Microstructure and Tribological Properties of Nanoparticulate WC/AL Metal Matrix Composites

The tribological property of Al metal matrix composites, reinforced with WC Nanoparticles is presented. Sliding tests were performed on a pin-on-disk apparatus under different contact loads. It was found that the reinforced Nano-WC particles could effectively reduce the frictional coefficient and wear rate, especially under higher normal loading conditions. In order to further understand the wear mechanisms, the worn surfaces were examined under the scanning electron microscope. A positive rolling effect of the nanoparticles between the material pairs was proposed which contributes to the remarkable improvement of the load carrying capacity of metal matrix nanocomposites

Enhancement of Coating Thickness and Microhardness of Ni-Sic Nanocomposite Coatings for the Variation in Bath Parameters

Ni-Sic nanocomposite coatings were prepared on a MS substrate by electrocodeposition process. The electro-co-deposition was carried using sulphamate bath. In the present work the effect of electrochemical bath parameters such as bath temperature, bath loading and current density on physical and mechanical properties of Ni-based SiC composite coating on mild steel substrate was studied. SiC loading, Current density and bath temperature were varied and the coating thickness was measured using Elektro Physik thickness gauge. The mechanical properties of the electrocodeposited Ni-SiC coatings containing ceramic particles are very much dependent on various factors like bath used, current density, duration of deposition, Thickness of the coating, bath temperature etc. The effects of current density, bath temperature and SiC nanoparticles concentration in the plating bath on the hardness of the coatings were determined by microhardness tests using Vicker’s microhardness tester. The Experimental results shows that, the microhardness of the codeposited coating increases with the increase in the current density and attains a maximum at the SiC concentration of 6 g/l. The decrease in the microhardness at higher concentrations may be due to agglomeration of nano sized particles in the plating bath

Development of Ni-Sic Composite Coatings for Corrosion Studies

In the present work, the effect of electrochemical bath parameter like corrosion rate on physical and mechanical properties of Nickel based SiC composite coating on Mild Steel substrate was studied. Ni-SiC nano-composite coatings were prepared on a MS substrate by electro-co-deposition process using a sulphamate bath. Corrosion rate, by using a salt spray test, was measured at different experimental conditions and the results were tabulated. The experimental results showed that the corrosion rate was lowest at SiC loading of 4 gm/l, 3 A/dm2 of Current density and 45oC of bath temperature

Simulation of Three Dimensional Flows in Hydraulic Pumps

Hydraulic efficiency of the centrifugal pump is mainly depends on mass flow rate, Head and RPM. Finding the best combination with the above said parameters and the best geometry of the pump is possible by using three dimensional CFD simulations. For designers, prediction of operating characteristics curve is most important. All theoretical methods for prediction of efficiency merely give a value; but one is unable to determine the root cause for the poor performance. Due to the development of CFD code, one can get the efficiency value as well as observe actual behaviour. One can find the root cause for poor performance by using CFD Analysis of equipment. We have considered centrifugal pump for the three dimensional fluid flow analyses and validated the pump hydraulic efficiency with the experiment results. We observed the behaviour of the hydraulic efficiency with respect to the pump performance characteristics. Centrifugal pumps should be run at best efficiency point. Generally the radial force developed on the shaft will be high, if operates away from the BEP and it may leads to shaft damage. So it is important to find out best efficiency point

Low-temperature coupling of methane

Methane is the main component of natural gas and its utilization amounts to ca. 1.7 109 tons of oil equivalent per year [1]. Since the present reserve of methane is located in remote places, its transportation is a major problem. Methane coupling to form C2+ hydrocarbons is, therefore, of a primary importance because before transportation methane should be converted into hydrocarbons with higher boiling points, such as ethane, propane, etc. The catalytic conversion of methane can be carried out in several ways which have excellently been reviewed in Refs. 1 and 2. Basically, three routes exist: (i) the indirect route in which methane is first converted into syngas in presence of water (steam reforming), CO2 (carbon dioxide reforming), or oxygen (partial oxidation) and the resultant syngas can be utilized in the traditional way; (ii) direct coupling in the presence of oxygen (oxidative coupling of methane, OCM) or hydrogen (two-step polymerization); and (iii) direct conversion in the presence of oxygen to oxygenates (CH3OH, HCOH), in the presence of Cl2, HCI to methane chlorides, in the presence of ammonia to HCN, etc

Numerical analysis of stresses on layer-by-layer basis in FML composite cylinder subjected to external hydrostatic loading.

The aim of the research work was to numerically investigate the residual stresses induced between the layers of fiber metal laminate (FML) cylinder (glass/epoxy reinforced aluminum laminates) under buckling hydrostatic loading. For the analysis of buckling behavior of FML cylinders, various fiber orientations such as 0/90˚, 60/30˚, ±45˚ and ±55˚ and different FRP thickness of 1, 2, and 3 mm were considered. The aluminum cylinder of inner diameter 80 mm, length 800 mm and wall thickness 1 mm was modeled with SHELL281 element type and a total of 1033 elements were used for computing the induced residual stresses between the layers. The results show that magnitude of residual stresses between the layers decreased along the thickness from outer layer towards the inner layer in sine wave form. The maximum residual Von-Mises stress was at inner aluminum layer while the maximum residual radial stress was at the outermost layer of FML cylinder due to the inward pressure. Among all types of FML cylinder 0/90˚ fiber oriented FML cylinder exhibited the least radial stress and a maximum Von-Mises stress along the FRP thickness

Numerical analysis of the effect of fiber orientation on hydrostatic buckling behavior of fiber metal composite cylinder

The external hydrostatic buckling behavior of fiber metal laminate (FML) composite cylinders was investigated numerically. The critical buckling pressure predicted by eigenvalue analysis was compared with experimental results. The numerical results showed different modes of buckling and buckling deformation for cylinders of different fiber orientation when subjected to external hydrostatic loading. FML cylinder with 0/90 fiber orientation exhibited higher buckling strength and lower buckling deformation as compared to FML cylinders of 60/30, 45, and 55 fiber orientations. The orientation of fiber has significant influence on the performance of FML composite cylinder as compared to fiberreinforced plastic thickness. The correlation between numerical and experimental results is discussed in terms of buckling strength, circumferential stiffness, and buckling deformations. It was observed that the cylinders were less sensitive to initial imperfections irrespective of fiber-reinforced plastic thickness. In addition, the results of finite element analysis and experimental results indicate good matches