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:
Microstructural and electrochemical studies of spark plasma sintered multiwall carbon nanotubes reinforced TiO2eMnO2 based composite
- Authors: Lephuthing, Senzeni Sipho , Okoro, Avwerosuoghene Moses , Ige, Oladeji Oluremi , Olunambi, Peter Apata
- Date: 2020
- Subjects: Microstructure , Spark plasma sintering , Electrochemical study
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/480894 , uj:43549 , Citation: Lephuting, S.S., Okoro, A.M., Ige, O.O., Olunambi, P.A. 2020. Microstructural and electrochemical studies of spark plasma sintered multiwall carbon nanotubes reinforced TiO2eMnO2 based composite. DOI:
- Description: Abstract: An electrochemical study was conducted to investigate the suitability of TiO2, TiO2- MWCNTs and (5,10 and 15 wt.%) of MnO2 in TiO2-MWCNTs composites as dimensional stable electrodes which were developed via conventional powder processing and spark plasma sintering. The following electrochemical tests were carried out including open circuit potential, galvanostatic chronoamperometry and cyclic voltammetry measurements. The results showed that an increase on MnO2 content in the composites did not only lower the potentials but enhanced the stability of the composites. The degradation which translates to corrosion susceptibility was favorable on composite samples with lower MnO2 content. Also, the presence of MWCNTs in the composites improved the electrocatalytic capacity of the material. Furthermore, the anodic layers formed on the composites during polarization was analyzed using SEM, XRD and cyclic voltammetry. The results showed that the formation of anodic layer during 24 h of polarization increased with the addition of MnO2 content and 15 MnO2eTiO2-MWCNT composite grade showed minimal pores after polarization which translates to higher protection.
- Full Text: