Splat-cooling

Splat cooling Spleen SPLENDA Splint Split peas... 

Unconventional melting of glasses includes splat cooling, which is used extensively to produce amorphous metals laser spin melting, which can produce 100-800 pm... 

In their initial work, Smith and coworkers [4.2] showed that Pd-Si glasses, made by splat cooling [4.51] are active catalysts for the hydrogenation with deuterium of cis-cyclododecene at room temperature. Pd-Si glasses produced more trans-isomerization, more dideutero-saturate, and less extensive exchange than crystalline Pd. Later, these studies were extended to include Pd-Ge glasses [4.33] and compared the catalytic behavior of the glassy metals with their crystalline counterparts. 

Splat cooling can also be used to prepare metastable phases and also thermodynamically stable phases which are difficult to prepare by other techniques. In this case the metastable amorphous metal alloy is slowly heated up to allow the appropriate crystalline phase to form. 

Sar] Sare, I.R., Honeycombe, R.W.K., Splat Cooling of Iron-Molybdenum-Carbon Alloys , J. Mater. Sci., 13(9), 1991-2002 (1978) (Phase Relations, Morphology, Experimental, 34)... 

Sar] Sare, I.R., Two Non-Crystalline Phases in a Splat-Cooled Fe-1.9 mass% Si - 4.2 mass% C Alloy , Scr. Metall, 9, 607-609 (1975) (Experimental, Crys. Stmcture, 7)... 

Rapid quenching of C-Fe-Ti alloys from the melt by splat cooling [1980Sar] produces stable phases such as ferrite, austenite, TiC and metastable phases such as cementite, martensite and a hexagonal s phases. Austenite deeomposes in the temperature range 200-400°C whereas TiC precipitates at 700°C and coarsens slowly at 700-800°C. 

Microstructures of glassy and metastable crystalline phases formed from Fe69Vi2Ci9 alloy were studied by [1982Hor]. It was shown that the non-stoichiometric monocarbide VCi t could be modified by splat cooling into a mixed carbide if V was partially substituted by Fe. 

Another group of amorphous semiconductors are the A compounds and alloys. a-SiO, which is a much investigated material with large technical uses, a-SnTe, a-PbTe and the whole series of a-Ge Te. and a-Ge Se. alloys can be obtained by vacuum evaporation or sputtering. Bulk glassy Ge Tej j and Gej Sei j alloys can be obtained by splat-cooling the melt or even slower quenching if relatively small quantities of P, As, S, Si, or I are added to the melt. This is most easily achieved around the compositions close to an eutecticum (Hilton, Jones, and Brau, 1966 Feltz et al, 1971), e.g. for X — 0.15 in the Ge-Te system. 

Bucher et al. (1969) have observed an fee form of Pr and Nd in splat-cooled samples. Since the metals were quite impure, it is possible the fee phase observed was impurity induced and/or induced by the strains of splat-cooling. 

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