Brass Foil Research Articles

The Analysis of Cymbal Transducer's Frequency Characteristics Based on 1–3 Piezocomposite

The frequency characteristic of Cymbal transducer based on 1–3 piezocomposite was analyzed with finite element analysis method in this paper. 1–3 piezocomposite was used as piezoelectric phase instead of piezoelectric ceramic and the brass foil was used as end cap. The mathematic model of this new type of piezocomposite transducer was established. Using ANSYS software, investigated the resonance frequency and the first, the second and the third order vibration models of this new piezocomposite structure. Fabricated the sample of Cymbal transducer based on 1–3 piezocomposite. Tested the first, the second and the third order of resonance frequencies of the transducer. The result showed that the theoretical value based on ANSYS is well agreement with the test result.

Growth of ZnO nanostructure on Cu 0.62Zn 0.38 brass foils by thermal oxidation

Cu 0.62Zn 0.38 brass foil was heated at temperatures of 400–700 °C in flowing N 2–5%O 2 at a pressure of 1 atm. for 1–24 h. The oxidized specimens were characterized with a scanning electron microscope, an X-ray diffractometer and a transmission electron microscope. The results show that hexagon ZnO nanowires and nanowalls grew on convoluted oxide scales when brass foils were oxidized at 500 and 600 °C. Thermodynamics of forming ZnO is analyzed based on oxidation theory of an alloy. Pilling–Bedworth ratio of Cu–Zn alloy is calculated based on the volume differences between the formed oxide and the consumed metal. The growth stresses caused by Pilling–Bedworth ratio of the alloy and stress relief of oxide scale at different oxidation temperature are analyzed. The mechanism of forming nanostructural ZnO on the convoluted oxide scales is explained by the change in the growth stresses and stress relief of oxide scale during thermal oxidation.

Vectors and submicron precision: redundancy and 3D stacking in silicon pixel detectors

Measurements are shown of GeV pions and muons in two 300μm thick, Si Medipix pixel detector assemblies that are stacked on top of each other, with a 25μm thick brass foil in between. In such a radiation imaging semiconductor matrix with a large number of pixels along the particle trail, one can determine local space vectors for the particle trajectory instead of points. This improves pattern recognition and track reconstruction, especially in a crowded environment. Stacking of sensor planes is essential for resolving directional ambiguities. Signal charge sharing can be employed for measuring positions with submicron precision. In the measurements one notices accompanying 'delta' electrons that emerge outside the particle trail, far beyond the boundaries of the 55μm pixel cells. The frequency of such corrupted position measurements is ∼ one per 2.5mm of traversed Si.

Pressure generated by the electric explosion of metal foils

We have measured the pressure generated by the electric explosion of various metal (Cu, Al, Fe, Ta, Ti, Pb, W, and brass) foils. The pressure amplitude as a function of the specific energy supplied to the exploding foil is well approximated by a linear dependence.

Deactivation of a Zn/TiO2 catalyst in the course of methanol steam reforming in a microchannel reactor

The service life tests of a Zn/TiO2 catalyst deposited on the microchannel plates of copper foam, nickel foam, and corrugated brass foil in the process of methanol steam reforming demonstrated that the catalyst stability and operation time depend on microchannel plate material. The rate of catalyst deactivation correlated with the thermal conductivity of the microchannel plate material. It was found that catalyst deactivation resulted from the decomposition of zinc titanates, which are active components, and it was accompanied by the appearance of a zinc oxide phase. The best results in the service life tests were obtained with the microchannel plates of copper foam. A microchannel reactor containing 16 copper plates continuously operated at 400°C for 150 h; in this case, the conversion of methanol decreased by 8%. The subsequent microreactor operation for 500 h caused a decrease in the methanol conversion by 26%. It was found that the loss of the catalyst activity was a reversible process, and the activity can be restored by annealing in air.

Efficiency of Zn/TiO2 catalyst operation in a microchannel reactor in methanol steam reforming

The activity of a Zn/TiO2 catalyst deposited on metal microchannel plates in methanol steam reforming was studied. The catalyst exhibited maximum activity upon deposition on microchannel plates made of copper foam. In this case, the specific hydrogen production of a microreactor at 450°C was 78.6 l (g Cat)−1 h−1. The catalysts deposited on a microchannel plate of nickel foam and on corrugated brass foil exhibited lower activity because of the lower efficiency of heat transfer to the reaction zone. A correlation between the thermal conductivity of the microchannel plate material and the activity of the catalyst was observed in the following order: copper, brass, and nickel. The kinetic parameters of the process of methanol steam reforming in a microreactor were calculated with the use of a plug-flow reactor model. In this case, the calculated formal activation energy of 132 kJ/mol was independent of the microchannel plate material. A comparison of the equilibrium concentrations of reaction products at the reactor outlet, which were calculated from thermodynamic data, with the experimental data demonstrated that methanol steam reforming at a temperature higher than 400°C occurred in the nonequilibrium region. The concentration of carbon monoxide at the microreactor outlet was lower than 1 mol %, which is lower than the equilibrium concentration by one order of magnitude. This effect was attributed to the suppression of the reversed water gas shift reaction on the catalyst.

THE ANALYSIS OF CYMBAL TRANSDUCER'S EFFECTIVE PIEZOELECTRIC COEFFICIENTS BASED ON ANSYS

ABSTRACT The cymbal transducer is a type of metal-ceramic piezocomposite transducer which developed in recent years. The effective piezoelectric coefficient (d 33 e ) of cymbal transducer is much higher than that of conventional piezoelectric ceramic. In this work the cymbal transducer working mechanism was researched and the finite element analysis model on this transducer was established using ANSYS which is a kind of software about finite element analysis. Piezoelectric ceramic PZT-5A was used as piezoelectric phase and brass foil was used as end cap electrode of cymbal transducer. It was analyzed for the relationship between the longitudinal displacement of cymbal and the force applied on the brass foil. The effective piezoelectric coefficient, d 33 e , was calculated. The calculated results were compared with the experimental results.

An Optical Method for the Detection of In-Plane Motion of Acoustic Waves Propagating in Solids

A new interference-based optical technique called in-plane displacement interferometer (IPDI) is introduced for the detection of in-plane (IP) motion of ultrasonic waves. The IPDI employs a tiny square indentation of about 30 microns in width on the sample surface and a relatively simple optical arrangement for the detection of IP motion of ultrasonics waves. With the IPDI, measurement of IP motions of Lamb waves propagating along a thin brass foil is demonstrated. Dispersion relations for the S0 mode dominated by in-plane motion in the low fd (frequency times thickness) regime is obtained with the IPDI.

Cymbal piezoelectric composite underwater acoustic transducer

The working principle of Cymbal piezoelectric composite underwater acoustic transducer was studied in this paper. PZT-5A piezoelectric ceramic disk was used as piezoelectric phase and brass foil was used as end cap electrode of the Cymbal transducer. The silicon rubber was used as the insulated proof layer of the underwater acoustic transducer. The properties of this transducer used as hydrophone, such as operation frequency, free-field voltage receiving sensitivity and directivity, were investigated. Several kinds of prototype of this transducer were fabricated and the properties of this transducer used as hydrophone were tested. The results show that the properties of this transducer used as hydrophone depend on the dimensions of Cymbal transducer because the piezoelectric properties of this transducer are dependent on the dimensions of Cymbal transducer’s end caps. The appropriate dimensions for getting higher free-field voltage receiving sensitivity with −184.7 dB were obtained.

Diagnosis of Laser-Induced Shock Waves in Brass Foil Using a Fiber-Optic Interferometer

A fiber-optic interferometer is developed to investigate shock waves in brass foil impacted by a Neodymium:Yttrium–Aluminium–Garnet (Nd:YAG) laser at a wavelength of 1064 nm and pulse width (FWHM) of 7 ns. Because of introduction of an optical transceiver module, the interferometer is compact and reliable. Appreciable signals due to shock waves have been detected using this interferometer. The shock-wave velocity is deduced from the measured arrival times of shock waves in brass foils with different thicknesses (0.200 and 0.300 mm), and is found to be 8.33 km/s.

Research on Electromechanical Properties of Cymbal Piezocomposite Transducer

The electromechanical properties of cymbal piezocomposite transducer were investigated in this paper. Piezoelectric ceramic PZT—5A was used as piezoelectric phase of transducer, and brass foil was used as end cap electrode of cymbal piezocomposite transducer. Several types of this transducer were fabricated. The displacements of this transducer as functions of the applied force and the applied electric field were investigated. It was calculated and analyzed for the energy transmission coefficient and electromechanical coupling coefficient of this transducer which optimum values were obtained.

Electrochemical investigation of the oxides formed at the surface of brass (Cu–10Zn) by a humid-air plasma treatment

Linear potential sweep voltammetry was used to characterize the metal oxides formed at the surface of brass (Cu–10Zn) foils exposed to a gliding-arc-humid-air plasma. This study confirmed the formation of copper and zinc oxides (i.e. Cu 2O, CuO, and ZnO). The electrochemical reduction curves in aqueous solutions of the different brass samples showed that copper and zinc oxides were characterized by their cathodic peaks. The reduction potentials of the oxides varied with the exposure time to the plasma at fixed working conditions. The analysis of the voltammetry curves showed that the initial oxide layer was formed in majority by the precursor oxide Cu x O ( x>4) and Cu 2O. The oxidation of Cu(I) oxide (Cu x O and Cu 2O) lead to the formation of CuO. When the CuO layer was extensively grown, the ZnO oxide began to grow. A mechanism was proposed for the reduction of thin films containing Cu 2O, CuO and ZnO oxides formed at the surface of the sample.

Plasma and wet oxidation of (63Cu37Zn) brass

A twin study of the oxidation mechanism of (63Cu37Zn) brass foil in oxygen plasma and in alkaline aqueous solution is reported. Brass foil was exposed to low-pressure rf oxygen plasma in given working conditions and the resulting surface was studied by means of linear sweep voltammetry. The plasma oxidation mechanism involves oxygen radicals, and results from their strong oxidising character. The precursor oxide Cu x O, Cu 2O and CuO were identified in the passive layer, in addition to ZnO. Most of these oxides also form as corrosion products when brass samples are oxidised in alkaline solution. The corrosive process involves oxygen depolarisation, which develops on a 63Cu37Zn brass rotating disc electrode. Complementary investigation performed for neutral 0.5 M NaCl solution results in voltammograms which evidence a four-electron reduction mechanism.

Stress corrosion cracking relation with dezincification layer-induced stress

Brass foil with a protective layer formed on one side was deflected during corrosion in an ammonia solution under various applied potentials, and then corrosion-induced stress generated at brass/dezincification layer under different potentials could be measured. At the same time, susceptibility to stress corrosion cracking (SCC) of brass in the ammonia solution under various applied potentials was measured by using a single-edge notched specimen. At open-circuit potential, both corrosion-induced tensile stress and susceptibility to SCC (Iσ) had a maximum value. Both tensile stress σp and susceptibility Iσ decreased slightly with decreasing potential under anodic polarization, but reduced steeply with a decrease in potential under cathodic polarization. At the cathodic potential of − 500 mVSCE, corrosioninduced stress became compressive because of the copper-plating layer; correspondingly, susceptibility to SCC was zero. Therefore, the variation of SCC susceptibility with potential is consistent with that of the corrosion-induced additive stress.

Dielectric properties of lead zirconate titanate thin films deposited on metal foils

Ferroelectric lead zirconate titanate (PZT) thin films deposited on metal foil substrates are suitable for developing a wide range of applications. In this letter, we report on PZT films deposited on a variety of foils, including titanium, stainless steel, brass, and nickel alloys, using sol–gel processing. The dielectric properties were shown to depend strongly on the foil material. Excellent properties for capacitors, including high dielectric constant (ε=400), low dielectric loss (loss tangent of <5%), and low leakage current (below 5×10−8 A at 5 V) were obtained on titanium and good results were also obtained on other foils, such as stainless steel and brass foils. Also, excellent high-frequency properties were observed for capacitors on titanium, stainless steel, and brass foils.

A thermal-elastic analysis on laser-induced reverse bulging and plugging in circular brass foil

A new failure mode is observed in circular brass foils induced by laser beam. The new failure is based on the following experimental facts : (1) the peripheries of the circular brass foils are fixed and the surfaces of the foils are radiated by laser beam ; (2) the laser beam used is considered to be non-Gaussian spatially, actually an approximately uniform distribution limited in a certain size spot ; (3) the pulse on time of laser beam should be 250 μs, i.e. so called long duration pulse laser. The failure process consists of three stages ; i.e. thermal bulging, localized shear deformation and perforation by plugging. The word reverse in reverse bulging and plugging mode means that bulging and plugging occur in the direction of incident laser beam. To study the newly-discovered type of failure quantitatively, analytical solutions for the axisymmetric temperature field and deflection curve are derived. The calculated results show that the newly discovered failure mode is attributed to the spatial structure effect of laser beam indeed.

Determination of tensile stress induced by dezincification layer during corrosion for brass

The brass foil with a protective layer formed on one side was deflected during original corrosion in 1 mol⧹L NH 4OH+5 g⧹LCuCl 2 solution. This was due to corrosion-induced tensile stress developed in the dezincification layer of the sample. The additive tensile stress grew gradually, and reached a steady value of about 24.4 MPa, i.e., 20% of the yield stress of brass.

Plasma elaboration of barrier layers: a study of the oxides formed at the surface of brass (90Cu10Zn) by RF electric discharges in oxygen

The metal oxides formed at the surface of brass (90Cu10Zn) foils exposed to a low-pressure inductively coupled oxygen plasma were identified by linear sweep voltammetry and X-ray diffraction spectroscopy. The plasma treatment confirms the formation of copper and zinc oxides (i.e., Cu 2O, CuO, and ZnO). The electrochemical reduction curves in aqueous solutions of the different brass samples show that ZnO oxide is reduced after all the copper oxides. The reduction potentials of copper and zinc oxides vary with the thickness of the oxide layer and decrease as the exposure time to the plasma at a fixed energy density increases. A mechanism is proposed for the reduction of thin films containing the Cu 2O, CuO, and ZnO oxides formed at the surface of the samples.

Conception of an experimental device for measuring the in-plane shear modulus of film materials

A freely oscillating torsional pendulum was designed and built for measuring the in-plane shear modulus of film materials. To make the work easier for the experimenter, an online computer application was also developed with the help of numeric tools (Fourier and Hillbert transforms) for data acquisition and processing. The experimental part was performed on various materials. Experiments on a brass foil (isotropic material) validated measurements achieved with this experimental device. Experiments on orthotropic materials (base papers with different basis weights) gave prominence to the good reproducibility of measurements and to the ability for using this torsional pendulum. For this kind of material (large basis weight base paper), the in-plane shear modulus seemed independent of the fiber orientation.

Rubber-brass bonding: morphology of cross-sections through the bonding layers as a possible basis for classification

The extensive literature on rubber-brass bonding provides a rather complex picture of the architecture of the bonding layers. In the present work, the morphology of cross-sections through the bonding layers perpendicular to the brass surface, seen in transmission electron microscopy (TEM), is used as a means of bonding layer classification. Previous experimental results with a simplified cure mixture (consisting of 1,4-polybutadiene, elemental sulfur, N,N-dicyclohexyl-2-benzothiazylsulfenamide, and, in some cases, zinc oxide) and brass foils are reconsidered. In nearly all cases, what we term a central layer is found. It consists of two sublayers with a different content of copper sulfides. Varying deposits of sulfides exist at the brass surface and also above the central layer in the direction of the rubber bulk. The various types of bonding layer with a different type of architecture are discussed in connection with previous results obtained by analytical electron microscopy (AEM) and bonding strength measurements.