The effect of surface plasmon-polaritons on the photostimulated diffusion in light-sensitive Ag–As4Ge30S66 structures

The effect of surface plasmon-polaritons (SPPs) excited at the interface between the profiled surface of the silver layer (in the form of a diffraction grating) and the As4Ge30S66 layer on the photostimulated diffusion of silver into chalcogenide has been studied. The gratings with the period a = 519 nm and modulation depth h/a ≈ 0.037 (where h is the grating depth) were formed on chalcogenide photoresist films by using interferential lithography and covered with the 80-nm-thick aluminum layer, 85-nm-thick silver layer, and thin As4Ge30S66 layer. Photostimulated changes in this structure were studied measuring the angular dependences of specular reflection (Rp) of p-polarized light with the wavelength 632.8 nm. It was found that as a result of exposure, “degradation” (broadening, increase in reflection at the minimum) of the minimum in the angular dependence of Rp (which is associated with the SPP resonance) occurs faster, when the samples are irradiated at the angle corresponding to SPP excitation. This observation indicates acceleration of the photostimulated diffusion process in this structure under the plasmon field action.

Effect of the Shape of Rolling Passes and the Temperature on the Corrosion Protection of the Mg/Al Bimetallic Bars

The paper presents the results of experimental tests of the rolling process of Mg/Al bimetallic bars in two systems of classic passes (horizontal oval-circle-horizontal oval-circle variant I) and modified (multi-radial horizontal oval-multi-radial vertical oval-multi-radial horizontal oval-circle-variant II). The feedstock in the form of round bimetallic bars with a diameter of 22 mm and 30% of the outer aluminum layer was made through explosive welding. The bimetallic bars consisted of an AZ31 magnesium core and a 1050A aluminum outer layer. Bars with a diameter of 17 mm were obtained as a result of rolling in four passes. The rolling process in the passes was conducted at two temperatures of 300 and 400 °C. Based on the analysis of the test results, it was found that the use of modified passes and a lower rolling temperature (300 °C) ensures a more homogenous distribution of the plating layer around the circumference of the core and results in an even grain decreasing, which improves the corrosion resistance of bimetallic bars compared to rolling bars in a classic system of passes and at a higher temperature (400 °C).

Plasma FIB Delayering and Nanoprobing with EBIRCH for Localizing Metal Shorts in DRAM

This paper demonstrates how to localize metal-to-metal short failures in DRAM, where defects can occur over a large area including the aluminum layer, by using the means of mechanical grinding, plasma FIB delayering, and EBIRCH (Electron Beam Induced Resistance Change). Our experiments show that a uniform mechanical grinding of an aluminum layer, and DX PFIB delayering, results in a high quality planer surface in the target layer and site, as the slope created during the grinding is compensated by PFIB delayering. This approach has advantages that are conducive to EBIRCH analysis. First, the target layer can be prepared at any given location (site-free). Second, the defective layer can be delayered to a desired depth without damage (layer-free). Last, after delayering, the surface of the device becomes evenly flat enough to allow the electron beam to evenly penetrate the device for EBIRCH analysis (higher-flatness).With the use of more advanced device preparation methods, EBIRCH analysis has a higher chance of successfully localizing metal line/via shorts even in a large region, which includes the aluminum layer.

Structure and Phase Composition of the Al-Ti System Composites after Heat Treatment

The studies results of the titanium with aluminum diffusion interaction at a temperature of 650 oC are presented. The phase and chemical composition of the diffusion interaction zone, the nature of the change in its thickness from the exposure time are determined. It is shown that accelerated cooling of explosion-welded composites from the heat treatment temperature leads to spontaneous separation of the aluminum layer with the formation of a coating based on the TiAl3 intermetallic compound on the titanium surface.

Enhancing the Fire Resistance of Concrete Structures by Applying Fire-Retardant Temperature-Resistant Metal Coatings

The issues relating to an increase in the fire-resistance of concrete structures by applying (heat dissipating) fire-retardant and fire resistant metal coatings onto them was considered. The experimental investigation data obtained for the heating rate of the brick coated with the aluminum layer as heat dissipating coating were given. The investigation was carried out through the comparison of a time-dependent change in the temperature of the material coated with the aluminum layer with the temperature of uncoated material. The obtained research results proved a decrease in the heating rate of the coated brick exposed to the thermal irradiation.

Creation of AlSi12 Alloy Coating by Centrifugal Induction Surfacing with the Addition of Low-Melting Metals

This paper investigates the structure and mechanical characteristics of a coating based on an AlSi12 alloy, obtained by centrifugal induction surfacing as an alternative to a bronze sliding bearing. To provide for the adhesion of an aluminum layer to the inner surface of a steel bearing housing, a sublayer of low-melting metals was formed, while the formation of the main layer and the sublayer was done in a single processing cycle. The low-melting metals had higher density, which ensured that the sublayer was created at the interface with the steel bearing housing under the action of centrifugal forces. It is shown that the low-melting sublayer forms a strong bond both with the aluminum alloy and with the steel base. Lead and tin are used as low-melting additives. It has been established that lead or tin used in a sublayer are indirectly involved in the structural formation of boundary layers of steel and aluminum claddings, acting as a medium for diffuse mass transfer. Thus, lead is not included in the composition of the main coating and does not change the chemical composition of the aluminum layer. After the addition of tin, the aluminum develops a dendritic structure, with tin captured in the interdendritic space. In this case, the deposited layer is saturated with iron with the formation of intermetallic (Fe, Al, Si) compounds, both at the interface and in the coating volume. This paper offers an explanation of the mechanism through which Pb and Sn act on the structure formation of the coating, and on the boundary layer of the steel bearing housing. Tribological tests have shown that the resulting materials are a promising option for plain bearings and highly competitive with the CuSn10P bronze.

Design of Novel Sensitive Terahertz Biosensors Based on Graphene-Plasmonic Nanostructures

In this paper, four different configurations of sensitive biosensors based on graphene-plasmonic combinations are designed and proposed. The nanostructures are made of graphene, SiO2, aluminum and gold layers on a silicon substrate. Graphene-ring shaped structures with diagonal strips in vertical and horizontal directions are considered in the structures which greatly affect the absorption characteristics (absorption peak value and wavelength). Aluminum layer is used in the structure to prevent the transmission of light throughout some layers and improving the absorption factor. To promote the functionality of the structures, effects of the structural parameters (R1 and R2) and chemical potentials (Ef1, Ef2, Ef3 and Ef4) on the absorption peak-wavelength and its value, are also studied. The four individual configurations with different layers and strip directions demonstrate distinct and different wavelength ranges; structure-1: 45-60 µm, structure-2: 50-70 µm, structure-3: 70-85 µm, and structure-4: 80-100 µm. Thus, they can be utilized for wide categories of applications. Sensitivities of 1500nm/RIU, 2250/RIU, 3750nm/RIU and 4850nm/RIU are obtained for four types, respectively. The proposed structures indicate more sensitivities and they can be used in acceptable sensing characteristics for different applications like hemoglobin and glucose concentrations in blood samples and can be utilized as refractive index bio-sensing sensors.

INVESTIGATION OF THE EFFECT OF HEATING ON THE STRUCTURE AND PHASE COMPOSITION OF AL-TI COMPOSITES

The results of studies of the diffusion interaction of titanium with aluminum at a temperature of 650 ° C are presented. The phase and chemical composition of the diffusion interaction zone and the nature of changes in its thickness from the exposure time are determined. It is shown that accelerated cooling of explosion-welded composites from the heat treatment temperature leads to spontaneous separation of the aluminum layer with the formation of a coating based on intermetallic TiAl on the titanium surface.