Oxalate co-precipitation synthesis of calcium zirconate and calcium titanate powders.

Hernandez-Sanchez, Bernadette A. ; Tuttle, Bruce Andrew

Sandia National Laboratories

关键词: Dissipation Factor Oxides.;    Dielectric Properties;    Dielectric Materials;    Phase Studies;    37 Inorganic, Organic, Physical And Analytical Chemistry;   

DOI  :  10.2172/984943
RP-ID  :  SAND2009-4743
RP-ID  :  AC04-94AL85000
RP-ID  :  984943

美国|英语

来源: UNT Digital Library

【 摘 要 】

Fine powders of calcium zirconate (CaZrO{sub 3}, CZ) and calcium titanate (CaTiO{sub 3}, CT) were synthesized using a nonaqueous oxalate co-precipitation route from Ca(NO{sub 3}){sub 2}{center_dot}4 H{sub 2}O and group(IV) n-butoxides (Ti(OBu{sup n}){sub 4} or Zr(OBu{sup n}){sub 4}). Several reaction conditions and batch sizes (2-35 g) were explored to determine their influence on final particle size, morphology, and phase. Characterization of the as-prepared oxalate precursors, oven dried oxalate precursors (60-90 C), and calcined powders (635-900 C) were analyzed with TGA/DTA, XRD, TEM, and SEM. Densification and sintering studies on pressed CZ pellets at 1375 and 1400 C were also performed. Through the developed oxalate co-precipitation route, densification temperatures for CZ were lowered by 125 C from the 1500 C firing temperature required for conventional mixed oxide powders. Low field electrical tests of the CZ pellets indicated excellent dielectric properties with dielectric constants of {approx}30 and a dissipation factor of 0.0004 were measured at 1 kHz.