrates in determing the practical use of Ti-C-N-coated steels.
Studies on the contact angle measurement of a liquid droplet, settled on a horizontal smooth surface of the substrate, using computer graphic image processing, are reported here. The contact angle is one of the technological measurements of adhesion wetting of liquid to solid surface, and many technical factors affect measurement. Therefore, it is important to control those factors for the sake of standardization of automatic measuring systems and its potentiality in future. In such a system, the drop shapes, affected by various measuring conditions, are classified and applied to image processing for automatic measurement.