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Title: Mechanical enhancement of the carbothermic formation of TiB{sub 2}

Abstract

A mixture of rutile, boron oxide, and graphite has been mechanically milled for 1, 10, and 100 hours with the intention of forming titanium diboride during subsequent thermal treatment. The resultant powders were examined after isothermal annealing by X-ray diffraction (XRD) to determine the effect of milling on the formation of TiB{sub 2}. No reaction was found to occur during milling, even for milling times of 100 hours. Annealing of the milled samples resulted in the formation of TiB{sub 2} at temperatures as low as 1,000 C for the 100 C-hour milled powder. The reaction mechanism during thermal processing changed with milling time, with TiBO{sub 3} predominant in samples milled for > 1 hour, whereas Ti{sub n}O{sub 2n{minus}1} phases predominated for 1 hour of milling. Titanium carbide became an increasingly abundant intermediate phase with longer milling times, but was converted to TiB{sub 2} at high temperatures. The annealed products showed the presence of acicular crystals of TiB{sub 2}, with those from 1 hour of milling being somewhat larger than those for longer milling times, where submicron particles were formed. This was attributed to the presence of a larger fraction of molten B{sub 2}O{sub 3} compared to the longer-milled powders wheremore » TiBO{sub 3} predominated.« less

Authors:
Publication Date:
Research Org.:
Australian National Univ., Canberra (AU)
OSTI Identifier:
20014063
Resource Type:
Journal Article
Journal Name:
Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science
Additional Journal Information:
Journal Volume: 31; Journal Issue: 1; Other Information: PBD: Jan 2000; Journal ID: ISSN 1073-5623
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; TITANIUM BORIDES; MILLING; HEAT TREATMENTS; PHASE STUDIES

Citation Formats

Welham, N J. Mechanical enhancement of the carbothermic formation of TiB{sub 2}. United States: N. p., 2000. Web. doi:10.1007/s11661-000-0072-8.
Welham, N J. Mechanical enhancement of the carbothermic formation of TiB{sub 2}. United States. doi:10.1007/s11661-000-0072-8.
Welham, N J. Sat . "Mechanical enhancement of the carbothermic formation of TiB{sub 2}". United States. doi:10.1007/s11661-000-0072-8.
@article{osti_20014063,
title = {Mechanical enhancement of the carbothermic formation of TiB{sub 2}},
author = {Welham, N J},
abstractNote = {A mixture of rutile, boron oxide, and graphite has been mechanically milled for 1, 10, and 100 hours with the intention of forming titanium diboride during subsequent thermal treatment. The resultant powders were examined after isothermal annealing by X-ray diffraction (XRD) to determine the effect of milling on the formation of TiB{sub 2}. No reaction was found to occur during milling, even for milling times of 100 hours. Annealing of the milled samples resulted in the formation of TiB{sub 2} at temperatures as low as 1,000 C for the 100 C-hour milled powder. The reaction mechanism during thermal processing changed with milling time, with TiBO{sub 3} predominant in samples milled for > 1 hour, whereas Ti{sub n}O{sub 2n{minus}1} phases predominated for 1 hour of milling. Titanium carbide became an increasingly abundant intermediate phase with longer milling times, but was converted to TiB{sub 2} at high temperatures. The annealed products showed the presence of acicular crystals of TiB{sub 2}, with those from 1 hour of milling being somewhat larger than those for longer milling times, where submicron particles were formed. This was attributed to the presence of a larger fraction of molten B{sub 2}O{sub 3} compared to the longer-milled powders where TiBO{sub 3} predominated.},
doi = {10.1007/s11661-000-0072-8},
journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science},
issn = {1073-5623},
number = 1,
volume = 31,
place = {United States},
year = {2000},
month = {1}
}