Oxygen removal and subsequent morphology transformation of TiO_x<1 powders in electrodeoxidation process

Abstract

In this study, TiO_x<1 powders obtained from the combustion synthesis of TiO₂ and Mg was used as cathode to prepare low-oxygen titanium powders by electrochemical deoxidation process. The mechanism of oxygen removal, composition and morphology change of TiO_x<1 powders during electrode oxidation were investigated. The residual oxygen content in electrodeoxidized TiO_x<1 powders is linearly related to the deoxidation time. An obvious sintering neck between titanium particles with less than 0.35wt% oxygen could be observed after electrodeoxidation for 2 h. The removal of oxygen from Ti lattice promotes the surface diffusion of titanium atoms and leads to subsequent sintering and growth of TiO_x<1 powders in electrodeoxidation. The morphology of TiO_x<1 powders was transformed into coral and porous flakes from agglomerated small particles with a decrease in residual oxygen content and an extension of deoxidation time.

Keywords

titanium metallurgy / titanium powders / electrochemical deoxidation / morphology

References

[1] TakedaO, OuchiT, OkabeT H. Recent progress in titanium extraction and recycling [J]. Metallurgical and Materials Transactions B, 2020, 51(4): 1315-1328

[2] ReddyR G, ShindeP S, LiuA-min. Review—The emerging technologies for producing low-cost titanium [J]. Journal of the Electrochemical Society, 2021, 168(4): 042502

[3] QiuG-z, GuoY-feng. Current situation and development trend of titanium metal industry in China [J]. International Journal of Minerals, Metallurgy and Materials, 2022, 294599-610

[4] FangZ Z, ParamoreJ D, SunP, et al. . Powder metallurgy of titanium—Past, present, and future [J]. International Materials Reviews, 2018, 63(7): 407-459

[5] TakedaO, OkabeT H. Current status of titanium recycling and related technologies [J]. JOM, 2019, 71(6): 1981-1990

[6] DringK, DashwoodR, InmanD. Voltammetry of titanium dioxide in molten calcium chloride at 900 °C [J]. Journal of the Electrochemical Society, 2005, 152(3): E104

[7] ZhangY, LuW-l, SunP, et al. . Deoxygenation of Ti metal: A review of processes in literature [J]. International Journal of Refractory Metals and Hard Materials, 2020, 91: 105270

[8] TsukihashiF, HattaT, TawaraE. Thermodynamics of calcium and oxygen in molten titanium and titanium-aluminum alloy [J]. Metallurgical and Materials Transactions B, 1996, 276967-972

[9] OkabeT H, OdaT, MitsudaY. Titanium powder production by preform reduction process (PRP) [J]. Journal of Alloys and Compounds, 2004, 364(1–2): 156-163

[10] ParkI, AbikoT, OkabeT H. Production of titanium powder directly from TiO₂ in CaCl₂ through an electronically mediated reaction (EMR) [J]. Journal of Physics and Chemistry of Solids, 2005, 66(2–4): 410-413

[11] SuzukiR O, AizawaM, OnoK. Calcium-deoxidation of niobium and titanium in Ca-saturated CaCl₂ molten salt [J]. Journal of Alloys and Compounds, 1999, 288(1–2): 173-182

[12] ZhangY, FangZ Z, SunP, et al. . Thermodynamic destabilization of Ti-O solid solution by H₂ and deoxygenation of Ti using Mg [J]. Journal of the American Chemical Society, 2016, 138(22): 6916-6919

[13] ZhangY, FangZ Z, XiaY, et al. . Hydrogen assisted magnesiothermic reduction of TiO₂ [J]. Chemical Engineering Journal, 2017, 308299-310

[14] ShinH S, HurJ M, JeongS M, et al. . Direct electrochemical reduction of titanium dioxide in molten lithium chloride [J]. Journal of Industrial and Engineering Chemistry, 2012, 18(1): 438-442

[15] ChenG. Interactions of molten salts with cathode products in the FFC Cambridge Process [J]. International Journal of Minerals, Metallurgy and Materials, 2020, 27(12): 1572-1587

[16] SuzukiR O, InoueS. Calciothermic reduction of titanium oxide in molten CaCl₂ [J]. Metallurgical and Materials Transactions B, 2003, 34(3): 277-285

[17] ZhangY, FangZ Z, SunP, et al. . A perspective on thermochemical and electrochemical processes for titanium metal production [J]. JOM, 2017, 69(10): 1861-1868

[18] ZhouX-y, DouZ-h, ZhangT-a, et al. . Preparation of low-oxygen Ti powder from TiO₂ through combining self-propagating high temperature synthesis and electrodeoxidation [J]. Transactions of Nonferrous Metals Society of China, 2022, 32(10): 3469-3477

[19] NakamuraM, OishiT, et al. . Electrochemical deoxidation of titanium [J]. Metallurgical and Materials Transactions B, 1993, 24(3): 449-455

[20] TaninouchiY K, HamanakaY, OkabeT H. Electrochemical deoxidation of titanium and its alloy using molten magnesium chloride [J]. Metallurgical and Materials Transactions B, 2016, 47(6): 3394-3404

[21] OhJ M, LeeB K, SuhC Y, et al. . Deoxidation of Ti powder and preparation of Ti ingot with low oxygen concentration [J]. Materials Transactions, 2012, 53(6): 1075-1077

[22] OhJ M, KwonH, KimW, et al. . Oxygen behavior during non-contact deoxidation of titanium powder using calcium vapor [J]. Thin Solid Films, 2014, 551: 98-101

[23] LefebvreL P, BarilE. Effect of oxygen concentration and distribution on the compression properties on titanium foams [J]. Advanced Engineering Materials, 2008, 10(9): 868-876

[24] LiD-y, HeH, LouJ, et al. . Effect of oxygen contents on predominant sintering mechanism during initial stage of pure titanium powder [J]. Powder Technology, 2020, 361: 617-623

[25] YangY F, QianM. Fundamental understanding of the dissolution of oxide film on Ti powder and the unique scavenging feature by LaB₆ [J]. Metallurgical and Materials Transactions A, 2018, 49(1): 1-6

[26] LiD-y, HeH, LouJ, et al. . Effect of oxygen contents on predominant sintering mechanism during initial stage of pure titanium powder [J]. Powder Technology, 2020, 361: 617-623

[27] PanigrahiB B, GodkhindiM M, DasK, et al. . Sintering kinetics of micrometric titanium powder [J]. Materials Science and Engineering A, 2005, 396(1–2): 255-262

[28] SongM, HanS, MinD, et al. . Diffusion of oxygen in β-titanium [J]. Scripta Materialia, 2008, 59(6): 623-626