10 kW Lepel high frequency generator. Helium gas was used to cool 
the specimen by varying the flow rate. Helium was used to orevent 
oxidation of the sample and control the temperature. 
The temperature of the levitated sample was measured by a two-color 
pyrometer (Ratioscope III) and was continuously recorded. The pyro- 
meter, covers a temperature range from 750°C to 1850°c, accuracy 6°C 
+0,75% of temperature reading, repeatability 1°c + 0,1% of temperature 
; reading. The temperature could also be altered by changing the 
ist current through the coil. If the current increases, the sample will 
rise from the force of the magnetic field and therefore not be heated 
as much; the result is a reduction of temperature. Similarly, a lower 
current would cause the sample to become hotter. The melting point of 
1. each levitated sample, however, was used as a reference point to 
and calculate the supercooling of that sample. The current at which the 
onsi- sample would be heated above the melting point and levitated was 
00 KC, determined experimentally. At a desired temperature, the levitation 
power was cut off, allowing the sample to fall through the plastic 
diaphragm into the quenching medium. The quenching medium placed 
directly below the levitation chamber was water, Woods metals 
(52,5% Bi + 32,0% Pb + 15,5% Sn), splat cooler, aluminium wheel, 
vacuum sucking unit or copper olate. The alloy was prepared from 
high purity nickel (99,99%) and tin (99,99%). Each series of alloy 
was prepared in a vacuum arc melting furnace, weights of the samples 
were between 0,3 and 1,0 gram, with a diameter of about 5,0 mm. The 
composition of the alloy used in this study is eutectic composition. 
The quenched samples were mounted, ground and polished, etchants 
used were Marble and Kalling reagents. 
The lamellar eutectic spacing was measured in a few instances, using 
linear intercept analysis. Figure 2 shows lamellar eutectic spacing 
as a function of supercooling. 
The average size of the Ni-rich phase within the irregular eutectic 
was measured using linear intercept analysis. Figure 3 shows size 
of the Ni-rich phase as a function of supercooling. 
A portion of "irregular" eutectic was measured by computerized imace 
analysis. Results are given on figure 4. 
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