硫化カドミウム粒子におよぼすハロゲン化アルカリの影響

抄録

In order to study fundamentally the nature of powder, the preparation of particles of uniform size is most important. But it is difficult to preparate the particles of uniform size.
For the one of the methods to obtain the powder of uniform size the mixture of cadmium sulfide and various additives was heated.
Cadmium sulfide prepared from cadmium nitrate solution by sodium sulfide solution was used as starting material. Halides of lithium, sodium, and potassium were used as the additive agents. Cadmium sulfide (The starting material) and alkali halide were mixed well and heated in a test tube at 350 to 500°C for 2 hours.
The shape and size of cadmium sulfide particles were observed with an electronmicroscope, and the surface area was measured by BET method of nitrogen adsorption at boiling point of liquid nitrogen. The following results were obtained;
The shape of cadmium sulfide particles tended to be affected by halogen, but slightly by alkali metal.
Alkali halides had an effect on cadmium sulfide particles below their melting point.
The spherical or nearspherical particles were obtained by heating the mixtures of the starting material and alkali iodide or bromide.
The particle sizes that were calculated from the surface areas were nearly equal to the apparent sizes observed by electronmicrographs. And so, it is suggested that these particles had no pore, but smooth surface.
The uniform and spherical particles of cadmium sulfide of particle size 100 to 2000mμ were obtained by the variation of the mixing ratio of the starting material to the additives, and by the adjustment of the heating temperature.