International Journal of Surface Science and Engineering (13 papers in press)
SLIDING WEAR OF AISI1040 STEEL AT DIFFERENT THERMO CHEMICAL SURFACE TREATED CONDITIONS
by A. Arulbrittoraj, P. Padmanabhan, M. DuraiSelvam
Abstract: This work aims to investigate the sliding wear of pack borided AISI1040steel, carried out at 1000C for 12hours with Na2B4O710H2O as low potential born source, using pin-on-disc apparatus as function of applied load and sliding distance at the sliding speed kept constant; compared with gas carburized samples carried at 930
Keywords: Boriding; Carburizing; Wear rate; Wear coefficient; Frictional forces.
Enhancement of Surface Properties of Nanocrystalline TiN Coated Plasma Nitrided AISI 310 Austenitic Stainless Steel
by Pankaj Singh, Arbind Kumar, Sanjay Sinha, Aman Aggarwal, Gajendra Singh
Abstract: The surface modification with combination of plasma nitriding and TiN coating on 310 stainless steel significantly improved the surface hardness and corrosion properties. X-ray diffraction (XRD) showed the expanded austenite, CrN and TiN phases along with austenite phase. The nitrided layer in the range of 10-50
Keywords: Austenitic steel; Plasma Nitriding; TiN; Corrosion; Hardness; ICR.
Effect of Process Parameters on the Microstructure, Hardness and Wear Resistance Properties of Zn-Sn-Ti Coatings on AISI 1015 Steel: Laser Alloying Technique
by Olawale S. Fatoba, Esther T. Akinlabi, Mamookho E. Makhatha
Abstract: The deterioration of materials during industrial application poses a serious threat to the materials structural integrity. A materials susceptibility to wear and surface damage can be reduced by alteration of its surface chemistry, morphology and crystal structure. Therefore, modification of surface properties plays an important role in optimizing a materials performance for a given application. The aim of the research was to investigate the enhancement in the microstructure and wear properties of Zn-Sn-Ti ternary coatings on AISI 1015 steel by laser alloying technique using Ytterbium Laser System (YLS). A laser power of 750-900 W, scanning speeds of 0.6 and 0.8 m/min, and alloy compositions of 25Zn-25Sn-50Ti and 20Zn-20Sn-60Ti were used in this study. Increase in Ti content from 50 to 60% at different laser processing conditions resulted in improved properties. The enhanced properties were obtained at 20Zn-20Sn-60Ti alloy at laser power of 950 W and speed of 0.8 m/min. At optimum composition and speed of 0.8 m/min, there was enhancement of 24% in wear resistance performance. In addendum, significant reduction in wear volume loss of 20Zn-20Sn-60Ti alloy at 0.8 m/min was attributed to excellent wear resistance performance due to metastable intermetallic phases. The coatings were free of cracks and pores with homogeneous and refined microstructures with good adhesion to the substrate. Iron content in the substrate modified the intermetallic compounds and the enhanced wear resistance performances of Zn-Sn-Ti ternary coatings can be attributed to major hard phases of iron-titanium (Fe2Ti), iron-zinc (FeZn6.67, FeZn15), iron-tin (FeSn2), and titanium-zinc (TiZn16) intermetallic compounds and high hardness and strong covalent dominant atomic bonds. Response Surface Model (RSM) used in this research authenticates reasonably with the experimental results.
Keywords: AISI 1015; Zn-Sn-Ti coatings; wear resistance; hardness; microstructure; Response Surface Model (RSM).
Neural network modelling of Abbott-Firestone roughness parameters in honing processes
by Maurici Sivatte-Adroer, Irene Buj-Corral, Xavier Llanas-Parra
Abstract: In present study, three roughness parameters defined in the Abbott-Firestone or bearing area curve, Rk, Rpk and Rvk, were modeled for rough honing processes by means of Artificial Neural Networks (ANN). Input variables were grain size and density of abrasive, pressure of abrasive stones on the workpieces surface, tangential or rotation speed of the workpiece and linear speed of the honing head. A back propagation algorithm was used for training the networks. Two strategies were considered, use of either one network for modeling the three parameters at the same time and use of three networks, one for each parameter. Best network was chosen among different structures, having either one or two hidden layers. Overall best neural network consists of three networks, one for each roughness parameter, with one hidden layer having 25, 9 and 5 neurons for Rk, Rpk and Rvk respectively. However, use of one network for the three roughness parameters would allow addressing an indirect model. In this case, best solution corresponds to two hidden layers having 26 and 11 neurons.
Keywords: Roughness; honing; artificial neural networks; neurons; back propagation algorithm; grain size; density of abrasive; linear speed; tangential speed; pressure.
Pack-boriding of AISI P20 steel: Estimation of boron diffusion coefficients in the Fe2B layers and tribological behaviour
by Mourad KEDDAM, Milton Elias-Espinosa, Martin Ortiz-Domínguez, I. Simón-Marmolejo, J. Zuno-Silva
Abstract: In the present study, the AISI P20 steel was pack-borided in the temperature range of 1123-1223 K for treatments times between 2 and 8 h. A new kinetic model based on the integral method was used to est
Keywords: Incubation time; Diffusion model; Activation energy; Growth kinetics; Cohesion; Wear.
Effect of microwave power on morphology of AgO thin film grown using microwave plasma CVD
by Akhalakur Rahman Ansari, Mohd. Imran, I.S. Yahia, M. Sh. Abdel-Wahab, Ahmed Alshahrie, Afzal Husain Khan, Chandan Sharma
Abstract: In this study, pure silver (Ag) thin film of 8 nm was deposited onto glass substrate by using Radio Frequency (RF) sputtering technique and was then exposed to microwave assisted oxygen plasma generated by microwave plasma CVD. The oxidation of Ag into AgO thin film was studied using varying microwave power. The influence of microwave power on morphology and size of oxide film was investigated. The crystal structure, crystal size, chemical composition, morphologies and optical properties of oxidized silver thin film (AgO) is characterized by using X- ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectroscopy and UV-Vis spectroscopy. Morphological characterization of these films reveals a systematic change from metallic silver (Ag) to silver oxide (AgO). The size of AgO thin film was calculated by using Scherrer equation and was observed as 11 nm, 12 nm and 13.5 nm at 400 W, 800 W and 1200 W respectively. A considerable change in UV-Vis spectra was observed with increase in annealing temperature.
Keywords: AgO; Thin Film; oxygen plasma; microwave CVD.
Effects of pH on CdO films deposited onto ITO coated glass substrates by electrodeposition
by Baris Altiokka, Ayca Kiyak Yildirim
Abstract: Thin films of CdO were deposited onto indium tin oxide (ITO) coated glass substrates using electrodeposition method. The pH of the final solutions was adjusted from 4 to 8 and effects of pH on the films were investigated. The maximum film thickness was reached at pH 5 and XRD studies showed that this film had relatively high peak intensities. Optical studies showed that band gap varies between 2.04 and 2.41 eV and depend on pH. The surface morphologies were analysed by SEM images and they revealed that films were deposited compact and there were no voids, cracks or pinholes.
Keywords: CdO; Thin Films; electrodeposition; pH.
In-situ formation, anti-Corrosion and Hardness values of Ti-6Al-4V Biomaterial with Niobium via Laser deposition.
by Phume L, Popoola Api, VICTOR AIGBODION, Pityana S
Abstract: Ti-6Al-4V alloy biomaterials have low hardness, wear resistance, high corrosion rate and toxicity as results of release of aluminium and vanadium ions that led to the premature failure of the implant. In order to overcome some of these problem that lead to laser cladding of Ti-6Al-4V alloy with Niobium. Three laser parameters (laser power, beam diameter and laser scan speed) were used to ascertain the proper operating condition for this laser process. RofinNd: YAG laser was used in the laser cladding. The electrochemical study was conducted using Hanks buffered salt solution an environment similar to the human body. The optimum improvement in corrosion resistance resulted to 81.79% when compared with substrate. It has been established that operating parameter for laser cladding of Nb on Ti6Al4V were obtained at: laser power(1000W), beam diameter (1mm) and scan speed (0.3m/min).
Keywords: Keywords: Niobium; Laser parameters; Ti-6Al-4V alloy; Microstructure and Corrosion.
Superficial alterations in the generation of a 3D surface. The case of machining by turning. Application of Principal Component Analysis to the study of the various factors involved
by Fernando Ancio, Antonio J. Gámez, Mariano Marcos
Abstract: Surface quality is an essential requisite in the manufacturing industry. In order to perform an in-depth study into the mechanisms that govern the formation of this surface, all factors involved in the machining process must be ascertained. The resulting surface after turning (real surface) is studied as the superposition of multiple surfaces. A first surface, (tool surface), is generated from the geometry of the tool and machining parameters. A second surface (vibration surface) is generated from the vibration of the tool. Finally, a third surface (other-factors surface) is taken as the joint result of fracture of material, elastic recoveries, plastic deformations, deposits and/or adhesions of material and/or tool wear. The comparison of these four surfaces enables this objective to be reached. A new parameter denominated dispersion, is defined. Principal Component Analysis (PCA) is used in the definition of this parameter.
Keywords: Surface quality; Manufacturing industry; Turning; Roughness; Vibration; Fracture of material; Elastic recoveries; Plastic deformations; Deposits and/or adhesions of material; Tool wear Principal Component Analysis (PCA); Characterisation of surfaces.
Electrochemical Studies and Surface Analysis of Laser Deposited Zn-Al-Sn Coatings on AISI 1015 Steel.
by Olawale S. Fatoba, Abimbola P. I. Popoola, Victor S. Aigbodion
Abstract: Surface hardening of mild steel with Zn-Sn bath is characterized by the traditional phases, whereas presence of Aluminium leads to coatings constitute by phase in the inner layers, and by an outer layer made of three phases and intermetallic phases which made the materials to be brittle. Enhancement in properties of Zn-Al-Sn coating led to the investigation of Zn-Al-Sn coating on mild steel by laser alloying technique. Composition of 25%Zn-50%Al-25%Sn and 30%Zn-40%Al-20%Sn with laser power of 750 W, scanning speed of 0.6 and 0.8 m/min were used in this research. Standard techniques were used for the characterization of the laser samples and 0.5 M H2SO4 was used for the electrochemical test. The results showed that all the properties were improved by increasing the Al content from 40 to 50%. The optimum properties were obtained at 25%Zn-50%Al-25%Sn at laser power of 750 W and speed of 0.8 m/min. The optimum composition significantly improved the corrosion resistance of Zn-Al-Sn coatings in 0.5 M H2SO4 solutions and 2.2-times the hardness of the substrate was also achieved. It has been established that laser alloying of mild steel with Zn-Al-Sn coatings is promising for improving the surface hardness values and corrosion resistance.
Keywords: Keywords: AISI 1015 steel; Zn-Al-Sn Coating; Hardness; Electrochemical properties; intermetallics.
Tribological Performance of DLC/DLC and Steel/DLC Contacts in The Presence of Additivated Oil
by Abdul Mannan, M.F.M. Sabri, M.A. Kalam, H.H. Masjuki
Abstract: In this study, the tribological properties of ta-C DLC were largely influenced by the counter surfaces and additives. The DLC/DLC contact showed approximately 60% lower wear when tested with additivated oil compared to that of base oil and this result was 66% in Steel/DLC contact. Friction coefficient in DLC/DLC contact was lower than in Steel/DLC contact under both oils. But however, both contacts showed slightly higher friction coefficient under additivated oil compared to that of base oil. In Steel/DLC, the thermo-chemical reaction between carbon and iron and/or the fusion of the transferred particles were prevented by additives which were present under base oil. The fracture found on DLC surface in Steel/DLC contact under additivated oil indicates that the tribolayer formed on the steel surface would be of brittle nature. The passivation of surfaces in DLC/DLC contact by additives prevented the damage which was observed under base oil.
Keywords: DLC Coatings; Vegetable Oil; Four Ball Tribo-testing; Anti-wear Additive; Fiction and Wear.
Copper Electrodeposition on Silicon Electrodes
by Frederico Lima, Ulrich Mescheder, Claas Müller, Holger Reinecke
Abstract: A two-step process is reported for the electrochemical deposition of copper layers on n-type silicon substrates using an acidic copper sulphate solution without addition of additives and neither light assistance. Metal layers were generated on electrodes with different crystal orientations. The process consists of a combination of two very common techniques: chronoamperometry and pulse plating. The former technique is applied to obtain an instantaneous nucleation on the working electrode. Therefore, a large amount of metal nuclei is formed on the substrate before the pulse technique starts. The latter is, then, used to grow the particles previously generated and form a homogeneous metal layer with full coverage onto the semiconductor electrodes. The potential magnitudes are carefully chosen in line with energy levels observed at the semiconductor-electrolyte interface and were also calculated in this work.
Keywords: seedless electroplating; silicon coating; semiconductor-electrolyte interface; pulse plating; copper plating.
Variation of surface roughness, micro-hardness and friction behaviour during sheet-metal forming
by Tomasz Trzepiecinski, Wojciech Bochnowski, Lucjan Witek
Abstract: The aim of the research described in this paper is to analyse the evolution of the main surface parameters values and friction coefficient value due to the sheet deformation. Frictional properties of the deep-drawing quality steel sheets were investigated using the strip drawing test under both dry and lubricated conditions. An increase in the plastic deformation of sheets in the range of true strain between 0 to 0.28 caused an increase in the value of amplitude roughness parameters Ra, Rp, Rt, measured along the rolling direction of the sheet metal and perpendicular to this direction. The character of frictional phenomena of the deformed sheets is a complex function of sheet directional topography, formed by pre-straining and strain-hardening phenomena. It was also found that owing to the strain-hardening phenomenon the micro-hardness of the sheet increased with the sheet deformation. However, this relation was near linear.
Keywords: friction; microhardness; sheet metal forming; strip drawing test; surface roughness; surface topography.