Silicon nitride is an important new structural ceramic material with high strength, especially hot pressed silicon nitride, which is one of the hardest materials in the world. Silicon nitride is highly resistant to high temperature. It can keep its strength at 1200 ℃ and will not decompose until 1900 ℃. Moreover, it has amazing chemical corrosion resistance. It can withstand almost all inorganic acids and less than 30% caustic soda solution. At the same time, it is also a high-performance electrical insulation material.

Silicon nitride has the advantages of high density, super hardness, lubricity, wear resistance, corrosion resistance, high temperature resistance and difficult heat transfer, which makes it widely used in the manufacture of mechanical components such as bearings, gas turbine blades, permanent mold, ceramic seal ring, thermocouple tube, rocket nozzle, crucible for melting metal and other high-temperature parts.

However, the anionic impurities in silicon nitride, especially halogen, will cause serious corrosion to the contact parts, which will affect the mechanical strength of the components and the sealing effect of the sealing ring. Therefore, the accurate determination of anionic impurities in silicon nitride is of great significance.

The anion in silicon nitride can be determined by using SHINE CIC-D150 intelligent ion chromatograph and SH-AC-11 column.

1.Sample pretreatment

Weigh about 1g of sample (powder sample), record the mass (accurate to 0.001g), add 100ml of ultrapure water, ultrasonic extraction for 30min, stand still, take the supernatant through 0.22 μ M filter membrane for sample injection analysis; take 100ml ultra pure water under the same conditions, filter 0.22 μ M filter membrane sample injection analysis as the control group.

2. Chromatographic conditions

SHINE CIC-D150 ion chromatograph

Instrument: CIC-D150 

Column: SH-AC-11

Eluent:  14mM KOH (EG)      

Flow rate: 1.0mL/min 

Detection method: suppressed conductivity method

Injection volume: 25uL 

Column pressure: 4.5Mpa 

Column temperature:35℃

Suppression current: 45 mA

SHINE CIC-D150 ion chromatograph pays attention to intellectualization, realizes the functions of remote control of mobile phone app, regular startup preheating, intelligent large screen real-time display of instrument parameters and operation status, one key intelligent maintenance and other functions, which is more convenient to use and greatly improves the laboratory productivity and user experience.

D150 has high precision and reliable analysis ability. It can easily determine 100ppb-100ppm concentration samples without setting the measuring range. The micro gas-liquid separator can separate the bubbles in the eluant.

3.Sample spectrogram

Spectrum of sample 1

Spectrum of sample 2

Matters needing attention

It is easy to be polluted in the process of experiment, so the experimenters are required to operate in strict accordance with the operation rules.

Feasibility analysis and conclusion

The results show that the method has good separation and is suitable for the determination of components in samples.