Surface Of Metallic Materials Research Articles

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.

Multiscaling of lattice curvature on friction surfaces of metallic materials as a basis of their wear mechanism

A comprehensive structural study has been performed to explore deformation and wear debris formation on friction surfaces of metallic materials. A hierarchy of structural scales of plastic deformation and failure during wear has been established. The nanoscale plays the major role in the hierarchical self-organization of multiscale debris formation processes. On this scale, bifurcational interstitial states arise in zones of local lattice curvature, with plastic distortion and motion of nonequilibrium point defects which determine the nonlinear dynamics of structure formation and wear of surface layers. Nonequilibrium vacancies on lattice sites form microporosity through the coalescence mechanism under plastic distortion. The microporosity is a precursor of meso- and macroscale plastic shearing that defines wear debris formation.

Inverse estimation of the material parameters at metal surface irradiated by laser pulse

Based on nonlinear conjugate gradient theory, a new inversion algorithm is proposed to estimate the reflection and absorption coefficients for the surface of metallic materials irradiated by pulsed laser. Firstly, the basic principle of direct and inverse problems of laser heating is showed, and analytical expression of sensitivity coefficient is obtained due to the analytical solution of direct problem. Then, the sensitivity analysis is carried out, and the change of the relative sensitivity coefficient is investigated. The algorithm is verified by the specific example, and the best condition of the convergence is analyzed. Finally, the influence of the iterative initial values on the convergence of the iterative process and the variation characteristics of the inversion results in the iterative process are investigated with the special model. Research results can be used for analysis of material properties and selection of parameters in the field of laser processing, and also can provide an effective means for the evaluation of the effect of laser damage, it has important theoretical and practical significance.

Anodization of Ti-based materials for biomedical applications: A review

Commercially pure titanium (cpTi) and titanium alloys are the most commonly used metallic biomaterials. Biomedical requirements for the successful usage of metallic implant materials include their high mechanical strength, low elastic modulus, excellent biocompatibility and high corrosion resistance. It is evident that the response of a biomaterial implanted into the human body depends entirely on its biocompatibility and surface properties. Therefore, in order to improve the performance of biomaterials in biological systems modification of their surface is necessary. One of most commonly used method of implant materials surface modification is electrochemical anodization and this method is reviewed in the present work.Aim of the presented review article is to explain the electrochemical anodization process and the way in which the nanotubes are formed by anodization on the metallic material surface. Influence of anodizing parameters on the nanotubes characteristics, such as nanotube diameter, length and nanotubular layer thickness, are described, as well as the anodized nanotubes influence on the material surface properties, corrosion resistance and biocompatibility.

Fabrication of broadband antireflective black metal surfaces with ultra-light-trapping structures by picosecond laser texturing and chemical fluorination

A hybrid method consisting of ultrafast laser-assisted texturing and chemical fluorination treatment was applied for efficiently enhancing the surface broadband antireflection to fabricate black titanium alloy surface with ultra-light-trapping micro-nanostructure. Based on the theoretical analysis of surface antireflective principle of micro-nanostructures and fluoride film, the ultra-light-trapping micro-nanostructures have been processed using a picosecond pulsed ultrafast laser on titanium alloy surfaces. Then fluorination treatment has been performed by using fluoroalkyl silane solution. According to X-ray diffraction phase analysis of the surface compositions and measurement of the surface reflectance using spectrophotometer, the broadband antireflective properties of titanium alloy surface with micro-nano structural characteristics were investigated before and after fluorination treatment. The results show that the surface morphology of micro-nanostructures processed by picosecond laser has significant effects on the antireflection of light waves to reduce the surface reflectance, which can be further reduced using chemical fluorination treatment. The high antireflection of over 98 % in a broad spectral range from ultraviolet to infrared on the surface of metal material has been achieved for the surface structures, and the broadband antireflective black metal surfaces with an extremely low reflectance of ultra-light-trapping structures have been obtained in the wavelength range from ultraviolet–visible to near-infrared, middle-wave infrared. The average reflectance of microgroove groups structured surface reaches as low as 2.43 % over a broad wavelength range from 200 to 2600 nm. It indicates that the hybrid method comprising of picosecond laser texturing and chemical fluorination can effectively induce the broadband antireflective black metal surface. This method has a potential application for fabricating antireflective surface used to improve the photothermal or photoelectric conversion efficiency of solar installations and enhancing the surface wave-absorbing capacity of devices.