Description
The Ga-Ni binary system is an important constituent of a number of ternary and higher-order systems of technological relevance, like As-Ga-Ni and Ga-Ni-Sb, which are of interest for the application of Ni as contact material for GaAs and GaSb compound semiconductors, respectively, or the system Ga-Ni-Sn which may be of interest for the admixture of small amounts of Ga to Sn-based solder alloys. Such Ga-containing alloys are used in the electronics industry, e.g. in micro connections between bare silicon chips and printed circuit boards or generally in the development of lead-free solders. Recently Ducher [1] et al. reinvestigated and subsequently modified the Ni-rich part of the system. In the present study a new version of the Ga-rich part of the Ga-Ni phase diagram was established based on DTA, X-ray diffraction and EPMA investigations. Two significant differences compared to previous versions of the phase diagram were discovered. The most Ga-rich compound Ga4Ni was not found as such. Instead the existence of Ga7Ni3, as already described earlier in literature, was confirmed. Furthermore the peritectic reaction GaNi + L ? Ga3Ni2 was found at a temperature of 950 °C, which is more than 50 °C higher than the indicated literature value. At 80 at.% Ga additional lines in X-ray diffractograms that had also been reported already in literature suggest the presence of a further, possibly metastable Ga-rich phase. Although no single crystal XRD measurements could be performed, the powder patterns could be indexed using a Ga5Pd type crystal structure including a refinement of the free atomic positions. The partial and integral enthalpies of mixing of liquid Ga-Ni alloys were determined at various temperatures (1031, 1134, 1246, 1261, 1321, and 1388 °C) using a drop calorimetric technique. No significant temperature dependence of ? mixH could be observed. The minimum was found at 57 at.% Ni with a value of -33 kJ/mol. [1] Ducher R, Kainuma R, Ishida K. Intermetallics 2007;15:148.| Period | 2009 |
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| Event title | 13. Österreichische Chemietage (GÖCH 2009) |
| Event type | Conference |
| Location | Wien, AustriaShow on map |