Controlled synthesis of high-quality W-Y2O3 composite powder precursor by ascertaining the synthesis mechanism behind the wet chemical method. (1st January 2020)

• Record Type: Journal Article
• Authors: Dong, Zhi; Liu, Nan; Hu, Weiqiang; Ma, Zongqing; Li, Chong; Liu, Chenxi; Guo, Qianying; Liu, Yongchang
• Is Part Of: Journal of materials science & technology. Volume 36(2020)
• Page Start: 118
• Page End: 127
• Publication Date: 2020-01-01
• Subjects: W-Y2O3 -- Wet chemical method -- W−OH bond -- Ligand -- Co-deposition mechanism; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2019.05.067
• Languages: English
• ISSNs: 1005-0302

Abstract

Graphical abstract: Abstract: As an emerging preparation technology, wet chemical method has been employed widely to produce lots of alloy materials such as W and Mo based alloys, owing to its unique technical advantages. Ascertaining the synthesis mechanism behind wet chemical method is indispensable for controlled synthesis of high-quality W-Y2 O3 composite powder precursor. The co-deposition mechanism of yttrium and tungsten component behind the wet chemical method of preparing yttrium-doped tungsten composite nanopowder was investigated systematically in this work. A series of co-deposited composite powders fabricated under different acidity conditions were used as research targets for investigating the effect of surface composition and structure on co-deposition efficiency. It was found that white tungstic acid has more WOH bonds and much higher co-deposition efficiency with Y 3+ ions than yellow tungstic acid. It is illustrated that the coordination reaction between WOH bonds on tungstic acid particles and Y 3+ ions brings the co-deposition of yttrium and tungsten component into being. Through displacing H + ions in WOH bonds, Y 3+ ions can be adsorbed on the surface of or incorporated into tungstic acid particles in form of ligand. Consequently, to control and regulate Y2 O3 content in powder precursor accurately, H + ion concentration in wet chemical reaction should be in range of 0.55–2.82 mol L −1 to obtain white tungstic acid. Besides, H + ion concentration also has prominent effect on the grain size and morphology of reduced powder precursor. The optimal value should be around 1.58 mol L −1, which can lead to minimum W grain size (about 17 nm) without bimodal structure. The chemical mechanism proposed in this work could produce great sense to preparation of high-quality precursor for sintering high-performance Y2 O3 dispersion strengthened W based alloys. Our work may also shed light on the approach to exploit analogous synthesis mechanism in other alloy systems.