Synthesis of Bismuth Sodium Titanate Fine Particles with Different Shapes by the Gel-Sol Method

Polycrystalline spherical Bi 0:5 Na 0:5 TiO 3 (BNT) particles with narrow size distributions were obtained by the gel-sol method, where the precursory gel was composed of BiX 3 (X ¼ OH, NO 3 ), NaOH, and stable Ti 4þ complex which was prepared by mixing Ti(i-C 3 H 7 O) 4 with triethanolamine to inhibit the uncontrolled hydrolysis in aqueous solution. The resulting morphology was readily controlled as single-crystalline rod-like and tubular shapes with the simple tuning of the Bi/Ti molar ratios in the presence of NaClO 4

含フッ素新規液晶材料の合成研究

京都大学0048新制・論文博士博士(工学)乙第10472号論工博第3536号新制||工||1189(附属図書館)UT51-2000-M55(主査)教授 檜山 爲次郎, 教授 大嶌 幸一郎, 教授 木村 俊作学位規則第4条第2項該当Doctor of EngineeringKyoto UniversityDFA

Influence of Sulfate Ions on Conversion of Fe(OH) 3 Gel to

Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and chemical analyses were used for characterizing the effect of sulfate ions on the conversion rate of condensed Fe(OH) 3 gel, prepared from FeCl 3 and NaOH solution, to -FeOOH and -Fe 2 O 3 particles by aging at 100 C. Fine particles and supernatant solution were sampled from the aged suspensions containing colloidal particles. XRD profiles and TEM observation showed that -FeOOH was formed from the gel and subsequently converted into -Fe 2 O 3 . It was revealed that the addition of sulfate ions accelerated the -FeOOH formation from the gel, but delayed the conversion from -FeOOH to -Fe 2 O 3 . The concentration changes of sulfate and chloride ions in the supernatant solution phases were in agreement with the conversion from Fe(OH) 3 gel to -FeOOH andFe 2 O 3 particles