The study of specific surface area is very important. The specific surface area detection data is only true and reliable when the results are detected by the BET method. At present, there are many instruments in China that can only be tested by the direct comparison method. Now it is also eliminated in China. At present, the multi-point BET method is used uniformly for the specific surface area testing at home and abroad. The specific surface area measurement standards developed at home and abroad are based on the BET test method. Please refer to China's national standard (GB / T 19587-2004)-Gas adsorption BET principle Method for determining the specific surface area of ​​solid materials. The measurement of specific surface area is actually a time-consuming task. Due to the different adsorption capacity of the sample, the test of some samples may take a whole day. If the test process is not fully automated, then the tester ca n’t leave at all times. A high degree of concentration, observing the instrument panel, manipulating the knob, and a little inattention will lead to the failure of the test process, which will waste a lot of precious time of the tester. The F-Sorb 2400 specific surface area analyzer is an instrument that can truly realize the detection function of the BET method (both with direct comparison method), and the more important F-Sorb 2400 specific surface area analyzer is the only fully automated intelligent specific surface area detection device in China The test results are highly consistent with international standards, and the stability is also very good. At the same time, it reduces human errors and improves the accuracy of test results.
Samples placed in an adsorbate gas atmosphere will undergo physical adsorption on the surface of the substance (the surface of the particles and the internal through holes) at low temperature. When the adsorption gas reaches equilibrium, the equilibrium adsorption pressure and the amount of adsorbed gas are measured. According to the BET equation, the monomolecular layer adsorption amount of the sample to be measured can be obtained, thereby calculating the specific surface area of ​​the sample. This standard stipulates the method for measuring the specific surface area of ​​solid substances based on the BET principle of gas adsorption. It is suitable for the determination of the specific surface area of ​​powders and porous materials (including nano-powders and nano-scale porous materials), and its measurement range is 0.001 ～ 1000㎡ / g. Measuring methods include volumetric specific surface area analysis test, gravimetric specific surface area analysis test and gas chromatography specific surface area analysis test. Nitrogen is generally used as the adsorption gas, but krypton gas can be used for samples with a positive surface area. Before the measurement, the sample needs to be degassed, which is especially important for nanomaterials. The material adsorbed on the sample surface can be removed by degassing, but the irreversible change of the surface should be avoided.
The standard is non-equivalent to adopt IS09277: 1995 Determination of the specific surface are La of solids by gas adsorpti On using the BET method.
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