12325-59-6Relevant articles and documents
Chemical vapour growth of HfP whiskers and their properties
Motojima,Hirano,Fujii,Iwanaga
, p. 5709 - 5715 (1996)
Whiskers and ribbon-like single crystals of β-HfP (hexagonal) have been prepared from HfCl4 + PCl3 + H2 + Ar gas mixtures at 1100-1200°C using a metal impurity-activated chemical vapour deposition process. The growth conditions, morphology and chemical properties were examined. The 3.5-6.5 mm (average 4 mm) long HfP whiskers were obtained at 1200°C using Si + Pt or Si + Pd mixed impurities. The HfP whiskers were very stable against oxidation up to 3 h exposure at 1000°C and for 80 min immersion in concentrated HCl solution at 50°C.
Self-propagating metathesis routes to metastable group 4 phosphides
Jarvis Jr., Robert F.,Jacubinas, Richard M.,Kaner, Richard B.
, p. 3243 - 3246 (2008/10/08)
Group 4 phosphides, which are typically prepared at high temperatures (>800 °C) over several days, are synthesized in self-propagating metathesis (exchange) reactions in seconds. These reactions produce cubic forms of zirconium phosphide (ZrP) and hafnium phosphide (HfP) which are normally made at temperatures greater than 1425 °C and 1600 °C, respectively. To test whether the high temperatures reached in the metathesis reactions are responsible for the formation of the cubic phases, inert salts are added to lower the maximum reaction temperatures. The lower temperature reactions still result in cubic phosphides, although smaller crystallites form. Further experiments with phosphorus addition indicate that the phosphorus content is not responsible for cubic phase formation. Templating is ruled out using lattice mismatched KCl and hexagonal ZnS as additives. Therefore, the direct synthesis of the high-temperature cubic phase in metathesis reactions appears to be caused by nucleation of the metastable cubic form that is then trapped by rapid cooling. Heating the cubic phase of either ZrP or HfP to 1000 °C for 18 h, or carrying out metathesis reactions in sealed ampules at 1000 °C, results only in the hexagonal phase.
