Graphite Product Testing

Determination of physical properties of carbon graphite materials

Determination of density and porosity

Carbon graphite material is a porous structural material, and its density is divided into bulk density and true density. The so-called bulk density refers to the ratio of the mass of the carbon graphite material to its volume. The true density is the ratio of the mass of the carbon graphite material to the true volume.

The pores of the carbon graphite material have internal pores and surface opening pores. The apparent porosity is the ratio of the volume of the open pores of the sample to the total volume of the sample. The measurement methods include the vacuum method and the boiling method. The true porosity is the ratio of the difference between the true density and the bulk density to the true density.

For the inspection of graphitized blanks and mechanically processed products:

(1) The inspection of machining quality is mainly the inspection of dimensional accuracy and surface roughness.

(2) Detection of chemical composition analysis, composition and element analysis, analysis of sulfur, phosphorus, barium, nickel, titanium and other trace elements according to different products.

(3) Measurement of general physical properties, including measurement of bulk density, true density, porosity, pore distribution and pore size distribution.

(4) The detection of structure analysis mainly includes metallurgical microscope, X-ray diffraction and electron microscope, and determination of graphitization degree.

(5) Measurement of mechanical properties, including compression, bending, tensile, elastic modulus and hardness. In addition, the coefficient of friction and the amount of wear are measured.

(6) Electromagnetic performance testing mainly includes the measurement of resistivity, magnetic susceptibility, Hall coefficient, magnetoresistance, etc.

(7) Thermal performance testing, mainly including heat capacity, thermal conductivity, linear expansion coefficient, oxidation degree, thermal creep, thermal shock, etc.

(8) Nuclear radiation performance testing, which includes neutron capture cross-sectional area and nuclear radiation damage testing.