White corundum and alumina are the same color, white. After all, white corundum is made of alumina by high-temperature electric furnace smelting.

aluminium oxide

(1) Appearance: white powder, crystal phase γ phase;

(2) Average particle size (nanometer): 20 5;

(3) Content%: greater than 99.9%;

(4) Melting point: 2010℃-2050℃;

(5) Boiling point: 2980℃;

(6) Relative density (water =1): 3.97-4.0;

(7) Color: white, and the color after calcination is dark blue.

White corundum

(1) Appearance crystal form: triangular crystal system;

(2) Density: 3.90 g/c? ;

(3) Hardness: Knoop hardness is 2000-2200Kg/m㎡, Mohs hardness is 9.0;

④ Melting point: 2250℃;

(5) Maximum service temperature:1900℃;

(6) specific heat (cal/g.c): 0.26 (20-90c);

(7) Thermal conductivity: 900℃ at room temperature (calories/cm3.sec);

(8) refractive index: e =1.760w =1.768 (naline);

(9) Linear expansion coefficient: (7-9) *10-6/k (0-1600c).

Through the comparison of density and appearance, it is found that the difference between them is not small.