As a nontraditional processing technology, electrochemical discharge machining (ECDM) can process glass and engineering ceramics precisely. This technology has proven to be a potential process for ...glass 3D microstructure. However, the key to expanding the application of ECDM is how to improve machining accuracy. This research conducted micro-hole and microgroove machining. Power voltage and frequency influence on hole processing efficiency, hole entrance diameter, and hole limit depth was explored. We considered four factors affecting ECDM—the voltage and frequency of the pulse power supply, the tool electrode feed rate, and the rotation speed. We studied their influence on the roughness of the microgrooves. The results show that machining efficiency, entrance diameter, and limit depth of micro-holes increased with the increase in voltage but decreased with the increase in power frequency. The results show that the roughness of microgrooves has an apparent positive correlation with the power voltage. In contrast, it had an evident negative correlation with the power frequency and electrode speed. The bottom surface roughness of microgrooves can be as minor as 0.605 μm. Various complex 3D microstructures on the glass surface by layer-by-layer method proved the great potential of ECDM.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Amorphous Ni–P coating generates great internal stress in the process of electrodeposition due to hydrogen evolution and internal chaotic structure, thus forming surface micro-cracks and decreasing ...the corrosion resistance. In this study, the amorphous Ni–P coating with three-dimensional (3D) morphology was electrodeposited using a solution containing the crystal modifier induced by laser irradiation. The results show that with increasing temperature and electrochemical deposition (ECD) time, the impact of the crystal modifier on the surface morphology became more significant. The roughness (Rz) value of the coating prepared by ECD (ECDed, 10 min) was 0.76 μm, whereas that of the coating prepared by laser-assisted ECD (LECD) (LECDed, 20 μJ, 10 min) was 2.97 μm. Meanwhile, the coating immediately exhibited hydrophobic properties, and the contact angle (CA, water) reached 112° ± 2°. After electrochemical corrosion, the surface was still hydrophobic, and the CA was 113° ± 2° when the laser single pulse energy was 20 μJ. The results of Tafel analysis and electrochemical impedance spectroscopy indicated that hydrophobic surfaces with a 3D microstructure have better corrosion resistance. This is because that the 3D surface morphology replaces the cracks to improve corrosion mode.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this paper, a method of laser enhanced electrodeposition is used for preparation of Fe-Ni alloy, which exhibits a significant advantage in fabrication of alloys. The effect of laser energy on ...Fe-Ni alloy electrodeposition by the manner of reciprocating scanning is studied. Results show that laser irradiation can improve the surface morphology, micro-structure and mechanical properties of Fe-Ni alloy. The results are useful for the development of a new method to synthesize Fe-Ni alloy with better properties.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Intense interest has been given to the fabrication of micro-through-holes with smaller tapering and higher aspect ratios in engineering ceramics due to their wide range of applications in MEMS and ...aerospace. A semi-water-immersed laser micro-trepanning (SWILT) scheme is proposed and investigated in this paper with alumina ceramics as the target material, and its performance is assessed and compared with the direct laser trepanning method. Relevant processing parameters influencing the trepanning process are explored through an orthogonally designed experiment, and their effects on hole profiles are adequately discussed to yield optimized parameters. It is revealed that SWILT is capable of producing micro-through-holes with minimized hole tapering and much straighter sidewalls compared with the direct trepanning results, whereas the ablated surface quality is relatively rougher. The micro-through-hole formation mechanisms are also amply analyzed, where the transition hole development may be purely attributed to the laser-material interaction in the direct laser trepanning condition, while the SWILT case features an enhanced material-removal rate, especially at the lower part of the through-hole. The latter is due to the strengthened mechanical effects coming from the water-confined plasma zone and the following cavitation bubble collapse, which may efficiently expel the molten material from sidewalls and result in significantly reduced hole tapering.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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•Laser irradiation improves grain size and degree of amorphous.•Laser irradiation removes the bubbles and improves the surface quality.•The laser energy offsets part of the residual ...tensile stress.•Laser irradiation improves the hardness, corrosion and wear resistance.
The formation of electrodeposited amorphous Ni-P alloy requires numerous tiny crystal nuclei and disorderly arranged atoms. In this paper, laser irradiation is introduced into the electrodeposition process by a cyclic reciprocating scanning manner. The laser thermal effect not only enhances the formation of amorphous Ni-P alloy with smaller nucleus and better density, but also accelerates the reduction of ions and hence hydrogen evolution at the cathode. The transient high-temperature zone occurs under laser irradiation, leading to micro-area agitation formation, so that the gas deposited in the cathode can be eliminated in time, and the pore defects generated in the deposited layer can be reduced. In addition, part of the heat generated by laser irradiation is absorbed by the reducing ions and deposited on the substrate in the form of compressive stress, which may reduce the overall residual tensile stress of the coating. Amorphous Ni-P alloy heat treatment will increase the hardness but decrease the corrosion resistance. However, the results show that laser irradiation can improve the corrosion and wear resistance of the coating simultaneously.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Laser breakdown in solution caused micro-area agitation and current rising.•Laser irradiation effectively reduced the particle aggregation.•The increasing laser energy led to smoother coating with ...fewer defects.•Higher hardness and better corrosion resistance were obtained because of laser.
This study introduces laser irradiation into the electrodeposition of Cu-Al2O3 composite coatings. The cavitation bubble generated by laser breakdown in the solution caused strong shockwaves and micro-area agitation that reduced the agglomeration of Al2O3 particles. The shockwave signal was then detected using a hydrophone. Laser irradiation also increased the electrodeposition current due to agitation and temperature rising. The samples prepared by laser assisted electrodeposition with different laser energies were studied. The surface and cross-section morphology were observed using scanning electron microscopy and the content of Al2O3 nanoparticles was measured using X-ray fluorescence spectroscopy. Moreover, the microhardness and corrosion resistance were also studied. The results showed a composite coating with a smoother surface and fewer defects compared to samples prepared by traditional electrodeposition. The content of Al2O3 nanoparticles was increased owning to laser irradiation. Finally, the increase in laser energy, enhanced the microhardness and corrosion resistance of the composite coating.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Electrodeposited amorphous Ni-P alloys have enormous internal stress and high brittleness, resulting in cracks and poor wear resistance. In this study, the surface cracks of an amorphous Ni-P ...coating, prepared by laser-assisted electrodeposition were removed by laser remelting. The surface quality was characterized and the wear mechanism was analyzed by evaluating its microhardness and wear resistance. The results showed that the remelted layer had a corrugated structure, and the surface roughness increased. The remelted layer is transformed from amorphous to crystalline, consisting of stable phases of Ni, and Ni-P compounds. Compared with the non-remelted coating, the microhardness and wear resistance of remelted coating are improved. The main wear mechanisms of remelted coatings include abrasive wear, oxidation wear, and plastic deformation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZRSKP
Electrodeposited amorphous alloys require numerous nuclei and irregular atomic arrangements. In this study, the impact of processing parameters (e.g., a nanosecond laser) on the current density in ...the electroplating solution for an electrodeposited Ni-P coating was tested using an electrochemical workstation. In addition, the effect of the laser on the temperature and micro-stirring caused by cavitation was simulated using COMSOL (version 5.4). The surface quality, wear, and corrosion resistance of the Ni-P coating prepared by laser-assisted electrodeposition (LECD) at different laser repetition frequencies (picosecond laser, 0.5, 1, 1.5, 2, and 2.5 MHz) were evaluated. The results showed that the stability of current change was best when the laser frequency, pulse width, scanning line spacing, and irradiation area were 1 MHz, 200 ns, 20 μm, 1 mm2, respectively. Excessive laser energy destroys the balance of electrochemical deposition process. The simulation results showed that the maximum instantaneous temperature of the laser-irradiated solution was 123 °C. Cavitation increases the flow rate of the solution and produces a jet impact on the substrate. The maximum velocity and instantaneous pressure were 0.13 m/s and 7.26 × 108 Pa at 0.1 ns, respectively. At the laser frequency of 0.5 MHz, the P content increases by approximately 2% compared to that of the coating prepared by LECD (1–2.5 MHz). The residual internal stress decreased with increasing frequency, and it existed in the form of tensile stress. The wear and corrosion resistances of the Ni-P coating were the best when the laser frequency was 1 MHz.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The laser thermal effect effectively reduces the internal stress of Ni-Fe-P coating, but it still exists in the form of tensile stress. In this paper, a steady-state magnetic field is introduced into ...laser-assisted electrodeposition (LECD). Whether the magnetohydrodynamic (MHD), magnetic, and magnetization effect can alleviate the residual tensile stress of amorphous Ni-Fe-P coating was discussed. The results indicate that magnetic field impacts the formation of particle clusters and the reduction of the number of micro-cracks. When the magnetic field strength is 15 mT, the internal stress exists in compressive stress (150 MPa). When the magnetic field strength is 25 mT, the surface micro-cracks formed directionality. Based on LECD, the influence of magnetic field on ECD rate is not significant, while the Fe content increases because of the MHD effect. In addition, when a magnetic field is added, the amorphous structure does not change. When the magnetic field intensity is 15 mT, the diffraction peak of XRD is broader and smoother, indicating that the size of the crystal nucleus is smaller. Moreover, compared with LECD, magnetic field and laser assisted ECD (MLECD) improves corrosion resistance, but decreases wear resistance.
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•MLECD makes Ni-Fe-P coating manifested with particle clusters.•MLECD reduces the residual internal stress existing in compressive stress.•MLECD makes the reduction of Fe preferentially because of the MHD effect.•MLECD improves corrosion resistance, but decreases wear resistance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Magnetic field is introduced into ECD based on laser irradiation.•Transverse magnetic field has a better impact on properties of Fe-Ni coating.•The magnetic field affects the grain ...growth orientation and forms flow pattern.•The Fe content is affected due to the MHD effect on the diffusion degree.•Magnetic field can improve the properties of Fe-Ni coating.
A steady-state magnetic field is introduced to prepare Fe-Ni coating based on laser-assisted electrodeposition (LECD) to control the change of element content and improve the surface quality. The internal structure, surface quality, and properties are tested to discuss under different magnetic field intensities. The results indicate that the comprehensive performance of Fe-Ni coating with a transverse magnetic field is better. The magnetohydrodynamic (MHD) and magnetization effect make the grain refinement and improve the surface quality of Fe-Ni coating. The surface morphology shows that the laser makes the surface denser, while the magnetic field causes the ions to magnetize so that the clusters form on the surface. The addition of the magnetic field does not change the grain structure, but the Fe content is increased because of the MHD effect on the diffusion degree. Besides, when the magnetic field intensity is 15 mT, the residual internal stress reaches 587 MPa in the form of compressive stress. Meanwhile, the test of micro-hardness, tensile strength, wear, and corrosion resistance indicates that the comprehensive performance of Fe-Ni coating by the magnetic field and laser-assisted electrodeposition (MLECD) is better than that of electrodeposition (ECD) and LECD.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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