氧化锆纳米粉体的制备及稳定性研究

发布时间：2018-03-10 08:26

本文选题：水热法　切入点：氧化锆掺杂氧化钇　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：稳定的纳米氧化锆材料具有低热导率、高温化学稳定性、表面酸性、氧化性和还原性等独特的物化性质,使其在光电器件、气体传感器、耐火材料、催化剂等诸多领域有着广泛的应用前景。但由于传统的纳米氧化锆制备方法和后期的高温煅烧老化处理,往往会造成其颗粒团聚严重、分散性差、晶体结构不稳定以及晶粒、晶型不可控等问题,从而限制了纳米氧化锆材料的推广和应用。本文的研究内容和结论如下:本论文主要研究了采用水热法制备氧化锆纳米粉体,考察了水热时间、pH值、温度和有机添加剂(丙三醇)对氧化锆粉体颗粒粒径、结晶度及稳定性的影响,并对其进行了定量分析,得出了不同温度、反应时间、pH的参数。通过XRD和SEM分析技术对不同条件下制备的样品进行表征。结果表明,结晶度随着水热反应温度的升高而提高,形核速率在250℃时快速增加,粒径在150℃~250℃出现先长大后减小的规律;反应溶液的pH值影响样品的结晶度,通过合适调节溶液pH值可以减小粉体颗粒之间的团聚,改善粉体的分散性;水热反应越充分,样品的平均粒径越大;向前驱液中添加丙三醇,在反应条件为200℃,pH=10,t=12h制备钇掺杂量3%的氧化锆粉体,经1000℃煅烧老化处理12 h,获得具有分散性好、粒径分布窄的纯立方相纳米氧化锆粉体。通过设定水热法反应温度、pH值、时间可以制备粒径可控的稳定氧化锆纳米粉体,并且钇的掺杂可有效提高氧化锆的稳定性。丙三醇的加入可以有效地改善粉体的分散性和稳定性,煅烧稳定氧化锆纳米粉体可以有效增大粉体粒径和提高粉体的结晶度。水热法制备不同掺杂比例的Zr_(1-x)Y_xO_(2-0.5x)(x=0,0.03,0.05,0.07,0.10,0.13)粉体,通过XRD、SEM分析技术研究了Y~(3+)的掺杂比例和煅烧温度对YSZ晶体结构和晶粒尺寸的影响。实验结果表明:掺杂Y~(3+)比例小于3mo%时YSZ粉体晶体结构是由单斜相和四方相组成,当Y~(3+)掺杂比例为5mol%-13mol%时是纯立方相氧化锆粉体;YSZ粉体的晶体结构影响着它的晶粒尺寸,C-ZrO_2粉体晶粒尺寸比其它晶体结构大;当Y~(3+)掺杂量低于10mol%时,随着煅烧温度的提高,ZrO_2样品的部分立方相和四方相晶体结构会向单斜相转变。转变比例随着掺杂量提高而降低,当Y~(3+)掺杂量在10mol%-13mol%时,随着煅烧温度提高1200℃,Zr O_2粉体晶体结构保持稳定,晶体平均粒径从14.6 nm长大到100 nm,粉体分散性好。采用水热法制备了几种不同掺杂比例的Ce_xY_(0.05)Zr_(0.95-x)O_(1.97)(x=0、0.03、0.06、0.09、0.12、0.15)的氧化锆粉体,实验结果表明:制备Ce_xY_(0.05)Zr_(0.95-x)O_(1.97)(x=0、0.03、0.06、0.09、0.12、0.15)均为纳米级粉体,其晶粒尺寸在10 nm左右的范围内,且分散性良好,Y~(3+)和Ce4+离子的掺杂引入了氧空位,改变了纯氧化锆的晶体结构,将立方相结构的氧化锆稳定至室温。且随着Ce掺杂比例的提高,导致ZrO_2的晶格常数变大,样品衍射峰向小角度偏移;对Ce_xY_(0.05)Zr_(0.95-x)O_(1.97)(x=0、0.03、0.09、0.15)煅烧老化处理,通过XRD和SEM表征,可知铈、钇掺杂氧化锆粉体其掺杂小于9%时,氧化锆粉体在800℃~1200℃煅烧老化处理,晶型转变为四方相和单斜相;当掺杂量大于9%时氧化锆晶体结构在800℃~1000℃之间由立方相向四方相转变,其晶粒尺寸的大小可以通过煅烧温度来控制,在1200℃煅烧之后,粉体具有单一四方相、粒径在110 nm左右的分散性良好的特性。
[Abstract]:Nano zirconia material stable with low thermal conductivity, high chemical stability, surface acidity, unique physicochemical properties of the oxidized and reduced, which in optoelectronic devices, gas sensors, refractory material, catalyst and other fields have a wide application prospect. But due to the traditional preparation method of nano zirconia and later calcined in high temperature aging treatment, often caused by the agglomeration of particles is serious, dispersion, unstable crystal structure and grain, crystal type is not controllable, which limits the popularization and application of nano zirconia materials. The research contents and conclusions are as follows: This paper mainly studies the preparation of nanometer zirconium oxide powder by hydrothermal method, hydrothermal time, the effects of pH, temperature and organic additives (glycerol) on zirconia powder particle size, crystallinity and stability influence, and has carried on quantitative analysis, obtained Different temperature, reaction time, pH parameters were characterized by XRD and SEM analysis of the samples fabricated under different conditions. The results showed that the crystallinity with the increase of hydrothermal reaction temperature increased, the nucleation rate increased rapidly at 250 DEG C, particle size at 150 DEG ~250 DEG to reduce after grow up the law; the pH value of the reaction solution affects the crystallinity of the sample by adjusting the pH value of the solution can reduce powder particles, improve the dispersion of powder; hydrothermal reaction more fully, the average particle sizes of the samples increased; add third three alcohol liquid drive forward, in the reaction conditions for 200 c, pH=10, zirconium oxide powder, preparation of t=12h doped yttrium 3%, 1000 calcined aging treatment for 12 h, with good dispersion and narrow particle size distribution of pure cubic phase nano zirconium oxide powder. By setting the reaction temperature, hydrothermal method, pH value, time can be prepared by particle size controllable Stabilized zirconia powders, and yttrium doping can effectively improve the stability of zirconia. The glycerin can effectively improve the dispersibility and stability of powder and calcined stabilized zirconia powders can effectively increase the particle size of the powder and improve the powder crystallinity. Hydrothermal preparation of different doping ratio Zr_ (1-x) Y_xO_ (2-0.5x) (x=0,0.03,0.05,0.07,0.10,0.13) powder, through XRD, SEM of Y~ (3+) the influence of doping ratio and calcination temperature on YSZ crystal structure and grain size. The experimental results show that the doping of Y~ (3+) ratio is less than 3mo% YSZ powder is composed of monoclinic phase and crystal structure tetragonal phase composition, when Y~ (3+) doping ratio of 5mol%-13mol% zirconium powder is pure cubic phase oxidation; crystal structure of YSZ powder affects the grain size of the C-ZrO_2 powder grain size than other crystal structure; when Y~ (3+) doped low In 10mol%, with the calcination temperature increased, the crystal phase of cubic and tetragonal ZrO_2 samples to monoclinic phase transition structure will change. The proportion decreased with increasing the dopant concentration, when Y~ (3+) doped in 10mol%-13mol%, with the increase of calcination temperature of 1200 DEG C, Zr O_2 powder crystal structure remained stable, the average crystal the particle size increased from 14.6 nm to 100 nm powder with good dispersibility. Several different doping ratio were prepared by hydrothermal method Ce_xY_ (0.05) Zr_ (0.95-x) O_ (1.97) (x=0,0.03,0.06,0.09,0.12,0.15) of zirconia powder, the experimental results showed that the preparation of Ce_xY_ (0.05) Zr_ (0.95-x (O_) 1.97) (x=0,0.03,0.06,0.09,0.12,0.15) are nanometer powder, the grain size in the range of about 10 nm, and good dispersion, Y~ (3+) and Ce4+ ions doped into the oxygen vacancy, changed the crystal structure of pure zirconia, cubic phase structure of stabilized zirconia To room temperature. With the doping ratio of Ce increased, resulting in the lattice constant of ZrO_2 and the sample to small angle; the Ce_xY_ (0.05) Zr_ (0.95-x) O_ (1.97) (x=0,0.03,0.09,0.15) calcining aging treatment by XRD and SEM characterization, the cerium, yttrium doped zirconia powders doping is less than 9%, zirconia powder aging treatment at 800 DEG ~1200 DEG calcination, crystal transition to tetragonal and monoclinic phase; when the doping amount is greater than 9% zirconia crystal structure between 800 DEG ~1000 DEG from cubic phase to tetragonal phase, the grain size can be controlled by the calcination temperature. After the 1200 calcined powder, has a single tetragonal phase, particle size of about 110 nm in good dispersion characteristics.

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ134.12;TB383.3

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