METHOD FOR MANUFACTURING NANOSPHERE PARTICLE CERIA COMPOUND POWDER HAVING EASY SINTERING PROPERTY

摘要

PROBLEM TO BE SOLVED: To provide spheric ceria powder particles having a nanoparticle size and high monodispersion property from an easily available material.;SOLUTION: The nanosphere particle ceria compound powder having easy sintering property is obtained by the following steps. A divalent or trivalent metal (M) nitrate is mixed with a cerium nitrate to obtain M_xCe_1-xO_2-δ, wherein x satisfies 0.05≤x≤0.3 and δ represents the oxygen deficient amount determined from the balance of charges in cations and anions. The obtained mixture is mixed with ammonium hydrogen carbonate as a precipitating agent in the molar ratio ranging from 2.5 to 15 of (concentration of divalent or trivalent metal nitrate aqueous solution)/(concentration of ammonium carbonate aqueous solution) to precipitate cerium carbonate expressed by Ce_1-xM_x(OH)_y(CO₃)_zH₂O, wherein x, y, z satisfy 0.05≤x≤0.3, 0.05≤y≤1 and 0.05≤z≤2, respectively. Then the product is aged at ≥50°C and ≤70°C, washed and calcined at a temperature of ≥400°C and ≤750°C to obtain spheric particles having ≤50 nm average particle size. The particles are sintered at ≤1,000°C to obtain the density as high as ≥98% of the theoretical density.;COPYRIGHT: (C)2004,JPO