【摘要】 以乙二醇为溶剂,醋酸为催化剂,部分无机盐代替醇盐的溶胶-凝胶工艺制备了不 同平均晶粒尺寸的纯SrBi2Ta2O9(SBT)纳米粉末,晶相粉末晶粒大小为4-70nm.用XRD、 TG-DTA、TEM系统研究了SBT纳米相的形成过程.通过改变干凝胶的热处理温度和热处 理时间,研究了温度与时间参数对SBT晶粒长大的影响规律.研究表明,碳的燃烧和二氧化 碳的蒸发对纳米团簇的长大具有一定的阻碍作用. SBT相的晶化行为分为金属-氧团簇向玻 璃态转变和玻璃态到晶态的转变过程,玻璃态到晶态的转变温度区间为500-550℃.两个过程 的长大激活能分别为:Eal=0.709eV,Ea2=0.093eV.温度是晶粒长大的主要因素,热处理时间 对晶粒长大影响不明显.更多还原

【Abstract】 A novel sol-gel process using inorganic salts as starting materials was successfully developed for preparing nano powders of ferroelectric strontium bismuth tantalate (SrBi2Ta209, known as SBT) with ethylene alcohol as a solvent and acetic acid (HOAc) as a catalyst. XRD, TEM and TG-DTA were used to analyze the precursor crystalline process. Crystalline samples with different average nanograin sizes ranging from 4nm to 70nm were prepared by calcining the dried gel at different annealing conditions. The metal-oxide clusters that embedded in highly polar matrix of mesoporous-carbon are responsible for nano-sized powder synthesis at lower temperature. The dependence of the grain growth behaviors of SBT under conventional furnace annealing (CFA) process on the annealing temperature (T) and time (t) were investigated systematically. By least square fitting, the crystalline and vitreous characteristic energies Eal=0.709eV, Ea2=0.093eV and the two other parameters T0=814K(541℃) and A=0.022 were obtained.更多还原