高频燃烧红外吸收法测定镍基耐蚀合金中碳和硫

Determination of carbon and sulfur in nickel-based corrosion resistant alloy by high frequency combustion infrared absorption method

以含量相近的镍基合金标准物质绘制校准曲线,对高频燃烧红外吸收法测定镍基耐蚀合金中碳和硫的实验条件进行了探讨,着重考察了助熔剂的种类及其用量、称样量对测定的影响。结果表明:分别以0.30 g纯铜-0.30 g纯铁和0.40 g纯铁-1.50 g纯钨为助熔剂对碳和硫进行测定时,试样燃烧完全,红外吸收峰型对称、平滑,测得结果的相对标准偏差(RSD)最小。称取(0.300±0.005)g试样进行碳和硫的测定,熔融后试样不会外溢且测得结果的相对标准偏差最小。结果表明,碳含量校准曲线线性相关系数r=0.9998,检出限为0.00012%,定量限为0.00040%。硫含量校准曲线线性相关系数r=0.9999,检出限为0.00011%,定量限为0.00036%。将实验方法应用于3个镍基耐蚀合金试样中碳和硫的测定,测得结果分别在0.0053%~0.156%和0.0011%~0.0032%之间,测得结果的相对标准偏差(RSD,n=6)分别小于1%和小于3%。按照实验方法对镍基耐蚀合金试样进行测定,并分别加入不同含量的基准试剂碳酸锂对样品中碳含量进行加标回收实验,加入不同含量的基准试剂硫酸钾对样品中硫含量进行加标回收试验,回收率分别在95%~104%和96%~105%之间。

The experimental conditions for the determination of carbon and sulfur in nickel-based corrosion resistant alloy by high frequency combustion infrared absorption method were discussed by preparing calibration curve using certified reference material of nickel-based alloy with similar content.The effect of flux type,dosage and sampling mass on the determination was mainly investigated.The results showed that the combustion of sample was complete and the infrared absorption peak was symmetrical and smooth under the following conditions:0.30 g of pure copper-0.30 g pure iron and 0.40 g of pure iron-1.50 g of pure tungsten were used as flux for the determination of carbon and sulfur.Meanwhile,the relative standard deviations(RSD)of results were minimal.When(0.300±0.005)g of sample was used for the determination of carbon and sulfur,the sample would not overflow after melting and the RSDs of measurement results were minimal.The results indicated that the correlation coefficient of the calibration curve of carbon content was r=0.9998.The limit of detection was 0.00012%and the limit of quantification was 0.00040%.The correlation coefficient of the calibration curve of sulfur content was r=0.9999.The limit of detection was 0.00011%and the limit of quantification was 0.00036%.The experimental method was applied for the determination of carbon and sulfur in three nickel-based corrosion resistant alloy samples.The found results were in range of 0.0053%-0.156%and 0.0011%-0.0032%,respectively.The RSD(n=6)of determination results was less than 1%and 3%,respectively.The nickel-based corrosion resistant alloy sample was determined according to the experimental method.The spiked recovery tests of carbon and sulfur in sample were conducted by adding different dosages of standard reagents(lithium carbonate and potassium sulfate,respectively).The recoveries for carbon and sulfur were 95%-104%and 96%-105%,respectively.