采用高温水解-离子色谱法测定氮化硅中氟和氯的含量。氮化硅样品经1 050 ℃高温水解,氢氧化钠溶液吸收挥发性氟化物和氯化物,使待测元素以相应阴离子形式存在。以8.0 mmol·L-1碳酸钠-1.0 mmol·L-1碳酸氢钠混合液为淋洗液,抑制型电导检测器测定。F-和Cl-的线性范围依次为0.10~1.00 mg·L-1,1.00~10.00 mg·L-1,检出限(3σ)依次为0.017,0.026 mg·L-1。方法应用于氮化硅样品的分析,测定值与能量散射X射线荧光法测定结果相符,测定值的相对标准偏差(n=7)小于4.0%。用标准加入法进行回收试验,测得回收率在84.5%~106%之间。

IC was applied to the determination of fluoride and chloride in silicon nitride after pyrohydrolysis. Sample of silicon nitride was pyrohydrolyzed at 1 050 ℃, and the volatile fluoride and chloride produced were absorbed by sodium hydroxide solution forming anions of F- and Cl- in solution, and determined by ion chromatography. 8.0 mmol·L-1 Na2CO3-1.0 mmol·L-1 NaHCO3 mixed solution was used as eluant, and restraining conductance detector was used in determination. Linearity ranges of F- and Cl- found were between 0.10-1.00 mg·L-1 and between 1.00-10.00 mg·L-1 with detection limits (3σ) of 0.017, 0.026 mg·L-1, respectively. The proposed method was applied to the analysis of silicon nitride sample, giving results in consistency with the values obtained by EDXRFS, and values of RSD′s (n=7) found were all less than 4.0%. Test for recovery was performed by standard addition method, giving values of recovery in the range of 84.5%-106%.