Effect of some of the process parameters involved in the industrial manufacture of R-10 and R-20 carbonyl iron powders on their temperature coefficients of magnetic permeability

Abstract

1. It is shown that raising the temperature in the reaction zone of the iron carbonyl decomposition apparatus (temperature tr) by 1°C increases the values of TCμ of R-10 and R-20 powders by 9·10−6 and 7·10−6 1/ deg C, respectively. 2. It was found that the values of TCμ of R-10 and R-20 powders tend to fall when the ammonia content of the reaction gases is increased from 2.2 to 7.4% at constant temperature in the upper zone of the reactor. 3. The optimum process parameters for the manufacture of R-10 and R-20 powders, ensuring that the TCμ requirements prescribed by GOST 13610-68 standard are fulfilled, ara upper zone temperature tr, 311–313°C, rate of Fe(CO)5 supply, 20–40 liters/h; and NH3 content of the reaction gases, 2.53%. 4. It was established that values of TCμ of cores from R-10 and R-20 powders measured at subzero temperatures are on average (40–50) · 10”−6 1/deg C lower than corresponding values measured at higher temperatures.