and nickel and spectrochemically for all the elements listed in Table I. The analysis of the buttons indicated that several elements had been partially lost in the vacuum melting operation. However, there was a varying concentration range of all the elements, although it was not of the magnitude originally calculated.
Table 111.
Coccentration Deviation, Impurity Range, P.P.M. %
AI Fe Co Ti
Sn
V SAMPLE PREPARATION
The eamples were received as chips, sponge, chunkiets, and various melted solid forms. All samples, except the latter, were made into a compact and melted in a button as in “Preparation of Standards.” The samples were then carefully machined on a lathe to give a clean, smooth, flat surface which served as the upper electrode. EXPERIMENTAL DATA
When the standards were completed, the first problem to be considered was the type of discharge to be used. To accomplish this, a series of shots was run on the standards, with the highest and lowest concentrations of the elements, using five discharges. A . Condenser discharge critically damped B. Condenser diecharge overdamped C. Rectifier discharge - condenser suatained arc D. 30-cycle overdamped spark E. High voltage RF (radio frequency) spark
The criterion for determining which of the above discharges was most suitable, was: line-to-background ratios, spark wandering, reproducibility, preceasion, etc. This evaluation indicated that the 3O-cycle overdamped spark was considerably better than the other discharge types studied. This discharge was the only one in the group studied that gave sufficient sensitivity for all the elements
Reproducibility
Ni Si Mg Mn
B Cr cu Cd
Table
Impurity A1 Fe co Ti Sn V Ni Si
M3
Mn B Cr cu Cd
20-100 200-2800 5-10 20-100 20-50 20-50 20-50
7.2 3.5 20.0 12.0 5.0 11.1 5.0 6.1 8.5
40-300 24l-40
20-150
7.0
0.2-0.8 20-450 10-7000
25.0 9.2 2.5 28.0
0.2-0.6
IV. Comparative Data Poinito- SpectroPlane graphic 29 26 250 233
