注凝成型制备莫来石增强磷酸铬铝复相陶瓷的工艺及性能研究

发布时间：2018-02-28 16:36

  本文关键词： 分散剂 浆料粘度 凝胶时间 单体用量 固相含量　出处：《西南科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：本论文主要采用注凝成型工艺制备莫来石颗粒增强磷酸铬铝复相陶瓷材料。选用丙烯酰胺为单体、N-N-亚甲基双丙烯酰胺为交联剂、N-N-N′-N′-四甲基乙二胺引发剂和过硫酸铵为催化剂,来探讨各因素对成型工艺影响。通过沉降实验、Zeta电位和浆料粘度分析来研究陶瓷粉体在水中的分散机理。选用单因素实验分别来探讨单体的用量、分散剂、p H值、固含量以及球磨时间等因素对成型所需的浆料流变性能的影响,以及单体、引发剂、催化剂用量和固化温度对固化时间的影响。采用不同的有机分子对坯体表面起皮现象的抑制机理进行探讨,以及坯体的干燥工艺进一步研究。主要研究了单体用量和固相含量对陶瓷素坯体和烧结体的机械性能、介电性能、微观结构的影响。在本试验条件下,在尝试三种分散剂后,发现聚丙烯酸铵的分散效果最佳,在p H=10下,悬浮液的粘度较小,Zeta电位绝对值较大,综合研究得浆料的分散属于静电位阻稳定机制。对浆料的流变性能进行研究分析,在一定的范围内,浆料的粘度达到所需要的最高要求,分散剂的最佳用量为0.48wt%,单体浓度最佳值为14wt%,固相含量最高的53vol%,浆料的最佳球磨时间为8h,最佳p H值为9。通过对凝胶时间的控制分析得在单体用量为14wt%,催化剂用量为0.375ml/g,引发剂用量为0.625ml/g,凝胶固化温度约为50℃时,浆料的凝胶固化时间可控制在20~30min,有利于浆料注模的进行。通过对注凝成型坯体的表面起皮现象和干燥变形问题研究,在聚丙烯酰胺、丙三醇和PVP三种高分子有机物的增润下,加入丙三醇为2%时浆料粘度总体较低,凝胶固化时间适当,抑制坯体表面起皮现象较好。在室温空气、不同浓度的PEG溶液里干燥的湿坯体,在45%的PEG溶液里干燥的坯体失水率最大,且不易发生变形和开裂。通过对单体和固含量的分析研究,陶瓷坯体和烧结体的微观形貌等各种性能会随之发生较大变化。随单体用量的增多,陶瓷坯体的弯曲强度、烧结线收缩率以及烧结体弯曲强度变化不大。但是固相含量对坯体以及烧结体的机械性能及介电性能等影响较大。在固相含量为53vol%时,烧结体的弯曲强度可达181.30MPa,维氏硬度可达13.8GPa,密度为2.86g/cm3,平均介电常数为3.72,制备的陶瓷性能较好。从微观结构分析可得,材料内部试样的断裂源主要来源于材料的内部气孔所致。
[Abstract]:In this paper, the mullite particle reinforced chromium aluminum phosphate multiphase ceramic material was prepared by the injection molding process. Acrylamide was used as the monomer N-N- methylene bisacrylamide as crosslinker, N-N-Na-tetramethyl ethylenediamine initiator and ammonium persulfate as catalyst. The dispersing mechanism of ceramic powder in water was studied by means of Zeta potential and viscosity analysis. The effect of solid content and ball milling time on rheological properties of slurry, monomer and initiator, The influence of the amount of catalyst and curing temperature on the curing time was discussed. The effects of monomer content and solid content on the mechanical properties, dielectric properties and microstructure of ceramic billets and sintered bodies were studied. It was found that the dispersion effect of ammonium polyacrylate was the best, and the viscosity of suspension solution was lower than that of Zeta potential at pH 10, the absolute value of Zeta potential was larger. It was found that the dispersion of the slurry belongs to the mechanism of electrostatic steric stability. The rheological properties of the slurry were studied and analyzed. Within a certain range, the viscosity of the slurry reaches the maximum required, The optimum dosage of dispersant is 0.48 wts, the optimum monomer concentration is 14wt, the highest solid content is 53volr, the optimum milling time of slurry is 8h, the optimal pH value is 9.Through the control of gel time, it is found that the monomer dosage is 14wtt and the catalyst dosage is 14wtmeter. When the amount of initiator is 0.625 ml / g, the gel curing temperature is about 50 鈩，

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