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Alternative Energy Sources for the Mineral Sector
Published in Sheila Devasahayam, Kim Dowling, Manoj K. Mahapatra, Sustainability in the Mineral and Energy Sectors, 2016
Sheila Devasahayam, Raman Singh
The emerging reduction technologies for titanium from ore produce metal powder instead of sponge. Conventional methods for sintering and melting of titanium powder are expensive and energy intensive as well as they require high vacuum (>10−6 Torr). Titanium reacts with oxygen at high temperatures to form a very stable oxide, which adversely affects its mechanical properties. Other melting processes such as plasma arcs require electrode consumption, and direct induction heating of the titanium powder is problematic due to high melt energy required (Technikon#1412-555 NA, 2007). On the other hand, microwave sintering or melting in argon at atmospheric pressures is potentially cost effective and energy efficient due to the possibility of direct microwave heating of the titanium powder augmented by hybrid heating in a ceramic casket (Bruce et al., 2010). Microwave heating has the following additional advantages compared with conventional heating techniques: AdvantagesHigher heating ratesNo direct contact between the heating source and the heated materialSelective heating may be achievedEasy to control the heating or dryingReduces the equipment size and waste
Biomaterials in Tissue Engineering
Published in Rajesh K. Kesharwani, Raj K. Keservani, Anil K. Sharma, Tissue Engineering, 2022
Blessing Atim Aderibigbe, Shesan John Owonubi
Methods used for creating a rough surface of titanium implant include titanium plasma spraying, anodization, blasting with ceramic particles, and acid etching (Bauer et al., 2013). In titanium plasma-spraying method, titanium powder is injected onto the implant resulting in the formation of a film with enhanced surface area and tensile strength (Jemat et al., 2015). Knabe et al. investigated a titanium surface having a porous titanium plasma-sprayed coating on rat bone marrow cells. The titanium surface enhanced facilitated rat bone marrow cells growth with high cell density which indicates that it is suitable for dental implants (Knabe et al., 2002). Hung et al. developed dental implants by plasma-sprayed HA coating on titanium (Ti-6Al-4V ELI) surfaces with a coating thickness of approximately 120 µm. The implants were uniformly covered by the HA coating and exhibited high biocompatibility (Hung et al., 2013). Eom et al. also showed that the HA coating of implants shortens the time of bone healing at poor bone quality sites and they are useful for early loading after the placement of the implant (Eom et al., 2012). Huang et al. reported the antibacterial effect of surface treatment of titanium. ZrO2–silver (Ag) and ZrO2–copper (Cu) coatings were sprayed onto titanium surface resulting in an improved antibacterial performance of the coated titanium implant when compared to the pure titanium implants (Huang et al., 2013). Titanium surface is also roughened by blasting with hard ceramic particles. However, particles must be stable, biocompatible, and should not interfere or hinder the osseointegration of the implants (Duraccio et al., 2015). Alumina has been used for blasting of titanium surfaces due to its insolubility in acid.
Interactions of polymeric components in a POM-based binder system for titanium metal injection moulding feedstocks
Published in Powder Metallurgy, 2023
Keemi Lim, Muhammad Dilawer Hayat, Kumar Debajoyti Jena, Wen Zhang, Lu Li, Peng Cao
Initially, the POM-based binder component without metal powder was prepared in a ThermoHaake Brabender mixer (Germany) at 180°C for 10 min with a rotor speed of 60 rev min−1. The binder system was based on the polymer blend containing POM as the primary binder, PP as the secondary binder, EGMA and E40 as a compatibiliser, and SA as a surfactant. The composition of the binder content is tabulated in Table 1. After mixing, the polymeric binder mixture is hot pressed into a thin film with a thickness of 1 mm for characterisation. Subsequently, the selected binder formulation based on the contact angle measurement and AFM was used to prepare the titanium feedstock. In feedstock preparation, mixing was performed at 180°C, 60 rev min−1 for 40 min. In this study, the formulation of 63 vol.-% powder loading of titanium powder was used for investigation.
Influence of titanium particulate reinforcement on microstructural evolution and mechanical performance of AZ91 magnesium matrix surface composite developed through friction stir processing
Published in Canadian Metallurgical Quarterly, 2023
Ketha Jaya Sandeep, Atul Kumar Choudhary, Ilyas Hussain, R.J. Immanuel
This study used a commercial AZ91D alloy as its matrix material. A plate with an 8-mm thickness was sourced from Technolloy Inc. in Mumbai. It was sliced into plates with dimensions of 150 mm × 60 mm × 8 mm for friction stir processing. Energy Dispersive X-ray Spectroscopy (EDS) was used to confirm the sample's chemical composition, and Table 1 lists the measured composition. Commercially pure (99.9%) Titanium powder was used as the reinforcement. To bring down the Ti particle to uniform size of size around 5 micrometres, mechanical milling was done for 4 hrs using a planetary ball mill machine followed by sieving to required grit size. A rectangular slot of size 75 mm length, 0.382 mm width and 2.8 mm depth was created on the surface of the plates by wire EDM for the purpose of packing the Ti particles.
Microstructure evolution and mechanical property of powder metallurgy Ti6Al4V alloy with high oxygen concentrations
Published in Powder Metallurgy, 2023
Yang Zhou, Fang Yang, Cunguang Chen, Zhimeng Guo
In the periodic table, zirconium and titanium belong the same subgroup and possess similar chemical properties and crystal structure, so there is a continuous solid solution zone in the Ti-Zr binary phase diagram [19,20]. This means that zirconium can dissolve indefinitely in titanium and will not strongly hinder the sintering of titanium powder. Zirconium is usually considered as a neutral solid solution element in titanium and can improve the corrosion resistance and mechanical strength of titanium [21–24]. In addition, recent reports indicate that zirconium has a weakening effect on the phase transition temperature of titanium [25]. And in our previous study, it was found that the grain size of pure titanium under the same sintering conditions showed a trend of increasing with the increase in ZrO2 content [26]. Thus it can be expected that zirconium may have promoting densification effect due to higher self-diffusion rate of β-Ti, which provides certain guarantee for the densification of vacuum pressure-less sintered Ti6Al4V products [27]. Therefore, powder metallurgy Ti6Al4V alloy with high oxygen concentration and good mechanical properties might be expected by adding zirconium dioxide (ZrO2) via vacuum pressure-less sintering and hot deformation, to trade off the oxygen threshold in powder metallurgy titanium alloy.