International Journal of Surface Science and Engineering (23 papers in press)
MICROSTRUCTURE, MECHANICAL PROPERTIES AND CORROSION RESISTANCE OF LASER SURFACE MELTED EN353 LOW CARBON LOW ALLOY STEEL
by Sivanandham Nallathambi, Rajadurai A, S.M. Shariff, Senthilselvan Jayaraman, Mahalingam Arumugam
Abstract: The efficacy of laser surface modification of EN353 low carbon low alloy steel is studied and discussed in this research work.The High Power Diode Laser (HPDL) treated layers were characterized by means of High Resolution Scanning Electron Microscopy (HRSEM), X-Ray Diffractometer(XRD). The mechanical properties like hardness, wear and corrosion resistance were studied. The hardness profile of the laser modified cross-sectional layer was determined by Vickers hardness tester. It was found that the microhardness improved to as high as 493 HV as compared to 215 HV of the substrate material. The laser surface melting by the HPDL resulted of martensite and bainite microstructure in low carbon low alloy steel. XRD phase analysis indicated the formation of martensite, Fe-Mn-C, Fe-Cr-C and M23C6 carbide phases at near surface regions of laser treated samples. The wear resistance of the laser surface melted EN353 steel was also found to be increased. Potentiodynamic electrochemical corrosion method revealed an improved corrosion resistance in the laser treated layers.
Keywords: Laser Melting; Microstructure; Vickers hardness; Wear resistance; Corrosion resistance.
The Characterization of Surface Treated Silica-Filled and Non-Filled Polydimethylsiloxane Films
by Michael Joyce, Alexandra Pekarovicova, Paul Fleming III
Abstract: In this work, various methods to enable tailoring of Polydimethylsiloxane film surfaces are implemented and compared to determine their influence on surface energy and roughness. Films were prepared containing various levels of hydrophilic silica filler. Ultraviolet-ozone, and Piranha Solution treatments were also implemented and characterized. Lastly, the combination of both silica filler and treatments were utilized and characterized to understand interactive effects. Influence of filler loading, and surface treatment on roughness, and surface energy of films was determined. Regardless of surface treatment, addition of silica significantly influences total surface energy. Addition of silica influenced total surface energy of the films by itself, and in combination with the Piranha and UV-ozone treatments. The lowest surface energy was that of the control Polydimethylsiloxane film 21.54 N/m. The overall highest surface energy achieved was that of the 10% filled 30-minute Piranha solution treated sample, having a surface energy of 44.14 N/m.
Keywords: Polydimethylsiloxane (PDMS; surface treatments; UV-Ozone; Piranha solution; surface energy; medical devices; wettability; silica-fill; ANOVA; biocompatible.
Dry sliding wear and friction characteristics of AA6061 TiB2/ZrB2 in-situ metal matrix composites at room temperature
by A. Mahamani
Abstract: In -situ synthesis is a process of developing high-performance material with the minimal reinforcement ratio. In this work dry sliding friction and wear behavior of AA6061 TiB2/ZrB2 in-situ metal matrix composites are investigated by using pin on disc wear testing machine against high chromium steel counter face at room temperature. The influences of normal load, sliding speed and reinforcement ratio on wear properties are studied. Wear transition maps are generated to establish the scheme of the wear rate and wears transition for a particular sliding condition. Worn-out surface analysis also carried out to study the debris layer formation on the sliding surfaces. Experimental investigation shows that normal load, sliding velocity and reinforcement ratio offer significant influence on wear performance.
Keywords: In-situ composites; TiB2; ZrB2; wear rate; wear resistance; coefficient of friction;.
Experimental Investigation on Erosion Performance and Wear Factors of Custom 450 Steel as the First Row Blade Material of an Axial Compressor
by Esmaeil Poursaeidi, Alireza Mohammadi Niaei, Masoud Arablu, Akbar Salarvand
Abstract: A first-stage blade of an axial compressor of a heavy-duty gas turbine was fractured after 30,895 hours of operation due to existence of pits and micro-cracks. It was hypothesized that the pits have been created by erosion and poor corrosion mechanisms. Therefore, in this research, using a specific test machine, erosion of the blade material (AISI Custom 450) is tested under simulated conditions of the real blade such as the impingement angle and velocity of abrasive particles. The impingement angles of 90
Keywords: Compressor Blade; Erosion; Deformation and Cutting Wear Factors; Pit.
Static Wetting Characteristics of Micro-Textured Stainless Steel Surfaces under Uniaxial Loading Condition
by Vivek Anand A, Arumugam V, Kannan R
Abstract: The wetting behaviour associated with the surface micro asperities is investigated on the groove and pillar textured an SS304 solid surface which is widely used in the different components of the flight vehicles where the stresses are induced by the uni-axial compressive loads on those surfaces for both positive and negative curvature. Micro structures are created using photolithographic technique and their surface structure characterizations are done using 3D optical Profilometer and Scanning Electron Microscope. The wettability behaviour are examined with the help of static contact angle and contact diameter of the liquid drop measured from the high resolution image captured using Keygence Video microscope, where the liquid drop is illuminated by the high power strobe lamp. A custom-made setup is fabricated for inducing uni-axial compressive load on the material by means of micrometer actuation. By varying the applied load on the groove-textured surfaces in the direction perpendicular to grooves, the positive curvature shows a decrease in static contact angle initially then increases for further increase in deflection; however, the negative curvature induced by the same applied load shows an opposite trend. At the same time, in the pillar-textured surface, the static contact angle decreases with increase in applied load for the positive curvature and the same wetting parameter shows an opposite trend for the negative curvature.The liquid drop exhibits an anisotropic wetting nature on the groove textured surfaces and at the same time, the drop shows orthotropic wetting behaviour along the contact front on the pillar textured solid surface. This phenomenon is mainly attributed to the pinning behaviour of the three phase contact line of the liquid drop on these two surfaces.
Keywords: Contact Angle; Contact diameter; Wettability; Curved surface; Surface micro asperity; Anisotropic and Isotropic.
Combined influence of couple stress lubricant and geometric imperfections of journal on the performance of membrane compensated two-lobe hybrid journal bearing
by Dharmendra Jain, Stish C. Sharma
Abstract: This paper deals with the comparative performance of the two-lobe and circular hybrid journal bearing systems compensated with membrane restrictor. The combined influence of geometric imperfection of journal and the couple stress behavior of the lubricant has been taken into the consideration. The non-Newtonian behavior of the lubricant has been modeled using Stokes couple stress fluid model. The Reynolds equation has been modified to consider the couple stress fluid behavior and has been solved by the FE Galerkins approach. The numerically computed results from present study indicates that the couple stress lubricant presents an improved bearing performance in terms of stability(threshold speed), fluid film stiffness and damping coefficients vis-
Keywords: two-lobe bearing; geometric imperfection; couple stress fluid; FEM.
Theoretical Investigation of Boundary Slip on the Hydrodynamic Lubrication Performance in Pocketed Bearings Including Cavitation
by M. Muchammad, Mohammad Tauviqirrahman, Ariawan Pratomo, J. Jamari, Dirk Schipper
Abstract: Boundary slip in bearings is becoming more and more popular to improve the hydrodynamic performance (pressure and shear stress). However, most of previously published works regarding textured bearings neglected the cavitation effect and make their results questionable. The main aim of this paper is to investigate the hydrodynamic performance of slip pocketed bearings considering cavitation by a theoretical approach. Cavitation was of particular interest with respect to pressure generation and shear stress. One main result presented here was that slip over the whole surface could retard the presence of cavitation and therefore the generated pressure and shear stress could be optimal. The work presented here leads to a design reference guideline that could be used by the designer/engineer to design slip pocketed bearings for improving the hydrodynamic performance.
Keywords: Cavitation; hydrodynamic performance; pocketed bearings; boundary slip.
HFCVD nanostructured diamond films deposited by a combination of seeding suspensions and novel nucleation process (NNP)
by Debarati Mukherjee, Riccardo Polini, Veronica Valentini, Shlomo Z. Rotter, Joana C. Mendes
Abstract: The deposition of thin diamond films on foreign substrates requires the ultrasonic treatment of the substrate with diamond suspensions. This procedure leaves nanometre-sized seeds on the substrate surface; the seeds coalesce and form a closed conformal film during early stages of diamond growth. To get insight on seeds early growth and to evaluate the seeding efficiency of different suspensions, silicon samples were placed inside a HFCVD system and half of each sample was exposed to diamond growth conditions; this pre-treatment leaves a thin carbon film on the surface of the exposed regions. Following this step samples were seeded with commercially available nanodiamond suspensions and exposed again to growth conditions. Finally, samples were characterized by SEM. Results showed that seeding suspensions played a role depending on particle size and nature of dispersing medium. The growth mode on pre-treated regions showed distinct features, in particular a larger seeding density and a more uniform distribution of nanoseeds. As a consequence, continuous films formed more quickly on these regions. The carbon film deposited before the seeding step improves deagglomeration of nanodiamond seeds via a more effective interaction between substrate surface and seeds. Therefore, this procedure represents a viable way to grow thin conformal diamond coatings by HFCVD.
Keywords: HFCVD; novel nucleation process (NNP); nanodiamond; seeding.
Analysis of oxide scale deformation and surface roughness characterisation in hot rolling of stainless steels
by Xiawei Cheng, Dongbin Wei, Zhengyi Jiang, Laizhu Jiang
Abstract: Stainless steels are iron-based alloys that contain a minimum of about 12% Cr. They have been classified by microstructure at room temperature, e.g., austenitic stainless steel grade 304 and martensitic stainless steel grade 410L. The quality of the finished product is significantly affected by the deformation of the oxide scale and its surface roughness characterisation in hot rolling of stainless steels. Two stainless steel grades 304 and 410L were studied in this paper. Hot rolling was performed on a Hille 100 experimental rolling mill under various reductions between 10 and 40% with consideration of the oxide scale thickness controlled by oxidation time. Oxide scale thickness and microstructures were analysed using scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). The experimental results show that the deformation behaviour of the oxide scale on the stainless steel 304 is sensitive to its thickness and exhibits higher resistance to be deformed. However, the reduction in thickness plays an important role in the uniformity of the oxide scale deformation for the stainless steel 410L. Friction coefficients were calculated and compared under different rolling parameters. Simulations results show that the reduction in thickness and initial surface roughness play roles on final surface roughness. Steel substrate surface is rougher than that of the oxide scale at different reductions.
Keywords: stainless steel; oxide scale; deformation; friction; surface roughness.
Wear study of coatings obtained using different parameters of thermal spraying
by Regita Bendikiene, Tilmute Pilkaite, Liudas Albinas Kuliavas
Abstract: Understanding the feedstock material behaviour in thermal spraying process under different parameters is a key factor in producing repeatable and controllable coatings. This article reviews three different technological regimes of thermal spraying process, with a particular focus on the wear behaviour under the different conditions of obtained coatings. Commercial RocDur 37 flexi cord was selected as feedstock material. A buffer bond layer was used to ensure proper adhesion of coating to substrate material. Three technological regimes applying different longitudinal feed of torch were conducted in the work presented: 1.43 cm/s (A), 1.85 cm/s (B), 0.88 cm/s (C); and different number of torch passes: 6 (A), 4 (B), and 11 (C) respectively. Rotation speed of the device in each of the regimes was the same 1.33 s-1. In order to evaluate application of coatings in the different exploitation conditions the wear behaviour of thermal sprayed coatings was tested on the contact sliding, edge wear and abrasive wear testing machines. Technological regimes B and C showed better wear performance particularly in contact sliding and edge wear tests. Hydro abrasive wear test results showed very similar wear performance of coatings obtained using three different technological parameters (A, B, C), therefore it can be concluded that RocDur 37 flexi cord coatings are suitable for work in abrasive wear conditions. In this type of wear technological parameters do not affect wear behaviour of coatings. The optimum technological regimes were defined: rotation speed 1.33 s-1, longitudinal feed 0.88 cm/s, and 11 torch passes.
Keywords: thermal spraying; wear resistance; flexi cord feedstock; wear test.
High Temperature Tribological Characterization of Laser Surface Melted Ni-based Superalloy
by V. Dillibabu, Duraiselvam Muthukannan, Muhammed Anaz Khan, K.P. Naveena
Abstract: Laser surface treatment was performed on nickel-based superalloy to improve their high temperature tribological properties for enhanced service life specifically in gas turbine applications. The laser power and scan speed were strategically controlled to optimally refine the microstructure. The metallurgical and mechanical modifications in the treated area were studied to understand the refining mechanism. The coarser grains in the base material reorient to fine dendrites during laser surface melting. The equiaxed grains are refined with increased laser power and reduced interaction time under the influence of higher cooling rate. The finely refined grains improve the microhardness of the treated surface. The tribological performance and its mechanism of the treated surfaces were evaluated at room temperature and at 500
Keywords: Laser surface melting; Ni-superalloy; High temperature; Wear.
Relative anti-wear property evaluation of nano garnet gear lubricant
by MAHESWARAN R, Sunil J
Abstract: In gear boxes, the life of gears is increased by reducing the wear caused due to the friction between the rubbing surfaces of gears. This paper addresses on the study of the relative anti-wear property of nano garnet gear lubricant which are formulated by dispersing 0.25 wt%, and 0.50 wt% of nano garnet particles in commercially available SN500 grade gear lubricant oil through a standard two-step method. The anti-wear property of the lubricant is estimated by a Four-ball wear test and is measured through the microscopic investigations on the surface texture modifications namely width of the wear ring and wear scar diameter. The width of wear ring is reduced to 3.83%, 6.39%, and the wear scar diameter is reduced to 6.1%, 2.44% due to the addition of 0.25 wt%, and 0.50 wt% of particle concentrations at a maximum applied load of 588N due to the rolling effect of nano garnet particles.
Keywords: lubricant; anti-wear; surface texture modification; Four-ball wear test; wear ring; wear scar.
Study of annular recess hydrostatic tilted thrust pad bearing under the influence of couple stress lubricant behaviour
by Vivek Kumar, Satish C. Sharma
Abstract: This paper concerns with the theoretical investigation to predict the combined influence of couple stress lubricant and tilt between bearing pad surfaces, on the performance of externally pressurized annular recess thrust pad bearing. Stokes micro-continuum theory is used to derive modified Reynolds equation accounting for the presence of couple stress additives in lubricant. A MATLAB code has been developed to solve the governing equation using FEM technique. Influence of annular recess location and tilt between pad surfaces are investigated on the performance of hydrostatic thrust pad bearing. It has been observed that the use of couple stress lubricant significantly improves the performance of annular recessed hydrostatic thrust pad bearing. Presence of tilt between bearing surfaces proved to be beneficial in terms of dynamic characteristics of bearing system.
Keywords: Hydrostatic tilted thrust pad bearing; Annular recess; Couple stress lubricant; FEM Technique.
The effect of substrate bias voltage on the adhesion strength of ta-C coated tools prepare by filtered cathode vacuum arc
by Young-Jun Jang, Yong-Jin Kang, Jong-Kuk Kim
Abstract: Filtered cathode vacuum arc (FCVA)-deposited ta-C coating have found application for cutting tools. In this study, the effect of bias voltage on the physical properties of the coating and cutting performance were experimentally investigated. A bias voltages were applied with 0, 75, 150, 300 V and thicknesses were fixed with 430 nm. The experimental results showed that the regardless of the bias voltage, the adhesion strength indicates that all ta-C coating were HF 1 level. However, increasing substrate bias voltage will increase the C=C boning at the ta-C coating, especially 150 and 300 V. Moreover, hardness values also decreased with increased bias voltage. For the cutting test, a selected the ta-C coating from the lowest I(D)/I(G) value (0.5) with 75 V bias condition. After cutting test, the adhesive of Al debris and delamination on the ta-C coated surface was 3 times lower than commercial DLC. This phenomenon summarized that heat resistance of ta-C coating is dominant with high portion of sp3 fraction.
Keywords: tetrahedral amorphous carbon (ta-C); FCVA; Adhesion; cutting tool; Raman.
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.
Investigation of the Tribological Behavior of Electrocodeposited Ni-MoS2 Composite Coatings
by Ebru Saraloğlu Güler, Erkan Konca, İshak Karakaya
Abstract: Composite electroplating of solid lubricants in a metal matrix is an effective way to lower coefficient of friction (COF) and improve wear resistance of surfaces in sliding contact. In this work, NiMoS2 composite coatings were deposited on AISI 304 stainless steel substrates by electroplating from Watts bath containing suspended MoS2 particles and their tribological behavior was studied. The effects of MoS2 particle concentration (5, 10 and 30 g/l), MoS2 particle size (1.440 and 5.156
Keywords: electrocodeposition; MoS2 particle; friction; wear; surfactant; sodiumlignosulfonate.
Experimental investigation on wear characteristics of sintered Fe-C-Cr low alloy steels
by Kandavel T.K., Panneerselvam T, Vignesh Mohan
Abstract: Wear is a common property exhibited when two materials rub against each other. The present research work aims to investigate the influence of chromium (Cr) on wear characteristics of powder metallurgy (P/M) plain carbon steel (Fe-0.5%C) and to find optimal parameters for minimum wear loss and frictional coefficient of the P/M alloy steels. The sintered-forged plain carbon steel and with addition of 1% and 2% Cr P/M alloy steels were made into cylindrical pins to conduct wear tests as per the standard. The Design Expert (DE) software was used for conducting the dry sliding wear tests. Addition of Cr reduces the mass loss due to the formation of chromium carbides embedded in the ferrite grain matrix in the microstructure. The optimum working parameters found for the minimum mass loss and coefficient of friction from the Taguchi-grey relational analysis are 50N load and 113.5rpm speed irrespective of the alloy steels.
Keywords: sintering; chromium; wear; microstructure; SEM; optimization; Taguchi method.
The evaluation of lubricant properties and environmental effect of Bio-lubricant developed from Rice Bran Oil
by S. Rani
Abstract: This paper deals with the comparison of lubricant properties and environmental effect of newly developed bio-lubricant based on rice bran oil. The various lubricant properties like rheological, tribological, thermal properties, oxidative stability, corrosive stability, biodegradability and toxicity of the formulated oil have been evaluated and compared with a commercially available lubricant SAE 20W40. The formulated oil from rice bran oil is found to be highly biodegradable, less corrosive and non-toxic. Even though the coefficient of friction of the formulated oil is less compared to SAE 20W40, the wear scar diameter is slightly high compared to SAE 20W40.
Keywords: Rice bran oil; bio-lubricants; non-toxic; biodegradability; Zebra fish.
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 µm and the TiN thickness about 200 nm were measured by SEM. The surface hardness is increased about eight times, i.e. 10.4 GPa in combined structure sample compare to untreated (1.6 GPa). The positive shift in corrosion potential corroborates improvement in corrosion resistance. The corrosion current density about 4.6×10-7 Acm-2was measured and the ICR was reduced from90 mΩcm2 to 11 mΩ cm2 at 150 N cm-2after hybrid coating. The conductivity is increased after hybrid coating due to conductive nature of TiN particles on the surface of the passive oxide layer which may provide path for the electron transportation.
Keywords: Austenitic steel; Plasma Nitriding; TiN; Corrosion; Hardness; ICR
Evaluation of effective models of offset CtP plate aluminum oxide surface roughness characterization
by Zivko Pavlovic, Sandra Dedijer, Nemanja Kašiković, Dragoljub Novaković, Magdolna Pál (Apro), Dubravko Risović
Abstract: In this study, three different approaches for characterization of printing plates non-printing elements surface structure and roughness were compared: stylus profilometric method, AFM, method and software (indirect), SEM image based profilometry. The comparison was made to evaluate the possibility of utilising the different methods for characterization of CtP offset printing plate surface roughness. The direct profilometric measurements involved the use of stylus profilometer visual analysis were made using AFM device and for indirect approach the Gwyddion software, for analysis of single and stereo SEM images and calculation of standard profilometric parameters, was used. The results of this study demonstrate that it is possible to obtain profilometric parameters from the analysis of AFM and SEM micrographs with appropriately calibrated grey scale intensity distribution and that the values of the parameters are comparable to those obtained by contact stylus profilometry. The results of this comparative study indicate that profilometric 2-D direct stylus method is more applicable when larger areas tend to be measured, while the indirect image-based 3-D profilometry is a valuable and efficient tool for characterization of various surface's topographies on micron scale sample areas.
Keywords: contact stylus profilometry, surface roughness, surface topography, AFM, SEM micrograph, printing plate, aluminium oxide
Mechanical responses of coated solids in elastohydrodynamically lubricated line contacts
by Yangyi Xiao, Wankai Shi, Jing Luo
Abstract: For layered solids consisting of physical vapor deposition coatings on steel substrates in lubricated line contacts, the elastohydrodynamic lubrication (EHL) behavior is studied by the full-system finite element approach. Numerical solutions illustrate that the coating thickness, elastic modulus, and operating conditions have significant influences upon the EHL film pressure and thickness profiles, along with the coefficient of friction. Results for stress distributions provide insight into the tendency for yielding, pitting, and interfacial delamination in coated bodies. Furthermore, the film pressure and stress status induced by the interfacial micro-valley as well as rough coating surface and interface are investigated. It is demonstrated that optimized multi-layer coatings are propitious to reduce the stress gradient and failure risks of coated materials.
Keywords: Elastohydrodynamic lubrication (EHL); Coating; Multi-layer; Mechanical response.
Special Issue on: Advances in Metrology of Surface Topography
Correlation between 3D Fractal Dimension and Abrasive Wear Resistance
by Abdeljalil Jourani
Abstract: Fractal theory is usually used to investigate the topography of machined surfaces, but the relationship between fractal dimensions and wear rate is less studied. A contribution in this field is proposed with wear tests performed on the AISI 1046 steel after the grinding by use of the P80, P180 and P320 abrasive sheets. A 3D fractal study of the worn surfaces is carried out by using power spectral density (PSD) in order to examine the relationship between rate of wear and its 3D fractal dimension. The 3D fractal analysis of the worn surfaces showed that higher values of fractal dimensions indicate a larger real contact area and therefore a better wear resistance of the AISI 1046 steel.
Keywords: wear; friction; surface topography; surface roughness; 3D fractal dimension.
3D inspection technology combining passive stereo matching and active structured light for steel plate surface sample
by Xin Wen, Kechen Song, Menghui Niu, Zhipeng Dong, Yunhui Yan
Abstract: Three-dimensional (3D) inspection technology is a new important research hotspot in the field of steel surface defect inspection. However, current 3D information acquisition methods (i.e., the passive stereo vision method and active structured light method) still suffer from several issues. In order to solve these issues, a three-dimensional inspection system is designed in this paper. In this system, the passive stereo vision method and active structured light method are combined to obtain the surface sample height information of high temperature steel plate. Furthermore, the Hg_Census (Hexagonal grid Census) transform is proposed to improve the robustness of census transform stereo matching. Moreover, the passive stereo disparity map is adopted as a constraint condition to realize phase matching using wrapped phase. In addition, the local phase matching and sub-pixel disparity refinement are proposed to obtain high measuring accuracy. Three high temperature steel plate surface samples are picked to verify the effectiveness of the proposed method. The actual experimental results present the average error is less than 1 mm.
Keywords: surface sample height; three-dimensional inspection; stereo vision; active structured light.