Compare item |
reference comparison method |
BET method |
Desorbed gas calibration |
Compare directly with standard sample peak area with known surface area, no need for real gas desorbed calibration. |
No standard sample required, use gas peak area of known set volume to calibrate the testing samples gas volume. |
Principle |
Adsorptions peak areas of a sample and standard are proportional to their adsorbed gad volumes, respectively, therefore samples surface are can be obtained through simple comparison. |
Based on multi-layer adsorption theory, single-layer saturation adsorption gas volume can be derived by BET equation for surface area calculation. BET method is the most popular nitrogen adsorption surface area testing method. |
Testing gas |
Fixed ratio of He to N2(4:1) |
High purity N2 and He, experiment need to choose various mix ratio. |
Application range |
Applicable samples which have similar adsorption performance to standards, domestically widely used in carbon black industry, not much use abroad. |
Applicable to all kinds of samples without micro-pores. This is internationally accepted method for various applications. |
Result |
Test accuracy varies depending on different samples |
Using standard set volume gas to calibrate nitrogen adsorption volume, this method enjoy high accuracy regardless samples varieties. |
Application area |
On-site product line monitoring, fast surface area testing. |
Research institutes, universities, enterprises for precise surface area testing |