Showing papers in "International Journal of Surface Science and Engineering in 2013"
TL;DR: In this article, a new parameter VRa [g] is proposed to detect the surface texture by vibration and new equations for detecting the surface quality were derived, which can be used for online controlling of surface texture created by abrasive waterjet.
Abstract: This paper deals with an experiment with the material of AISI 309 with thickness of 15 mm, to carry out the research into material vibration phenomena as the tool of the online controlling of surface texture created by abrasive waterjet. Vibrations of the material were collected by accelerometers of PCB IMI 607 A11. The generated topography on material was measured with optical profilometer MicroProf FRT and the data were confronted with the resultant vibration parameters. A new parameter VRa [g] is proposed to detect the surface texture by vibration. New equations for detecting the surface quality were derived.
13 citations
TL;DR: Plumbagin recrystallised by cold crystallization technique using a variety of polar and non-polar solvents was investigated for pharmaceutical properties as mentioned in this paper, which demonstrated approximately two-fold increase in saturation solubility (155.01 ± 3.86 μg/ml), higher Q5min (cumulative percentage dissolution in 5 min) and lower t65% (time required for 65% dissolution) owing to greater surface area.
Abstract: Plumbagin recrystallised by cold crystallisation technique using a variety of polar and non-polar solvents was investigated for pharmaceutical properties. Different solvents gave varying sized and shaped plumbagin. Powder X-ray diffraction, differential scanning calorimetery and fourier transform infrared spectroscopy too confirmed differing crystal habit. Platy crystals, the most significant forms, obtained from cyclohexane possessed small size (62.93 ± 3.74 μm), higher bulk density (0.108 ± 0.014 g/ml) and lower enthalpy of fusion (∆H 62.62 ± 3.67 J/g). These demonstrated approximately two-fold increase in saturation solubility (155.01 ± 3.86 μg/ml), higher Q5min (cumulative percentage dissolution in 5 min) and lower t65% (time required for 65% dissolution) owing to greater surface area. In-vivo anti-inflammatory study in Wistar rats demonstrated improvement in therapeutic efficacy of recrystallised plumbagin. In conclusion surface modification led to enhanced efficacy of plumbagin; an approach capable of improving the bioavailability and clinical efficacy of other poorly water soluble phytomedicine.
13 citations
TL;DR: In this article, a focused review of the previous studies on the deformations of monocrystalline Si induced by nanoscratching was summarised and the deformation route of Si appears to be different from those reported from the nanoindentation studies.
Abstract: This focused review includes two parts. In the first part, the previous studies on the deformations of monocrystalline Si induced by nanoscratching were summarised. In the second part, our recent studies on the scratching-induced deformation of Si were systematically presented. The studies have demonstrated that lateral force in nanoscratching plays a key role in the amorphization and phase transformation of Si under mechanical loading. The deformation route of Si appears to be different from those reported from the nanoindentation studies.
11 citations
TL;DR: In this article, a comparative study has been performed on three-body abrasive wear of normal plough tool and hard-faced plough material as per ASTM G 65 standard.
Abstract: Abrasive wear is the most important influencing factor to be considered to determine life span of soil-engaging tools, especially in the case of agricultural tillage tools. A comparative study has been reported on three-body abrasive wear of normal plough tool and hardfaced plough tool materials as per ASTM G 65 standard. Hardfacing is done by manual arc welding using ZEDALLOY VB hardfacing electrode. An orthogonal array and analysis of variance are employed to investigate the optimal testing parameters. The experimental results demonstrated that the major parameter found is applied load among the other controlling factors on abrasive wear. The hardfaced plough tool material shown marked wear resistance compared to normal plough tool material.
7 citations
TL;DR: In this article, an improved boundary friction model was introduced to predict the friction coefficients and the real contact areas around the punch nose portion, and a good agreement was obtained between the theoretical and the experimental results.
Abstract: Punch friction test is considered to be the best simulator of sheet metal stretching over the punch corner. In this study, an improved punch friction test eliminating the error due to the strain-rate effect was developed. This method enables the direct force measurement and the online evaluation of the friction coefficient. Also, an improved boundary friction model was introduced to predict the friction coefficients and the real contact areas around the punch nose portion. The predicted values were then compared with the experimental one obtained from the newly developed test for verification. A good agreement was obtained between the theoretical and the experimental results. Finite element simulation of the punch friction test under dry friction condition for annealed aluminium was performed using the experimental friction coefficients. Since the simulated force-displacement results are in good agreement with the experimental one, the accuracy of the test is high and reliable.
7 citations
TL;DR: In this paper, the influence of interface roughness on the life of thermal barrier coating (TBC) layer has been investigated and three different cases of interfaces roughness have been studied.
Abstract: Methodology development for life estimation of thermal barrier coating (TBC) applied on a gas turbine engine combustor liner has been undertaken using finite element method. 3-D finite element analyses (FEA) are performed using ABAQUS followed by fatigue analysis through FESAFE for life estimation of a TBC layer. Analysis considers a typical mission cycle of a gas turbine engine while modelling the transition liner of a reverse flow combustion chamber. This paper presents the influence of interface roughness on the life of TBC layer. Three different cases of interface roughness have been studied. Roughness is found to affect TBC life adversely. In addition to effect of interface roughness, the life estimation methodology is also discussed.
7 citations
TL;DR: In this article, the torsional wear behaviors of ultra high molecular weight polyethylene (UHMWPE) were investigated in ball-on-plate torsion wear device.
Abstract: The torsional wear behaviours of ultra high molecular weight polyethylene (UHMWPE) were investigated in ball-on-plate torsional wear device. Alumina femoral head and Ti6Al4V alloy ball, were selected as the counterballs in this study. It was found that the torsional fretting running regimes transferred from partial slip regime (PSR) to slip regime (SR) were analysed, however the mixed fretting regime (MFR) was never appeared in this tests. In PSR (lower angular displacement amplitudes), slight damage occurred at small angular displacement and several wear appeared at large value. Adhesion appeared at the centre zone of all fretting scars in SR. Detachment of particles, ripples and ploughs were observed under higher angular displacement amplitudes. The UHWMPE/Ti6Al4V pair showed higher contact stiffness, friction torque, wear damage and material transfer than that of the presentation of UHWMPE/Al2O3pairs. The wear mechanisms of UHWMPE/Ti6Al4V were combined with abrasive wear and delamination. The generation of radial ripples and micro-cracking were the main damage modes for UHMWPE/Al2O3.
6 citations
TL;DR: In this paper, a novel MoSi2-SiC ceramic matrix nanocomposite was prepared using high energy mechanical ball milling in various concentrations followed by hot press sintering to generate a target.
Abstract: A novel MoSi2-SiC ceramic matrix nanocomposite was prepared using high-energy mechanical ball milling in various concentrations followed by hot press sintering to generate a target. Ceramic coatings were deposited on mild steel substrates using the MoSi2-SiC target in the RF magnetron sputtering process. The thicknesses of the coatings were controlled and varied between 25, 75 and 125 nm. The morphology of the ceramic nanocoating was explored by XRD, SEM and AFM and the composition of the deposit was analysed by EDX analysis. The corrosion resistance of the MoSi2-SiC coating was evaluated using the acidic bath method by dipping the mild steel substrate in different acid environments (H2SO4, HCl and HNO3) with various concentrations. The results reveal that the prepared ceramic nanocomposites are notably good inhibitors at low concentrations. A response surface methodology (RSM) design tool was used to optimise the corrosion parameters to obtain maximum corrosion resistance and corrosion inhibition efficiency.
5 citations
TL;DR: In this paper, the study of two different techniques, high-velocity oxygen fuel and air plasma spray, was performed on a steel surface and the results indicated that both the different coatings typology tested have an optimal internal cohesion, a good adhesion on the substrate and good wear resistance.
Abstract: In many industrial applications it could be useful to cover the mechanical components with harder coatings For this reason, thermal spray technology is finding widespread use due to the high wear and corrosion resistance of the coatings achieved with these technologies This paper is focused on the study of two different techniques, high-velocity oxygen fuel and air plasma spray In particular, two different coatings sprayed on a steel surface were studied In order to characterise the coatings a whole experimental campaign was carried out Moreover, both the adhesion to the surface and the wear properties in different conditions were evaluated In order to evaluate the attitude of these technologies to realise thick coatings were tested coatings with different thickness The obtained results suggest that both the different coatings typology tested have an optimal internal cohesion, a good adhesion on the substrate and good wear resistance
5 citations
TL;DR: In this paper, the wear performance of the FeSiNiNiCr-containing coating formulations were thermally sprayed onto a grey cast iron substrate by the high velocity oxy fuel (HVOF) method under controlled conditions.
Abstract: Thermally sprayed coatings that are based on FeSiNiCr-related alloy powders are widely used to improve properties such as the surface hardness, the wear resistance and the corrosion resistance of a variety of coated metal substrate materials. For the current study, the FeSiNiCr-containing coating formulations were thermally sprayed onto a grey cast iron substrate by the high velocity oxy fuel (HVOF) method under controlled conditions. The microstructure and micro abrasive wear performance of both the uncoated substrates and the coated substrates were characterised by optical microscopy as well as by scanning electron microscope (SEM). In addition, X-ray diffraction (XRD) and thermogravimentric analyses (TGA) were undertaken in the partial characterisation of the coating. The densely layered coating had porosity levels that were below 1.5% and a high surface hardness, of the order of 920 HV0.1. The coating exhibited excellent wear resistance when subjected to the ball-cratering test method. The wear rate of coating was significantly less than the wear rate of the substrate. Low coefficients of friction of hard coating on the substrate were recorded. The wear performance of the coating was nearly 80% better than that of the substrate, with a 0.05 N load, even under severe three body abrasive conditions. A tribometer was used to assess the wear testing to evaluate the change in the coefficient of friction and the wear rate with respect to the change in time.
4 citations
TL;DR: In this article, a simple and cost effective in-house process has been developed by combining the ultrasonication bath and electroless metal deposition and etching (EMDE) technique for the growth of vertically oriented, single-crystalline, silicon nanowire (SiNW) arrays with uniform coverage over the whole surface area of the wafer without using any template.
Abstract: In this work, a simple and cost effective in-house process has been developed by combining the ultrasonication bath and electroless metal deposition and etching (EMDE) technique for the growth of vertically oriented, single-crystalline, silicon nanowire (SiNW) arrays with uniform coverage over the whole surface area of the wafer without using any template. The scanning electron microscopy (SEM) analysis shows the uniformity in distribution of SiNW arrays by the proposed method. The samples with as-grown SiNW arrays appear to be blackish in colour and provide a very low reflectance of less than 0.15% in the wavelength range of 300-900 nm. This implies that the as-grown SiNW arrays can be used as the antireflection coating-layer in SiNW-based solar cells and photodetector devices. The compatibility of these Si nanostructures with the well-matured Si-based CMOS technology also assure their application in the development of future generation nanoelectronic and nano-optoelectronic devices.
TL;DR: In this article, laser surface texturing (LST) was performed on the AZ91D magnesium alloy blocks using a Nd:YAG pulsed laser and the regular-arranged dimples with diameter of 100 µm were fabricated on their surfaces.
Abstract: Laser surface texturing (LST) was performed on the AZ91D magnesium alloy blocks using a Nd:YAG pulsed laser and the regular-arranged dimples with diameter of 100 µm were fabricated on their surfaces. The friction reduction and anti-wear properties of textured surface combined with solid lubricant were assessed using a pin-disk tester. The results show that the cooperation of LST with solid lubricant is effective at reducing the wear of magnesium alloy. The densities of dimple reservoirs were investigated in terms of the friction and wear of solid lubricant films burnished on the magnesium alloy surfaces. Optimum density (38%) of the dimples is revealed. It is shown that long wear life of burnished film on the textured surfaces of magnesium alloy is apparently provided by preservation of MoS2 film around the dimples and by supply of solid lubricant from the dimples to the interface.
TL;DR: In this article, a full numerical solution of a thermal elastohydrodynamic lubrication of infinite line contact rough surfaces considering pressure and shear flow factors is obtained, and the modified average Reynolds equation, elasticity equation and energy equations are solved simultaneously using a modified Houpert and Hamrock fast approach.
Abstract: A full numerical solution of a thermal elastohydrodynamic lubrication of infinite line contact rough surfaces considering pressure and shear flow factors is obtained. The modified average Reynolds equation, elasticity equation and energy equations are solved simultaneously using a modified Houpert and Hamrock fast approach. The present study demonstrates an efficient computational scheme and the combined effects of the stochastic surface roughness with thermal actions on the bearing characteristic with a wide range of load, rolling speed and roughness parameters.
TL;DR: In this paper, the authors present a numerical and experimental analysis of the contact interaction between two elastic bodies "cylinder and flat" using the Hertz theory to determine contact width of elastic contacts.
Abstract: The phenomenon of two surfaces in contact is important in the field of tribology and has been studied by many researchers. The tribological problem arises from the points of contact between two surfaces. This paper presents a numerical and experimental analysis of the contact interaction between two elastic bodies ‘cylinder and flat’. In the numerical analysis Hertz theory is used to determine contact width of elastic contacts. Experimental investigation has been performed using aluminium foil, ink of carbon paper and by footprint method which is used to analyse a real contact area between two bodies for applied load conditions. A comparison of contact width between experimentally evaluated and numerically calculated is carried to validate the experimental procedure. The test results of footprint method are almost equal and very close with the numerical data. The experimental analysis suggested in this paper is useful to determine contact width and distribution of the load and stress in cylindrical roller bearing. Using this experimental method elastic contact between hollow cylinder of 67% hollowness and flat body has been studied. Finally in the present work extended Hertz equation was developed for the calculation of half contact width for hollow cylinder and cylinder/flat body contact.
TL;DR: In this paper, the safer hydrogen halide was used to prepare the MgO-MgI2/MgBr2 layers onto AZ91 magnesium alloy in alkaline solution.
Abstract: The present research uses the safer hydrogen halide to prepare the MgO-MgI2/MgBr2 layers onto AZ91 magnesium alloy in alkaline solution. The water-soluble metal salts (MgI2/MgBr2) were not responsible for the corrosion protection; whereas Mg(OH)2 formed first and then converted to MgO by heat-treatments and this MgO was responsible for the corrosion protection. The electrochemical results showed that the development of MgO mitigated the corrosion process and improved the corrosion resistance. This new treatment was then used as a pre-treatment for further electroless nickel (EN) deposition and it showed the good corrosion current density and better corrosion potential on the magnesium substrate. This new treatment and EN depositions were characterised by XPS and SEM. The electrochemical polarisation and EIS test of these EN depositions were evaluated in 3.5 wt.% NaCl. In addition, pitting behaviour of these EN depositions were evaluated by linear sweep voltammetry test.
TL;DR: In this article, the velocity of a droplet on a solid surface is a function of the dynamic contact angle formed at a point on the contact line of solid and liquid phases, and a general correlation for the microscopic displacement frequency which has a wide range of variations is developed.
Abstract: The velocity of wetting a droplet on solid surface is a function of dynamic contact angle formed at a point on the contact line of solid and liquid phases. In this paper, the velocity of wetting obtained using the Arrhenius empirical equation is related to that of the dynamic contact angle. The resulting relationship, however, introduces two microscopic parameters, namely microscopic displacement frequency and length, which are not known as a priori and are usually obtained using a curve-fitting of the measured data. A general correlation for the microscopic displacement frequency which has a wide range of variations is developed that is only a function of the known values of a wetting process. This correlation is presented by improving the available correlation for the surface component of the specific activation free energy of a wetting process using a curve-fitting of a wide range of experimental data. The predicted values from the correlation are in good agreement with those of the reported experiments even when a rough estimate value for the microscopic displacement length is used.
TL;DR: In this paper, the deformation characteristics and interfacial adhesion properties of silicon nitride/gallium arsenide film/substrate systems were investigated by use of nanoscratch.
Abstract: Deformation characteristics and interfacial adhesion property of silicon nitride/gallium arsenide film/substrate systems were investigated by use of nanoscratch. During scratching, three different types of deformation, elastic, elastoplastic and fracture, were discovered. The critical loads for film failure were obtained. The critical loads, together with the other scratch parameters, were used to determine the interfacial adhesion energies. The practical adhesion energies per unit area of the bilayers obtained were 2.72 and 3.73 Joules/m2, respectively. The tensile stress developed just behind the contact area and at the interface was attributed to the film failure. It was also found that residual compressive stress strengthened, but tensile stress weakened the interfacial adhesion.
TL;DR: In this paper, the effect of the floating potential (FP) on diamond film uniformity, surface morphology and crystallite orientation was studied, which may be important in low power optoelectronics devices.
Abstract: Variation in substrate bias greatly influences diamond film properties, which may be important in low power optoelectronics devices. In this work, effect of the floating potential (FP) on film uniformity, surface morphology and crystallite orientation was studied. Diamond films deposited on two pieces of silicon substrates, by using the hot-filament chemical vapour deposition technique, with one substrate set at ground potential (GP) while the other at a floating potential (FP). The standard techniques like scanning electron microscope and Raman spectra were used for film characterisation. It was observed that FP leads to increase in the density of {100} oriented grains but at the cost of growth rate and film uniformity.
Journal Article•
TL;DR: In this paper, the growth mechanism of the smooth region is believed to be the 2D nucleation mechanism and that of the rough region is the spiral growth mechanism, and a conclusion was drew that the controlling growth mechanism for sapphire crystal grown from melt through SAPMAC method is 2D nuclear growth mechanism.
Abstract: Observations of the microtopography evolution on a crystallisation surface of sapphire crystal grown from Al2O3 melt show the smooth region was formed by thin atomic layers with wave-like edge trace and the rough region was mainly of aligning long bar-like structure formed by many spiral hillocks spreaded along lines corresponding to the direction Moreover, decreasing the undercooling would enhance the width of the bars and decrease the width of the grooves adjacent the bars. According to these observations, the growth mechanism of the smooth region is believed to be the 2D nucleation mechanism and that of the rough region is the spiral growth mechanism. Consequently, a conclusion was drew that the controlling growth mechanism of sapphire crystal grown from melt through SAPMAC method is 2D nucleation mechanism.
TL;DR: In this article, the surface and subsurface deformation characteristics of cemented tungsten carbide during nanoscratching were systematically investigated, and the results indicated that the deformation of the material was significantly influenced by its microstructure.
Abstract: Surface and subsurface deformation characteristics of cemented tungsten carbide during nanoscratching were systematically investigated. Nanoscratch tests were performed at various normal loads and different scratch velocities and the surface and subsurface after scratching were examined using scanning electron microscopy. The results indicated that the deformation of cemented tungsten carbide was significantly influenced by the microstructure of the material. The deformation of subsurface structure was caused by combination of plastic deformation of cobalt binders, relocation of tungsten carbide grains, fractures and chipping.
TL;DR: In this paper, the results of laser surface melting on microstructure and mechanical properties on the surface layer of the EN32B steel carried out using a high power diode laser (HPDL) are presented.
Abstract: This work presents the findings of laser surface melting (LSM) on microstructure and mechanical properties on the surface layer of the EN32B steel carried out using a high power diode laser (HPDL). The laser treated specimens were characterised by high resolution scanning electron microscopy (HRSEM) and X-ray diffractometer (XRD) for phase analysis. The hardness profile of the laser treated cross-sectional layer was determined by using Vickers hardness tester. It was found that the micro hardness improved to as high value of 405 HV from a value of 160 HV of the substrate material. The wear resistance of the laser surface melted EN32B steel was also found to be increased. The low carbon steel laser surface melted by the HPDL has created lath martensite microstructure. XRD phase analysis confirms the formation of martensite, Fe-Mn-C and iron carbide phases at near surface regions of laser treated samples. Salt spray corrosion testing and potentiodynamic electrochemical corrosion method reveal improved corrosion resistance in the laser treated layers. The hardness value is found to increase from 160 HV to 405 and wear resistance also increases 5–6 times upon laser surface treatment. Corrosion resistance increases tremendously from a period of 7 hours to 49 hours.