Mechanical alloying of graphite and magnesium powders, and their hydrogenation

Akito Takasaki, Yoshio Furuya, Masanori Katayama

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Graphite and elemental magnesium (Mg) powders, whose chemical compositions were C100-xMgx (0 ≤ x ≤ 40 at.%), were mechanically alloyed (milled) in an argon gas atmosphere, and these powders were loaded with hydrogen in a high-pressure vessel at a temperature of 308 K. The initial hydrogen gas pressure for hydrogenation experiment was 4 MPa. The periodicity of the c-axis of the graphite crystal structure was destroyed completely for C100 powders and partly for the powder containing Mg at an early stage of mechanical alloying (MA), indicating the formation of a turbostratic structure (graphene) for all powders. Although elemental Mg still remained in Mg-rich powders (C60Mg40) even after longer MA (80 h), other powders reached to mostly the turbostratic structure with no sign of crystalline Mg. The maximum hydrogen concentration levels after hydrogenation for C100 powder were 0.1 wt.% after MA for 25 h and 0.4 wt.% after MA for 80 h, suggesting that nanostructured graphite uptakes more hydrogen. On the other hand, hydrogen concentration level for C90Mg10 powders was less than 0.1 wt.% after MA for 15 h, but it reached to about 1 wt.% after MA for 25 h, and dropped down slightly from 1 wt.% after MA for 80 h. Furthermore, hydrogen absorption occurred smoothly and quickly for C90Mg10 powders, although longer induction time was required for C100 powders. Further addition of Mg to graphite reduced the maximum hydrogen concentration level in the powders, and the powders containing more than 30 at.% Mg did not absorb hydrogen at all at 308 K.

Original languageEnglish
Pages (from-to)110-113
Number of pages4
JournalJournal of Alloys and Compounds
Volume446-447
DOIs
Publication statusPublished - 2007 Oct 31

Fingerprint

Magnesium powder
Graphite
Mechanical alloying
Powders
Hydrogenation
Hydrogen
Magnesium
Gases
Argon
Pressure vessels
Graphene

Keywords

  • Graphite
  • Hydrogen storage
  • Magnesium
  • Mechanical alloying
  • X-ray diffraction

ASJC Scopus subject areas

  • Metals and Alloys

Cite this

Mechanical alloying of graphite and magnesium powders, and their hydrogenation. / Takasaki, Akito; Furuya, Yoshio; Katayama, Masanori.

In: Journal of Alloys and Compounds, Vol. 446-447, 31.10.2007, p. 110-113.

Research output: Contribution to journalArticle

Takasaki, Akito ; Furuya, Yoshio ; Katayama, Masanori. / Mechanical alloying of graphite and magnesium powders, and their hydrogenation. In: Journal of Alloys and Compounds. 2007 ; Vol. 446-447. pp. 110-113.
@article{630a1f358b8e445890b97cd4d5b08089,
title = "Mechanical alloying of graphite and magnesium powders, and their hydrogenation",
abstract = "Graphite and elemental magnesium (Mg) powders, whose chemical compositions were C100-xMgx (0 ≤ x ≤ 40 at.{\%}), were mechanically alloyed (milled) in an argon gas atmosphere, and these powders were loaded with hydrogen in a high-pressure vessel at a temperature of 308 K. The initial hydrogen gas pressure for hydrogenation experiment was 4 MPa. The periodicity of the c-axis of the graphite crystal structure was destroyed completely for C100 powders and partly for the powder containing Mg at an early stage of mechanical alloying (MA), indicating the formation of a turbostratic structure (graphene) for all powders. Although elemental Mg still remained in Mg-rich powders (C60Mg40) even after longer MA (80 h), other powders reached to mostly the turbostratic structure with no sign of crystalline Mg. The maximum hydrogen concentration levels after hydrogenation for C100 powder were 0.1 wt.{\%} after MA for 25 h and 0.4 wt.{\%} after MA for 80 h, suggesting that nanostructured graphite uptakes more hydrogen. On the other hand, hydrogen concentration level for C90Mg10 powders was less than 0.1 wt.{\%} after MA for 15 h, but it reached to about 1 wt.{\%} after MA for 25 h, and dropped down slightly from 1 wt.{\%} after MA for 80 h. Furthermore, hydrogen absorption occurred smoothly and quickly for C90Mg10 powders, although longer induction time was required for C100 powders. Further addition of Mg to graphite reduced the maximum hydrogen concentration level in the powders, and the powders containing more than 30 at.{\%} Mg did not absorb hydrogen at all at 308 K.",
keywords = "Graphite, Hydrogen storage, Magnesium, Mechanical alloying, X-ray diffraction",
author = "Akito Takasaki and Yoshio Furuya and Masanori Katayama",
year = "2007",
month = "10",
day = "31",
doi = "10.1016/j.jallcom.2006.12.049",
language = "English",
volume = "446-447",
pages = "110--113",
journal = "Journal of Alloys and Compounds",
issn = "0925-8388",
publisher = "Elsevier BV",

}

TY - JOUR

T1 - Mechanical alloying of graphite and magnesium powders, and their hydrogenation

AU - Takasaki, Akito

AU - Furuya, Yoshio

AU - Katayama, Masanori

PY - 2007/10/31

Y1 - 2007/10/31

N2 - Graphite and elemental magnesium (Mg) powders, whose chemical compositions were C100-xMgx (0 ≤ x ≤ 40 at.%), were mechanically alloyed (milled) in an argon gas atmosphere, and these powders were loaded with hydrogen in a high-pressure vessel at a temperature of 308 K. The initial hydrogen gas pressure for hydrogenation experiment was 4 MPa. The periodicity of the c-axis of the graphite crystal structure was destroyed completely for C100 powders and partly for the powder containing Mg at an early stage of mechanical alloying (MA), indicating the formation of a turbostratic structure (graphene) for all powders. Although elemental Mg still remained in Mg-rich powders (C60Mg40) even after longer MA (80 h), other powders reached to mostly the turbostratic structure with no sign of crystalline Mg. The maximum hydrogen concentration levels after hydrogenation for C100 powder were 0.1 wt.% after MA for 25 h and 0.4 wt.% after MA for 80 h, suggesting that nanostructured graphite uptakes more hydrogen. On the other hand, hydrogen concentration level for C90Mg10 powders was less than 0.1 wt.% after MA for 15 h, but it reached to about 1 wt.% after MA for 25 h, and dropped down slightly from 1 wt.% after MA for 80 h. Furthermore, hydrogen absorption occurred smoothly and quickly for C90Mg10 powders, although longer induction time was required for C100 powders. Further addition of Mg to graphite reduced the maximum hydrogen concentration level in the powders, and the powders containing more than 30 at.% Mg did not absorb hydrogen at all at 308 K.

AB - Graphite and elemental magnesium (Mg) powders, whose chemical compositions were C100-xMgx (0 ≤ x ≤ 40 at.%), were mechanically alloyed (milled) in an argon gas atmosphere, and these powders were loaded with hydrogen in a high-pressure vessel at a temperature of 308 K. The initial hydrogen gas pressure for hydrogenation experiment was 4 MPa. The periodicity of the c-axis of the graphite crystal structure was destroyed completely for C100 powders and partly for the powder containing Mg at an early stage of mechanical alloying (MA), indicating the formation of a turbostratic structure (graphene) for all powders. Although elemental Mg still remained in Mg-rich powders (C60Mg40) even after longer MA (80 h), other powders reached to mostly the turbostratic structure with no sign of crystalline Mg. The maximum hydrogen concentration levels after hydrogenation for C100 powder were 0.1 wt.% after MA for 25 h and 0.4 wt.% after MA for 80 h, suggesting that nanostructured graphite uptakes more hydrogen. On the other hand, hydrogen concentration level for C90Mg10 powders was less than 0.1 wt.% after MA for 15 h, but it reached to about 1 wt.% after MA for 25 h, and dropped down slightly from 1 wt.% after MA for 80 h. Furthermore, hydrogen absorption occurred smoothly and quickly for C90Mg10 powders, although longer induction time was required for C100 powders. Further addition of Mg to graphite reduced the maximum hydrogen concentration level in the powders, and the powders containing more than 30 at.% Mg did not absorb hydrogen at all at 308 K.

KW - Graphite

KW - Hydrogen storage

KW - Magnesium

KW - Mechanical alloying

KW - X-ray diffraction

UR - http://www.scopus.com/inward/record.url?scp=35148869260&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=35148869260&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2006.12.049

DO - 10.1016/j.jallcom.2006.12.049

M3 - Article

VL - 446-447

SP - 110

EP - 113

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

ER -