耐高温材料的制备及性能研究
发布时间：2019-07-07 20:06
【摘要】：耐高温材料已经成为近几年的科研热点,其中ZrB_2因其优异的物理化学性质而逐渐成为了研究重点。上世纪60年代ZrB_2的制备工艺就已经相当成熟,但是ZrB_2具有的稳定共价键使其难以烧结,在空气中容易氧化等缺点已经成为其应用的障碍。本文在对ZrB_2充分的调研基础上,分别对微米级ZrB_2粉体的制备、无压烧结和SPS烧结对材料致密度的影响进行了分析和探究。为了得到抗氧化性能较好的ZrB_2复合材料,本文利用SPS烧结所得的块体ZrB_2-SiC的三层氧化结构对材料抗氧化性能的提高进行了研究,以及ZrB_2-SiC块体复合材料的电学性能基础进行了分析和探究。本文研究了溶胶-凝胶工艺对于制备ZrB_2粉体的影响,利用溶胶-凝胶法制备得到前驱体粉末,研磨干燥后在1550℃的高温下煅烧得到ZrB_2粉体,在四种不同原料配比中选择了适合实验条件的配比。研究发现,在蔗糖2.5 g,正丙醇锆5.3 g,硼酸2.97 g的原料分配下得到了较为纯净的Zr B2粉体,制备得到的Zr B2为10-20μm大小的棒状颗粒;煅烧的保温时长有助于颗粒的不规则生长。本文重点研究了ZrB_2的氧化特性,首先对ZrB_2颗粒和块体在空气中的氧化温度做了定量分析,实验表明颗粒和块体都在600-700℃时氧化,块体在1000℃以下为钝化氧化,有着阻碍氧化的作用。同时在研究了其烧结性能的基础上,利用烧结致密度相对较高的ZrB_2-10mol%SiC进行了抗氧化研究,ZrB_2-10mol%SiC材料随着氧化温度的不断升高,在材料的表面会有一层ZrO2来隔离其与空气的联系,能够防止材料内部的继续氧化;在低温氧化的过程中,氧化时长对于氧化的影响并不明显。ZrB_2-10mol%SiC材料在高温氧化中,由于B2O3的挥发性将会形成三层的块状结构,第一层为SiO2和ZrO2的保护层,第二层为SiO2和ZrO2以及ZrB_2-SiC的混合层以及第三层的ZrB_2-SiC材料层。同时利用SPS烧结所得的ZrB_2样品,研究了ZrB_2材料的电学特性,实验表明,ZrB_2在室温下的电阻率为8.062μΩ·cm;ZrB_2-SiC复合材料的电阻率与SiC的加入量成正比的关系,室温下,ZrB_2-10mol%SiC、ZrB_2-20mol%SiC、ZrB_2-30mol%SiC的电阻率分别为:9.836μΩ·cm、13.987μΩ·cm、15.124μΩ·cm。
[Abstract]:High temperature resistant materials have become a hot research topic in recent years, among which ZrB_2 has gradually become the focus of research because of its excellent physical and chemical properties. In the 1960s, the preparation process of ZrB_2 has been quite mature, but the stable covalent bond of ZrB_2 makes it difficult to sintering, and its easy oxidation in air has become an obstacle to its application. In this paper, based on the full investigation of ZrB_2, the preparation of micron ZrB_2 powder, the effect of pressuresless sintering and SPS sintering on the density of the material were analyzed and investigated. In order to obtain ZrB_2 composites with good oxidation resistance, the improvement of oxidation resistance of bulk ZrB_2-SiC sintered by SPS was studied in this paper, and the electrical properties of ZrB_2-SiC bulk composites were analyzed and investigated. In this paper, the effect of sol-gel process on the preparation of ZrB_2 powder was studied. The precursor powder was prepared by sol-gel method. The ZrB_2 powder was calcined at 1550 鈩，
本文编号：2511410
[Abstract]:High temperature resistant materials have become a hot research topic in recent years, among which ZrB_2 has gradually become the focus of research because of its excellent physical and chemical properties. In the 1960s, the preparation process of ZrB_2 has been quite mature, but the stable covalent bond of ZrB_2 makes it difficult to sintering, and its easy oxidation in air has become an obstacle to its application. In this paper, based on the full investigation of ZrB_2, the preparation of micron ZrB_2 powder, the effect of pressuresless sintering and SPS sintering on the density of the material were analyzed and investigated. In order to obtain ZrB_2 composites with good oxidation resistance, the improvement of oxidation resistance of bulk ZrB_2-SiC sintered by SPS was studied in this paper, and the electrical properties of ZrB_2-SiC bulk composites were analyzed and investigated. In this paper, the effect of sol-gel process on the preparation of ZrB_2 powder was studied. The precursor powder was prepared by sol-gel method. The ZrB_2 powder was calcined at 1550 鈩，
本文编号：2511410
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