Table 1.

Chemical analysis of the aluminum samples and the estimated depression of the freezing point by the impurities

	Batch 1558	Batch 2571		Estimated effect from each impurityd
Element	Supplier ppma	Supplier ppma	NBS ppmb	mK/ppm
Ca	0.2	0.2		−0.6
Fe	0.5	0.1	1.4	−0.3
Mg	<0.1	0.1	0.2	−0.6
Mn	0.1	0.2	C⩽0.3	−0.1
Si	0.3	0.3		−0.7
Cr	0.2		⩽0.04	+ 0.2
Cu	0.2	0.1	0.1	−0.3
Ni			⩽0.2
Ti			⩽0.05
V			⩽0.04
Na			0.2	−0.7
Ga			⩽0.06
Zn			5	−0.2
Estimate of total effect of impurities	−0.57 mK	−0.47 mK	−1.7mK

^aBased on spectrochemical analysis.

^bMass spectrometric analysis by P. J. Paulsen, Analytical Mass Spectrometry Section, NBS.

^cThe values preceded by the symbol ⩽ indicate the upper limit of the elements not detected. These values were not included in determining the total change in the freezing point from the impurities.

^dEstimated from phase diagram data [11].