Jayashree Bijwe - Academia.edu (original) (raw)

Papers by Jayashree Bijwe

Nanomaterials

The current study focuses on studying the effect of reinforcement of carbon fabric (CF) decorated... more The current study focuses on studying the effect of reinforcement of carbon fabric (CF) decorated with in-situ grown silver (Ag) nanoparticles (NPs) on the performance properties of epoxy composite. The Ag NPs were grown on carbon fabric by reducing silver nitrate. The main objective of developing such an innovative reinforcement was to improve thermal conductivity, interlaminar strength, and tribological properties of CF-epoxy composites. The growth of NPs on the surface of CF was confirmed through scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDAS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction studies. The development of composites was conducted by the impregnation method, followed by compression molding. It was observed that in-situ growth of Ag NPs enhanced thermal conductivity by 40%, enhanced inter-laminar shear strength by 70%, enhanced wear resistance by 95%, and reduced the friction coefficient by 35% in comparison to untreated CF.

Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering

Although extensive research has been carried out for predicting and mitigating brake noise proble... more Although extensive research has been carried out for predicting and mitigating brake noise problems over the past decades, it is still challenging to predict its occurrence due to the complex nature of the brake system. Friction-induced vibration between the tribo couple (i.e. brake disk-pads) is one of the key players for increasing the noise and vibration issues in the brake system. The composition of friction materials (FMs) (i.e. pads/shoes) controls both tribological and noise-vibration (NV) performance. Binder (i.e. resin) is the heart of FMs which binds all the ingredients firmly and provides strength. A lot is reported on the types and amount of resin on the tribological performance, but no study addresses the noise and vibration performance adequately. This work investigates the role of binder in controlling the NV performance of the Cu-free brake-pads. Four types of copper-free brake-pads were developed with varying content (viz., 6, 8, 10, and 12 wt.%) of phenolic resin a...

Wear, 2021

Abstract A synthetic hydrated calcium silicate (commercially available as Promaxon-D) is used as ... more Abstract A synthetic hydrated calcium silicate (commercially available as Promaxon-D) is used as one of the ingredient in some friction materials (FMs) since it has the ability to improve the porosity of the product due to its very special crystalline structure. The present work aims to evaluate the detailed noise and vibration (NV) performance of Promaxon-D (PD) based pads in comparison with the non-PD based ones. Five different types of Cu-free brake-pads were developed with identical composition but varying wt.% of PD particles (0, 5, 10, 15, and 20) and compensating the difference with barite, a space filler. After characterizing these brake-pads for physical and mechanical properties, NV performance was evaluated following SAE J2521 test standard and also the friction-performance based on the data generated on the same rig. As the PD contents increased, the brake NV performance improved considerably for the selected operating conditions. In view of the overall improvement in both noise and vibration aspects, the pad with 20 wt.% PD (P20) performed best with an overall ~ 3 dBA drop in noise level and ~11% drop in vibration vis-a-vis PD-free pads leading to a conclusion that 20 wt.% PD may be used for improving the NV performance of brake-pads and also increasing the friction level.

Graphite is commonly used in brake pads. The use of graphite powder has the main goal of solid st... more Graphite is commonly used in brake pads. The use of graphite powder has the main goal of solid state lubrication and friction coefficient stabilization. In this article results on resin bonded brake pads with focus on noise performance and heat dissipation are presented. Experimental tests are based on model friction materials with a known formulation and a reduced number of components for a better identification of the role of the graphite type. Results clearly indicate that both noise performance and thermal conductivity are strongly affected by the type of graphite. Guidelines for the selection of graphite types for optimized friction materials are given.

A new class of thermoset polymers was synthe- sized based on agrochemical renewable cardanol—a by... more A new class of thermoset polymers was synthe- sized based on agrochemical renewable cardanol—a by-prod- uct of cashew nut industry. A solventless synthesis of bisbenzoxazine monomers based on bisphenol-A (b) and ani- line (abbreviated as Bzb-A) and cardanol (c) with diamines namely bis-(4-(4-aminophenoxy)phenyl)ether (HP), bis-(3-(4- aminophenoxy)phenyl)ether (HM), 4,4 0 -diaminodiphenylsul- phone (DDS) and 2,2-bis(4-(4-aminophenoxy)phenyl)propane (BA) was carried out. The benzoxazine monomers (Bzc-HP, Bzc-HM, Bzc-DDS and Bzc-BA) were characterized by 1 H- NMR and FTIR spectroscopy. The curing exotherm depended on the structure of the monomers. The onset curing temperature (To) was lowest for Bzb-A (460 K) and highest in Bzc-HM (518 K). The decomposition temperature for 5% mass loss (T5%) of resins followed the order PBzb-A \ PBzc-DDS \ PBzc-BA \ PBzc-HM & PBzc-HP. The materials showed their potential as adhesives. Lap shear strength on steel plates followed the trend PBzc-DDS \ PBz...

World Academy of Science, Engineering and Technology, International Journal of Mechanical and Mechatronics Engineering, 2018

Composites Science and Technology, 2021

Wear of Composite Materials, 2018

Applied Surface Science, 2021

Abstract Nano-particles (NPs) and their role in controlling the performance of composites is the ... more Abstract Nano-particles (NPs) and their role in controlling the performance of composites is the most intensively researched field with still limited understanding. The domain of investigating nano-mechanisms operative during tribological contacts, especially when particles of contrasting properties are simultaneously added in the polymer composite for exploration of synergism, is almost an untouched area. In this work, graphite particles (soft and layer-lattice structure) (15%) were co-added with 2% NPs of alumina (hard and spherical) in a composite containing PAEK (poly aryl ether ketone) and short glass fibers (35%). In another composite, these NPs were siloxane functionalized to investigate the effect of functionalization. In-depth investigations on physical, mechanical, and tribological properties along with detailed analysis of mechanisms by FESEM-EDAX (Field-Emission Scanning electron microscopy-Energy Dispersive Spectroscopy), Micro-Raman spectroscopy (MRS), atomic force microscopy (AFM), goniometry, nano-indentation, etc. led to a conclusion that the inclusion of hard and spherical NPs changes the fundamental process of area contact to a point contact to a great extent resulting in further reduction in friction and wear. Particles of graphite, on the other hand, were finally found to be converted into nano-graphene sheets during severe shearing based on AFM investigations. Increase in hardness due to NPs was found to be a reason for enhanced wear resistance (WR). Functionalized NPs led to the best properties in every case because of enhanced adhesion with the resin, which minimized the chances of being thrown out in wear debris.

Composites Part C: Open Access, 2021

Abstract In this paper tribo-comparison of two SLs viz. graphite and PTFE as a secondary lubrican... more Abstract In this paper tribo-comparison of two SLs viz. graphite and PTFE as a secondary lubricant in composites with identical composition (20 wt%) is presented. The mechanical, thermal and tribological properties as well as mechanism of PAEK composites were investigated in detail. It was found that although incorporation of PTFE reduced most of the mechanical properties and thermal conductivity, it was responsible for increasing the tribo- potential of composites to a significant level. Compared to a composite with graphite as a secondary SL, a reduction in wear rate (18–30 %) and friction (2–18%) was exhibited due to PTFE and nano-PTFE. The composites showed very high PV s a f e (pressure x velocity) value of 182 MPa m/s with low (0.04) and wear rate ( 1.33 × 10 − 16 MPa m/s). It was shown that the formation of a polymeric transfer film on a metal countersurface is crucial in achieving ultralow wear and friction in dry condition. The investigations on worn surfaces and the transfer films with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) analysis and Raman spectroscopy proved useful to understand wear mechanisms.

Journal of Materials Research and Technology, 2021

Abstract Some specialty polymers such as polyetheretherketone (PEEK), Polyaryletherketone (PAEK),... more Abstract Some specialty polymers such as polyetheretherketone (PEEK), Polyaryletherketone (PAEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyamideimide (PAI), and polyimide (PI) are the ideal choices for developing high performance bidirectionally reinforced composites that would excel in specific strength performance. However, these polymer composites are extremely challenging from a processing point of view and have limited choices. Most of the time, a lot of compromises are to be made on the fiber-matrix wetting issues. The current research elaborated on a method to exploit two techniques together to opt for advantages from both. Polyetherimide (PEI) solutions of various concentrations/viscosities were used as sizing agents for the fibers so as to wet the cross-over points on graphite fabric and inter-tow filaments. It was expected that the PEI and PAEK would form a blend at the interface, although fiber would necessarily be covered with only PEI. It was also anticipated that there could be an optimum amount of PEI on the fibers’ surface for the best performance properties. Based on the in-depth studies on the performance properties, it was concluded that PEI solution in the range of 5–10 wt. % would lead to the best combination of performance properties. Compared to the classical method of developing PAEK-graphite fabric composites by film technique, the current method of combination of impregnation and film technique led to excellent results.

Surface and Coatings Technology, 2021

Abstract The present paper reports on the interaction of low-pressure plasma (LPP) with the surfa... more Abstract The present paper reports on the interaction of low-pressure plasma (LPP) with the surfaces of different stainless steels (SS) (viz. austenitic, martensitic, and ferritic). Plasma treatment was standardized by optimizing the power and duration of plasma exposure. The criteria for such standardization were the extent of decrease in contact angle and hence increase in surface energy (SE), which would increase the lap shear strength (LSS) of these surfaces in the form of joints using phenolic resin. It was found that argon LPP was more effective than the argon-oxygen LPP and, the best results were obtained with a plasma exposure of 500W power for 20 min. The LSS of SS316 got improved by almost 100 % for the plasma-treated surface compared to the untreated one. Contact angles got reduced to different extents for all the three types of SS, and a significant improvement (~175 %) in SE was observed. The increase in SE was supported by atomic force micrographs that showed a decrease in the surface roughness. X-ray photoelectron spectroscopy (XPS) indicated a significant change in the surface chemistry due to the Ar-LPP treatment.

Composites Part B: Engineering, 2021

Abstract Fabric-(BD-bi-directionally) reinforced high performance polymer composites are well-kno... more Abstract Fabric-(BD-bi-directionally) reinforced high performance polymer composites are well-known for their exceptional mechanical, thermal and tribological properties. However, their processing is generally challenging, especially for specialty polymers like Polyetheretherketone (PEEK), Polyaryletherketone (PAEK) etc. mainly because of unavailability of a right kind of solvent which restricts exploitation of solution impregnation technique. Having very high melting points along with high melt-viscosity and high oxidation tendency, the possibility of melt-impregnation also gets eliminated. Furthermore, unavailability in fibrous form restricts the processing possibility by commingling technique. The possible options left for developing such composites perhaps are by film-stacking and powder-sprinkling techniques although the major issue of non-wetting at cross-over points remains unaddressed. This paper reports on the maiden effort on developing, characterizing and in depth performance analysis of graphite fabric reinforced PAEK composites. Powder-sprinkling and film-stacking techniques were employed in this work by maintaining identical processing parameters and fabric amount. The comparative performance evaluation led to a conclusion that film-stacking technique excelled in almost all performance properties barring thermal conductivity and thermo-mechanical performance. The performance analysis was based on various techniques such as thermal-conductivity, field emission scanning electron microscopy (FESEM) on polished cross-sections, thermal and thermo-mechanical analysis, mechanical testing, micro-computed tomography, abrasive wear studies etc.

Wear, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

SAE Technical Paper Series, 2020

International Journal of Surface Science and Engineering, 2019

The current study aims to investigate the effect of silane-treatment of wollastonite on the mecha... more The current study aims to investigate the effect of silane-treatment of wollastonite on the mechanical, tribological performance of non-asbestos organic frictional brake-pad material. Two main friction lining specimens in the shape of brake-pads containing treated wollastonite (Wt) and untreated wollastonite (Wu) were produced to carry on the experiments. All produced samples were characterised and examined for their mechanical, chemical and tribological properties. The experimental results show that all parameters of tribological performance are within the acceptable standard range and that the tribological performance for all samples is almost the same in terms of friction coefficient and fade performance. Regarding wear, recovery performance and disc temperature rise (DTR), Wt samples offer better performance than Wu samples which was attributed to the good adhesion between wollastonite and the polymeric matrix after treatment. Moreover, scanning electron microscopy analysis is done on the tested samples and show overall improved surface of Wt than Wu. Finally, for full use of wollastonite silane-treatment advantages, it is recommended to be used in vehicles with less severe operating conditions such as motorbike and alike.

Surface and Coatings Technology, 2018

Investigations on influence of nano and micron sized particles of SiC on performance properties o... more Investigations on influence of nano and micron sized particles of SiC on performance properties of PEEK coatings

Composites Part B: Engineering, 2016

Two series of UHMWPE composites were developed using boron carbide (B 4 C) particles in different... more Two series of UHMWPE composites were developed using boron carbide (B 4 C) particles in different amounts and sizes. Micro-series contained micro B 4 C particles (2e5 mm) in various wt% (0, 2, 4, 6, 8 and 10) while nano-series contained nano-particles (NPs) of size 70e90 nm in 0, 2 and 3%. Abrasive wear studies against silicon carbide (SiC) paper in a single pass condition were conducted under varying loads and speeds. Inclusion of B 4 C particles proved beneficial to enhance the wear resistance and optimum amounts of filler for micro and nano-series were z 6e8% and 3% respectively. Scratch hardness showed fairly good linearity with the wear resistance. SEM studies confirmed that inclusion of hard fillers mainly reduced the severity of micro-cutting mechanism and hence wear.

Wear, 2016

Abstract A novel type of graphite (thermographite) having higher thermal conductivity (TC) due to... more Abstract A novel type of graphite (thermographite) having higher thermal conductivity (TC) due to a patented treatment is commercialized recently. It was anticipated that such particles would be more effective in conducting away frictional heat generated on the tribo-surfaces leading to the enhanced performance. Hence two composites were developed based on high performance Polyarylether ketone (PAEK) (50% by wt) containing 30% short glass fibers (GF) and hexa-boron nitride (hBN) 10% apart from 10% graphite. First composite designated as CNG contained 10% natural graphite (NG) while the other designated as CTG contained 10% thermographite (TG). These were processed by identical method (twin screw extrusion followed by injection molding). The tribo-performance was evaluated in a pin on disc (mild steel) configuration under very high load and speeds. It was observed that both the composites exhibited excellent tribo-performance. However, CNG performed better than the CTG in all respects only under severe operating conditions. Under low PV conditions, difference was not clear. It showed lower friction coefficient, and wear rate as compared to CTG. CNG showed PVlimit value 96.6 MPa-m/s which was decisively superior to CTG (91 MPa-m/s). CNG could sustain higher speed (3.45 m/s) than the CTG (3.25 m/s) under 900 N in spite of slightly lower TC. It was concluded that during treatment (patented by the company) TG has slightly distorted layer-lattice structure as compared to the natural graphite, which could be responsible for transferring less beneficial film under severe operating conditions. SEM and EDAX studies were conducted to understand wear mechanisms. Such composites with such high PVlimit values low, µ (0.04) and low wear rates (1×10−16 m3/Nm) are not reported in the literature and may prove as ideal materials for dry bearings in harsh operative conditions.

Nanomaterials

The current study focuses on studying the effect of reinforcement of carbon fabric (CF) decorated... more The current study focuses on studying the effect of reinforcement of carbon fabric (CF) decorated with in-situ grown silver (Ag) nanoparticles (NPs) on the performance properties of epoxy composite. The Ag NPs were grown on carbon fabric by reducing silver nitrate. The main objective of developing such an innovative reinforcement was to improve thermal conductivity, interlaminar strength, and tribological properties of CF-epoxy composites. The growth of NPs on the surface of CF was confirmed through scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDAS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction studies. The development of composites was conducted by the impregnation method, followed by compression molding. It was observed that in-situ growth of Ag NPs enhanced thermal conductivity by 40%, enhanced inter-laminar shear strength by 70%, enhanced wear resistance by 95%, and reduced the friction coefficient by 35% in comparison to untreated CF.

Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering

Although extensive research has been carried out for predicting and mitigating brake noise proble... more Although extensive research has been carried out for predicting and mitigating brake noise problems over the past decades, it is still challenging to predict its occurrence due to the complex nature of the brake system. Friction-induced vibration between the tribo couple (i.e. brake disk-pads) is one of the key players for increasing the noise and vibration issues in the brake system. The composition of friction materials (FMs) (i.e. pads/shoes) controls both tribological and noise-vibration (NV) performance. Binder (i.e. resin) is the heart of FMs which binds all the ingredients firmly and provides strength. A lot is reported on the types and amount of resin on the tribological performance, but no study addresses the noise and vibration performance adequately. This work investigates the role of binder in controlling the NV performance of the Cu-free brake-pads. Four types of copper-free brake-pads were developed with varying content (viz., 6, 8, 10, and 12 wt.%) of phenolic resin a...

Wear, 2021

Abstract A synthetic hydrated calcium silicate (commercially available as Promaxon-D) is used as ... more Abstract A synthetic hydrated calcium silicate (commercially available as Promaxon-D) is used as one of the ingredient in some friction materials (FMs) since it has the ability to improve the porosity of the product due to its very special crystalline structure. The present work aims to evaluate the detailed noise and vibration (NV) performance of Promaxon-D (PD) based pads in comparison with the non-PD based ones. Five different types of Cu-free brake-pads were developed with identical composition but varying wt.% of PD particles (0, 5, 10, 15, and 20) and compensating the difference with barite, a space filler. After characterizing these brake-pads for physical and mechanical properties, NV performance was evaluated following SAE J2521 test standard and also the friction-performance based on the data generated on the same rig. As the PD contents increased, the brake NV performance improved considerably for the selected operating conditions. In view of the overall improvement in both noise and vibration aspects, the pad with 20 wt.% PD (P20) performed best with an overall ~ 3 dBA drop in noise level and ~11% drop in vibration vis-a-vis PD-free pads leading to a conclusion that 20 wt.% PD may be used for improving the NV performance of brake-pads and also increasing the friction level.

Graphite is commonly used in brake pads. The use of graphite powder has the main goal of solid st... more Graphite is commonly used in brake pads. The use of graphite powder has the main goal of solid state lubrication and friction coefficient stabilization. In this article results on resin bonded brake pads with focus on noise performance and heat dissipation are presented. Experimental tests are based on model friction materials with a known formulation and a reduced number of components for a better identification of the role of the graphite type. Results clearly indicate that both noise performance and thermal conductivity are strongly affected by the type of graphite. Guidelines for the selection of graphite types for optimized friction materials are given.

A new class of thermoset polymers was synthe- sized based on agrochemical renewable cardanol—a by... more A new class of thermoset polymers was synthe- sized based on agrochemical renewable cardanol—a by-prod- uct of cashew nut industry. A solventless synthesis of bisbenzoxazine monomers based on bisphenol-A (b) and ani- line (abbreviated as Bzb-A) and cardanol (c) with diamines namely bis-(4-(4-aminophenoxy)phenyl)ether (HP), bis-(3-(4- aminophenoxy)phenyl)ether (HM), 4,4 0 -diaminodiphenylsul- phone (DDS) and 2,2-bis(4-(4-aminophenoxy)phenyl)propane (BA) was carried out. The benzoxazine monomers (Bzc-HP, Bzc-HM, Bzc-DDS and Bzc-BA) were characterized by 1 H- NMR and FTIR spectroscopy. The curing exotherm depended on the structure of the monomers. The onset curing temperature (To) was lowest for Bzb-A (460 K) and highest in Bzc-HM (518 K). The decomposition temperature for 5% mass loss (T5%) of resins followed the order PBzb-A \ PBzc-DDS \ PBzc-BA \ PBzc-HM & PBzc-HP. The materials showed their potential as adhesives. Lap shear strength on steel plates followed the trend PBzc-DDS \ PBz...

World Academy of Science, Engineering and Technology, International Journal of Mechanical and Mechatronics Engineering, 2018

Composites Science and Technology, 2021

Wear of Composite Materials, 2018

Applied Surface Science, 2021

Abstract Nano-particles (NPs) and their role in controlling the performance of composites is the ... more Abstract Nano-particles (NPs) and their role in controlling the performance of composites is the most intensively researched field with still limited understanding. The domain of investigating nano-mechanisms operative during tribological contacts, especially when particles of contrasting properties are simultaneously added in the polymer composite for exploration of synergism, is almost an untouched area. In this work, graphite particles (soft and layer-lattice structure) (15%) were co-added with 2% NPs of alumina (hard and spherical) in a composite containing PAEK (poly aryl ether ketone) and short glass fibers (35%). In another composite, these NPs were siloxane functionalized to investigate the effect of functionalization. In-depth investigations on physical, mechanical, and tribological properties along with detailed analysis of mechanisms by FESEM-EDAX (Field-Emission Scanning electron microscopy-Energy Dispersive Spectroscopy), Micro-Raman spectroscopy (MRS), atomic force microscopy (AFM), goniometry, nano-indentation, etc. led to a conclusion that the inclusion of hard and spherical NPs changes the fundamental process of area contact to a point contact to a great extent resulting in further reduction in friction and wear. Particles of graphite, on the other hand, were finally found to be converted into nano-graphene sheets during severe shearing based on AFM investigations. Increase in hardness due to NPs was found to be a reason for enhanced wear resistance (WR). Functionalized NPs led to the best properties in every case because of enhanced adhesion with the resin, which minimized the chances of being thrown out in wear debris.

Composites Part C: Open Access, 2021

Abstract In this paper tribo-comparison of two SLs viz. graphite and PTFE as a secondary lubrican... more Abstract In this paper tribo-comparison of two SLs viz. graphite and PTFE as a secondary lubricant in composites with identical composition (20 wt%) is presented. The mechanical, thermal and tribological properties as well as mechanism of PAEK composites were investigated in detail. It was found that although incorporation of PTFE reduced most of the mechanical properties and thermal conductivity, it was responsible for increasing the tribo- potential of composites to a significant level. Compared to a composite with graphite as a secondary SL, a reduction in wear rate (18–30 %) and friction (2–18%) was exhibited due to PTFE and nano-PTFE. The composites showed very high PV s a f e (pressure x velocity) value of 182 MPa m/s with low (0.04) and wear rate ( 1.33 × 10 − 16 MPa m/s). It was shown that the formation of a polymeric transfer film on a metal countersurface is crucial in achieving ultralow wear and friction in dry condition. The investigations on worn surfaces and the transfer films with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) analysis and Raman spectroscopy proved useful to understand wear mechanisms.

Journal of Materials Research and Technology, 2021

Abstract Some specialty polymers such as polyetheretherketone (PEEK), Polyaryletherketone (PAEK),... more Abstract Some specialty polymers such as polyetheretherketone (PEEK), Polyaryletherketone (PAEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyamideimide (PAI), and polyimide (PI) are the ideal choices for developing high performance bidirectionally reinforced composites that would excel in specific strength performance. However, these polymer composites are extremely challenging from a processing point of view and have limited choices. Most of the time, a lot of compromises are to be made on the fiber-matrix wetting issues. The current research elaborated on a method to exploit two techniques together to opt for advantages from both. Polyetherimide (PEI) solutions of various concentrations/viscosities were used as sizing agents for the fibers so as to wet the cross-over points on graphite fabric and inter-tow filaments. It was expected that the PEI and PAEK would form a blend at the interface, although fiber would necessarily be covered with only PEI. It was also anticipated that there could be an optimum amount of PEI on the fibers’ surface for the best performance properties. Based on the in-depth studies on the performance properties, it was concluded that PEI solution in the range of 5–10 wt. % would lead to the best combination of performance properties. Compared to the classical method of developing PAEK-graphite fabric composites by film technique, the current method of combination of impregnation and film technique led to excellent results.

Surface and Coatings Technology, 2021

Abstract The present paper reports on the interaction of low-pressure plasma (LPP) with the surfa... more Abstract The present paper reports on the interaction of low-pressure plasma (LPP) with the surfaces of different stainless steels (SS) (viz. austenitic, martensitic, and ferritic). Plasma treatment was standardized by optimizing the power and duration of plasma exposure. The criteria for such standardization were the extent of decrease in contact angle and hence increase in surface energy (SE), which would increase the lap shear strength (LSS) of these surfaces in the form of joints using phenolic resin. It was found that argon LPP was more effective than the argon-oxygen LPP and, the best results were obtained with a plasma exposure of 500W power for 20 min. The LSS of SS316 got improved by almost 100 % for the plasma-treated surface compared to the untreated one. Contact angles got reduced to different extents for all the three types of SS, and a significant improvement (~175 %) in SE was observed. The increase in SE was supported by atomic force micrographs that showed a decrease in the surface roughness. X-ray photoelectron spectroscopy (XPS) indicated a significant change in the surface chemistry due to the Ar-LPP treatment.

Composites Part B: Engineering, 2021

Abstract Fabric-(BD-bi-directionally) reinforced high performance polymer composites are well-kno... more Abstract Fabric-(BD-bi-directionally) reinforced high performance polymer composites are well-known for their exceptional mechanical, thermal and tribological properties. However, their processing is generally challenging, especially for specialty polymers like Polyetheretherketone (PEEK), Polyaryletherketone (PAEK) etc. mainly because of unavailability of a right kind of solvent which restricts exploitation of solution impregnation technique. Having very high melting points along with high melt-viscosity and high oxidation tendency, the possibility of melt-impregnation also gets eliminated. Furthermore, unavailability in fibrous form restricts the processing possibility by commingling technique. The possible options left for developing such composites perhaps are by film-stacking and powder-sprinkling techniques although the major issue of non-wetting at cross-over points remains unaddressed. This paper reports on the maiden effort on developing, characterizing and in depth performance analysis of graphite fabric reinforced PAEK composites. Powder-sprinkling and film-stacking techniques were employed in this work by maintaining identical processing parameters and fabric amount. The comparative performance evaluation led to a conclusion that film-stacking technique excelled in almost all performance properties barring thermal conductivity and thermo-mechanical performance. The performance analysis was based on various techniques such as thermal-conductivity, field emission scanning electron microscopy (FESEM) on polished cross-sections, thermal and thermo-mechanical analysis, mechanical testing, micro-computed tomography, abrasive wear studies etc.

Wear, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

SAE Technical Paper Series, 2020

International Journal of Surface Science and Engineering, 2019

The current study aims to investigate the effect of silane-treatment of wollastonite on the mecha... more The current study aims to investigate the effect of silane-treatment of wollastonite on the mechanical, tribological performance of non-asbestos organic frictional brake-pad material. Two main friction lining specimens in the shape of brake-pads containing treated wollastonite (Wt) and untreated wollastonite (Wu) were produced to carry on the experiments. All produced samples were characterised and examined for their mechanical, chemical and tribological properties. The experimental results show that all parameters of tribological performance are within the acceptable standard range and that the tribological performance for all samples is almost the same in terms of friction coefficient and fade performance. Regarding wear, recovery performance and disc temperature rise (DTR), Wt samples offer better performance than Wu samples which was attributed to the good adhesion between wollastonite and the polymeric matrix after treatment. Moreover, scanning electron microscopy analysis is done on the tested samples and show overall improved surface of Wt than Wu. Finally, for full use of wollastonite silane-treatment advantages, it is recommended to be used in vehicles with less severe operating conditions such as motorbike and alike.

Surface and Coatings Technology, 2018

Investigations on influence of nano and micron sized particles of SiC on performance properties o... more Investigations on influence of nano and micron sized particles of SiC on performance properties of PEEK coatings

Composites Part B: Engineering, 2016

Two series of UHMWPE composites were developed using boron carbide (B 4 C) particles in different... more Two series of UHMWPE composites were developed using boron carbide (B 4 C) particles in different amounts and sizes. Micro-series contained micro B 4 C particles (2e5 mm) in various wt% (0, 2, 4, 6, 8 and 10) while nano-series contained nano-particles (NPs) of size 70e90 nm in 0, 2 and 3%. Abrasive wear studies against silicon carbide (SiC) paper in a single pass condition were conducted under varying loads and speeds. Inclusion of B 4 C particles proved beneficial to enhance the wear resistance and optimum amounts of filler for micro and nano-series were z 6e8% and 3% respectively. Scratch hardness showed fairly good linearity with the wear resistance. SEM studies confirmed that inclusion of hard fillers mainly reduced the severity of micro-cutting mechanism and hence wear.

Wear, 2016

Abstract A novel type of graphite (thermographite) having higher thermal conductivity (TC) due to... more Abstract A novel type of graphite (thermographite) having higher thermal conductivity (TC) due to a patented treatment is commercialized recently. It was anticipated that such particles would be more effective in conducting away frictional heat generated on the tribo-surfaces leading to the enhanced performance. Hence two composites were developed based on high performance Polyarylether ketone (PAEK) (50% by wt) containing 30% short glass fibers (GF) and hexa-boron nitride (hBN) 10% apart from 10% graphite. First composite designated as CNG contained 10% natural graphite (NG) while the other designated as CTG contained 10% thermographite (TG). These were processed by identical method (twin screw extrusion followed by injection molding). The tribo-performance was evaluated in a pin on disc (mild steel) configuration under very high load and speeds. It was observed that both the composites exhibited excellent tribo-performance. However, CNG performed better than the CTG in all respects only under severe operating conditions. Under low PV conditions, difference was not clear. It showed lower friction coefficient, and wear rate as compared to CTG. CNG showed PVlimit value 96.6 MPa-m/s which was decisively superior to CTG (91 MPa-m/s). CNG could sustain higher speed (3.45 m/s) than the CTG (3.25 m/s) under 900 N in spite of slightly lower TC. It was concluded that during treatment (patented by the company) TG has slightly distorted layer-lattice structure as compared to the natural graphite, which could be responsible for transferring less beneficial film under severe operating conditions. SEM and EDAX studies were conducted to understand wear mechanisms. Such composites with such high PVlimit values low, µ (0.04) and low wear rates (1×10−16 m3/Nm) are not reported in the literature and may prove as ideal materials for dry bearings in harsh operative conditions.