Surface Characterization

Atoms in solids are arranged in a fixed position by the electrical attraction forces of neighboring atoms. However, atoms on the surface of solid matter have fewer neighboring atoms than those below them. Surface atoms try to attract surrounding gas atoms to compensate for this electrical force imbalance. This leads to a process called adsorption, which provides useful information for the characterization of solids.

Physical adsorption studies are mainly carried out to obtain the surface area, pore size distribution and pore shape of a sample.

Instrument: Quantachrome Corporation, Autosorb-6

The device can be used in physical adsorption experiments on any solid sample. The device has 6 sample chambers that can measure at the same time. A degas unit with 6 chambers is available to degas the samples under vacuum prior to measurement.

Specifications

• Heating: Vacuum heating up to 350°C, 1°C intervals (physical adsorption)
• Relative Pressure Range: 1x10-5 - 1.0 (Nitrogen)
• Minimum Surface Area: 0.05 m2/g
• Pore ​​Diameter Range: 5 - 500 Angstrom (Micropore analysis is done in the range of 5-20 Angstrom, mesopore analysis is in the range of 20-500 Angstrom)

Sample Requirements

Measurements can be made on pellets, powders and solids. The samples must be pre-warmed to be free of water and moisture. At least 5 g of sample should be provided for measurement.

Applications

• Surface area
• Pore ​​size distribution (in micro-meso scale)
• Pore ​​shape