A series of reproducibility tests was carried out, early in the program, using one of the production triple carbonates. The batches of coated filaments were prepared at different times from individually baH-milled suspensions of the same powder. The two coatings differed with respect to their bulk densities by 4.3%. The sample weights had a 2.2% difference, and the coating thickness variation was 2.5%. Examination of the pressure-time curves for six samples in each test batch revealed that the average peak pressures were 1.82 • 10 -~___ 0.05 • 10 -3mm and 1.83 • 10 -8_0.09 • 10 ~ mm, respectively. The corresponding average temperatures at these pressure peaks were 878 ~ and 876~ The decomposition times (see text) were 70.6 and 67.3 sec. While individual results in each batch showed deviations from the average of 1 to 5%, the difference between batches was only about 1%. The production carbonate used in these tests continued to serve as a control material with which the reliability of the over-all test equipment and procedure were checked periodically.ABSTRACT It has been found that high-resistivity AISb ingots result from the zone refining of the compound in ALO. crucibles. Distribution coefficients of the spectroscopically observed impurities in A1Sb were found to be 0.1 and smaller. Resistivity and Halt coefficients have been determined for some single-crystal specimens cut from the zone-melted ingots. Single crystals of A1Sb have been grown by pulling from the melt. These crystals exhibited low resistivities. The mobility for holes in the crystals has been found to range between 300 and 500 cm~/v-sec.Of the nine Group III-V semiconducting intermetallic compounds, AISb, GaAs, and InP are of major interest for use in the fabrication of solidstate rectifiers and transistors. A considerable amount of work has been done recently on the purification and growth of single crystals and on the study of the electrical properties of the compounds (1). In this paper, the preparation of A1Sb by zone melting and the growth of AISb crystals by crystal pulling are described.