ASTM C1274 Determination of ceramic surface area through physical adsorption

Scope:

The ASTM C1274 standard is suitable for measuring surface areas of enhanced ceramic powders up to 0.05 m² (if krypton at 77.35 K is used as an adsorbent in combination with nitrogen). Both – suppliers and customers – of advanced ceramics can use this standard method for material improvement and comparison, product characterization, design data, quality control, and engineering/manufacturing specifications. 

Test Procedure:

In ASTM C1274, frequently used absorbent materials are used. The argon adsorptive material has a temperature of 77.35 K with 0.138 nm2 area, Nitrogen at 77.35 K with the cross-sectional area of 0.162 nm2, and Krypton at 77.35 K with 0.202 nm2 of the cross-sectional area. The manometric apparatus is used in volumetric tests. The outgassing techniques and temperatures must not cause any change in the powder sample’s constitution, form, or surface morphology. Before determining an adsorption equilibrium, start removing any physically adsorbed contaminants from the specimen surface. Many ceramic materials may be appropriately outgassed within a few hours at reasonably extreme temperatures (200 to 300 °C). Different ceramic materials have different outgassing temperatures. Quartz at 200 °C attain outgassing condition in 3 minutes, silica takes 3 minutes at 200 °C, and alumina takes 3 minutes at 300 °C.

Specimen Size : 

The ASTM C1274 test method evaluates ceramic materials, primarily silicon compounds like silicon nitride, silicon carbide, kaolin, etc.

Data:

The ASTM C1274 standards are based on the BET (Brunauer, Emmett, and Teller) method.

The monolayer capacity is calculated by:  Nm=Vm/Mv=Wm/Mad

Where Nm = monolayer capacity.

Wm = monolayer capacity of the gas.

Mv = molar volume.

M_ad = molar mass of adsorbate.

Vm = monolayer capacity of the sample.

Conclusion:

The standard ASTM C1274 determines the ceramic surface area through physical adsorption.