This standard specifies a method for the determination of fluoride and chloride ion content in silicon nitride powders by Ion chromatography. It is suitable for the determination of fluoride and chloride ions in silicon nitride powders, and the test range is 0.0500 mg/g to 0.600 mg/g. The principle of the method involves combustion of the sample in a mixed gas stream of oxygen and water vapor, so that the fluorine and chlorine are converted into volatile fluorides and chlorides, which are then dissolved in water and analyzed by Ion Chromatography. The standard also points out the influence of sample weighing, mixing uniformity, oxygen Flow rate and device sealing on the test results to ensure the accuracy of the measurement results.