1988 Volume 74 Issue 10 Pages 2041-2046
The alkali fusion-coulometric titration method has been studied for the determination of nitrogen as nitride in steel.
(1) The procedure, which has been established by using nitride reagent, is as follows.
a) The nitride reagent is fused by molten alkali (450°C) containing water vapor.
b) Nitrogen in the reagent is extracted as ammonia with carrier gas (Ar) and the ammonia is determined by the coulometric titration method.
All nitrides excepting Cr2N, ZrN can be determined by this method.
(2) This method was applied for the determination of nitrogen in the residues extracted by 15%I2-methanol decomposition method for steel.
The results are as follows.
a) The determination is completed within 20min.
b) Nitrogen blank of this method is very small. (0-2μg)
c) The trace amount of nitrogen as nitride can be determined with excellent precision. (N=7ppm C.V.=45%)