DSpace Arşivi :: by Yazar "Calin, R." değerine göre listeleniyor

Yazar "Calin, R." seçeneğine göre listele

Listeleniyor 1 - 14 / 14

Agro-waste shaped porous Al2O3/Ni composites: Corrosion resistance performance and artificial neural network modelling
(Elsevier Science Inc, 2018) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Norkhairunnisa, M.; Sobri, S.; Calin, R.; Ismarrubie, Z. N.
In the present study, an analysis on the combined effect of nickel (Ni) reinforcement and pore former type in characterizing the corrosion behavior of composite porous alumina ceramics was performed. In order to showcase the potential of the new porous ceramics, pore-forming agents (PFAs) from rice husk (RH) and sugarcane bagasse (SCB) were used in shaping the plain and composite porous alumina samples having sample formulation of Al2O3-xNi-PFA; x = 0, 2, 4, 6 and 8 wt%. Results showed that the emergence of a highly stable Ni3Al2SiO8 spinelloid phase in the RH-graded composites enhanced their chemical stability in the corrosive mediums (10 wt% NaOH and 20 wt% H2SO4) relative to the plain and the corresponding SCB-graded counterparts. An artificial neural network (ANN) model has been developed for predicting the corrosion behavior of the plain and composite porous alumina ceramics based on the experimental data. The developed ANN model satisfactorily predicted the percent mass losses of the porous ceramics in strong alkali and strong acid solutions with coefficient of determination (R-2) of approximately 0.99.
Effect of nickel addition on the microstructure and corrosion resistance properties of porous alumina composites shaped with sugarcane bagasse pore-forming agent
(Iop Publishing Ltd, 2019) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Norkhairunnisa, M.; S Sobri; Calin, R.; Ojo-Kupoluyi, O. J.
In this study, the effect of nickel (Ni) addition on the microstructure and corrosion resistance properties of porous alumina (Al2O3) composites shaped with sugarcane bagasse pore-forming agent were evaluated. Plain and Ni-reinforced porous alumina sampels (Al2O3-xNi-RH; x = 2, 4, 6 and 8wt%) were prepared using the powder metallurgy method. Experimental results showed that the porosity (50.4-57.1vol%) and the pore size (62-109 mu m) of the porous alumina composites increased with rising content of Ni reinforcement. The XRD results showed that the Al2O3 matrix and Ni reinforcement reacted during the heat treatment process to produce nickel aluminate (NiAl2O4) spinel. Corrosion resistance results showed that the porous alumina composites exhibited better chemical stability in strong alkali solution as compared with strong acid solution.
Effects of reinforcement volume fraction on the abrasive wear behaviour of Al-MgO composites produced by the vacuum infiltration method
(Sage Publications Ltd, 2011) Pul, M.; Kucukturk, G.; Calin, R.; Seker, U.
In this study, the effects of the reinforcement volume fraction on the abrasive wear behaviour of reinforced MgO composites produced by the vacuum infiltration method with 5, 10, and 15 vol% of the volume fraction of Al matrix were investigated. The abrasive wear tests were carried out by 80, 100, and 180 mesh Al2O3 abrasive paper and the pin-on-disc wear device under 10, 20, and 30 N loads at 0.2 m/s sliding speed for 3 s. At the end of the wear tests, scanning electron microscope photographs of worn surfaces were taken and the microstructures were analysed by energy dispersive spectrometer (EDS). By checking the images of the worn surfaces, it was observed that the abrasive wear effect increased by increasing the reinforcement ratio. The maximum wear loss was reported under 30 N loads and by 80 mesh abrasive paper. It was found that according to the increment of reinforced MgO in the composite, the amount of wear also increased. On the other hand, the amount of porosity and the reinforcement volume fraction are crucial parameters in the abrasive wear effect.
Impact of different isothermal aging conditions on the IMC layer growth and shear strength of MWCNT-reinforced Sn-5Sb solder composites on Cu substrate
(Elsevier Science Sa, 2019) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Ojo-Kupoluyi, O. J.; Calin, R.
In this study, the effect of multi-walled carbon nanotubes (MWCNTs) reinforcement on the intermetallic compound (IMC) layer growth and shear strength of Sn-5Sb-xCNT/Cu composite solder joints subjected to different isothermal aging conditions has been investigated. A series of plain and composite lead-free solder systems (Sn-5Sb-xCNT; x = 0, 0.01, 0.05 and 0.1 wt%) was successfully developed through the powder metallurgy method. Isothermal aging process was performed on the solder/Cu joints at 120 degrees C, 150 degrees C and 170 degrees C temperatures in order to investigate the evolution of the interfacial IMC layers and the shear strength property. Experimental results showed that the thickness of the total IMC layer increased with rising aging temperature. While the Cu3Sn IMC maintained a layer-type morphology for all aging conditions, morphology of the Cu6Sn5 IMC transformed from a scallop-type to a layer-type after aging at intermediate (150 degrees C) and high (170 degrees C) temperatures. Given the potential of MWCNTs as a reinforcement material, significant suppression in IMC layer growth was demonstrated by the composite solder joints relative to the plain counterpart. Comprehensive investigation on the growth kinetics showed that the presence of MWCNTs in the composite solder joints was effective in slowing down the diffusion mechanism responsible for IMC growth. Overall, the Sn-5Sb-0.05CNT composite solder joint exhibited the lowest diffusion coefficient within the range of 0.09 x 10(-14)-1.03 x 10(-14) cm(2)/s and 0.95 x 10(-14)-9.8 x 10(-14) cm(2)/s for Cu6Sn5 and Cu3Sn IMC layers respectively. Moreover, the strengthening effect of the MWCNTs reinforcement was well marked in the composite solder joints as the maximum shear strength within a range of 24.2-15.2 MPa was exhibited by the Sn-0.01CNT/Cu composite solder joint subjected to reflow soldering and isothermal aging conditions. (C) 2019 Elsevier B.V. All rights reserved.
Interfacial microstructure evolution and shear strength of MWCNTs-reinforced Sn-1.0Ag-0.5Cu (SAC105) composite solder interconnects on plain Cu and ENIAg surface finish
(Springer, 2022) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Vidyatharran, K.; Matori, K. A.; Azlina, O. Saliza; Calin, R.
The combined effect of MWCNTs (multi-walled carbon nanotubes) and ENIAg (Electroless Nickel Immersion Silver) surface finish on the formation of interfacial microstructure and shear strength of the Sn-1.0Ag-0.5Cu (SAC105) solder was investigated in this study. Plain and composite solders (SAC-xCNT; x = 0, 0.01, 0.05 and 0.1 wt%) were successfully synthesized through the powder metallurgy route and afterwards soldered on the ENIAg surface finish and plain Cu substrates. Detailed analysis of the microstructure revealed the formation of the Cu6Sn5 IMC at the SAC solder/Cu substrate interface of the SAC-xCNT/Cu solder interconnects. Whereas, the Ni3Sn4 IMC and (Cu,Ni)(6)Sn-5 IMC appeared at the SAC solder/ENIAg substrate interface of the SAC-xCNT/ENIAg. The MWCNTs-reinforced SAC composite solder interconnects exhibited thinner interfacial IMC layer thicknesses relative to the plain counterparts for both substrates used. Given the prospects of the ENIAg as a reliable surface finish material, the SAC-xCNT/ENIAg exhibited IMC thickness values within the range of 2.98-2.65 mu m as compared to the 5.23-3.61 mu m demonstrated by the SAC-xCNT/Cu. Overall, the strengthening capacity of the MWCNTs was well-defined in both sample grades, with the SAC-0.05CNT/Cu and SAC-0.05CNT/ENIAg exhibiting the highest shear strength values of 10.23 MPa and 11.14 MPa, respectively.
Investigating the effect of porosity level and pore former type on the mechanical and corrosion resistance properties of agro-waste shaped porous alumina ceramics
(Elsevier Sci Ltd, 2017) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Norkhairunnisa, M.; Sobri, S.; Calin, R.
The strength integrity and chemical stability of porous alumina ceramics operating under extreme service conditions are of major importance in understanding their service behavior if they are to stand the test of time. In the present study, the effect of porosity and different pore former type on the mechanical strength and corrosion resistance properties of porous alumina ceramics have been studied. Given the potential of agricultural wastes as pore-forming agents (PFAs), a series of porous alumina ceramics (Al2O3-xPFA; x=5, 10, 15 and 20 wt%) were successfully prepared from rice husk (RH) and sugarcane bagasse (SCB) through the powder metallurgy technique. Experimental results showed that the porosity (44-67%) and the pore size (70-178 mu m) of porous alumina samples maintained a linear relationship with the PFA loading. Comprehensive mechanical strength characterization of the porous alumina samples was conducted not just as a function of porosity but also as a function of the different PFA type used. Overall, the mechanical properties showed an inverse relationship with the porosity as the developed porous alumina samples exhibited tensile and compressive strengths of 20.4-1.5 MPa and 179.5-10.9 MPa respectively. Moreover, higher strengths were observed in the SCB shaped samples up to the 15 wt% PFA mark, while beyond this point, the silica peak observed in the XRD pattern of the RH shaped samples favored their relatively high strength. The corrosion resistance characterization of the porous alumina samples in hot 10 wt% NaOH and 20 wt% H2SO4 solutions was also investigated by considering sample formulations with 5-15 wt% PFA addition. With increasing porosity, the mass loss range in RH and SCB shaped samples after corrosion in NaOH solution for 8 h were 1.25-3.6% and 0.44-2.9% respectively; on the other hand, after corrosion in H2SO4 solution for 8 h, the mass loss range in RH and SCB shaped samples were 0.62-1.5% and 0.68-3.3% respectively.
Mechanical and physical performance of the advanced biopolymer-based composites with addition of filler and challenges with additive manufacturing
(Elsevier, 2021) Hanim, M.A. Azmah; Tahir, S.M.; Jung, D.W.; Calin, R.
The interest regarding biopolymer-based composites are growing with the aim in mind to improve the quality of life with extended trend of life expectancy. Biopolymer-based composite have the prospect of being the base material for implants, prosthetic limbs, prosthetic organs, drug-delivery system, and others. Aside from synthetic source of monomers, bio-derived or naturally sourced monomer is also the trend to be explored for renewable source of polymers. By doing so, the physical and mechanical aspect of the biopolymer composites need to be look into other than its interaction with the human body. Filler is one way to modify the properties. Additive manufacturing is also a lucrative prospect that will be a big game changer in the biotechnology industry. Combination of renewable materials, filler, and additive manufacturing is the future of biopolymer composite. This chapter briefly discusses different types of synthetic and natural polymers available, current fillers, their effect on some of the mechanical and physical properties, and challenges faced in applying this material to additive manufacturing. © 2022 Elsevier Ltd. All rights reserved.
Microstructure evolution and hardness of MWCNT-reinforced Sn-5Sb/Cu composite solder joints under different thermal aging conditions
(PERGAMON-ELSEVIER SCIENCE LTD, 2020) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Calin, R.; Ilyas, R. A.
In this work, multi-walled carbon nanotubes (MWCNTs) reinforced Sn-5Sb/Cu composite solder joints were synthesized and the effects of MWCNTs addition on the microstructure evolution and hardness of the Sn-5Sb solder alloy during various thermal aging conditions were investigated. After conducing a thorough microstructural analysis, the SbSn and Cu6Sn5 intermetallic compounds (IMCs) were observed in the beta-Sn matrix of the composite solder joints subjected to reflow soldering while the latter was also present at the solder/Cu interface. However, after subjecting the composite solder joints to isothermal aging, the Cu3Sn IMC emerged between the Cu6Sn5 IMC at the solder/Cu interface and the Cu substrate. With the promising properties exhibited by MWCNTs as a reinforcement material, experimental results showed that MWCNTs refined the bulk solder microstructure and inhibited growth of the interfacial IMC layer in the Sn-5Sb-xCNT/Cu samples. In general, the composite sample reinforced with 0.05 wt% MWCNTs showed the least IMC layer thickness and diffusion coefficient in the ranges of 2.6-11.99 mu m and 1.07 x 10(-14 )-14.9 x 10(-14) cm(2)/s respectively. Meanwhile, the strengthening mechanism triggered by MWCNTs addition was clearly evident in the MWCNT-reinforced Sn-5Sb/Cu as superior hardness values within a range of 20.6-15.3 HV were registered for the as-soldered and aged composite solder joints with 0.05 wt% MWCNTs reinforcement.
PLA-based bionanocomposites in tissue engineering and regenerative medicine
(Elsevier, 2021) Azmah Hanim, M.A.; Calin, R.; Jung, D.W.
Tissue engineering and regenerative medicine explore rehabilitation of the affected human body by guiding the healing process to promote cell regeneration. The procedure reduces the need for multiple invasive surgeries, increases the probability and speed for self-healing, and possibly in the near future, it will also have the ability to replace major organs and tissues that have been damaged without the need for human donors. Other than the structure, the material is an important aspect in promoting the regeneration of cells. This chapter explores the possibility of using PLA and its bionanocomposite polymers as the candidate material for tissue engineering. The different types of nanofillers and their manufacturing methods are discussed to see the different effects they have on cell regeneration. © 2021 Elsevier Ltd All rights reserved.
Research trend in the development of macroporous ceramic components by pore forming additives from natural organic matters: A short review
(Elsevier Sci Ltd, 2017) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Norkhairunnisa, M.; Sobri, S.; Calin, R.
Macroporous ceramics with tailored porosity offer a great deal of advantage in wide-ranging industrial applications including fluid filtration, thermal insulation and lately, waste water treatment. To a large extent, attempts by researchers in enhancing the development of ample homogenous porous ceramics through the exploitation of state of the art processing technologies have thus far been successful. However, these technologies are capital intensive hence making room for more exploration in finding affordable alternatives. With the growing recognition of low cost sacrificial fugitives processing route for developing porous ceramic materials, pore forming agents from natural organic matters have been one of the most sought after materials for imbuing pores within ceramic matrices. This review intends to document the progress made thus far in the development of porous ceramic systems with natural organic matter inclusion. The article covers critical evaluation and comprehensive comparison of the fabrication routes and the physical properties of porous ceramics processed with varying natural organic matters.
Rice Husk as a Pore-Forming Agent: Impact of Particle Size on the Porosity and Diametral Tensile Strength of Porous Alumina Ceramics
(Mdpi, 2022) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Jung, D. W.; Ilyas, R. A.; Calin, R.; Izzah, A. R. Nurul
This study describes the porosity and particle size effects of rice husk pore former on the diametral tensile strength of porous alumina (Al2O3) ceramics. Porous Al2O3 ceramics with high porosity and sufficient diametral tensile strength were successfully prepared by the pore-forming agent method using rice husk (RH) as the pore former according to the sample formulation Al2O3-(RHy)-R-x (where 'x' denotes the particle size range in mu m and 'y' denotes the percent weight content (wt%) of RH). The thermogravimetric analysis (TGA) and X-ray diffractometer (XRD) results revealed that silica was retained as rice husk ash in the developed porous Al2O3 after the decomposition of the starting rice husk pore former. Microstructures of the as-prepared porous Al2O3 ceramics having different RH additions exhibited hierarchical pore structures with increased particle size of the pore-forming agent. Porosity increased with larger particle size range of rice husk where the Al2O3-(RH5)-R-63 demonstrated the least porosity (44.2 vol%), while the highest porosity (70.9 vol%) was demonstrated by the Al2O3-125-250RH20. The diametral tensile strength of the RH-shaped porous alumina ceramics declined from 16.97 to 0.65 MPa with increased particle size of the rice husk.
Significant effect of rice husk and sugarcane bagasse pore formers on the microstructure and mechanical properties of porous Al2O3/Ni composites
(Elsevier Science Sa, 2018) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Norkhairunnisa, M.; Sobri, S.; Calin, R.; Ismarrubie, Z. N.
Porous alumina systems are suitable for application in wide-ranging industrial processes that require extreme service conditions such as high temperatures and corrosive mediums due to their remarkable thermal and chemical stability. Given the inherent brittleness of ceramics and their high sensitivity to thermo-mechanical loading, large-scale production of porous alumina components is constrained. In this study, the reinforcement of porous alumina ceramics with nickel (Ni) particles has been reported. Plain and Ni-reinforced porous alumina ceramics were developed through the powder metallurgy method with agro-waste materials from rice husk (RH) and sugarcane bagasse (SCB) as the pore-forming agents (PFAs). Experimental results showed that the formation of a stable Ni3Al2SiO8 spinelloid phase in the RH-graded composites actuated the emergence of a relatively refined microstructure while on the other hand, microstructural defects such as dislocated grains and localized voids were observed for the SCB-graded counterparts due to the presence of poorly crystallized NiAl2O4 spinel phase. Generally from the mechanical strength characterization, an inverse relationship was established between the mechanical properties and Ni reinforcement which agrees well with the Griffith's model. Moreover, the strengthening effect of the Ni3Al2SiO8 spinelloid phase was well marked in the RH-graded composites as maximum hardness, tensile and compressive strengths of 167.3HV, 12.6 MPa and 55.3 MPa respectively were achieved for the composite reinforced with 2 wt% Ni. (c) 2018 Elsevier B.V. All rights reserved.
Tailored pore structures and mechanical properties of porous alumina ceramics prepared with corn cob pore-forming agent
(WILEY, 2021) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Ojo-Kupoluyi, O. J.; Calin, R.; Zuhri, M. Y. M.
In this work, the effects of porosity and different particle sizes of pore-forming agent on the mechanical properties of porous alumina ceramics have been reported. Different grades of porous alumina ceramics were developed using corn cob (CC) of different weight contents (5, 10, 15, and 20 wt%) and particle sizes (<63 mu m, 63-125 mu m and 125-250 mu m) as the pore-forming agent. Experimental results showed that total porosity and pore cavity size of the porous alumina ceramics increased with rising addition of CC pore former. Total porosity increased with increasing particle size of CC with the Al2O3-(<63)CC(5)sample exhibiting the lowest total porosity of 41.3 vol% while the highest total porosity of 68.1 vol% was exhibited by the Al2O3-125-250CC20. The particle size effect of CC on the mechanical properties revealed that diametral tensile strength and hardness of the porous alumina ceramics deteriorated with increasing particle size of CC pore former. The Al2O3-(<63)CC(5)sample exhibited the highest diametral tensile strength and hardness of 25.1 MPa and 768.2 HV, respectively, while Al2O3-(125-250)CC(20)exhibited the lowest values of 1.1 MPa and 35.9 HV. Overall, porous alumina ceramics with the smallest pore sizes under each particle size category exhibited superior mechanical properties in their respective categories.
Tensile strength and corrosion resistance properties of porous Al2O3/Ni composites prepared with rice husk pore-forming agent
(Elsevier Sci Ltd, 2018) Dele-Afolabi, T. T.; Hanim, M. A. Azmah; Norkhairunnisa, M.; Sobri, S.; Calin, R.; Ismarrubie, Z. N.
The mechanical performance and chemical stability of porous alumina materials operating under harsh service conditions are of utmost importance in understanding their operational behavior if they are to stand the test of time. In the present study, the joint effect of nickel (Ni) reinforcement and rice husk (RH) pore-forming agent (PFA) on the tensile strength and the corrosion resistance properties of composite porous alumina ceramics was studied. To exploit the potential of this new porous alumina system, plain and Ni-reinforced porous alumina samples (Al2O3-xNi-RH; x = 2, 4, 6 and 8 wt%) were developed through the powder metallurgy technique. Comprehensive investigation on the tensile strength properties of the developed porous alumina ceramics showed that relative to the plain sample (tensile strength and elastic modulus; 6.1 MPa and 1201 MPa), the presence of highly stable Ni3Al2SiO8 spinelloid promoted the tensile strength enhancement (12.6-6.4 MPa) and the elastic modulus decline (897-627 MPa) of the composite samples. Similarly, corrosion resistance test was performed on the composite porous alumina samples in both 10wt% NaOH and 20wt% H2SO4 hot aqueous solutions. Overall, the composite samples demonstrated superior chemical stability in NaOH solution as compared with the plain sample. On the other hand, the composites were more prone to attack in H2SO4 solution, except for the Al2O3-2Ni-10RH composite sample which maintained its superiority over the plain counterpart.

Yazar "Calin, R." seçeneğine göre listele

Sayfa Başına Sonuç

Sıralama seçenekleri