gul awan - Academia.edu (original) (raw)
Papers by gul awan
Journal of the Pakistan Institute of Chemical Engineers, 2015
Addition of other elements in Ni-P matrix is common practice for the improvement of electroless n... more Addition of other elements in Ni-P matrix is common practice for the improvement of electroless nickel deposit’s characteristics. Copper improves corrosion resistance, hardness and other properties of electroless nickel coatings. In this work Ni-P, Ni-Cu-P and Ni-Al 2 O 3 -P coatings were deposited on mild steel. Coatings thickness and composition were measured using elcometer and EDX respectively. Anti-corrosion properties of coatings were investigated in 0.5M Na 2 SO 4 solution. The results showed that the corrosion resistance of Ni-Cu-P coatings in Na 2 SO 4 solution was superior to Ni-P and Ni-Al 2 O 3 -P coatings. Coated samples were heat treated at 400 0 C for 1 hr and hardness of as plated and heat treated samples was compared. The improvement in the hardness of coatings after heat treatment can be explained by the precipitation of nickel phosphide Ni 3 P.
In recent years RFeB based magnets have derived wide range attraction and popularity due to their... more In recent years RFeB based magnets have derived wide range attraction and popularity due to their excellent magnetic properties such as high remanence, coercivity and large energy product. However, the sintered NdFeB magnets are sensitive to temperature and corrosiveness of the working environment due to the electrochemically active phases in their microstructure, that deteriorate their efficiency as they corrode during exposure to humid or moist environments. The low corrosion resistances and Curie temperature of these magnets have strictly limited their wide application in many industrial cases. The paper describes the recent developments, microstructure, magnetic properties and corrosion resistance of sintered ReFeB permanent magnets with and without coatings. An innovative composite coating composed of an undercoat of electrodeposited nickel and a top layer of CAPVD Ti 2 N ceramic coating was successfully employed for corrosion protection of sintered NdFeB permanent magnets. Th...
Journal of the Pakistan Institute of Chemical Engineers, 2015
Aluminum alloys particularly 2219 is being abundantly used in aerospace industry due to high stre... more Aluminum alloys particularly 2219 is being abundantly used in aerospace industry due to high strength to weight ratio and excellent weldability. After welding, the sudden reduction in mechanical properties of joint as compared to that of the parent metal is a serious issue in fabrication industry. In this research work, a comparative study has been made to investigate the dependence of mechanical properties on variation of filling material composition and resultant microstructure developed in a square butt joint of 2219 aluminum alloy plates welded by tungsten inert gas (TIG) welding process using different filler materials including ER-2319, ER-4043 and ER-5356. The variation in hardness and ultimate tensile strength values was correlated with the grain morphology, composition, morphology and volume of eutectic phase along the grain boundaries found in base metal (BM), heat affected zone (HAZ) and weld zone (WZ).It was observed that ER-2319 WZ gives better properties due to its com...
Nanocrystalline semiconductor metal oxides have achieved a great importance in our industrial wor... more Nanocrystalline semiconductor metal oxides have achieved a great importance in our industrial world today. They may be defined as metal oxides with crystal size between 1 and 100 nm. TiO2 nanosize particles have attracted significant interest of materials scientists and physicists due to their special properties and have attained a great importance in several technological applications such as photocatalysis, sensors, solar cells and memory devices. TiO2 nanoparticles can be produced by a variety of techniques ranging from simple chemical to mechanical to vacuum methods, including many variants of physical and chemical vapor deposition techniques. In the present research work we report the synthesis of TiO2 nanoparticles by Sol-Gel technique. The characterization of particles was carried out by XRD, TEM and XPS techniques. The importance and applications of these nanoparticles are discussed in detail. 1 Department of Metallurgical and Materials Engineering University of Engineering ...
Polymer matrix composites have wide range engineering applications. These polymers are usually re... more Polymer matrix composites have wide range engineering applications. These polymers are usually reinforced by glass fibers and carbon nanotubes. Glass fiber and carbon nanotubes reinforced PMCs have superior properties of principal interest. The composites in question are non-biodegradable. Present research mainly focusses upon hybrid composites of polypropylene reinforced with biofibres like bamboo, banana and also with ash of rice husk. With these reinforcements properties of principal interest of the composite have been reported on the rise. Different composites are developed by varying the amount of reinforcement fibers as well as by combination of fibers and ash. The rise in the properties would be interpreted in the light of already published research. Role of binding agents on the properties has also been included. These composites are developed by compression molding technique. Samples are prepared according to ASTM standards and characterized for the properties of princi...
International Journal of Applied Ceramic Technology, 2018
Neodymium cerate (Nd 2 Ce 2 O 7) was lab-synthesized by solid state reactions of neodymia and cer... more Neodymium cerate (Nd 2 Ce 2 O 7) was lab-synthesized by solid state reactions of neodymia and ceria and spray dried to get the feedstock for plasma spraying. Hot corrosion behavior of air plasma sprayed 10% Nd 2 Ce 2 O 7 / yttria stabilized zirconia (YSZ) topcoat was studied in the presence of V 2 O 5 and Na 2 SO 4 salts at 950°C for 10 to 60 hours. It was observed that due to presence of relatively higher basic compounds Nd 2 O 3 and CeO 2 (form Nd 2 Ce 2 O 7) than Y 2 O 3 in YSZ changed the reaction dynamics during hot corrosion and the major part of corrosive (NaVO 3) was consumed by Nd of Nd 2 Ce 2 O 7 , making NdVO 4. The Y 2 O 3 of YSZ contributed in the corrosive reaction partially, relieving majority tetragonal zirconia (t-ZrO 2) in topcoat (YSZ). No remarkable cracking was developed in the topcoat even after 60 hours of accelerated hot corrosion, which was attributed to the retention of in-relief t-ZrO 2 in YSZ.
Nanomaterials and Nanotechnology, 2016
This paper aims to present a brief overview of different biosynthesis routes of silver nanopartic... more This paper aims to present a brief overview of different biosynthesis routes of silver nanoparticles (NPs), their applications and influence of the method used on the size and morphology of these nanoparticles. A detailed and comprehensive study of available biological methods, also referred to as a bottom-up approach, as well as techniques reported, have been provided with an eye for details and comparison between the techniques involving fungi, bacteria, algae and plant extracts. Plant-derived bioreductants such as leaf, stem or root extracts of various plants are seen as suitable solutions to green synthesis of silver NPs, implementing an easy, non-toxic, clean and environmentally friendly approach. Furthermore, reports on the antimicrobial activities with the zone of inhibition for various pathogens have also been included.
Welding is one of the important methods of fabrication where strength and pressure tightness are ... more Welding is one of the important methods of fabrication where strength and pressure tightness are prime requirements. This research work involves welding of two dissimilar steels to overcome problems like HAZ embitterment, strain age embitterment and lots of residual stresses that can cause failure during subsequent use of components. Post weld heat treatment (PWHT) is one of important technique or step that can be used to overcome above mentioned problems. Keeping in view above mentioned situation this project consists of welding of two different kinds of steels by the same technique and then post heated at different temperature to study the effect of post heating temperature on mechanical properties of welds. Medium carbon steel was welded with 20MnCr5 steel by using filler metal ER309 to produce dissimilar welds. To assure that these welds are sound they were tested by X-ray radiography. These welded specimens were post heated at different temperatures of 200C, 350C, 500C, 650C, a...
FACULTY OF ENGINEERING …, 2010
Unsaturated polyesters are important matrix resins used for glass fiber reinforced composites/pla... more Unsaturated polyesters are important matrix resins used for glass fiber reinforced composites/plastics. The strength of fiber glass reinforced polyester composite is mainly related to the glass content of the material and the arrangement of glass fibers. In general, the higher the weight percent glass in the composites, the stronger is the reinforced composite. Polyester matrix composites (PMC) have good specific strength, high thermal conductivity and low coefficient of thermal expansion at lower temperatures. They are being widely used for making boat hulls, building panels, structural panels for automobiles, plastic pipes, storage containers, etc. In spite of having enough strength, they are not very stiff and do not display the rigidity that is necessary for certain applications such as for structural members for airplanes and bridges. Due to this reason, most of them are limited to service temperatures below 200 degree Celsius. A detailed study of production and evaluation of properties of glass fiber reinforced polyester composites has been carried out by using various cross-sections of fibers in 1-ply, 2-ply and 3-ply sheets. The hand lay-up method has been chosen as the processing route for this purpose. PMC developed were evaluated in terms of their mechanical and metallurgical applications and characterized.
Materials Science and Engineering: A, 2008
In hot-dip-aluminized (HAD) steels, the morphology and the profile of the interface between the a... more In hot-dip-aluminized (HAD) steels, the morphology and the profile of the interface between the aluminum coating and the substrate steel, are affected both by the composition of the molten aluminum as well as by the composition, and even the microstructure, of the substrate steel. This effect has been investigated using optical and scanning electron microscopy, and X-ray diffraction. The reaction between the steel and the molten aluminum leads to the formation of Fe-Al inter-metallic compounds on the steel surface. The thickness of the inter-metallic compound layer as well as the morphology of the interface between the steel and the interlayer varies with the silicon content of the molten aluminum. In hot-dip-aluminizing with pure aluminum, the interlayer is 'thick' and exhibits a finger-like growth into the steel. With a gradually increasing addition of silicon into the aluminum melt, the thickness of the interlayer decreases while the interface between the interlayer and the substrate gradually becomes 'smoother'. With an increase in the carbon content of the substrate steel the growth of the interlayer into the steel is impeded by the pearlite phase, whereas the ferrite phase appears to dissolve more readily. X-ray diffraction and electron microscopic studies showed that the interlayer formed in samples aluminized in pure aluminum, essentially consisted of orthorhombic Fe 2 Al 5. It was further observed that the finger-like grains of Fe 2 Al 5 phase exhibited a preferred lattice orientation. With a gradual addition of silicon into the aluminum melt, a cubic phase based on Fe 3 Al also started to form in the interlayer and replaced most of the Fe 2 Al 5 .
Key Engineering Materials, 2012
The paper presents the role of equiaxed α׳ in the bimodal microstructure to attain an optimal com... more The paper presents the role of equiaxed α׳ in the bimodal microstructure to attain an optimal combination of ductility and strength. The study revealed that the production of bimodal microstructure and volume fraction of equiaxed α׳ were reliant on the forging temperature and subsequent heat treatment. The Ti-6Al-4V alloy was forged in the two phase region and different heat treatment cycles were employed to get the desired bimodal microstructure and thus the combination of strength and ductility. The mechanical properties of fully lamellar microstructure were compared with bimodal microstructure containing equiaxed α׳. The experimental results showed that the amount of equiaxed α׳ in the bimodal microstructure was critical for achieving a well-balanced profile of mechanical properties.
Metallurgical and Materials Transactions A, 2013
ABSTRACT Shielded metal arc welding was applied to AISI 1045 medium carbon steel. The microstruct... more ABSTRACT Shielded metal arc welding was applied to AISI 1045 medium carbon steel. The microstructural changes and electrochemical corrosion behavior of the heat-affected zone (HAZ), base metal (BM), and weld zone (WZ) were investigated. The effect of welding passes on microstructural changes of BM, HAZ, and WZ were elucidated using optical microscopy, potentiodynamic Tafel scan, and linear polarization resistance (LPR) methods in plain water and 3.5 pct (w/v) NaCl solution under standard temperature and pressure using corrosion kinetic parameters. From microstructural observations, the variations in ferrite morphology in the BM and WZ showed dissimilar electrochemical corrosion behavior and a corrosion rate than that of HAZ.
Journal of the Pakistan Institute of Chemical Engineers, 2015
Addition of other elements in Ni-P matrix is common practice for the improvement of electroless n... more Addition of other elements in Ni-P matrix is common practice for the improvement of electroless nickel deposit’s characteristics. Copper improves corrosion resistance, hardness and other properties of electroless nickel coatings. In this work Ni-P, Ni-Cu-P and Ni-Al 2 O 3 -P coatings were deposited on mild steel. Coatings thickness and composition were measured using elcometer and EDX respectively. Anti-corrosion properties of coatings were investigated in 0.5M Na 2 SO 4 solution. The results showed that the corrosion resistance of Ni-Cu-P coatings in Na 2 SO 4 solution was superior to Ni-P and Ni-Al 2 O 3 -P coatings. Coated samples were heat treated at 400 0 C for 1 hr and hardness of as plated and heat treated samples was compared. The improvement in the hardness of coatings after heat treatment can be explained by the precipitation of nickel phosphide Ni 3 P.
In recent years RFeB based magnets have derived wide range attraction and popularity due to their... more In recent years RFeB based magnets have derived wide range attraction and popularity due to their excellent magnetic properties such as high remanence, coercivity and large energy product. However, the sintered NdFeB magnets are sensitive to temperature and corrosiveness of the working environment due to the electrochemically active phases in their microstructure, that deteriorate their efficiency as they corrode during exposure to humid or moist environments. The low corrosion resistances and Curie temperature of these magnets have strictly limited their wide application in many industrial cases. The paper describes the recent developments, microstructure, magnetic properties and corrosion resistance of sintered ReFeB permanent magnets with and without coatings. An innovative composite coating composed of an undercoat of electrodeposited nickel and a top layer of CAPVD Ti 2 N ceramic coating was successfully employed for corrosion protection of sintered NdFeB permanent magnets. Th...
Journal of the Pakistan Institute of Chemical Engineers, 2015
Aluminum alloys particularly 2219 is being abundantly used in aerospace industry due to high stre... more Aluminum alloys particularly 2219 is being abundantly used in aerospace industry due to high strength to weight ratio and excellent weldability. After welding, the sudden reduction in mechanical properties of joint as compared to that of the parent metal is a serious issue in fabrication industry. In this research work, a comparative study has been made to investigate the dependence of mechanical properties on variation of filling material composition and resultant microstructure developed in a square butt joint of 2219 aluminum alloy plates welded by tungsten inert gas (TIG) welding process using different filler materials including ER-2319, ER-4043 and ER-5356. The variation in hardness and ultimate tensile strength values was correlated with the grain morphology, composition, morphology and volume of eutectic phase along the grain boundaries found in base metal (BM), heat affected zone (HAZ) and weld zone (WZ).It was observed that ER-2319 WZ gives better properties due to its com...
Nanocrystalline semiconductor metal oxides have achieved a great importance in our industrial wor... more Nanocrystalline semiconductor metal oxides have achieved a great importance in our industrial world today. They may be defined as metal oxides with crystal size between 1 and 100 nm. TiO2 nanosize particles have attracted significant interest of materials scientists and physicists due to their special properties and have attained a great importance in several technological applications such as photocatalysis, sensors, solar cells and memory devices. TiO2 nanoparticles can be produced by a variety of techniques ranging from simple chemical to mechanical to vacuum methods, including many variants of physical and chemical vapor deposition techniques. In the present research work we report the synthesis of TiO2 nanoparticles by Sol-Gel technique. The characterization of particles was carried out by XRD, TEM and XPS techniques. The importance and applications of these nanoparticles are discussed in detail. 1 Department of Metallurgical and Materials Engineering University of Engineering ...
Polymer matrix composites have wide range engineering applications. These polymers are usually re... more Polymer matrix composites have wide range engineering applications. These polymers are usually reinforced by glass fibers and carbon nanotubes. Glass fiber and carbon nanotubes reinforced PMCs have superior properties of principal interest. The composites in question are non-biodegradable. Present research mainly focusses upon hybrid composites of polypropylene reinforced with biofibres like bamboo, banana and also with ash of rice husk. With these reinforcements properties of principal interest of the composite have been reported on the rise. Different composites are developed by varying the amount of reinforcement fibers as well as by combination of fibers and ash. The rise in the properties would be interpreted in the light of already published research. Role of binding agents on the properties has also been included. These composites are developed by compression molding technique. Samples are prepared according to ASTM standards and characterized for the properties of princi...
International Journal of Applied Ceramic Technology, 2018
Neodymium cerate (Nd 2 Ce 2 O 7) was lab-synthesized by solid state reactions of neodymia and cer... more Neodymium cerate (Nd 2 Ce 2 O 7) was lab-synthesized by solid state reactions of neodymia and ceria and spray dried to get the feedstock for plasma spraying. Hot corrosion behavior of air plasma sprayed 10% Nd 2 Ce 2 O 7 / yttria stabilized zirconia (YSZ) topcoat was studied in the presence of V 2 O 5 and Na 2 SO 4 salts at 950°C for 10 to 60 hours. It was observed that due to presence of relatively higher basic compounds Nd 2 O 3 and CeO 2 (form Nd 2 Ce 2 O 7) than Y 2 O 3 in YSZ changed the reaction dynamics during hot corrosion and the major part of corrosive (NaVO 3) was consumed by Nd of Nd 2 Ce 2 O 7 , making NdVO 4. The Y 2 O 3 of YSZ contributed in the corrosive reaction partially, relieving majority tetragonal zirconia (t-ZrO 2) in topcoat (YSZ). No remarkable cracking was developed in the topcoat even after 60 hours of accelerated hot corrosion, which was attributed to the retention of in-relief t-ZrO 2 in YSZ.
Nanomaterials and Nanotechnology, 2016
This paper aims to present a brief overview of different biosynthesis routes of silver nanopartic... more This paper aims to present a brief overview of different biosynthesis routes of silver nanoparticles (NPs), their applications and influence of the method used on the size and morphology of these nanoparticles. A detailed and comprehensive study of available biological methods, also referred to as a bottom-up approach, as well as techniques reported, have been provided with an eye for details and comparison between the techniques involving fungi, bacteria, algae and plant extracts. Plant-derived bioreductants such as leaf, stem or root extracts of various plants are seen as suitable solutions to green synthesis of silver NPs, implementing an easy, non-toxic, clean and environmentally friendly approach. Furthermore, reports on the antimicrobial activities with the zone of inhibition for various pathogens have also been included.
Welding is one of the important methods of fabrication where strength and pressure tightness are ... more Welding is one of the important methods of fabrication where strength and pressure tightness are prime requirements. This research work involves welding of two dissimilar steels to overcome problems like HAZ embitterment, strain age embitterment and lots of residual stresses that can cause failure during subsequent use of components. Post weld heat treatment (PWHT) is one of important technique or step that can be used to overcome above mentioned problems. Keeping in view above mentioned situation this project consists of welding of two different kinds of steels by the same technique and then post heated at different temperature to study the effect of post heating temperature on mechanical properties of welds. Medium carbon steel was welded with 20MnCr5 steel by using filler metal ER309 to produce dissimilar welds. To assure that these welds are sound they were tested by X-ray radiography. These welded specimens were post heated at different temperatures of 200C, 350C, 500C, 650C, a...
FACULTY OF ENGINEERING …, 2010
Unsaturated polyesters are important matrix resins used for glass fiber reinforced composites/pla... more Unsaturated polyesters are important matrix resins used for glass fiber reinforced composites/plastics. The strength of fiber glass reinforced polyester composite is mainly related to the glass content of the material and the arrangement of glass fibers. In general, the higher the weight percent glass in the composites, the stronger is the reinforced composite. Polyester matrix composites (PMC) have good specific strength, high thermal conductivity and low coefficient of thermal expansion at lower temperatures. They are being widely used for making boat hulls, building panels, structural panels for automobiles, plastic pipes, storage containers, etc. In spite of having enough strength, they are not very stiff and do not display the rigidity that is necessary for certain applications such as for structural members for airplanes and bridges. Due to this reason, most of them are limited to service temperatures below 200 degree Celsius. A detailed study of production and evaluation of properties of glass fiber reinforced polyester composites has been carried out by using various cross-sections of fibers in 1-ply, 2-ply and 3-ply sheets. The hand lay-up method has been chosen as the processing route for this purpose. PMC developed were evaluated in terms of their mechanical and metallurgical applications and characterized.
Materials Science and Engineering: A, 2008
In hot-dip-aluminized (HAD) steels, the morphology and the profile of the interface between the a... more In hot-dip-aluminized (HAD) steels, the morphology and the profile of the interface between the aluminum coating and the substrate steel, are affected both by the composition of the molten aluminum as well as by the composition, and even the microstructure, of the substrate steel. This effect has been investigated using optical and scanning electron microscopy, and X-ray diffraction. The reaction between the steel and the molten aluminum leads to the formation of Fe-Al inter-metallic compounds on the steel surface. The thickness of the inter-metallic compound layer as well as the morphology of the interface between the steel and the interlayer varies with the silicon content of the molten aluminum. In hot-dip-aluminizing with pure aluminum, the interlayer is 'thick' and exhibits a finger-like growth into the steel. With a gradually increasing addition of silicon into the aluminum melt, the thickness of the interlayer decreases while the interface between the interlayer and the substrate gradually becomes 'smoother'. With an increase in the carbon content of the substrate steel the growth of the interlayer into the steel is impeded by the pearlite phase, whereas the ferrite phase appears to dissolve more readily. X-ray diffraction and electron microscopic studies showed that the interlayer formed in samples aluminized in pure aluminum, essentially consisted of orthorhombic Fe 2 Al 5. It was further observed that the finger-like grains of Fe 2 Al 5 phase exhibited a preferred lattice orientation. With a gradual addition of silicon into the aluminum melt, a cubic phase based on Fe 3 Al also started to form in the interlayer and replaced most of the Fe 2 Al 5 .
Key Engineering Materials, 2012
The paper presents the role of equiaxed α׳ in the bimodal microstructure to attain an optimal com... more The paper presents the role of equiaxed α׳ in the bimodal microstructure to attain an optimal combination of ductility and strength. The study revealed that the production of bimodal microstructure and volume fraction of equiaxed α׳ were reliant on the forging temperature and subsequent heat treatment. The Ti-6Al-4V alloy was forged in the two phase region and different heat treatment cycles were employed to get the desired bimodal microstructure and thus the combination of strength and ductility. The mechanical properties of fully lamellar microstructure were compared with bimodal microstructure containing equiaxed α׳. The experimental results showed that the amount of equiaxed α׳ in the bimodal microstructure was critical for achieving a well-balanced profile of mechanical properties.
Metallurgical and Materials Transactions A, 2013
ABSTRACT Shielded metal arc welding was applied to AISI 1045 medium carbon steel. The microstruct... more ABSTRACT Shielded metal arc welding was applied to AISI 1045 medium carbon steel. The microstructural changes and electrochemical corrosion behavior of the heat-affected zone (HAZ), base metal (BM), and weld zone (WZ) were investigated. The effect of welding passes on microstructural changes of BM, HAZ, and WZ were elucidated using optical microscopy, potentiodynamic Tafel scan, and linear polarization resistance (LPR) methods in plain water and 3.5 pct (w/v) NaCl solution under standard temperature and pressure using corrosion kinetic parameters. From microstructural observations, the variations in ferrite morphology in the BM and WZ showed dissimilar electrochemical corrosion behavior and a corrosion rate than that of HAZ.