Laser cladding Ni–Co duplex coating on copper substrate

Ni–Co duplex coating has been successfully cladded on copper substrate by continuous wave CO₂ laser. The average microhardness of cladded coating was 635 HV_0.05, which was about 7 times of Cu substrate (92 HV_0.05). During sliding wear tests, the volume loss of copper substrate was about 7 times of Ni–Co duplex coating at 60 min. The high microhardness and crack free advantages of Ni–Co duplex coating, were favorable to reduce the plastic deformation and adhesive wear of copper substrate, resulting in the improvement of wear properties.     

Studies on Poplar Parthenogenesis Induced by Laser

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Study on Laser Conditioning of Optical Coatings

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Dependence of Electromagnetically Induced Transparency on Laser Linewidth

The influence of the linewidth of coupling laser on the electromagnetically induced transparency (EIT) spectral width is theoretically investigated. The model to describe the EIT spectral width is based on the standard semi-classical theory. The result shows that the effect of the linewidth of coupling laser is equivalent to an additional relaxation between two ground states in the A-type configuration. A broadening linewidth of coupling laser implies the increasing relaxation between the two ground states, which will make the wider EIT spectral linewidth.     

Manipulating Light in Coupled Asymmetric Nanostructures Induced by a Visible–NIR Laser

We design an asymmetric nanostructure in the longitudinal direction at the visible–NIR range, which enables high enhancement factor and has the properties of Fano resonance induced by a visible–NIR laser. By simulating and analyzing the resonance frequency spectra of various nanorods, nanodipoles, and combined nanoantennas, we optimize the resonant spectra and enhanced factor of such nanoantennas. It has broad-band resonant spectra with a FWHM from 800 to 1,100 nm and possesses two resonant peaks at 870 and 1,000 nm, with an enhancement factor of 24. The current density distribution in such nanoantennas with different phases is also simulated in order to investigate its resonant mode. This theoretical study paves the way towards nanoscale lightwave control and spectral splitting. The designed nanodevices provide great potential for applications in ultrasensitive color sorters and biosensors induced by visible–NIR lasers.     

Structure and Phase Composition of Heat-Resistant Ni–Al–Co Alloy After Annealing and Creep

Russian Physics Journal - The paper presents research into the structure and phase composition of Ni–Al–Co alloy modified by rhenium (~3 аt.%) alloying. Observations are carried...     

Deuterium Clusters Fusion Induced by the Intense Femtosecond Laser Pulse

Neutrons （2.45MeV） from deuterium cluster fusion induced by the intense femtosecond （3Ors） laser pulse are experimentally demonstrated. The average neutron yield 103 per shot is obtained. It is found that the yield slightly increases with the increasing laser spot size. No neutron can be observed when the laser intensity I 〈 4.3 × 10^15 W/cm^2.     

Metal-Polymer Nanocomposites Based on Pyrolyzed Polyacrylonitrile with Fe–Ni–Co Inclusions

Russian Physics Journal - The paper presents the results of the computational modeling and quantum-chemical investigations of metal-polymer composites based on pyrolyzed polyacrylonitrile (PAN)...     

Structure and Magnetoresistance of Co–Gd and Al–Co–Gd Alloy Films

Technical Physics - Structural data and dependences of the film resistance on magnetic field strength R(H) are presented for Co–Gd and Al–Co–Gd alloy films obtained by vacuum...     

Influence of Cobalt on the Adhesion Strength of Polycrystalline Diamond Coatings on WC–Co Hard Alloys

The influence of cobalt on the phase composition and adhesion strength of polycrystalline diamond coatings has been studied using scanning electron microscopy, Raman spectroscopy, and X-ray microanalysis. The coatings have been deposited on WC–Co hard alloy substrates in glow discharge plasma. It has been found that the catalytic amorphization of carbon only takes place during the direct synthesis of the diamond coating, when the cobalt vapor pressure over the substrate is high and the cobalt-related degradation of the synthesized diamond is absent.     

Laser–Induced Fluorescence Detection of Carbamates Traces in Water

The absorption and fluorescence spectra of carbaryl (CB), carbofuran (CF) and carbendazim (MBC) have been studied. Fluorescence lifetime and fluorescence quantum yields are also reported as well as the influence of pH, solvent and presence of humic acids on fluorescence. The limit of detection (LD) of the three compounds has been measured by direct analysis by laser-induced fluorescence (LIF) using a pulsed YAG laser with an Optical Parametric Oscillator (OPO) as excitation source and an Intensified Charged Coupled Device (ICCD) camera for the fluorescence detection. Instrumental LD found for CB, for MBC and for CF are respectively 4, 50 and 1000 ng L⁻¹. In tap water, the LD obtained is 800 ng L⁻¹ for MBC and 20,000 ng L⁻¹ for CF. For CB, the use of a time shift between excitation and emission allows to reach a LD of 20 ng L⁻¹ in tap water.     

Interdiffusion and solid solution strengthening in Ni–Co–Pt and Ni–Co–Fe ternary systems

Diffusion couple experiments are conducted in Co–Ni–Pt system at 1200?°C and in Co–Ni–Fe system at 1150?°C, by coupling binary alloys with the third element. Uphill diffusion is observed for both Co and Ni in Pt rich corner of the Co–Ni–Pt system, whereas in the Co–Ni–Fe system, it is observed for Co. Main and cross interdiffusion coefficients are calculated at the composition of intersection of two independent diffusion profiles. In both the systems, the main interdiffusion coefficients are positive over the whole composition range and the cross interdiffusion coefficients show both positive and negative values at different regions. Hardness measured by performing the nanoindentations on diffusion couples of both the systems shows the higher values at intermediate compositions.     

Effect of Process Parameters on Laser Damage Threshold of TiO2 Coatings

We investigate the laser damage behaviour of an electron-beam-deposited TiO2 monolayer at different process parameters. The optical properties, chemical composition, surface defects, absorption and laser-induced damage threshold （LIDT） of films are measured. It is found that TiO2 films with the minimum absorption and the highest LIDT can be fabricated using a TiO2 starting material after annealing. LIDT is mainly related to absorption and is influenced by the non-stoichiometric defects for TiO2 films. Surface defects show no evident effects on LIDT in this experiment.     

Adhesive Strength of Ni–Cu Surface Alloy Formation by Low-Energy High-Current Electron Beam

Russian Physics Journal - The paper presents the adhesive strength measurements of the Ni–Cu surface alloy formed on a copper substrate at a different thickness of the transition layer. The...     

Effect of Laser Processing on Strength and Portevin–Le Chatelier Serrated Deformation of Aluminum Alloy

Physics of the Solid State - The effect of surface processing by laser IR radiation on strength and Portevin–Le Chatelier serrated deformation of AlMg6 aluminum–magnesium alloy is...     

Microstructure on Surface of LiNbO3：Fe Induced by a Single Ultra—Short Laser Pulse

A tightly focused femtosecond Ti:sapphire laser pulse is used to initiate micro-explosions on the surface and internal to an Fe:LiNb03 crystal. The resulting structure is morphologically different from that induced in an isotropic sample such as fused silica. The regular pyramid and irregular pyramid craters on the surface of the sample are produced at different positions of focal points. The craters suggest vaporization of materials in the process of micro-explosion due to the expansion of high temperature plasma. The embossment pyramids on the surface present the dynamical process of large volume material displacements under high temperature and pressure, and recrystallization of anisotropy crystal materials.     

Investigation of the Periodic Microstructure Induced by a 355nm UV Polarized Laser on a Polyimide Surface

We investigate a periodic microstructure induced by a 355nm ultraviolet polarized laser on a polyimide surface and the dependence of the structures on laser parameters.Laser-induced periodic surface structures (LIPSS) of sub-micrometre size were generated on three kinds of polyimide films by a polarized Nd:YAG laser of 355nm within a wide range of laser fluence.The chemical structure of the polyimide,the film-making process,the number of laser pulses and the laser fluence greatly influenced the formation of LIPSS.The periodicity of LIPSS was decided by the wavelength,the incidence angle of the laser beam and the apparent refractive index of the material.     

Laser Rapid Melting Structure and Property for Ni－based Tungsten Carbide Alloy

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