Abstract
An infrared spectroscopic method was developed for a rapid identification of trace amounts of boron nitride (BN, less than 0.0001% of boron as BN in steel) in the residues extracted with sulphuric acid from steel samples. From the studies on commercial boron nitride (BN) and the residues which were found to contain boron nitride by elementary analysis and electron diffraction, boron nitride was newly found to have strong characteristic absorption bands at 819 and 1383 cm−1 and to be readily identified by these bands without interference from compounds usually contained in the residues. A recommendable procedure is as follows : The residues by the acid extraction from 2∼5 g of the chipped sample is collected through the Millipore filter (100 mμ) and dried at room temperature. The residue is transfered into 300 mg of potassium bromide powder with Johnson’s method and ground well in an agate mortar with potassium bromide for about 20 min. Infrared spectrum is measured over the frequency region between 600 and 1600 cm−1, using the disk-like pressed powder (13 mm in diameter and 1 mm in thickness). Boron nitride is identified by the characteristic bands at 819 and 1383 cm−1. This method may be developed for a quantitative analysis of trace amounts of boron nitride in the residues extracted from steel.
