凝胶注模成型硼化锆多孔陶瓷
发布时间：2019-03-05 19:17
【摘要】：ZrB2以其优异的物理化学性能,如高熔点、高强度、良好的导电导热性以及优异的抗腐蚀性,近年来吸引了越来越多的关注。然而,由于其较高的体积密度(6.085g/cm3)和低的抗热震性,也在一定程度上影响到了ZrB2的开发应用。轻质、热稳定性好是多孔陶瓷两个突出优点。把ZrB2陶瓷设计成一种多孔结构降低其体积密度并改善其抗热震性能有效地解决上述问题。本文以微米级ZrB2为原料,通过凝胶注模成型的方式成功制得了ZrB2多孔陶瓷。论文的主要内容包括： (1)ZrB2料浆制备。研究结果表明,分散剂PAA和PEI更适合于用来分散ZrB2。 PAA做ZrB2粉体的分散剂时,当料浆pH值为9、添加2wt%的PAA,球磨12h后能够获得分散稳定性很好的ZrB2料浆；以PEI为ZrB2粉体的分散剂时,调节pH值为5、添加2wt%的PEI、球磨10h后同样能够获得分散稳定性很好的ZrB2料浆。 (2)ZrB2湿坯成型及干燥。研究结果表明,当单体(AM)含量为4wt%时,ZrB2陶瓷浆料不仅具有最低的粘度,料浆凝胶时间也能控制在10min左右；APS、 TEMED的添加量分别为0.02g/100g、0.03g/100g浆料,温度为40℃时,最有利于ZrB2陶瓷浆料的注凝操作。之后ZrB2陶瓷湿坯会先浸入液体干燥剂(无水乙醇)中,时间为24h,之后取出置于室温下干燥10h,最后将生坯放入真空干燥箱(50℃)中干燥,这样既能使湿坯快速的脱水干燥又能避免产生开裂、变形等缺陷。而生坯的干燥收缩率也随着固含量的增大而减小,当生坯固含量小于35vo1%时,生坯干燥过程中收缩较大,均大于10%。 (3)ZrB2多孔陶瓷的制备研究。研究发现,烧结温度、烧结助剂B4C的添加量、生坯固含量、保温时间等参数都对ZrB2多孔陶瓷的性能有较大关系。在最佳工艺条件下,B4C添加量为6wt%,固含量为35vol%,在2050℃下烧结2h所得ZrB2多孔陶瓷的孔隙率为45.9%,抗压强度达到最大值400MPa。
[Abstract]:ZrB2 has attracted more and more attention in recent years for its excellent physical and chemical properties, such as high melting point, high strength, good conductivity and thermal conductivity, and excellent corrosion resistance. However, due to its high volume density (6.085g/cm3) and low thermal shock resistance, it also affects the development and application of ZrB2 to a certain extent. Light weight and good thermal stability are two outstanding advantages of porous ceramics. The ZrB2 ceramic is designed as a porous structure to reduce its volume density and improve its thermal shock resistance to effectively solve the above problems. In this paper, ZrB2 porous ceramics were successfully prepared by gel injection molding using micrometer ZrB2 as raw material. The main contents of this paper are as follows: (1) preparation of ZrB2 slurry. The results show that the dispersants PAA and PEI are more suitable for dispersing ZrB2.. When PAA is used as dispersant of ZrB2 powder, the ZrB2 slurry with good dispersion stability can be obtained by adding 2 wt% PAA, ball mill for 12 h when the slurry pH is 9; When PEI is used as dispersant of ZrB2 powder, ZrB2 slurry with good dispersion stability can also be obtained by adjusting pH value to 5 and adding 2 wt% PEI, ball mill for 10 h. (2) ZrB2 wet billet forming and drying. The results show that when the monomer (AM) content is 4 wt%, the ZrB2 ceramic slurry not only has the lowest viscosity, but also can control the gelation time of the slurry to about 10min. When the addition of APS, TEMED is 0.02g / 100g and 0.03g / 100g respectively and the temperature is 40 鈩，
本文编号：2435203
[Abstract]:ZrB2 has attracted more and more attention in recent years for its excellent physical and chemical properties, such as high melting point, high strength, good conductivity and thermal conductivity, and excellent corrosion resistance. However, due to its high volume density (6.085g/cm3) and low thermal shock resistance, it also affects the development and application of ZrB2 to a certain extent. Light weight and good thermal stability are two outstanding advantages of porous ceramics. The ZrB2 ceramic is designed as a porous structure to reduce its volume density and improve its thermal shock resistance to effectively solve the above problems. In this paper, ZrB2 porous ceramics were successfully prepared by gel injection molding using micrometer ZrB2 as raw material. The main contents of this paper are as follows: (1) preparation of ZrB2 slurry. The results show that the dispersants PAA and PEI are more suitable for dispersing ZrB2.. When PAA is used as dispersant of ZrB2 powder, the ZrB2 slurry with good dispersion stability can be obtained by adding 2 wt% PAA, ball mill for 12 h when the slurry pH is 9; When PEI is used as dispersant of ZrB2 powder, ZrB2 slurry with good dispersion stability can also be obtained by adjusting pH value to 5 and adding 2 wt% PEI, ball mill for 10 h. (2) ZrB2 wet billet forming and drying. The results show that when the monomer (AM) content is 4 wt%, the ZrB2 ceramic slurry not only has the lowest viscosity, but also can control the gelation time of the slurry to about 10min. When the addition of APS, TEMED is 0.02g / 100g and 0.03g / 100g respectively and the temperature is 40 鈩，
本文编号：2435203
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