An investigation to identify the chlorides in hydrogenated–dehydrogenated Kroll processed titanium powder was carried out in this study. Jigsaw-like agglomerates containing submicroscopic particles were observed on titanium particles, and the microcompositional analysis suggests the presence of magnesium and chlorine. Further detailed surface chemical analysis carried out by X-ray photoelectron spectroscopy and corresponding curve fitting work revealed that the magnesium and chlorine mainly exist as Mg(OH)Cl and titanium chloride respectively. A mechanism is provided to explain the presence of these chlorides in the Ti powder. The chlorides are considered to arise from the decomposition of hydrated magnesium chloride during the hydrogenation–dehydrogenation process and are supported by thermal analysis of a pure hydrated magnesium chloride. This analysis suggests that the Mg(OH)Cl can further decompose into hydrogen chloride gas and magnesium oxide at high temperature. The implications of the formation of these gaseous species on the sintering of Ti powders are discussed.
QianM., SchafferG. B. and BettlesC. J.:‘Sintering of titanium and its alloys’, in ‘Sintering of advanced materials: fundamentals and processes’, (ed. FangZ. Z.), 324–355; 2010, Philadelphia, PA, Woodhead Publishing.
5.
WangH. T., FangZ. Z. and SunP.:Int. J. Powder Metall., 2010, 46, (5), 45–57.
6.
LiuY., ChenL. F., TangH. P., LiuC. T., LiuB. and HuangB. Y.:Mater. Sci. Eng. A, 2006, A418, 25–35.
VuurenD. S. V., OosthuizenS. J. and HeydenrychM. D.:J. South Afr. Inst. Min. Metall., 2011, 111, 141–148.
10.
TakedalO. and OkabeT. H.:‘Synthesis and enrichment of titanium subchlorides in molten salts’, in ‘Innovations in titanium technology’, (ed. GungorM. N..), 69–78; 2007, Warrendale, PA, Minerals, Metals & Materials Society.
11.
DoblinC., ChryssA. and MonchA.:Key Eng. Mater., 2012, 520, 95–100.
12.
GlennA., DoblinC. and MacRaeC.:Microsc. Microanal., 2009, 15, 680–681.
13.
IvasishinO. M., SavvakinD. G., GumenyakM. M. and BondarchukO. B.:Key Eng. Mater., 2012, 520, 121–132.
AlmanD. E. and GerdemannS. J.:P/M Sci. Technol. Briefs, 2004, 6, (1), 11–14.
16.
QianM.:Int. J. Powder Metall.2010, 46, (5), 29–44.
17.
LowR. J., QianM. and SchafferG. B.:Metall. Mater. Trans. A, 2012, 43A, 5271–5278.
18.
LowR. J., QianM. and SchafferG. B.:‘Chloride impurities in titanium powder metallurgy – a review’, Proc. 12th World Conf. on ‘Titanium’, (ed. ZhouL..), 1770–1774; 2011, Beijing, Science Press Beijing.
19.
FanZ., NiuH. J., CantorB., MiodownikA. P. and SaitoT.:J. Microsc., 1997, 185, 157–167.
AndersenP. J. and EloffP. C.:‘Development of higher performance blended elemental powder metallurgy Ti alloys’, Proc. Cong. on ‘Powder metallurgy of titanium alloys’, Las Vegas, NV, USA,February, 1980, TMS-AIME, 175–188.
22.
MahajanY., EylonD., BaconR. and FroesF. H.:‘Microstructure property correlation in cold pressed and sintered elemental Ti–6Al–4V powder compacts’, Proc. Cong. on ‘Powder metallurgy of titanium alloys’, Las Vegas, NV, USA,February, 1980, TMS-AIME, 189–202.
23.
JacksonA., MoteffJ. and FroesF.:Metall. Trans. A, 1984, 15A, 248–249.
24.
MoodyN. R., GarrisonW. M., SmugereskyJ. E. and CostaJ. E.:Metall. Trans. A, 1993, 24A, 161–174.
25.
FroesF. H. and EylonD.:Int. Mater. Rev., 1990, 35, 162–182.
26.
YanM., LiuY., LiuY. B., KongC., SchafferG. B. and QianM.:Scr. Mater., 2012, 67, 491–494.
27.
LeeY. T., SchurmannH., GrundhoffK. J. and PetersM.:Powder Metall. Int., 1990, 22, 11–16.
28.
HillS. D. and MrazekR. V.:Metall. Trans., 1974, 5, 53–58.
29.
BedjanianY. and LoukhovitskayaE.:Atmos. Environ., 2011, 45, 2373–2378.
30.
BedjanianY. and LoukhovitskayaE.:J. Atmos. Chem., 2009, 63, 97–108.
31.
Kashani-NejadS., NgK. W. and HarrisR.:Metall. Mater. Trans. B, 2005, 36B, 153–157.
Kashani-NejadS., NgK. W. and HarrisR.:Metall. Mater. Trans. B, 2004, 35B, 405–406.
34.
LongG. M. and MaP. H.:Thermochim. Acta, 2003, 403, 231–235.
35.
KipourosG. J. and SadowayD. R.:J. Light Met., 2001, 1, 111–117.
36.
LapovokR., TomusD., SkripnyukV. M., BarnettM. R. and GibsonM. A.:Mater. Sci. Eng. A, 2009, A513–A514, 97–108.
37.
GosoX. and KaleA.:J. South Afr. Inst. Min. Metall., 2011, 111, 203–210.
38.
MoustydesbuquoitC., RigaJ. and VerbistJ. J.:J. Chem. Phys., 1983, 79, 26–32.
39.
HaukkaS., LakomaaE. L., JylhaO., VilhunenJ. and HornytzkyjS.:Langmuir, 1993, 9, 3497–3506.
40.
SeyamaH. and SomaM.:J. Chem. Soc. Faraday Trans., 1984, 80, 237–248.
41.
MoulderJ. F., StickleW. F., SobolP. E. and BombenK. D.:‘Handbook of X-ray photoelectron spectroscopy’, Chap. III, ‘Appendix’, 243–251; 1992, Eden Prairie, MN, Perkin-Elmer Corporation.
42.
SiokouA., KefalasD. and NtaisS.:Surf. Sci., 2003, 532, 472–477.
43.
SleighC., PijpersA. P., JaspersA., CoussensB. and MeierR. J.:J. Electron Spectrosc. Relat. Phenom., 1996, 77, 41–57.
44.
CastilloR., KochB., RuizP. and DelmonB.:J. Catal., 1996, 161, 524–529.
45.
JiaQ., ChenZ., WuY. L., YangM. D., WangX. K. and TangN.:Chin. J. Inorg. Chem., 2011, 27, 1529–1535.
46.
EsmailW. A., DarwishA. M. Y., IbrahimO. A. and AbadirM. F.:J. Therm. Anal. Calorim., 2001, 63, 831–838.
47.
DanesF. E., SaintamanE. and CoudurierL.:J. Therm. Anal., 1988, 34, 821–833.
