Ball-End Mill with a Loxodromic Cutting Edge

Russian Engineering Research - Attention focuses on the design of a ball-end mill whose spherical section has a loxodromic cutting edge. The grinding width and depth required to obtain the rake and...     

Stages of surface erosion under ion irradiation

Initial stages of surface erosion have been studied for NaCl and LiF single crystals bombarded by Ar⁺ ions with 20 keV. For irradiation with doses D=10¹⁰-10¹¹ ions/cm², exoelectron emission has been used, whereas for higher doses, we have used electron microscopy. Two stages of initial surface erosion have been identified; for small doses, there is slow development of atomic-scale roughening, which reaches its peak when areas damaged by closest incident ions start to overlap, and then, beginning with D=10¹⁶ ions/cm², there is rapid etching, deep into the crystal, followed by the emergence of secondary microscopic structure, i.e. caverns, concentric closed steps and terraces. Ion-induced surface structure of alkali halide crystals has been shown to depend strongly on the presence of foreign particles on the surface, as well as on segregation. Topography of thin carbon films and some metals have been discussed.     

The effect of self-organizing vinyl siloxane nanolayers on the corrosion behavior of aluminum in neutral chloride-containing solutions

The methods of quartz crystal microbalance, atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier-transform IR spectroscopy, and X-ray structural microanalysis were is used to show that adsorption of vinyl silane on an aluminum surface from an aqueous solution results in formation of a uniform, self-organizing protective vinyl siloxane nanolayer covalently bound with surface metal groups. Its thickness can be controlled by variation of application conditions. The effect of a vinyl siloxane nanolayer on dissolution of aluminum is studied in chloride-containing solutions. It is found that an ordered vinyl siloxane nanolayer with a thickness of up to 5 molecular layers causes efficient inhibition of uniform and local corrosion of aluminum. It is shown that the vinyl siloxane nanolayer is preserved on the surface of aluminum after 10 days of corrosion tests, which indicates its stability at exposure to water and corrosive components.     

Improving the Anticorrosion Characteristics of Polymer Coatings in the Case of Their Modification with Compositions Based on Organosilanes

Protection of Metals and Physical Chemistry of Surfaces - The effect of a series of organosilanes and their mixtures with corrosion inhibitors on the anticorrosion properties of polymer and paint...     

The Effect of Organosilanes on Protective Properties of Polymer Coatings for Underground Pipelines. Inhibition of Cathodic Peeling-off of Polymer Coatings from Metal

Protection of Metals and Physical Chemistry of Surfaces - Protective properties of polymer coatings are mainly determined by their adhesion properties. Organosilanes represent the most commonly...     

Initial stages of local corrosion destruction of pipe steel in solutions imitating underfilm electrolyte

Using the method of scanning reflectometry, it was determined that the pipe steel dissolves non-uniformly with a high rate of the appearance of local corrosion defects (pittings) in neutral solution imitating electrolyte. The parameters of individual pittings were determined, along with the fact that they propagate mainly at a depth that may cause corrosion cracking under cyclic mechanical stresses. Factors of stress intensity that cause local corrosion defects were calculated.     

Secondary ion emission of Fe-Ni alloys in the temperature range including the Curie point

The temperature dependence of secondary ion emission was investigated for Fe-Ni ferromagnetic alloys with different Curie points T_c and elemental composition: 35% Ni 65% Fe (T_c=240°C), 40% Ni 60% Fe (T_c=360°C), and 50% Ni 50% Fe (T_c=530°C). The alloy 79% Ni 16% Fe 5% Mo (T_c=345°C) was also studied. The spatial distribution of Ni⁺ and Fe⁺ secondary ions emitted from the (1 1 1) face of invar and permalloy single crystals was shown to be anisotropic with pronounced ion-yield maximum for both components in the 〈1 1 0〉 directions. The shape of the energy distribution of Ni⁺ and Fe⁺ ions was found to be virtually identical for all the alloys under investigation with a most probable energy at 7 eV and a width at half-maximum of 12 eV. The temperature dependence of the Ni⁺ and Fe⁺ emission has a maximum near the Curie point of the investigated alloys and another maximum at the Curie point of nickel which may indicate the precipitation of nickel into microscopic islands on the surface as a result of heating and sputtering. Auger analysis of the surface composition in the surface layers showed a variation in concentration of oxygen and carbon atoms when Fe-Ni alloys pass from the ferromagnetic to the paramagnetic state and this must affect also the secondary ion emission of alloy components.     

Emission of secondary particles during ion bombardment of metals in the phase transition region—Part 1. Sputtering

A review of recent studies of the emission of secondary particles (neutral atoms, ions and photons) under ion bombardment of metals in the phase transition region of the first and second type is given. A discussion of the observed anomalies in emission is presented and theoretical models allowing explanation of experimental data are considered. In the present first part of the review results on sputtering are given.     

Adaptive Lathe Tools with Modified Geometry

Russian Engineering Research - A design is proposed for the attachment of a replaceable polyhedral insert in the housing of a pass-through lathe cutter with two fixed positions of the insert. This...