List of Titles

A comparative study of spark plasma sintering and hybrid spark plasma sintering of W-4.9ni-2.1Fe heavy alloy

- Shongwe, Mxolisi Brendon, Diouf, Saliou, Durowoju, Mondiu Olayinka, Olubambi, Peter Apata, Ramakokovhu, Munyadziwa Mercy, Obadele, Babatunde Abiodun

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.
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Crystallite size determination of thermally deposited gold nanoparticles

- Ogundare, Olasupo Daniel, Akinribide, Ojo Jeremiah, Adetunjib, Adelana Rasak, Adeoye, Mosobalaje Oyebanji, Olubambi, Peter Apata

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.
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Datasets on the measurement of mechanical properties of ferrite and austenite constitutive phases using nanoindentation and micro hardness techniques

- Olanipekun, Ayorinde Tayo, Malendi, Nthabiseng, Ayodele, Olusoji Oluremi, Mphahlele, M R, Mampuya, Bob Mpinda, Olubambi, Peter Apata

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 :
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Densification characteristics, microstructure and wear behaviour of spark plasma sintering processed titanium-niobium pentoxide (Ti-Nb2O5) based composites

- Alaneme, Kenneth Kanayo, Adu, Oluwaseun P., Oke, Samuel Ranti, Falodun, Oluwasegun Eso, Olubambi, Peter Apata

Authors: Alaneme, Kenneth Kanayo , Adu, Oluwaseun P. , Oke, Samuel Ranti , Falodun, Oluwasegun Eso , Olubambi, Peter Apata
Date: 2020
Subjects: Metallic biomaterial , Ti based composite , Niobium pentoxide
Language: English
Type: Article
Identifier: http://hdl.handle.net/10210/457519 , uj:40601 , Citation: Kenneth Kanayo Alaneme, O.P. Adu, Samuel Ranti Oke et al., Densification characteristics, microstructure and wear behaviour of spark plasma sintering processed titanium-niobium pentoxide (Ti-Nb2O5) based composites, Journal of King Saud University – Engineering Sciences, https://doi.org/ 10.1016/j.jksues.2020.10.005
Description: Abstract: Please refer to full text to view abstract.
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Development and size distribution of polystyrene/ZnO nanofillers

- Ayeleru, Olusola Olaitan, Dlova, Sisanda, Ntuli, Freeman, Kupolati, Williams Kehinde, Olubambi, Peter Apata

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.
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Effect of build direction on the microhardness and dry sliding wear behaviour of laser additive manufactured Ti-6Al-4V

- Palanisamy, Chandramohan, Bhero, Shepherd, Obadele, Babatunde Abiodun, Olubambi, Peter Apata

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.
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Effect of built orientation on direct metal laser sintering of Ti-6Al-4V

- Chandramohan, P., Bhero, Shepherd, Obadele, Babatunde Abiodun, Olubambi, Peter Apata, Ravisankar, B.

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.
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Effects of ternary metal additions on corrosion of spark plasma sintered Ni-Fe alloys in H2SO4 and NaCl

- Shongwe, Mxolisi Brendon, Makena, Isaac Moraka, Ajibola, Olawale Olarewaju, Olubambi, Peter Apata, Adams, Feyisayo Victoria

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.
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Fabrication and characterization of titanium-nickel-zirconia matrix composites prepared by spark plasma sintering

- Obadele, Babatunde Abiodun, Ige, Oladeji Oluremi, Olubambi, Peter Apata

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.
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Flow-induced corrosion behaviour of low alloy steel in the presence of mono-ethylene glycol

- Aribo, Sunday, Sesheweni, Mantsha, Sanumi, Olufemi, Ogunbadejo, Adekunle, Ige, Oladeji, Olubambi, Peter Apata

Authors: Aribo, Sunday , Sesheweni, Mantsha , Sanumi, Olufemi , Ogunbadejo, Adekunle , Ige, Oladeji , Olubambi, Peter Apata
Date: 2018
Language: English
Type: Conference proceedings
Identifier: http://hdl.handle.net/10210/279871 , uj:30065 , Citation: Aribo, S. et al. 2018. Flow-induced corrosion behaviour of low alloy steel in the presence of mono-ethylene glycol. IOP Conf. Series: Materials Science and Engineering 430 (2018) 012040 doi:10.1088/1757-899X/430/1/012040
Description: Abstract: The flow-induced corrosion behaviour of welded low ally steel in 1 wt. % NaCl environment containing monoethylene glycol at 0oC and 25 oC respectively, was investigated. A modified submerged impinging jet rig was adopted to simulate the low temperature environment. Varying speeds between 1 and 3 m/s were used to study the degradation mechanism of the welded steel. Also, the ratio of MEG: 1 wt. % NaCl was kept at 1:4 for the MEG/NaCl solution. Static corrosion condition was also studied and compared with the flowing conditions. Results indicated that the alloy degraded with observable weight loss in pure 1wt. % NaCl at both temperatures whereas there was very negligible weight loss in all the samples in MEG/NaCl solution.
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Influence of aluminium content on the microstructure and densification of spark plasma sintered nickel aluminium bronze

- Okoro, Avwerosuoghene Moses, Lephuthing, Senzeni Sipho, Oke, Samuel Ranti, Olubambi, Peter Apata

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.
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Influence of nanocrystalline nickel powder on oxidation resistance of spark plasma sintered Ni-17Cr6.5Co1.2Mo6Al4W7.6Ta alloy

- Babalola, Bukola Joseph, Maledi, Nthabiseng, Shongwe, Mxolisi Brendon, Bodunrin, Michael Oluwatosin, Obadele, Babatunde Abiodun, Olubambi, Peter Apata

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.
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Influence of SiAlON ceramic reinforcement on Ti6Al4V alloy matrix via spark plasma sintering technique

- Falodun, Oluwasegun Eso, Oke, Samuel Ranti, Obadele, Babatunde Abiodun, Okoro, Avwerosuoghene Moses, Olubambi, Peter Apata

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.
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Mechanical properties of ultrafine graphite –Ti (C0.9, N0.1) solid solutions fabricated via spark plasma sintering

- Akinribide, Ojo Jeremiah, Mekgwe, Gadifele Nicolene, Ajibola, Olawale Olarewaju, Obadele, Babatunde Abiodun, Akinwamide, Samuel Olukayode, Falodun, Eso Oluwasegun, Olubambi, Peter Apata

Authors: Akinribide, Ojo Jeremiah , Mekgwe, Gadifele Nicolene , Ajibola, Olawale Olarewaju , Obadele, Babatunde Abiodun , Akinwamide, Samuel Olukayode , Falodun, Eso Oluwasegun , Olubambi, Peter Apata
Date: 2019
Subjects: Ti (C0.9, N0.1), Graphite, Spark plasma sintering
Language: English
Type: Article
Identifier: http://hdl.handle.net/10210/396125 , uj:32876 , 2351-9789 (Online) , Akinribide, O.J. et al. 2019: Mechanical properties of ultrafine graphite –Ti (C0.9, N0.1) solid solutions fabricated via spark plasma sintering , https://creativecommons.org/licenses/by-nc-nd/4.0/
Description: Abstract : Spark plasma sintering technique was used to consolidate solid solution of graphite–Ti (C0.9, N0.1) using ultrafine size of graphite and titanium carbonitride powder with carbon to nitrogen composition of 90:10 at 2000 oC for 5 mins. The densification of the sintered graphite (0-1 wt. %) –Ti (C0.9, N0.1) was 98-99% at 2000 oC in the matrix. The carbide rich and Ti rich were the two distinct solid solution phases observed, although Graphite –Ti (C0.9, N0.1) solid solution as a solitary phase was attained at 2000 oC. This could be attributed to changes in the parameters with in the lattice site due to excess heat and causing the solid solutions phases to favour the carbide and titanium phases, respectively. The graphite–Ti (C0.9, N0.1) solid solution upon the application of different load the value of the hardness decreases as the load increases for unreinforced and reinforced Ti (C0.9, N0.1). Furthermore, the fracture toughness (KIC ) was within the range of (1.04 – 7.99) in MPa m1/2.
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Mineralogical and leaching characteristics of altered ilmenite beach placer sands

- Ramakokovhu, Munyadziwa Mercy, Olubambi, Peter Apata, Mbaya, Richard Kady Kadiambuji, Mojisola, Tajudeen, Teffo, Moipone Linda

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.
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Mineralogical and leaching characteristics of altered ilmenite beach placer sands

- Ramakokovhu, Munyadziwa Mercy, Olubambi, Peter Apata, Mbaya, Richard Kady Kadiambuji, Mojisola, Tajudeen, Teffo, Moipone Linda

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.
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Nanoindentation studies and a alysis of the mechanical properties of Ti-Nb2O5 based composites

- Alaneme, Kenneth Kanayo, Fatokun, Ayoyemi Adebanji, Oke, Samuel Ranti, Olubambi, Peter Apata

Authors: Alaneme, Kenneth Kanayo , Fatokun, Ayoyemi Adebanji , Oke, Samuel Ranti , Olubambi, Peter Apata
Date: 2020
Subjects: Titanium based composites , Niobium pentoxide , Nanoindentation
Language: English
Type: Article
Identifier: http://hdl.handle.net/10210/453348 , uj:40020 , Citation: Alaneme, K.K. et al. 2020. Nanoindentation studies and a alysis of the mechanical properties of Ti-Nb2O5 based composites. , DOI: https://doi.org/10.1051/mfreview/2020017
Description: Abstract: In this study, nanoindentation tests were used to evaluate the mechanical properties of spark plasma sintered Ti based composites containing 5, 10 and 15 wt.% Nb2O5, targeted for potential use as biomedical material. Nanoindentation tests were performed on the samples using indenter loads of 20 and 100 mN, while the microstructures were characterized using scanning electron microscopy. It was noted that with increasing Nb2O5 wt.%, there is transition from the lamellar structure of pure Ti to fully bimodal structures for the Ti-10 wt.% Nb2O5 and Ti-15 wt.% Nb2O5 composites. The hardness (6.0–40.67 GPa (20 mN) and 2.4–12.03 GPa (100 mN)) and reduced elastic modulus (115–266.91 GPa (20 mN) and (28.05–96.873 GPa (100 mN)) of the composites increases with increase in the Nb2O5 content, attributed to contributions of load transfer from the Ti matrix to the relatively harder Nb2O5 particles, particle and dispersion strengthening mechanisms. The elastic recovery index also improved with increase in Nb2O5 content, while the inverse was noted with respect to plasticity index. The elastic strain to failure and yield pressure both improved with increase in Nb2O5 content, which suggests that the antiwear properties and resistance to impact loading equally improves with Nb2O5 addition.
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Nanoindentation studies and analysis of the mechanical properties of Ti-Nb2O5 based composites

- Alaneme, Kenneth Kanayo, Fatokun, Ayoyemi Adebanji, Oke, Samuel Ranti, Olubambi, Peter Apata

Authors: Alaneme, Kenneth Kanayo , Fatokun, Ayoyemi Adebanji , Oke, Samuel Ranti , Olubambi, Peter Apata
Date: 2020
Subjects: Titanium based composites , Niobium pentoxide , Nanoindentation
Language: English
Type: Article
Identifier: http://hdl.handle.net/10210/464025 , uj:41433 , Citation: Alaneme, K.K. et al. 2020. Nanoindentation studies and analysis of the mechanical properties of Ti-Nb2O5 based composites. , DOI: https://doi.org/10.1051/mfreview/2020017
Description: Abstract: Please refer to full text to view abstract.
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Optical properties of bimetallic (SrO-K2O) nanofillers

- Ayeleru, Olusola Olaitan, Dlova, Sisanda, Ntuli, Freeman, Kupolati, Williams Kehinde, Olubambi, Peter Apata

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.
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Processing of pure titanium containing titanium-based reinforcing ceramics additives using spark plasma sintering

- Diouf, Saliou, Durowoju, Mondiu Olayinka, Shongwe, Mxolisi Brendon, Olubambi, Peter Apata

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...
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