Effects of ternary metal additions on corrosion of spark plasma sintered Ni-Fe alloys in H2SO4 and NaCl
- Authors: Shongwe, Mxolisi Brendon , Makena, Isaac Moraka , Ajibola, Olawale Olarewaju , Olubambi, Peter Apata , Adams, Feyisayo Victoria
- Date: 2018
- Subjects: Spark plasma sintering , Corrosion , Ni-Fe based alloy
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/279685 , uj:30039 , Citation: Shongwe, M.B. et al. 2018. Effects of ternary metal additions on corrosion of spark plasma sintered Ni-Fe alloys in H2SO4 and NaCl. Bulletin of the Chemical Society of Ethiopia, 32(2), 337-349. DOI: https://dx.doi.org/10.4314/bcse.v32i2.12 , ISSN 1011-3924
- Description: Abstract: Effect of ternary additions on electrochemical behavior of Ni-Fe binary alloys developed by Spark Plasma Sintering (SPS) were investigated and reported. All specimens revealed common passivity behavior in H2SO4. Both binary and ternary alloys did not reveal passivity region under saline conditions. The alloys have lower corrosion rates in NaCl than in H2SO4. Binary Ni50Fe50 alloy is characterized by large pits in H2SO4 and homogeneous corrosion on surface in NaCl. Ni50Fe40Ta10 shows better passivity in 1 M H2SO4 and Ni50Fe40Al10 has the lowest corrosion rate in 3.5 wt.% NaCl.
- Full Text:
A comparative study of spark plasma sintering and hybrid spark plasma sintering of W-4.9ni-2.1Fe heavy alloy
- Authors: Shongwe, Mxolisi Brendon , Diouf, Saliou , Durowoju, Mondiu Olayinka , Olubambi, Peter Apata , Ramakokovhu, Munyadziwa Mercy , Obadele, Babatunde Abiodun
- Date: 2016
- Subjects: Tungsten heavy alloys , Spark plasma sintering , Microstructure
- Type: Article
- Identifier: http://hdl.handle.net/10210/123454 , uj:20793 , Citation: Shongwe, M.B. et al. 2016. A comparative study of spark plasma sintering and hybrid spark plasma sintering of W-4.9ni-2.1Fe heavy alloy.
- Description: Abstract: Mixed 93W-4.9Ni-2.1Fe powders were sintered via the spark plasma sintering (SPS) and hybrid spark plasma sintering (HSPS) techniques with 30 mm and 60 mm samples in both conditions. After SPS and HSPS, the 30 mm and 60 mm alloys (except 60mm-SPS) had a relative density (>99.2%) close to the theoretical density. Phase, microstructure and mechanical properties evolution of W-Ni-Fe alloy during SPS and HSPS were studied. The microstructural evolution of the 60 mm alloys varied from the edge of the sample to the core of the sample. Results show that the grain size and the hardness vary considerable from the edge to the core of sintered sample of 60 mm sintered using conventional SPS compared to hybrid SPS. Similarly, the hardness also increased from the edge to the core. The 60 mm-HSPS alloy exhibit improved bending strength than the 60 mm-SPS, 1115 MPa and 920 MPa respectively, former being similar to the 30 mm-SPS and HSPS alloys. The intergranular fracture along the W/W grain boundary is the main fracture modes of W-Ni-Fe, however in the 60 mm-SPS alloy peeling of the grains was also observed which diminished the properties. The mechanical properties of SPS and HSPS 93W-4.9Ni-2.1Fe heavy alloys are dependent on the microstructural parameters such as tungsten grain size and overall homogeneity.
- Full Text:
Mineralogical and leaching characteristics of altered ilmenite beach placer sands
- Authors: Ramakokovhu, Munyadziwa Mercy , Olubambi, Peter Apata , Mbaya, Richard Kady Kadiambuji , Mojisola, Tajudeen , Teffo, Moipone Linda
- Date: 2020
- Subjects: Ilmenite , Characterization , Pseudo-rutile
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/457394 , uj:40586 , Citation: Ramakokovhu, M.M. et al. 2020. Mineralogical and leaching characteristics of altered ilmenite beach placer sands.
- Description: Abstract: Please refer to full text to view abstract.
- Full Text:
Mineralogical and leaching characteristics of altered ilmenite beach placer sands
- Authors: Ramakokovhu, Munyadziwa Mercy , Olubambi, Peter Apata , Mbaya, Richard Kady Kadiambuji , Mojisola, Tajudeen , Teffo, Moipone Linda
- Date: 2020
- Subjects: Ilmenite , Characterization , Leaching
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/464080 , uj:41443 , Citation: Ramakokovhu, M.M. et al. 2020. Mineralogical and leaching characteristics of altered ilmenite beach placer sands.
- Description: Abstract: In order to have a good understanding of the treatment process and improvement on the market value of ilmenite beach placer sands, knowledge of its mineral composition and phase distribution is fundamental. In this study, a combination of characterization techniques including high-resolution scanning electron microscopy (HR-SEM), high-resolution transmission electron (HR-TEM) microscope, and X-ray diffraction (XRD) techniques was used to understand the mineralogical characteristics of ilmenite beach placer sands obtained from Richards Bay, South Africa. The mineral phase constituents of the ilmenite beach placer sands were studied before pre-oxidation and additive leaching in a chloride environment. During observations using XRD and HR-SEM, the ilmenite beach placer sands exhibited signature rhombohedral crystal form and crescentic pits with evidence of alteration phases. The characterized pre-oxidized ilmenite showed the presence of a ferric oxide film deposit of the particles. The leaching characteristics of both raw and pre-oxidized ilmenite was studied in the presence of additives. The leaching efficiency of the pre-oxidized ilmenite in the presence of additives increased by 20% at atmospheric conditions. The characterized residues show the improved amenability of pre-oxidized leach in chloride media. The formation of new phases containing pseudo-rutile indicated crystallographic disintegration by the movement of atoms during dissolution. Some particles retained the crescentic pit and the subangular grain structure; however, the phase changes were observed at the grain boundaries and grain edges. The leached residue’s EDS results still indicated the presence of pseudo-rutile and some minor unreacted oxides such as SiO2, Al2O3, and other trace metals. The trace metals impurities present in the as-received ilmenite were reduced by 80% in the final residue after the leaching.
- Full Text:
Effect of build direction on the microhardness and dry sliding wear behaviour of laser additive manufactured Ti-6Al-4V
- Authors: Palanisamy, Chandramohan , Bhero, Shepherd , Obadele, Babatunde Abiodun , Olubambi, Peter Apata
- Date: 2016
- Subjects: Laser , Titanium , Sintering
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/232113 , uj:23670 , Citation: Palanisamy, C. et al. 2016. Effect of build direction on the microhardness and dry sliding wear behaviour of laser additive manufactured Ti-6Al-4V. nternational Conference on Processing of Materials, Minerals and Energy (July 29th – 30th) 2016, Ongole, Andhra Pradesh, India.
- Description: Abstract: This work presents micro structural and tribological behaviour of Ti-6Al-4V fabricated by direct metal laser sintering technique. The laser sintering was carried out at laser power of 170 W in an argon atmosphere. The microstructure, phase composition, micro hardness and wear study were determined. It has been found that specimens built vertically (VB) contained vanadium carbide (VC) and titanium oxide (TiO) phases in the present of α and β phases resulting in higher micro hardness as compared to horizontal build (HB) specimens. Wear volume loss was determined in a dry sliding wear configuration. An increase in applied load from 5 N to 25 N resulted in an increment in wear volume loss. The presence of delamination could be observed on the worn surface of HB specimen.
- Full Text:
The investigation of the exposure time effects with pressure in the atomic layer deposition process over micro-trench surface
- Authors: Olufunsho, Oladipo Olotu , Coetzee, Rigardt Alfred Maarten , Jen, Tien-Chien , Olubambi, Peter Apata
- Date: 2019
- Subjects: Atomic layer deposition , Computational fluid dynamic , Exposure time
- Language: English
- Type: Conference proceeding
- Identifier: http://hdl.handle.net/10210/398293 , uj:33149 , Citation: Olufunsho, O.O. et al. 2019. The investigation of the exposure time effects with pressure in the atomic layer deposition process over micro-trench surface.
- Description: Abstract: Tremendous interest has been drawn towards the atomic layer deposition (ALD) as an ultrathin film deposition technique to deposit conformal quality films in the micro-semiconductor industry. However, a further grasp of the ALD process is mandatory to increase the probability of the industry in achieving the necessary improvement which can have a substantial impact on device performance. However, little has been done to investigate the specific effects of the operation pressure on the mechanistic, species transport and reaction rates. Moreover, the effects of these prior properties due to the change of pressure on a complex micro-trench substrate have not been studied yet. Hence, this study focuses on numerically investigating the effect between one and 10 torr operating pressure in the ALD process using the computational fluid dynamic approach. A two-dimensional numerical simulation of the Al2O3 ALD thin film fabrication process over a surface with micro-trenches on a substrate is studied. Trimethyl-Aluminium and Ozone were utilized as the metal and oxidation source reactants. To assist the precursor reaction process a 2.5 second exposure time is added within the ALD sequence. The findings illustrated the fluid flow velocity, mass fraction, and growth of the thin-film process. The evaluations unveil close comparison to literature.
- Full Text:
Datasets on the measurement of mechanical properties of ferrite and austenite constitutive phases using nanoindentation and micro hardness techniques
- Authors: Olanipekun, Ayorinde Tayo , Malendi, Nthabiseng , Ayodele, Olusoji Oluremi , Mphahlele, M R , Mampuya, Bob Mpinda , Olubambi, Peter Apata
- Date: 2019
- Subjects: Duplex stainless steel , Ferrite , Austenite
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/406805 , uj:34217 , Citation: Olanipekun, A.T. et al. 2019 : Datasets on the measurement of mechanical properties of ferrite and austenite constitutive phases using nanoindentation and micro hardness techniques. DOI: https://doi.org/10.1016/j.dib.2019.104551.
- Description: Abstract :
- Full Text:
Influence of aluminium content on the microstructure and densification of spark plasma sintered nickel aluminium bronze
- Authors: Okoro, Avwerosuoghene Moses , Lephuthing, Senzeni Sipho , Oke, Samuel Ranti , Olubambi, Peter Apata
- Date: 2021
- Subjects: Spark plasma sintering , Nickel aluminium bronze , Microstructure
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/480910 , uj:43551 , Citation: Okoro, A.M. et al. 2021. Influence of aluminium content on the microstructure and densification of spark plasma sintered nickel aluminium bronze. DOI: https://doi.org/10.1051/mfreview/2021006
- Description: Abstract: In this study, nickel aluminium bronze alloys (NAB) with appreciable densification and improved microhardness was consolidated via spark plasma sintering technique. The NAB alloy was synthesized from starting elemental powders comprised nickel (4 wt.%), aluminium (6, 8 & 10 wt.%) and copper using dry milling technique. Starting powders were homogeneously milled using gentle ball mill for 8 h at a speed of 150 rpm and a BPR of 10:1. Subsequently, the milled powders were consolidated using the spark plasma sintering technique at 750 °C under a compressive pressure of 50MPa and rate of heating (100 °C/min). Furthermore, the powders and sintered alloys were characterized using SEM and XRD to ascertain the microstructural and phase evolutions during the synthesis of the NAB. The density and microhardness of the alloys were further investigated to ascertain the integrity of the sintered alloys. The results indicated that the increase in aluminium content resulted in the formation of intermetallic and beta phases on the alloy after sintering and the microhardness of the alloys improved with the increase in aluminium content.
- Full Text:
Crystallite size determination of thermally deposited gold nanoparticles
- Authors: Ogundare, Olasupo Daniel , Akinribide, Ojo Jeremiah , Adetunjib, Adelana Rasak , Adeoye, Mosobalaje Oyebanji , Olubambi, Peter Apata
- Date: 2018
- Subjects: Crystallite size, Thermal deposition, Gold nanoparticles,
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/395693 , uj:32825 , 2351-9789 (Online) , https://creativecommons.org/licenses/by-nc-nd/4.0/) , Citation : Ogundare, O.D. et al. 2018. Crystallite size determination of thermally deposited gold nanoparticles
- Description: Abstract : This paper has x-rayed an approach to investigate the crystallite size of thermally deposited gold nanoparticles on a glass substrate. The mined and beneficiated gold sample was deposited on glass slide in Nano-38 thermal depositor after the substrate has been technically prepared. The crystallite size and profile fitting of the nanoparticles were determined by X-ray Diffractometer (XRD). The result showed that the average crystallite size of Au nanoparticles thermally deposited on glass slide was 14.4 ± 6.7 nm with lattice constants: a, b, c; 4.0789, 4.0789, and 4.0789 (Å) respectively. The TEM images have confirmed that high quality spherical Au NPs that were between 18 nm – 24 nm were successfully synthesized. The XRD has shown that the material of the gold nanoparticles is gold and crystalline in structure. Narrow size distribution and small monosize gold nanoparticles produced may proffer advantages for self-assembled monolayer formation and enhanced surface area.
- Full Text:
Tribocorrosion behaviours of AISI 310 and AISI 316 austenitic stainless steels in 3.5% NaCl solution
- Authors: Obadele, Babatunde Abiodun , Andrews, Anthony , Shongwe, Mxolisi Brendon , Olubambi, Peter Apata
- Date: 2016
- Subjects: Metals , Electrochemical techniques , Corrosion
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/123414 , uj:20788 , Citation: Obadele, B.A. et al. 2016. Tribocorrosion behaviours of AISI 310 and AISI 316 austenitic stainless steels in 3.5% NaCl solution.
- Description: Abstract: In this paper the tribocorrosion behaviours of AISI 310 and AISI 316 stainless steels have been studied under reciprocating sliding condition in 3.5% NaCl solution, using a pin-on-disk tribometer integrated with a potentiostat for electrochemical control. Different sliding loads were used at a constant rotational speed of 60 rpm. The results show that sliding load has significant effect on the tribocorrosion behaviour of both materials. Corrosion attack was severe at sliding load conditions in both materials suggesting corrosion-induced wear as the dominant of the two synergistic components. However, at low sliding load, anodic dissolution and pit formation in AISI 316 was accelerated by sliding action causing wear-induced corrosion to be dominant.
- Full Text:
Fabrication and characterization of titanium-nickel-zirconia matrix composites prepared by spark plasma sintering
- Authors: Obadele, Babatunde Abiodun , Ige, Oladeji Oluremi , Olubambi, Peter Apata
- Date: 2017
- Subjects: Spark plasma sintering , Zirconia , Titanium
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/225471 , uj:22773 , Citation: Obadele, B.A., Ige, O.O. & Olubambi, P.A. 2017. Fabrication and characterization of titanium-nickel-zirconia matrix composites prepared by spark plasma sintering.
- Description: Abstract: Ti–Ni–ZrO2 composites were prepared by spark plasma sintering (SPS). The effect of ZrO2 content on the densification, microstructure and microhardness properties of the composites were investigated. Samples were characterized by SEM, EDS and XRD analyses. Noticeably, SPS process under the sintering conditions was achieved at a sintering temperature of 950 ºC, for 10 min holding time, at 100 °C/min of heating rate and at an applied pressure of 50 MPa. This resulted in maximum densification of the powder compact and the formation of a distinguishable spherical globules rich in Ni surrounding the retained Ti. Gradient composition distribution of ZrO2 at the grain boundaries resulted into pinning effect of the grain growth. As the ZrO2 content increased from 5 to 10 vol.%, it was accompanied by a significant increase in hardness values of the sintered composites from 480 to 713 HV.
- Full Text:
Thermal stability and reactivity of titanium halide precursors for the atomic layer deposition of TiO2 on a Pt (111) surface
- Authors: Mohlala, Lesego M. , Jen, Tien-Chien , Olubambi, Peter Apata
- Date: 2020
- Subjects: ALD , DFT , Platinum
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/458243 , uj:40694 , Mohlala, L.M., Jen, T., Olubambi, P.A.: Thermal stability and reactivity of titanium halide precursors for the atomic layer deposition of TiO2 on a Pt (111) surface.
- Description: Abstract: Please refer to full text to view abstract.
- Full Text:
Influence of SiAlON ceramic reinforcement on Ti6Al4V alloy matrix via spark plasma sintering technique
- Authors: Falodun, Oluwasegun Eso , Oke, Samuel Ranti , Obadele, Babatunde Abiodun , Okoro, Avwerosuoghene Moses , Olubambi, Peter Apata
- Date: 2019
- Subjects: Powder metallurgy , Ti6Al4V , SiAlON
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/406789 , uj:34215 , Citation: Falodun, O.E. et al. 2019 : Influence of SiAlON ceramic reinforcement on Ti6Al4V alloy matrix via spark plasma sintering technique. DOI: https://doi.org/10.1007/s12540-019-00553-3.
- Description: Abstract : The titanium-based composite was fabricated by strengthening Ti6Al4V alloy with addition of SiAlON ceramics utilizing spark plasma sintering technique. Ti6Al4V and SiAlON powders were mixed in a T2F Turbula mixer with different propor- tions (5, 10, 15 and 20 vol%) and the admixed powders were consolidated using spark plasma sintering to produce titanium matrix composites. The characterization of the sintered composites was performed using X-ray diffraction, optical microscopy and scanning electron microscopy. The influence of SiAlON additions on densification, microstructure, microhardness and fracture morphology were investigated on the sintered composites. The experimental results revealed that the densification of the sintered titanium matrix composites was in the range of 95%–98%, which decreased with an increase in SiAlON addition. However, an increase in microhardness values ranging from 363 to 574 HV0.1 was achieved. The microstructure shows that the SiAlON ceramic particle was uniformly distributed within the titanium matrix composites which comprises of a mixture of lamellar colonies with β grain boundaries. The fracture features of all composites exhibit mixed fracture of both intergranular and transgranular fracture mechanism.
- Full Text:
Synthesis and characterization of commercial pure titanium-nickel alloy behavior reinforced with titanium diboride
- Authors: Falodun, Oluwasegun Eso , Oke, Samuel Ranti , Olubambi, Peter Apata
- Date: 2020
- Subjects: Titanium , Nickel , TiB2
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/458331 , uj:40705 , Falodun, O.E., Oke, S.R., Olubambi, P.A.: Synthesis and characterization of commercial pure titanium-nickel alloy behavior reinforced with titanium diboride.
- Description: Abstract: Commercial pure titanium alloy with Ni-TiB2 ceramic additions (5, 10, 15 and 20 vol.%) were synthesized through the spark plasma sintering approach with sintering temperature of 1000 oC, the heating rate of 100 oC/min, holding time of 5 min at a constant pressure of 50 MPa. The study investigated the effect of Ni-TiB2 on the densification, phase change, microhardness, microstructure, and wear properties of the sintered titanium-based composites. Results showed that Ti-Ni-TiB2 composites relative density ranges from 97 to 99 %, while microhardness values increase with addition of nickel and titanium diboride from 228 to 587 HV0.1. The microstructural evolution shows that pure titanium transformed from lamellar phase to equiaxed alpha phase upon addition of nickel alloy and further get refined with a distinct grain boundary comprises of titanium diboride around the boundaries. The average coefficient of friction for the titanium-based composite was higher for commercially pure titanium (0.73) while the addition of TiB2 exhibit (0.66, 0.63, 0.58, 0.55 and 0.46 respectively) improvement in the wear behavior.
- Full Text:
Processing of pure titanium containing titanium-based reinforcing ceramics additives using spark plasma sintering
- Authors: Diouf, Saliou , Durowoju, Mondiu Olayinka , Shongwe, Mxolisi Brendon , Olubambi, Peter Apata
- Date: 2017
- Subjects: Spark plasma sintering , Titanium matrix composites , Ceramics
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/240416 , uj:24730 , Citation: Diouf, S. 2017. Processing of pure titanium containing titanium-based reinforcing ceramics additives using spark plasma sintering. Leonardo Electronic Journal of Practices and Technologies. 269-286. , ISSN: 1583-1078
- Description: Abstract: The densification behaviour, microstructural changes and hardness characteristics during spark plasma sintering of CP-Ti reinforced with TiC, TiN, TiCN and TiB2 were investigated. Commercially pure Ti powders were dry mixed with varied amounts (2.5 and 5 wt. %) of the ceramic additives using a T2F Turbula mixer for 5 h and at a speed of 49 rpm. The blended composite powders were then sintered using spark plasma sintering system (model HHPD-25 from FCT Germany) at a heating rate of 100oC min-1, dwell time of 5 min and sintering temperature of 950ºC. The sintering of CP-Ti was used as a base study to select the proper spark plasma sintering temperature for full density. Densification was monitored through analysis of the recorded punch displacement and the measured density of the sintered samples using Archimedes method. High densities ranging from 97.8% for 5% TiB2 addition to 99.6% for 5% TiCN addition were achieved at a relatively low temperature of 950°C...
- Full Text:
Effect of built orientation on direct metal laser sintering of Ti-6Al-4V
- Authors: Chandramohan, P. , Bhero, Shepherd , Obadele, Babatunde Abiodun , Olubambi, Peter Apata , Ravisankar, B.
- Date: 2018
- Subjects: Titanium , Laser , Sintering
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/273288 , uj:29111 , Citation: Chandramohan, P. et al. 2018. Effect of built orientation on direct metal laser sintering of Ti-6Al-4V. Indian Journal of Engineering & Material Sciences. Vol. 25, February 2018, pp. 69-77.
- Description: Abstract: Please refer to full text to view abstract.
- Full Text:
Influence of nanocrystalline nickel powder on oxidation resistance of spark plasma sintered Ni-17Cr6.5Co1.2Mo6Al4W7.6Ta alloy
- Authors: Babalola, Bukola Joseph , Maledi, Nthabiseng , Shongwe, Mxolisi Brendon , Bodunrin, Michael Oluwatosin , Obadele, Babatunde Abiodun , Olubambi, Peter Apata
- Date: 2020
- Subjects: Nickel based superalloy , Nanostructured , Spark plasma sintering
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/453453 , uj:40033 , Citation: Babalola, B.J. et al. 2020. Influence of nanocrystalline nickel powder on oxidation resistance of spark plasma sintered Ni-17Cr6.5Co1.2Mo6Al4W7.6Ta alloy. , DOI: https:// doi.org/10.1016/j.jksues.2019.01.002
- Description: Abstract: An investigation was carried out to evaluate the isothermal oxidation behavior of nickel based superal- loys at 1100 °C for 120 h. The alloys which were microstructured and nanostructured were developed by spark plasma sintering system. The oxidation test was carried out at a temperature of 1100 °C in air at different exposure time up to 120 h. The nanostructured nickel based alloy possessed better oxidation resistance with the formation of continuous adherent alumina, chromia scales, and spinel on the alloy surface and with no significant internal oxides. The oxidation rate of NiO was observed to be lower in the nanostructured nickel superalloy due to low diffusion rate of Nickel. The oxidation kinetics followed a parabolic oxidation law.
- Full Text:
Optical properties of bimetallic (SrO-K2O) nanofillers
- Authors: Ayeleru, Olusola Olaitan , Dlova, Sisanda , Ntuli, Freeman , Kupolati, Williams Kehinde , Olubambi, Peter Apata
- Date: 2019
- Subjects: Bimetallic, nanofillers, K2O
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/396163 , uj:32881 , 2351-9789 (online) , Citation : Ayelerua, O.O. et al. 2019. Optical properties of bimetallic (SrO-K2O) nanofillers , https://creativecommons.org/licenses/by-nc-nd/4.0/
- Description: Abstract : In this study, bimetallic nanofiller capable of usage as reinforcement was synthesized from expanded polystyrene (EPS). Bimetallic materials consist of two different metals. The bimetallic nanofiller consisting of SrO and K2O was successfully developed by the hydrothermal method which many researchers have well utilized to prepare nanoparticles in recent times. This study aims to synthesize and characterize bimetallic SrO-K2O, nanofillers from recycled expanded polystyrene (EPS). Products obtained were characterized by Zeta potential and Raman spectra. The Zeta potential was used to determine the surface charge of the nanofillers in solution. The Raman spectroscopy was used to determine the crystalline structure of the nanofillers. Based on the results, it was concluded that stability of nanoparticle materials in acidic medium decreases as the pH increases, and for the basic medium, stability reduces with decrease pH. The mixture of SrO and K2O to form SrO-K2O bimetallic oxide affects the stability of the nanofillers produced both in the acidic and basic medium. The Raman spectra indicated the Dband and Gband of the synthesized SrO, K2O and bimetallic SrO-K2O at 1006, 1008 and 1004 cm-1 and 1598, 1610 and 1606 cm-1 respectively. It was concluded that the shift in band gaps were because of structural changes in the molecules of the recycled expanded polystyrene.
- Full Text:
Synthesis and characterization of Sno2 nanofiller from recycled expanded polystyrene
- Authors: Ayeleru, Olusola Olaitan , Dlova, Sisanda , Ntuli, Freeman , Kupolati, Williams Kehinde , Olubambi, Peter Apata
- Date: 2019
- Subjects: Environment, Nanofillers, Polymer wastes
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/395311 , uj:32772 , 2351-9789 (online) , https://doi.org/10.1016/j.promfg.2019.02.089
- Description: Abstract : Under the concept of "Industry 4.0", production processes will be pushed to be increasingly interconnected, information based on a real time basis and, necessarily, much more efficient. In this context, capacity optimization goes beyond the traditional aim of capacity maximization, contributing also for organization’s profitability and value. Indeed, lean management and continuous improvement approaches suggest capacity optimization instead of maximization. The study of capacity optimization and costing models is an important research topic that deserves contributions from both the practical and theoretical perspectives. This paper presents and discusses a mathematical model for capacity management based on different costing models (ABC and TDABC). A generic model has been developed and it was used to analyze idle capacity and to design strategies towards the maximization of organization’s value. The trade-off capacity maximization vs operational efficiency is highlighted
- Full Text:
Development and size distribution of polystyrene/ZnO nanofillers
- Authors: Ayeleru, Olusola Olaitan , Dlova, Sisanda , Ntuli, Freeman , Kupolati, Williams Kehinde , Olubambi, Peter Apata
- Date: 2019
- Subjects: Fourier transform infrared spectroscopy, Nanofillers, Particle size analysis
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/395844 , uj:32841 , 2351-9789 (Online) , Citation : Ayelerua, O.O. et al. 2019. Development and size distribution of polystyrene/ZnO nanofillers , https://creativecommons.org/licenses/by-nc-nd/4.0/
- Description: Abstract : In this paper, the preparation and characterization of ZnO nanofillers from polystyrene (PS) polymer waste for use as reinforcement was presented. This was done to achieve a better means of upcycling polymer wastes that have become social menace in recent times. The PS/ZnO nanofillers was synthesized through the hydrothermal synthesis of nanocomposites in an enclosed reactor. The reactor was kept in an oven at a specified temperature for a period. A product obtained was characterized using Fourier transform infrared (FTIR) analysis and Particle size analyser (PSA). The FTIR was utilized to determine the functional groups present in the synthesized nanofillers. The Particle size analyser was used to determine the distribution of particle size within the polymer matrix. The absorption peak obtained in the FTIR analysis confirmed the presence of ZnO in the synthesized material and the results from particle size analysis showed that about 80% of the particle was accommodated within the whole sample.
- Full Text: