CHROMIUM HYDROXIDE, METHOD FOR PRODUCING THE SAME, TRIVALENT CHROMIUM-CONTAINING SOLUTION USING THE SAME, AND CHROMIUM PLATING METHOD

摘要

Disclosed is a chromium hydroxide which is characterized by having an average particle diameter D of 40-200 nm and an aggregation degree, which is represented by the ratio D50/D between the volume average particle diameter D50 measured by a particle size distribution measuring instrument and the average particle diameter D determined by a scanning electron microscopic image, of not less than 10 but less than 70. This chromium hydroxide is suitably obtained by adding an aqueous solution containing trivalent chromium into an inorganic aqueous alkaline solution under such a condition that the temperature of the reaction liquid is not less than 0°C but less than 50°C. A hydroxide of an alkali metal is preferably used as the inorganic alkali.