碳化锆液相陶瓷前驱体的制备及陶瓷化

Preparation and Ceramization of Liquid ZrC Precursor

以聚锆氧烷PNZ为锆源、炔丙基酚醛PN为碳源制备了一种ZrC液相陶瓷前驱体PNZ-PN，该前驱体经1600℃热解能够转化为高度结晶的ZrC陶瓷。通过FT-IR、DSC、TGA对前驱体的固化过程及固化样的热失重行为进行了分析；通过XRD、元素分析和SEM对热解产物的晶相组成及微观形貌进行了分析。结果表明：1200℃以下，热解产物主要是ZrO2，1400℃时开始发生碳热还原反应出现结晶度较小的ZrC，经1600℃热解后可完全转化为ZrC；PN的加入量会影响热解过程中陶瓷样品的ZrO2晶相及1600℃热解产物的碳含量，通过调整PN的加入量最终可得到自由碳含量1．66％、近似纯相的ZrC陶瓷；得到的陶瓷粒子Zr、C元素分布均匀、粒径主要分布为100～200nm。

A novel liquid precursor for ZrC was prepared by blending of polyzirconoxanesal （PNZ） and proparg- yl modified novolac resin（PN）. The precursor could be converted into ZrC upon heat treatment at 1 600℃. The cross- linking behavior of PNZ-PN precursor was characterized by FF-IR and DSC. The thermal stability of the cured PNZ- PN was evaluated by TGA. The microstrueture and components of the ceramic samples were analyzed by XRD, SEM and elements analysis. The results showed that the ceramic sample consisted of ZrO2 below 1 200℃ and low crystalline ZrC appeared initially at 1 400℃ due to carbothermal reduction. At 1 600℃, the ZrO2could be converted into pure ZrC completely. The ZrO2erystalline phase and carbon content in 1 600℃ceramic samples could be controlled by the amount of PN to get near pure phase ZrC with free carbon of 1.66%. The Zr, and C elements are well distributed in the ceramic sample consisted of high crystalline degrees of ZrC particles with a size distribution of 100 to 200 nm.