Surface Of Metallic Materials Research Articles

Reutilization of workpiece-reflected energy assisted laser machining of metallic materials with high laser reflectivity

The reutilization of workpiece-reflected energy assisted laser machining (REALM), combining nanosecond laser and the optimized optical system, was developed skillfully to modify the surface of metallic materials with high laser reflectivity. The characteristics of REALM were clarified via the theoretical analysis and the 6061 Aluminum machining test. It was observed that with respect to normal laser machining (NLM), the total energy utilization ratio and the processing efficiency for REALM could be significantly enhanced. Moreover, the nominal ablation threshold of aluminum for REALM could be decreased. These superiorities of REALM stem from its specific regime of reuse of the laser energy scattered and reflected, and thus the enhancement of the effective laser energy density and the effective utilization of absorbed energy.

Toward the characterisation of non-intentionally added substances migrating from polyester-polyurethane lacquers by comprehensive gas chromatography-mass spectrometry technologies

Polyester-polyurethane lacquer, used to cover the inner surface of metallic food contact materials, may transfer non-intentionally added substances (NIAS) to the food. The identification of such a diversity of compounds, considered as migrating substances, requires taking advantage of complementary analytical platforms. Therefore, four types of gas chromatography-mass spectrometry (GCMS) couplings were investigated and compared for their abilities to identify migrating substances after acetonitrile extraction of two commercialised lacquers. In parallel, various ionisation sources, i.e. electron ionisation (EI) (70 eV and soft energies) and atmospheric-pressure chemical ionisation (APCI) as well as various mass analysers, i.e. quadrupole, time-of-flight (low and high resolution) and Orbitrap, were tested. Comparison of mass spectra with a commercial library for EI ionisation source led to the identification of two NIAS compounds, isophorone diisocyanate and 4,4′-diphenylmethane diisocyanate. Additionally, many cyclic oligoesters (four monomer units) were unambiguously identified according to supplier’s declaration on starting materials used, primarily based on the molecular ion observed by APCI mode and characteristic fragment ions. High resolution mass analysers also enhanced confidence level in such NIAS identification. One- and two-dimensional GC were also investigated for separation assessment. Although GC × GC did not reveal additional NIAS, its use provided a valuable mapping of oligomers according to monomers composition. These results were compared to our previously published LC–MS study, carried out on the same lacquer samples. This study shows that LC and GC, along with their related ionisation techniques and their own selectivity, are complementary approaches, revealing different classes of compounds covering a wide range of volatility and polarity.

Identifikasi Penyebaran Zona Mineralisasi Endapan Timah Menggunakan Metode Induksi Polarisasi Konfigurasi Dipole - Dipole Di Bukit Sambunggiri Kecamatan Merawang Kabupaten Bangka

Tin is one of the many mining products found in the Bangka Belitung Islands region. Geophysical exploration was carried out in the Bukit Sambunggiri area, Merawang District, Bangka Regency using the dipole-dipole configuration polarization to detect polarizationel ectricity on surface of metal material and induction method to identify the distribution of tin deposit mineralization. The parameters is measuring area of ​​21 Ha with 6 tracks, length A, B, C is 640 meters, D, E, F is 840 meters, spacing between tracks 50 meters, spacing between electrodes 10 meters and equipment used is Multy Channel RS / IP Supersting. Processing measurement data using Res2dinv software to create 2D cross sections and Montaj Oasis for 3D cross sections. The results of resistivity and chargeability data processing of a total of six trajectories have 3 trajectories which have a clear mineralization area, that is, A trajectory is assumed to be at a distance of 250 - 350 meters and depths from 0 - 50 meters which are characterized by medium-high chargeability - 30) msec and low resistivity (<700) Ohm.m. On track D, it is estimated that there are three parts at a distance of 100 - 220 meters in depth of 50-50 meters, distance of 335 - 440 meters in depth of 50-130 meters and distance of 590 - 680 meters in depth of 50-130 meters. 430 meters at a depth of 0 - 150 meters. The results of interpretation of track A to track C are suspected to have zones of tin mineralization with secondary deposits and it is known that the mineralized zone is thought to be located below the bog iron zone with secondary tin deposits. This is due to the fact that the bog iron is hard rock like granite which is oxidized, so minerals that have a high level of resistance to weathering such as cassiterite and quartz will be released from the rock body and deposited in the lower layer. While path D to trajectory F is suspected to be the continuation of the zone of tin mineralization with primary deposits. This is presumably because the location of the mineralization area spreads between intrusion of granite rocks which have a high chargeability and resistivity value.

Influence of the variable magnetic field on the corrosive properties of amorphic alloys based on Fe in 0.5 M water solutions H2SO4

By chronopotentiometry and cyclic voltammetry methods it was investigated the corrosion resistance of the tape amorphous alloys Fe 78,5 Ni 1,0 Mo 0,5 B 6,0 Si 14,0 and Fe 73,1 Cu 1,0 Nb 3,0 Si 15,5 B 7,4 in an aqueous solution of0,5 M sulfuric acid. The samples alloyed with Cu and Nb showed more corrosion resistance in the aggressive medium of sulfuric acid. Modification of surface of the investigated amorphous samples by an alternating magnetic field leads to an increasing in their corrosion resistance in acidic medium. Surface oxidations in the presence of cuprous and niobium in Fe–Si–B alloy are two-stage processes. In addition of oxidizing Cu in Cu 2 O and sulfates, Nb adsorbs O 2 to form solid solutions of Nb 6 O, Nb 2 O. Oxides with higher oxidation levels (Nb 2 O 5 ) are covalent compounds with low electron conductivity and they can create a passivating superficial layer. In case of amorphous metallic alloys Fe 78,5 Ni 1,0 Mo 0,5 B 6,0 Si 14,0 and Fe 73,1 Cu 1,0 Nb 3,0 Si 15,5 B 7,4 , alternating magnetic field contributes to a significant exit on surface such elements as ferrum and boron (they form the Fe 3 B compound). In the surface layers of the Fe 73,1 Cu 1,0 Nb 3,0 Si 15,5 B 7,4 alloy modified by magnetization, an increase in at. % of Cu, and Nb is observed. Such elements form dense oxide surface protective layers. Weak alternating magnetic field significantly affects not only diffusion, but also the formation of phases in metallic alloys. Thus, alternating magnetic field has a strong influence on the diffusion processes in solid metallic materials, which causes them to homogenize the phases, change the component composition of the domains. These characteristics are directly related to the chemical activity of the surface of metallic materials; therefore, as main instrumental method for testing the effects of alternating magnetic field can be used electrochemical techniques: chronopotentiometry and voltammetry. Keywords : amorphous metallic alloys, corrosion resistance, sulfuric acid, alternating magnetic field.

Light absorption by surface nanoholes and nanobumps

This paper deals with a numerical investigation of the energy deposition induced by ultrafast laser interaction with nanostructures. We calculate and analyze the intensity near-field reactive and radiative patterns resulted from the interference of the incident light with light scattered by individual subwavelength holes and bumps on the surface of metallic and dielectric materials. The role of light polarization, optical material properties, collective effects and nature of the imperfections in localized energy absorption is elucidated. The results open new perspectives in precise light manipulation by surface inhomogeneities and well-controlled surface nanostructuring by ultrashort laser.

A method for overcoming thermo EMF of shunt connected meters for measuring electric energy

The thermoelectric potential mainly exists in the contact surface of different metal materials, from a few micro volts to dozens of micro volts, which is not easy to eliminate and the measurement is complex. It introduces large error to the calibration of the shunt connected electric energy meter. In this paper, the current reversing method is used to measure the positive and reverse power, and then the influence of the thermoelectric potential on the mV voltage of the shunt is eliminated by the software revision, so as to improve the precision of the detection of the shunt electric energy meter. The starting time is calculated by measuring the time of receiving a pulse in a positive and reverse direction to improve the accuracy of the starting test. At the same time, the low thermal potential is reduced by placing the shunt in the uniform temperature non conducting material. In the end, the improved electrical energy verification device is used for experimental testing to provide a higher precision technical means for tracing and detecting the source and detection of indirect access DC power meter.

Surface modification of AISI 1045 steel by pseudospark based pulsed electron beam

In this paper, the surface modification of AISI 1045 steel by a hollow cathode discharge (HCD) based pulsed electron beam and the formation of the surface microstructure via a short time duration of the pulsed beam treatment are the main focus under investigation. The electron beam in our work is generated by a compact HCD electron beam device named pseudospark discharge, which is characterized by the fast plasma ignition and quenching rates. And the surface microstructure, composition and microstructure crystallographic information of AISI 1045 steel pre and post pseudospark based pulsed electron beam modification are investigated by using metallographic microscope, scanning electron microscope (SEM), X ray diffraction (XRD) and Electron Back Scatter Diffraction Patterns (EBSD). The experimental results demonstrate that a microstructure consisting of cementite and C-supersaturated austenite is formed in the near-surface region after the pseudospark based pulsed electron beam irradiation. Both the phenomenon of the metal target grain refinement and the mechanism of the grain refinement evolution are investigated by a diversity of diagnostic methods. It is also showed that the material surface modification process is highly dependent on the transient properties of the HCD-based pulsed electron beams, which offers a new and effective method to improve the performances of the metallic material surface microstructure and other properties.

The Influence of Atmospheric Pressure Plasma Processing as Coating Pretreatment on Metal Material Surfaces

The Influence of Atmospheric Pressure Plasma Processing as Coating Pretreatment on Metal Material Surfaces

CORROSION PROTECTION AND CHACRACTERISTICS OF Ni-CeO2-CuO ELECTROPLATING LAYER ON STEEL SUBSTRATE

The particles of CeO2 and CuO are capable of catalyzing the oxidation reaction of carbon monoxide and hydrocarbons at low temperature, especially at nanometer size. They can be deposited on the metal material surface by using electroplating method. This paper reports some results on corrosion resistance, wear resistance, adhesion strength and catalytic behavior of Ni-CeO2-CuO composite by electroplating on steel substrate from nickel sulfate solution using CeO2 and CuO particles with 40÷60 nm size.

Beam polarization effect on the surface quality during steel cutting by a CO2 laser

The beam polarization effect on the quality of oxygen-assisted laser cutting of low-carbon steel by a CO2 laser is studied experimentally and theoretically. The cut surface roughness is examined as a function of cutting parameters in the case with linear polarization of the laser beam. It is demonstrated that the minimum roughness level is reached if the electric field vector is aligned perpendicular to the cutting velocity vector. The distribution of the absorbed laser power inside a narrow cut channel is computed numerically. It is concluded that the absorbed power distribution exerts a significant effect on the surface quality and it is important to provide radiative heating of the side walls to ensure lower-level roughness. Based on the results obtained, a possible explanation is proposed for the worse quality of the cut surface of metal materials by a fiber laser as compared to a CO2 laser.

Research on Formation Mechanism of Dynamic Response and Residual Stress of Sheet Metal Induced by Laser Shock Wave

In order to reveal the quantitative control of the residual stress on the surface of metal materials, the relevant theoretical and experimental studies were carried out to investigate the dynamic response of metal thin plates and the formation mechanism of residual stress induced by laser shock wave. In this paper, the latest research trends on the surface residual stress of laser shock processing technology were elaborated. The main progress of laser shock wave propagation mechanism and dynamic response, laser shock, and surface residual stress were discussed. It is pointed out that the multi-scale characterization of laser and material, surface residual stress and microstructure change is a new hotspot in laser shock strengthening technology.

Multiplex Binding of Amyloid-like Protein Nanofilm to Different Material Surfaces

The development of a reliable universal way to form strongly bonded coating with underlying substrate independent on material chemistry is ideal surface modification strategy and remains great challenge. Recently developed polydopamine and amyloid-based adhesion systems are two representative examples reported so far to fulfill this aim, and nonetheless the universal surface adhesion mechanism in these two cases is still unclear up to now. Herein the systematical studies on the adhesive strength of the amyloid-like coating on metal, organic and inorganic material surfaces reveal a novel multiplex bonding model on polar and non-polar abiotic surfaces, and different binding mode for respective material chemical structure including metal-sulfur coordination bonding, hydrogen bonding, electrostatic and hydrophobic interaction is elucidated with affirmative bonding strength. Our findings lend insight into amyloid adhesion mechanisms and reveal strategies for theory-driven design of engineered adhesives that harness great promise for advanced materials and devices.

Analysis of meso-inhomogeneous deformation on a metal material surface under low-cycle fatigue

A polycrystalline Voronoi aggregation with a free surface is applied as the representative volume element (RVE) of the nickel-based GH4169 superalloy. Considering the plastic deformation mechanism at the grain level and the Bauschinger effect, a crystal plasticity model reflecting the nonlinear kinematic hardening of crystal slipping system is applied. The microscopic inhomogeneous deformation during cyclic loading is calculated through numerical simulation of crystal plasticity. The deformation inhomogeneity on the free surface of the RVE under cyclic loading is described respectively by using the following parameters: standard deviation of the longitudinal strain in macro tensile direction, statistical average of first principal strains, and standard deviation of longitudinal displacement. The relationship between the fatigue cycle number and the evolution of inhomogeneous deformation of the material's free surface is investigated. This research finds that: (1) The inhomogeneous deformation of the material free surface is significantly higher than that of the RVE inside; (2) the increases of the characterization parameters of inhomogeneous deformation on the free surface with cycles reflect the local maximum deformation of the RVE growing during cyclic loading; (3) these parameters can be used as criteria to assess and predict the low-cycle fatigue life rationally.

Inspection possibilities of metallic material surface integrity by conventional ultrasonic technique

AbstractThe article is focused on the possibilities of ultrasound surfaces control on metallic materials by conventional ultrasonic techniques. Physical principles, types of ultrasonic waves to be used for surface control are described in the theoretical part. Three surface control techniques are listed in the experimental part of article. The first technique is a common control by angle ultrasonic probe with using transverse waves. The second technique is surface control by 30-70-70 creep waves and third techniques is surface testing by Rayleigh waves. Practical examples of ultrasonic testing for all techniques are illustrated. The conclusion of the article is devoted to the advantages and limitations of the individual testing methods.

Friction Reduction for a Rotational Gyroscope with Mechanical Support by Fabrication of a Biomimetic Superhydrophobic Surface on a Ball-Disk Shaped Rotor and the Application of a Water Film Bearing.

Friction between contacting surfaces of metal materials restricts the application of mechanical support in the high-precision inertial device of a rotational gyroscope. Instead, a disk- or ring-shaped rotor is electrostatically or magnetically suspended. However, stability of the rotor suspension restricts further improvement of the measurement precision. In the developed rotational gyroscope, a stable mechanical rotor supporting scheme with low friction is achieved by fabrication of a superhydrophobic surface with similar nanostructures of the lotus leaf on the carbon steel ball of the ball-disk-shaped rotor and the addition of a water film between the rotor ball and bronze hemispherical supporting bowl, which forms a water film bearing. The special design of the ball-disk-shaped rotor makes it possible for the application of a low-friction water bearing in the gyroscope, with rotor tilting motion. With a superhydrophobic surface, friction is further decreased and the rated spinning speed increases 12.4%, resulting in approximately the same proportion of increase in the scale factor. Moreover, superhydrophobic surface reduces mechanical damping torque for precessional motion to one order smaller than electrostatic feedback torque. Thus, through close-loop control, stable damping characteristics for precessional motion are obtained. The gyroscope exhibits excellent performance with the parameters of the measurement range, scale factor, nonlinearity, resolution, bias stability, and dynamic setting time tested to be −30°/s to 30°/s, −0.0985 V/(°/s), 0.43%, 0.1°/s, 0.5°/h, 0.1 s, respectively.

Microstructural and hardness gradients in Cu processed by high pressure surface rolling

The surface of an annealed Cu plate was processed by a high pressure surface rolling (HPSR) process. It is found that the deformed surface layer in the Cu plate after HPSR can be as thick as 2 mm and is characterized by a gradient microstructure, with grain sizes varying from the nanoscale in the topmost surface to the microscale in the bulk. The hardness varies from 1.37 GPa at the topmost surface to about 0.6 GPa in the coarse-grained matrix. The results of the investigation demonstrate that the HPSR process shows good potential for the generation of thick gradient microstructures on the surface of bulk metallic materials.

Electro-Chemical Behavior of Low Carbon Steel Under H2S Influence

A commercial low carbon steel material (P265GH) with application at industrial scale for natural gas delivery and transportation systems was analyzed in H2S atmosphere. The article proposed a new experimental cell in order to establish the behavior of the material in sulfur contaminated environment. In most of the industrial processes for gas purification the corrosion rate is speed up by the presence of S (sulfur) especially as ions or species like H2S. The H2S (hydrogen sulfide) is, beside a very toxic compound, a very active element in the acceleration of metallic materials deterioration especially in complex solicitations like pressure and temperature in the same time. For experiments we used a three electrodes cell with Na2SO4 + Na2S solution at pH 3 at room temperature (∼ 25 °C) to realize EIS (electrochemical impedance spectroscopy) and potentio-dynamic polarization experiments. Scanning electron microscopy and X-ray dispersive energy spectroscopy were used to characterize the metallic material surface exposed to experimental environment.

A portable embedded contactless system for the measurement of metallic material conductivity and lift-off

This paper describes the development, implementation and characterization of a portable embedded measurement system for the contactless estimation of a metallic material conductivity and of the lift-off between the system probe and the metallic material surface. The system consists on an absolute probe with compensation and is capable of measuring the in-phase and in-quadrature components of the probe output voltage using as a reference the probe stimulus voltage. The stimulus module includes a direct digital synthesizer (DDS) to set the measurement frequency, while the acquisition module includes analog voltage amplification and analog-to-digital conversion. A microcontroller is used to control the measurement, process the acquired voltage samples, estimate the desired parameters and perform USB communication. The final dimensions of the pen-like system, its capability of communication with a smartphone and its ability to power the system from the smartphone make it highly portable and especially suited for non-destructive testing (NDT) and field measurements.

Super-hydrophobic coating used in corrosion protection of metal material: review, discussion and prospects

The corrosion can be widely found in metal materials, which greatly restricts the utilization of metal. Super-hydrophobic coating, known as a material surface with a contact angle greater than 150°, which has been gradually used as a protect film on the surface of metallic material in recent studies. The article presents a review of recent literatures which covers aspects of using super-hydrophobic film as a smart protect surface to protect metallic materials. Different super-hydrophobic systems obtained by different preparation technologies were introduced in this work. Overall, the obtained results indicate that the super-hydrophobic coatings can effectively enhance the anti-corrosion ability of the metal surface, which supports the possibility of using super-hydrophobic film as a substitute of chromate-containing passivation coatings to protect metallic substrates.

In-situ study of structural evolution of tribological materials using synchrotron radiation

In this paper, we propose an approach for estimation of structural changes at the surface of metallic materials during running-in stage of friction. The application of synchrotron microbeam for in-situ observation of structural evolution in thin layers subjected to friction load is substantiated. A design of experimental apparatus intended for in-situ studies of friction processes using synchrotron radiation is described. This apparatus maintains constant position of the sample surface with respect to the incident beam. The ring shaped experimental sample with a thickness of 1 mm is pressed with constant pressure against a pin shaped indenter and rotated with constant speed. The pressure on the sample is determined by the mass of the load placed in the loading basket. The surface of the sample that comes out of indenter is probed by synchrotron beam. The proposed experimental scheme allows receiving X-ray diffraction patterns even under condition of severe plastic deformation of the surface. The preliminary results on the synchrotron assisted study of the dry friction of a Cu sample are described.