ZrO_2纤维模板自蔓延高温合成ZrB_2/Al_2O_3复合粉

Preparation of ZrB_2/Al_2O_3 Composite Powders by Self-propagating High-temperature Synthesis with ZrO_2 Fibers as Template

ZrB_2纤维或含ZrB_2纤维复合粉的制备对于发展纤维增强超高温结构陶瓷基复合材料具有重要的意义。以ZrO_2纤维、B_2O_3和Al粉为原料,通过自蔓延高温合成法制备了含ZrB_2纤维的ZrB_2/Al_2O_3复合粉。通过X射线衍射、场发射扫描电子显微镜、X射线能谱,对产物的相组成、微观形貌及化学组成进行了分析表征,用差示扫描量热-热重分析研究了原料混合粉在加热过程中的反应过程。研究了氩气压力对燃烧合成产物的物相组成及ZrB_2纤维结构的影响,重点分析了产物中ZrB_2的存在状态。结果表明:氩气压力为1.5 MPa下,产物相组成为ZrB_2和Al_2O_3。部分ZrB_2以ZrO_2纤维为模板形成ZrB_2纤维;部分ZrB_2以颗粒形式分散在ZrB_2/Al_2O_3复合粉中。生成的ZrB_2纤维,表面粗糙,结构较为完整,直径约为10μm。

Preparation of ZrB2 fiber or composite powder containing ZrB2 fiber is great significance for the development of fiber reinforced ultrahigh temperature structural ceramic matrix composites. The ZrB2/ Al2O3 composite powders containing ZrB2 fiber was prepared by self-propagating high-temperature synthesis method with Zr02 fibers, B2O 3 and Al powders. The phase composition, micro-morphology and chemical composition of the products were characterized by X-ray diffraction, field emission scanning electron microscopy and X-ray energy dispersive spectroscopy. The reaction process of raw materials in the heating process were studied by DSC-TG. The state of ZrB2 and the effect of argon pressure on the phase composition of the combustion synthesis products and structure of the ZrB2 fiber were analyzed emphatically. The results show that the phase composition of the SHS products are ZrB2 and Al2O3 with the argon pressure of 1. 5 MPa. A part of ZrB2 were formed as ZrB2 fibers with ZrO2 fibers as the template, another part of ZrB2 are dispersed in ZrB2/Al2O3 composite powders in granular form. The ZrB2 fibers have a rough surface and a relatively complete structure with a diameter of about 1 0 μm.