Determination of resistance value of graphite powder
Release time:
2021-11-29 11:37
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Graphite powder is a substance with very sensitive chemical reaction. Its resistivity will change in different environments, that is, its resistance value will change, but one thing will not change. Graphite powder is a good non-metallic conductive substance. One, as long as the graphite powder is kept uninterrupted in an insulating object, it will be energized like a thin wire. However, the resistance value is not an accurate number, because the thickness of the graphite powder is different. The resistance value of graphite powder will be different in different materials and environments.
1. Determination of particle size (microscope method) The general microscope particle determination method is used to measure the particle size of graphite, which is expressed in microns.
2. Determination of ash content of graphite powder is the same as the determination of ash content of coal char in Chapter 15.
3. Determination of insoluble hydrochloric acid in graphite powder ash (weighing method) 1. Analysis step Weigh 0.04009 ash, put it in a 150mL beaker, and add 50mL of hydrochloric acid to dissolve. Boil the solution at a low temperature for 30 minutes until all the iron oxides are dissolved (judged by the color of the insoluble matter), then add 50 mL of water, filter with medium-speed quantitative filter paper, and wash the precipitate on the beaker and filter paper with hot water 4 to 5 times. Move the filter paper and the precipitate into the quantified porcelain crucible, dry and ashing at 800850°C. C box-type resistance furnace burning for 20min, take out and cool in the air, and then put it in a desiccator to cool to room temperature and weigh. 2. Calculate the mass fraction of substances insoluble in hydrochloric acid in the ash in the formula side-yrtl×z side-^Zm; m. ——The mass of the hydrochloric acid insoluble matter, g; m—weigh the mass of the ash, g; z—the mass fraction of the ash. 3. Tolerance tolerance ≤ content × 10%.
4. Grinding performance test and analysis step Weigh 0.50009 sample, place it between two 80mm×30mm glass sheets and rub for 10-15s. Observe with the naked eye that there should be no obvious scratches on the glass sheets.
V. Determination of sieve residues on meshes of No. 0.063, No. 0.075 and No. 0.100 , and then brush with a soft brush until the residue cannot be sieved. 2. The calculation is called (sieve residue) 1 drop × 100%, and in formula f is called (sieve residue) - the mass fraction of the sample sieve residue; excellent. ——the mass of the sieve residue, g; m——the amount of the sample weighed, g. 3. Tolerance tolerance ≤ content × 5%.
6. Determination of moisture content is the same as the determination of moisture content of coal char in Chapter 15.
7. The determination of sulfur is the same as the determination of sulfur in coal char in Chapter 15.
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