Physical Properties of Diamond Coatings on a WC—6% Co Substrate

We have investigated the physical properties,including the morphology,texture,adhesion and chemical quality,of high-frequency chemical vapour deposited diamond coatings on WC-6% Co substrates,which were pre-treated by a two-step etching method.The results indicate that the increasing Co content from 0.12 to 3.05% within the etching depth of 5μm caused a morphology transformation from prism diamond to spherulitic diamond,and a texture transformation from a {111} orientation to a {110} orientation.The Raman spectrum shows that the spherulitic diamond film contains more non-diamond phases (graphite,amorphous carbon and diamond-like carbon,etc) and has lower chemical quality than diamond films on a WC-6% Co substrate.The diamond coating grain sizes became about four times smaller when the deposition temperatures on the substrate surface were reduced from 1000 to 900℃.Compared with spherulitic diamond films,the prism diamond films exhibit better adhesion on the WC-6% Co substrate.     

Crystallographic Features of the Structure of Cast and Quenched Cobalt–Niobium Alloys

Technical Physics - Specific features of structure formation at the β → α (fcc → hcp) polymorphic transformation in Co–Nb binary alloys have been investigated by...     

Power Source Types Effects on the Properties of Oxide Ceramic Coatings on Magnesium Alloys

Magnesium alloys have some excellent properties such as ligh quality, high specific strength and stiffness, high damp and recoverd easily. So magnesium alloys have been used widely for the housings of automobile parts, cellular phones and notebook computers in recent years However, a drawback due to the poor corrosion resistance of magnesium alloys has limited their engineering applications, especially when the concentrations of heavy metal impurities such as iron, nickel and copper are high. On the other hand, surface treatments are necessary to protect against corrosion because electrochemically.     

Deformation Effect on Microtwinning and Crystal Lattice Distortion of Polycrystalline Cu–Al Alloys

Russian Physics Journal - The paper considers the dynamics of changing of misoriented dislocation substructures appearing at a stage of developed plastic deformation. The types of defects, which...     

Influence of Thermomechanical Treatment on Structural-Phase Transformations and Mechanical Properties of the Cu–Al–Ni Shape-Memory Alloys

Russian Physics Journal - Using the methods of optical and electron microscopy and electron and X-ray diffraction analyses, the influence of thermomechanical treatment on the mechanical properties,...     

Ab Initio Study of the Structural Properties of the Co–Ni–Sn Heusler Alloys

Physics of the Solid State - The ab initio investigations of the structural and magnetic properties of the Co2Ni1 + xSn1 – x (x = 0,...     

Influence of Co–Zr substitution on coercivity in Ba ferrites

Polycrystalline BaCo_xZr_xFe_11.5−2xO_18.25 samples with 0?x?0.6$0?x?0.6$ ions per formula units were prepared by modified citrate precursor method with the initial ratio of Ba:Fe equal to 1:11.5. The cationic site preferences of Co²⁺ and Zr⁴⁺ in Co–Zr substituted Ba ferrite were investigated by magnetic measurements and X-ray diffractometer (XRD) analysis. The coercivity H_c was decreasing with increasing Co–Zr substitution. The datum showed that the max coercive force (H_c) was obtained when substitution of 0.2, while the best saturation magnetizations (M_s) was obtained when substitution of 0.4.     

Influence of the Guinier–Preston Zones on the Concentration Dependence of the Yield Point of the Aged Two-Component Alloys in Conditions of High-Speed Deformation

Physics of the Solid State - The glide of an ensemble of edge dislocations at the high-speed deformation of an aged binary metal alloy is theoretically analyzed. The yield stress of the alloy is a...     

Influence of environment on the corrosion of glass–metal connections

‘Glass sensors’ of the eighteenth century Backer glass and the sixteenth century enamel from Limoges have been chosen for a series of experiments. Combinations of these materials with different base materials such as copper and bronze has been investigated. To create surface changes on the ‘glass sensor’, a corrosion process was induced in a controlled environment. A variety of corrosive agents such as hydrochloric acid, sulfuric acid, water and formaldehyde were used. The sample immersed in the corrosive solution was exposed alternately to light and high temperature for a total of 38 weeks. During this period, macroscopic and microscopic observations were made and series of tests such as SEM/EDS and Raman spectroscopy were performed on the surface of the samples. ICP-MS methods were used to determine the change in the chemical composition of the solutions where the samples had corroded. The primary aim of this study was to identify the impact of a number of external corrosive variables such as temperature, humidity and local environment to identify the most damaging environments for glass–metal objects. The obtained results showed the chemical and physical phenomena acting on the surface of the glass, metal or in the place of their joints. Information obtained on this study was used to explain the influence of the environment on the surface of glass–metal materials. Results can be used in the design of conservation work as well as for sustainable conservation.     

Influence of Co:Cu ratio on properties of Co–Cu films deposited at different conditions

A series of Co–Cu films with different Co:Cu ratio was electrodeposited at different electrolyte pH, deposition potential and film thickness, and their morphology, crystal structure and magnetic properties were investigated. Compositional analysis by energy dispersive x-ray spectroscopy disclosed that the Co and Cu content were 75 and 25 wt%, respectively, at high pH (3.2) level, while for films at low pH (2.5) level the compositions are 61 Co and 39 wt% Cu, and further decrease of Co:Cu ratio occurred as the film thicknesses increased. The surface morphology of the films changed from an initial dendritic stage to expanded dendrites with increasing Cu content by the electrolyte pH. The dendrites became more obvious at 3 μm and the dendritic structures increased with further increase of film thickness as the Co:Cu ratio decreased. Hence, the increase of the Cu content is thought to be the cause of the increase of dentritic structure. Structural characterizations by x-ray diffraction (XRD) showed that all films have face-centered cubic structure. In the XRD patterns, the peak intensity of Co (111) is lower for the films grown at low pH compared to that of high pH, and the (111) peaks of Co and Cu slightly separated at 3 μm and then the intensity of the Cu (111) increased with increasing film thickness from 4 to 5 μm, so that the Co:Cu ratio changed at all deposition parameters. Magnetic measurements displayed that the saturation magnetization decreased and the coercivity increased as the Co:Cu ratio decreased with all deposition parameters. Also, the magnetic easy axis was found to be in the film plane for all films. It was seen that the variations in the properties of the films might be attributed to the change of Co:Cu ratio caused by the deposition parameters.     

Influence of Positive Bias on Electrical Properties of Undoped Nanocrystalline Diamond Films

By means of electron assisted hot filament chemical vapour deposition technology, nanocrystalline diamond films are deposited on polished n-（100）Si wafer surface at I kPa gas pressure. The deposited films are characterized with a Raman spectrometer, atomic force microscope, semiconductor characterization system and Hall effect measurement system. The results show that, when bias current is larger than 2 A, sheet hole concentration can increase to a value greater than 1013 cm-2 and undoped nanocrystalline diamond films with a p-type semiconducting characteristic form. Heterojunction between n-Si substrate and the nanocrystalline diamond films deposited with 2 A and 6 A bias current has an evident junction effect. Hole formation mechanisms in the films are discussed.     

Microtextures Induced by Nanosecond Laser on Ni–Co Alloy Coatings

Ni–Co alloys have a wide range of applications in various fields owning to their excellent physical, chemical, and mechanical properties. In this paper, we prepare Ni–Co alloy coatings on 316L stain steel surfaces by electroplating. We present a novel approach utilizing a nanosecond laser to induce microtextures on Ni–Co alloy coatings. We study experimentally the effects of laser power and scanning rate on the surface morphologies of Ni–Co alloy coatings. The results indicate that the shape and size of induced microtextures can be controlled by the laser power and scanning rate. The size of grains increases with increase in the work current of the laser (WCL) at a certain scanning rate. With the WCL constant, the size of grains decreases with increase in scanning rate while their average height increases. It is a simple and easily-controlled method for the fabrication of microstructures on Ni–Co alloy coatings, which has promising applications in investigations of the properties of microtextured surfaces, such as friction, adhesion, and wetting.     

Effect of the Energy of Krypton Ions on the Structure and Hardening of Ti–Cr–N Coatings

Russian Physics Journal -     

Synthesis of Polycrystalline Diamond Compact with Selenium: Discovery of a New Se–C Compound

Sintering of polycrystalline diamond with selenium was investigated under pressure of 6.5-10.5 GPa at a constant temperature of 1850℃.A new carbon-selenium compound with a most plausible chemical formula of SeC and a WC-type hexagonal structure(space group P6 m2) has been discovered in the recovered samples sintered at 10.5 GPa and 1850℃.Refined lattice parameters are as follows:a=2.9277(4) A,c=2.8620(4) A,V=21.245(4) A3.The diamond compacts hot-pressed at 10.5 GPa have excellent mechanical prop...     

The Influence of Dimesions and Phase State of Structural Elements on Mechanical Properties of Binary Alloys of the Ti–Nb and Zr–Nb Systems

Russian Physics Journal - The results of investigation of the influence of the structural element size and phase state of the Ti – 45 wt.% Nb and Zr – 1 wt.% Nb binary alloys on their...     

Influence of differential stress on the galvanic interaction of pyrite–chalcopyrite

The effect of stress action on pyrite–chalcopyrite galvanic corrosion was investigated using polarization curves and electrochemical impedance spectroscopy (EIS) measurements. When stress increased from 0 to 4?×?10⁵ Pa, the corrosion current density of pyrite–chalcopyrite increased from 5.678 to 6.719 μA cm^?2, and the corrosion potential decreased from 281.634 to 270.187 mV, accompanied by a decrease in polarization resistance from 25.09 to 23.79 Ω·cm². EIS results show there have three time constants in the Nyquist diagrams, which indicated the presence of different steps during the corrosion process. Stress dramatically enhanced pyrite–chalcopyrite galvanic corrosion by affecting the Cu_1???x Fe_1???y S₂ film and the double layer, whereas had little impact on the adsorption species. When the stress changed from 0 to 4?×?10⁵ Pa, the pore resistance and capacitance of the Cu_1???x Fe_1???y S₂ film, R _p and Q _p, changed by 25.72 and 72.28 %, respectively. The adsorption species resistance, R _sl, and capacitance, Q _sl, only changed by 9.77 and 2.31 %, respectively.     

Unoccupied Electron States of Ultrathin Films of Thiophene–Phenylene Cooligomers on the Surface of Polycrystalline Gold

Physics of the Solid State - Unoccupied electronic states in the energy range from 5 to 20 eV above the Fermi level have been studied in ultrathin films of dimethyl-substituted...     

Influence of Vacuum Organic Contaminations on Laser-Induced Damage of 1064 nm Anti-Reflective Coatings

We investigate the influence of vacuum organic contaminations on laser-induced damage threshold （LIDT） of optical coatings. Anti-reflective （AIR） coatings at 1064 nm made by Ta2 O5/SiO2 are deposited by the ion beam sputtering method. The LIDTs of AR coatings are measured in vacuum and in atmosphere, respectively. It is exhibited that contaminations in vacuum are easily to be absorbed onto optical surface because of lower pressure, and they become origins of damage, resulting in the decrease of LIDT from 24.5J/cm^2 in air to 15.TJ/cm^2 in vacuum. The LIDT of coatings in vacuum has is slightly changed compared with the value in atmosphere after the organic contaminations are wiped off. These results indicate that organic contaminations are the main reason of the LIDT decrease in vacuum. Additionally, damage morphologies have distinct changes from vacuum to atmosphere because of the differences between the residual stress and thermal decomposability of filmy materials.