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Title: Microstructure and martensitic transformation in Si-coated TiNi powders prepared by ball milling

Graphical abstract: - Highlights: • Amorphous Si-coated TiNi powders were prepared successfully by ball milling. • Ti{sub 4}Ni{sub 4}Si{sub 7} was formed at the interface between Si and TiNi after annealing. • Si-coated Ti–Ni powders displayed the R phase after annealing. - Abstract: Si was coated on the surface of Ti–49Ni (at%) alloy powders by ball milling in order to improve the electrochemical properties of the Si electrodes of secondary Li ion batteries and then the microstructure and martensitic transformation behavior were investigated by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Ti–Ni powders coated with Si were fabricated successfully by ball milling. As-milled powders consisted of highly deformed Ti–Ni powders with the B2 phase and amorphous Si layers. The thickness of the Si layer coated on the surface of the Ti–Ni powders increased from 3–5 μm to 10–15 μm by extending the milling time from 3 h to 48 h. However, severe contamination from the grinding media, ZrO{sub 2} occurred when the ball milling time was as long as 48 h. By heating as-milled powders to various temperatures in the range of 673–873 K, the highly deformed Ti–Ni powdersmore » were recovered and Ti{sub 4}Ni{sub 4}Si{sub 7} was formed. Two-stage B2–R–B19′ transformation occurred when as-milled Si-coated Ti–49Ni alloy powders were heated to temperatures below 873 K, above this temperature one-stage B2–B19′ transformation occurred.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [1]
  1. School of Materials Science and Engineering, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of)
  2. ReSEAT Program, KISTI, Daejeon 305-806 (Korea, Republic of)
  3. Department of Advanced Materials Engineering, Keimyung University, 1000 Shindang-dong, Dalseo-gu, Daegu 704-701 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22290359
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 48; Journal Issue: 12; Conference: ISFM 2012: 5. international symposium on functional materials, Perth, WA (Australia), 17-20 Dec 2012; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; CALORIMETRY; ELECTROCHEMISTRY; ELECTRODES; INTERMETALLIC COMPOUNDS; LAYERS; LITHIUM IONS; MICROSTRUCTURE; MILLING; PHASE TRANSFORMATIONS; POWDERS; SCANNING ELECTRON MICROSCOPY; SURFACES; THICKNESS; X-RAY DIFFRACTION; ZIRCONIUM OXIDES