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Susmita Bose - One of the best experts on this subject based on the ideXlab platform.

  • Compositionally graded doped hydroxyapatite Coating on titanium using laser and Plasma Spray deposition for bone implants
    Acta Biomaterialia, 2019
    Co-Authors: Dongxu Ke, Ashley A. Vu, Amit Bandyopadhyay, Susmita Bose
    Abstract:

    Plasma Sprayed hydroxyapatite (HA) Coating is known to improve the osteoconductivity of metallic implants. However, the adhesive bond strength of the Coating is affected due to a mismatch in coefficients of thermal expansion (CTE) between the metal and HA ceramic. In this study, a gradient HA Coating was prepared on Ti6Al4V by laser engineered net shaping (LENS™) followed by Plasma Spray deposition. In addition, 1 wt% MgO and 2 wt% Ag2O were mixed with HA to improve the biological and antibacterial properties of the coated implant. Results showed that the presence of an interfacial layer by LENS™ enhanced adhesive bond strength from 26 ± 2 MPa for just Plasma Spray Coating to 39 ± 4 MPa for LENS™ and Plasma Spray Coatings. Presence of MgO and Ag2O did not influence the adhesive bond strength. Also, Ag+ ions release dropped by 70% less with a gradient HA LENS™ layer due to enhanced crystallization of the HA layer. In vitro human osteoblast cell culture revealed presence of Ag2O had no deleterious effect on proliferation and differentiation when compared to pure HA as control and provided antibacterial properties against E. coli and S. aureus bacterial strands. This study presents an innovative way to improve interfacial mechanical and antibacterial properties of Plasma Sprayed HA Coating for load-bearing orthopedic as well as dental implants. Statement of significance: Implants are commonly composed of metals that lack osteoconductivity. Osteoconductivity is a property where bone grows on the surface meaning the material is compatible with the surrounding bone tissue. Plasma Sprayed hydroxyapatite (HA) Coating improves the osteoconductivity of metallic implants, however, the adhesive bond strength can be weak. This study incorporates a gradient HA Coating by using an additive manufacturing technique, laser engineered net shaping (LENS™), followed by Plasma Spray deposition to enhance the adhesive bond strength by incorporating a thermal barrier. The proposed system has not been well studied in the current literature and the results presented bring forth an innovative way to improve the interfacial mechanical and antibacterial properties of Plasma Sprayed HA Coating for load-bearing orthopedic implants.

  • mechanical in vitro antimicrobial and biological properties of Plasma Sprayed silver doped hydroxyapatite Coating
    ACS Applied Materials & Interfaces, 2012
    Co-Authors: Gary A Fielding, Amit Bandyopadhyay, Haluk Beyenal, Susmita Bose
    Abstract:

    Implant-related infection is one of the key concerns in total joint hip arthroplasties. To reduce bacterial adhesion, we used silver (Ag)/silver oxide (Ag2O) doping in Plasma Sprayed hydroxyapatite (HA) Coating on titanium substrate. HA powder was doped with 2.0, 4.0, and 6.0 wt % Ag, heat-treated at 800 °C and used for Plasma Spray Coating using a 30 kW Plasma Spray system, equipped with supersonic nozzle. Application of supersonic Plasma nozzle significantly reduced phase decomposition and amorphous phase formation in the HA Coatings as evident by X-ray diffraction (XRD) study and Fourier transformed infrared spectroscopic (FTIR) analysis. Adhesive bond strength of more than 15 MPa ensured the mechanical integrity of the Coatings. Resistance against bacterial adhesion of the Coatings was determined by challenging them against Pseudomonas aeruginosa (PAO1). Live/dead staining of the adherent bacteria on the Coating surfaces indicated a significant reduction in bacterial adhesion due to the presence of Ag...

Poh Seng Lee - One of the best experts on this subject based on the ideXlab platform.

  • reduction of harmful emissions from a diesel engine fueled by kapok methyl ester using combined Coating and sncr technology
    Energy Conversion and Management, 2014
    Co-Authors: S Vedharaj, R Vallinayagam, Wenming Yang, S K Chou, K J Chua, C G Saravanan, Poh Seng Lee
    Abstract:

    This research work has been formulated to reduce the stinging effect of NOX emission on atmospheric environment from a coated diesel engine fueled by biodiesel. As such, in the current study, we attempted to harness the renewable source of energy from in-edible kapok oil, which is normally under-utilized despite being a viable feedstock for biodiesel synthesis. Notably, steam treatment process followed by crushing of the kapok seeds in a mechanical expeller was done to extract large quantities of kapok oil for the application of diesel engine, which is quite distinct of a method adopted herein. The conventional trans-esterification process was availed to synthesize KME (kapok methyl ester) and the physical and thermal properties of it were estimated by ASTM standard methods. Subsequently, two blends of KME with diesel such as B25 (KME – 25% and diesel – 75%) and B50 (KME – 50% and diesel – 50%) were prepared and tested in a single cylinder diesel engine with thermal barrier Coating. To help realize the Coating process, PSZ (partially stabilized zirconia), a pertinent Coating material in respect of its poor thermal conductivity and better durability, has been chosen as the Coating material to be applied on engine components by Plasma Spray Coating technique. As an outcome of the Coating study, B50 was found to show improved BTE (brake thermal efficiency) than that in an uncoated engine, with notable decrease in major emissions such as HC (hydrocarbon), CO (carbon monoxide) and smoke. However, due to reduction in heat losses and increase in in-cylinder temperature, the NOX (oxides of nitrogen) emission was expected to be increased in a coated diesel engine. Therefore, in order to reduce the NOX emission, urea based SNCR system was incorporated in the exhaust pipe and by which, NOX emission was reduced.

  • experimental and finite element analysis of a coated diesel engine fueled by cashew nut shell liquid biodiesel
    Experimental Thermal and Fluid Science, 2014
    Co-Authors: S Vedharaj, R Vallinayagam, Wenming Yang, S K Chou, K J Chua, Poh Seng Lee
    Abstract:

    Abstract The main purpose of this study is to utilize a low cost feedstock, CNSL (cashew nut shell liquid) as a source for producing biodiesel and operate it in a diesel engine with and without Coating. The further scope of the work delineates to conduct a thermal–stress analysis of the coated engine piston so as to understand the physical mechanism underlying the impact of Coating on engine performance characteristics. With this intent, in the current work, a different approach to extract CNSL has been adopted and the extracted CNSL was subjected to double stage trans-esterification to synthesize CNSL biodiesel. In face of its insulating properties, PSZ (partially stabilized zirconia), used in high temperature application, has been designated as the perfect Coating material to be applied on engine piston, valves and cylinder head by Plasma Spray Coating technique. From the experimental investigation of CNSLME (CNSL biodiesel – 25% and diesel – 75%) in coated engine, it was observed that the BTE (brake thermal efficiency) of the engine was increased by 6%, when compared to uncoated engine. Further, the emissions such as CO (carbon monoxide), HC (hydro carbon) and smoke were reduced by 27.7%, 7.2% and 14.3%, respectively, at full load condition, while NOX (oxides of nitrogen) emission was increased. Finally, from the simulation study using FEA (finite element analysis), the average temperature, heat flux and thermal stress were noted to be lower for coated piston, confirming the substantial improvement in thermal efficiency in the experimental study.

A. Behera - One of the best experts on this subject based on the ideXlab platform.

  • parametric optimization of atmospheric Plasma Spray Coating using fuzzy topsis hybrid technique
    Journal of Alloys and Compounds, 2021
    Co-Authors: B. Swain, S. S. Mohapatra, Manisha Priyadarshini, Ram K Gupta, A. Behera
    Abstract:

    Abstract In the work, an elemental mixture of Ni and Ti was deposited by atmospheric Plasma Spray technology on the mild steel substrate by varying the process parameters such as primary gas flow rate and Plasma arc current. The properties such as surface roughness, microhardness, and erosion rate of the Coating were determined and the relationship between process parameters and Coating properties was established. To optimize the process parameters and to find out the optimum parametric setting, the fuzzy technique for order preference by similarity to an ideal solution hybrid technique was implemented. By keeping all the parameters constant, the Coating with better properties was obtained at an optimum parametric setting of 550 A arc current and 45 lpm primary gas flow rate. Furthermore, by implementing the Analysis of Variance, the primary gas flow rate was found to be a significant contributing factor. The X-ray diffraction analysis of the Coating developed at an optimized parametric setting revealed Ni, Ti, NiTi-B2 phase, Ni3Ti, Ti2Ni, Ni4Ti3, TiO, and NiO phases. The bonding of the Coating with the substrate was confirmed by the line scan energy dispersive spectroscopy analysis. The surface morphology of the eroded surface of the Coating developed at the optimum parameter revealed the crater formation, chip formation, lip formation, plastic deformation, and groove formation mechanisms.

  • Mechanical Properties of NiTi Plasma Spray Coating
    Journal of Thermal Spray Technology, 2020
    Co-Authors: B. Swain, P. Mallick, S. K. Bhuyan, S. S. Mohapatra, S. C. Mishra, A. Behera
    Abstract:

    NiTi shape-memory alloy Coatings were deposited by atmospheric Plasma Spray (APS) on mild-steel substrates and their mechanical properties such as hardness (Vickers’s microhardness), adhesion strength (ASTM C-633), and wear resistance (solid particle erosion) analyzed. The physical characteristics of the surface and interface of the as-deposited Coating were investigated using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and x-ray diffraction (XRD) analysis. Also, the as-deposited Coatings were exposed to airborne particle erosion to investigate their wear behavior for different erodent impact angles. The correlations between various Plasma parameters and the erosive wear resistance and mechanical properties of the Coating were established. In addition, the surface morphology of the eroded surface was investigated by scanning electron microscopy to analyze the different wear mechanisms (plastic deformation, crater formation, splat boundary pile-up, and lip formation) occurring on the surface.

  • processing and characterization of Plasma Spray Coatings of industrial waste and low grade ore mineral on metal substrates
    2012
    Co-Authors: A. Behera
    Abstract:

    Emerging portable applications and the rapid advancement of technology have posed rigorous challenges to Metallurgical engineers for development of an efficient material which can sustain for long period at any type of environment. The foremost objectives are to develop required surface properties with economical process. Now-a-days the investigation explores the Coating potential of industrial wastes. Fly-ash emerges as a major waste of thermal power plants. It mainly comprises of oxides of silicon, iron, aluminium, and titanium along with some other minor constituents. Fly-ash premixed with quartz and illmenite which are low cost minerals available in plenty are excellent candidates for providing protection against abrasive wear and resistant to erosion. Plasma Spraying is gaining acceptance for development of quality Coatings of various materials on a wide range of substrates. Utilization of such kind of industrial waste as Coating material minimizes the cost of Plasma Spray Coating deposition, which posed to be the major hindrance to its wide spread application due to high cost of the Spray grade powders. Fly-ash+quartz+illmenite (weight percentage ratio: 60:20:20) is deposited on mild steel and copper substrates by atmospheric Plasma Spraying, at various operating power levels ranging from 11 to 21kW and then characterization of the Coatings is carried out. The properties of the Coatings depend on the materials used, operating condition and the process parameters. The Plasma Spraying process is controlled by the parameter interdependencies, co-relations and individual effect on Coating characteristics. The particle sizes of the raw materials used for Coating are characterized using Laser particle size analyzer of Malvern Instruments. Coating interface adhesion strength is evaluated using Coating pull out method, confirming to ASTM C-633 standard. Deposition efficiency is an important factor that determines the techno economics of the process. It is evaluated for the deposited Coatings. In view of tribological applications, hardness is one of the most required mechanical properties. Hardness measurement is done on the polished cross section of the samples using Leitz Micro- Hardness Tester. Coating porosity is measured by image analysis technique. Coating thickness is measured on the polished cross-sections of the samples, using an optical microscope. To ascertain the phases present and phase changes/transformation taking place during Plasma V Spraying, XRD analysis is made. The Coating quality and behavior depends on Coating surface & interface morphology are studied with Scanning Electron Microscope. For wear resistance application, wear properties of these Coatings are studied by “Air Jet Erosion Test Rig”. The erosion wear behaviour of these Coatings is evaluated with angular solid particle erosion tests under various operating conditions. In order to optimize the surface property for different application, one of the challenges is to recognize parameter interdependencies; correlations and their individual effects on process so that the Coating can be useful for a specific application. This challenge can be analysed/predicted by Artificial Inteligence Methods. Statistical analysis of the experimental results using Artficial Neural Network and Taguchi experimental design is been made. Spraying parameters such as impact angle, size of the erodent, standoff distance and impact velocity are identified as the significant factors affecting the Coating tribological property. This work establishes that fly-ash+quartz+illmenite composite mixture can be used as a potential Coating material suitable for depositing Plasma Spray Coating. It also opens up a new pathway for value added utilization of this industrial waste and low-grade ore mineral.

  • prediction and analysis of deposition efficiency of Plasma Spray Coating using artificial intelligence method
    Open Journal of Composite Materials, 2012
    Co-Authors: A. Behera, S. C. Mishra
    Abstract:

    Modern industrial technologies call for the development of novel materials with improved surface properties, lower costs and environmentally suitable processes. Plasma Spray Coating process has become a subject of intense research which attempts to create functional layers on the surface is obviously the most economical way to provide high per- formance to machinery and industrial equipments. The present work aims at developing and studying the industrial wastes (Flay-ash, Quartz and illmenite composite mixture) as the Coating material, which is to be deposited on Mild Steel and Copper substrates. To study and evaluate Coating deposition efficiency, artificial neural network analysis (ANN) technique is used. By this quality control technique, it is sufficient to describe approximation complex of in- ter-relationships of operating parameters in atmospheric Plasma Spray process. ANN technique helps in saving time and resources for experimental trials. The aim of this work is to outline a procedure for selecting an appropriate input vec- tors in ANN Coating efficiency models, based on statistical pre-processing of the experimental data set. This methodology can provide deep understanding of various co-relationships across multiple scales of length and time, which could be essential for improvement of product and process performance. The deposition efficiency of Coatings has a strong dependence on input power level, particle size of the feed material, powder feed rate and torch to substrate distance. ANN experimental results indicate that the projection network has good generalization capability to optimize the deposition efficiency, when an appropriate size of training set and network is utilized.

Sanjeev Chandra - One of the best experts on this subject based on the ideXlab platform.

  • dynamics of splat formation in Plasma Spray Coating process
    Plasma Chemistry and Plasma Processing, 2002
    Co-Authors: J Mostaghimi, Mohammad Pasandidehfard, Sanjeev Chandra
    Abstract:

    The paper describes recent developments in modeling formation of Plasma Spray Coatings. Specific attention is paid to the three-dimensional simulation of droplet impact and solidification under Plasma Spraying conditions. It is shown that the extent of maximum spread is primarily determined by the Reynolds number and, to a lesser degree, by the Weber number. Splashing and break-up is shown to be the result of solidification; fluid instabilities do not play a significant role in this regard. Finally, the effect of solidification on droplet spreading is insignificant when the ratio of Stefan number to Prandtl number is much smaller than unity.

  • splat formation in Plasma Spray Coating process
    Pure and Applied Chemistry, 2002
    Co-Authors: J Mostaghimi, Sanjeev Chandra
    Abstract:

    The paper describes recent developments in modeling formation of Plasma-Spray Coatings. This is a stochastic process in which particle-impact conditions, thermophysical properties, substrate topology, and temperature all play important roles in determining the structure of Coating. Specific attention is paid to the simulation of droplet impact and solidi- fication under Plasma-Spraying conditions. Results of 3-dimensional models show that on a flat surface solidification may cause splashing and break-up of the impacting particle. Undercooling effects result in faster solidification and, thus, smaller extent of spreading. More recent works investigate the effect of surrounding gas on dynamics of impact. It is shown that this could result in entrapment of a bubble under the droplet.

K Srithar - One of the best experts on this subject based on the ideXlab platform.

  • performance characteristics of a glowplug assisted low heat rejection diesel engine using ethanol
    Applied Energy, 2011
    Co-Authors: B Karthikeyan, K Srithar
    Abstract:

    Conventional diesel engines with ethanol as fuel are associated with problems due to high self-ignition temperature of the fuel. The hot surface ignition method, wherein a part of the injected fuel is made to touch an electrically heated hot surface (glowplug) for ignition, is an effective way of utilizing ethanol in conventional diesel engines. The purpose of the present study is to investigate the effect of thermal insulation on ethanol fueled compression ignition engine. One of the important ethanol properties to be considered in the high compression ratio engine is the long ignition delay of the fuel, normally characterized by lower cetane number. In the present study, the ignition delay was controlled by partial insulation of the combustion chamber (low heat rejection engine) by Plasma Spray Coating of yttria stabilized zirconia for a thickness of 300Â [mu]m. Experiments were carried out on the glowplug assisted engine with and without insulation in order to find out the possible benefits of combustion chamber insulation in ethanol and diesel operation. Highest brake thermal efficiency of 32% was obtained with ethanol fuel by insulating the combustion chamber. Emissions of the unburnt hydrocarbons, oxides of nitrogen and carbon monoxides were higher than that of diesel. But the smoke intensity and was less than that of diesel engine. Volumetric efficiency of the engine was reduced by a maximum of 9% in LHR mode of operation.