Diamond like Carbon (DLC) was deposited on aluminum substrate using Plasma Assisted Chemical Vapor Deposition (PACVD) route. Spattering, the surface was activated before deposition for increasing adhesion. Deposition time was varied from 60 minutes to 5 hours. Deposit was characterized using with grazing incidence X-ray diffraction and atomic force microscope. The mechanical property was measured using microhardness and roughness tester. The analysis showed that the deposit consisted of columnar growth of submicron and micron meter scale. Compared to substrate material, deposit showed higher hardness and roughness. These results show that growth of DLC layer includes three stages. The first stage is primary growth of nuclei, and then these nuclei join together in second stage. In third stage, secondary growth of these nuclei happens. تفاصيل المقالة

In this work, Diamond Like Carbon (DLC) thin films were deposited on aluminum alloy 6061 by Plasma-Assisted Chemical Vapor Deposition (PACVD). Nitiding prior to coated leads to appropriate hardness gradient and it can greatly improve the mechanical properties of the coatings. The composition, crystalline structure and phase of the films were investigated by Grazing Incidence X-ray Diffraction (GIXRD). Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) were employed to observe the morphology and structure of the film. The DLC layer exhibited a columnar structure. The adhesion force between the film and the aluminum alloy 6061 was 30.8 Mpa. The DLC film was determined by the pull of test. The hardness of the DLC film was 12.75 Gpa. The improvement of the adhesion DLC was attributed to a less gradient hardness configuration. In addition, the mean friction coefficient of the films was about 0.2 determined by nanoindentation test. According to the results, the high and unique hardness of this coating leads to increase of the wear resistance and thus the useful life of parts. تفاصيل المقالة

This study investigated the compressive strength of hardened concrete and the formation of Calcium Silicate Hydrate (C-S-H) with the addition of nanosilica (SiO2). Compressive strength testing was performed using ASTM C496 to determine stress-strain curves and compressive strength of the materials. The hydration process and formation of C-S-H and Calcium Hydroxide (CH) was examined using Atomic Force Microscopy (AFM) and Fourier Transform Infrared Spectroscopy (FTIR). Results indicate an increase in compressive strength using 1, 3 and 5% of nanosilica to concrete replacement by volume in comparison to the control mix (without nanosilica). The optimum concrete replacement to yield maximum strength was of the 5% nanosilica content. Comparing the 56 day results for the 3 and 5% of nanosilica replacement samples, notice the same percentage of C-S-H formation of 83 and 85%, respectively تفاصيل المقالة

Plasma-assisted chemical vapor deposition method was used to construct a diamond-like carbon coating on aluminum substrate 6061-T6. Sedimentation was carried out using CH4 as a process gas at different temperatures of 250-300 Celsius with constant flow rate and power. Raman spectroscopy was used to describe these samples. Raman analysis of DLC coatings at different temperatures has been done in detail for two different wavelengths of stimulation of 514 and 785 nm and the results are shown in this paper. Peak changes were observed in both D and G peaks of Raman spectrum with increasing sediment temperature, indicating the formation of compressive strain in DLC coatings at high temperatures. Scattering is observed at both D and G peaks for different wavelengths of excitation, indicating that the DC coating is hydrogenated. It seems that the degree of hydrogenation of DLC coating decreases due to sediment temperature. The study of nano-indentation with increasing sediment temperature shows a marginal increase in hardness. تفاصيل المقالة

Plasma assisted chemical vapor deposition (PACVD) technique was used to make a diamond-like carbon (DLC) coating on the Aluminum 6061- T6 substrate. The deposition was carried out using CH4 as the process gas, at different temperatures, 250°C and 300°C with constant power and flow rate. Characterization technique Raman spectroscopy was used to characterize these samples. Raman analysis of DLC coatings at different temperatures is carried out in detail for two different excitation wavelengths i.e. 514 and 785 nm and, results are presented in the paper. Blue shifts were observed in both D and G peaks of the Raman spectrum with an increase in deposition temperature, which indicates the formation of compressive strain in high-temperature deposited DLC coatings. Dispersion in both D and G peaks is observed for different excitation wavelengths suggesting that the coating is hydrogenated DLC. The degree of hydrogenation of the DLC coating appears to decrease for the deposition temperature. Nano-indentation study shows a marginal increase in hardness with an increase in deposition temperature. تفاصيل المقالة

In polymer-based nanocomposites, carbon nanofibers have been used to improve mechanical properties in various applications. In this research, the tensile properties of carbon nanofibers have been used to create carbon-epoxy nanocomposite and improve the mechanical properties of epoxy nanocomposite, and the effect of the weight percentage of carbon nanofibers on the mechanical properties of epoxy nanocomposite has been investigated. Epoxy with weight percentages of 1.0, 5.0 and 1.5 carbon nanofibers were produced and their mechanical properties were investigated. The results showed that the use of even a small percentage of carbon nanofibers can lead to the improvement of mechanical properties. تفاصيل المقالة