凝胶注模-固相反应法制备硼酸铝多孔陶瓷  

Preparation of porous aluminum borate ceramics by gel casting-solid state reaction method

作　　者：李鑫 李昊明 张强 曹岳岐 刘幸儿 郭安然[2] Li Xin;Li Hao-ming;Zhang Qiang;Cao Yueqi;Liu Xing’er;Guo Anran(Key Laboratory of Advanced High-temperature Structural Materials,AECC Bejing Institute of Aeronautical Materials,Beijing 100095,China;不详)

机构地区：[1]中国航发北京航空材料研究院先进高温结构材料重点实验室,北京100095 [2]天津大学材料科学与工程学院先进陶瓷与加工技术教育部重点实验室,天津300072

出　　处：《耐火材料》2023年第4期277-280,共4页Refractories

基　　金：国家自然科学基金(No.51872194)。

摘　　要：为了提高硼酸铝基陶瓷的强度和隔热性能,以Al_(2)O_(3)纳米粉和B_(2)O_(3)微粉为主要原料,采用叔丁醇基凝胶注模结合原位固相反应工艺制备硼酸铝多孔陶瓷,研究了Al、B物质的量比(分别为9∶2、9∶4和9∶6)、热处理温度(分别为1000、1200和1400℃)对硼酸铝多孔陶瓷性能的影响。结果表明:1)由于B_(2)O_(3)在高温下易挥发,过量的B_(2)O_(3)有利于硼酸铝晶须的生成;但过量太多会使生成的硼酸铝晶须过于粗大,导致试样致密度过高。2)热处理温度过低,硼酸铝晶须发育较差,试样致密度较低;而热处理温度过高,晶须之间会发生烧结致密化。3)当Al、B物质的量比为9∶4,热处理温度为1200℃时,硼酸铝晶须长径比较大,并相互交织形成三维网络结构;所得多孔陶瓷具有较小的体积密度(0.67 g·cm^(-3))、较低的热导率(室温下0.141 W·m^(-1)·K^(-1))和较高的常温耐压强度(6.23 MPa)。In order to improve the strength and thermal insulating performance,porous aluminum borate ceramics were fabricated by tert-butyl alcohol-based gel casting combined with in situ solid state reaction technology with Al_(2)O_(3) nanopowder and B_(2)O_(3)micropowder as raw materials.Effects of aluminum/boron molar ratios(9∶2,9∶4 and 9∶6)and heat treatment temperatures(1000,1200,and 1400℃)on the properties of porous aluminum borate ceramics were investigated.The findings are as follows.(1)Because B_(2)O_(3)volatiles easily at high temperatures,excessive B_(2)O_(3)is conducive to the formation of aluminum borate whiskers.However,too much B_(2)O_(3)leads to the formation of over-thick aluminum borate whiskers,resulting in over-high density.(2)Low heat treatment temperatures are not suitable for the development of aluminum borate whiskers,resulting in low bulk density,while over-high heat treatment temperatures can lead to sintering densification between whiskers.(3)When the aluminum/boron molar ratio is 9∶4 and the heat treatment temperature is 1200℃,the generated aluminum borate whiskers show a large length/diameter ratio and interlock with each other to form a three-dimensional network structure.The obtained porous aluminum borate ceramic exhibits low density(0.67 g·cm^(-3)),low thermal conductivity(0.141 W·m^(-1)·K^(-1)at room temperature),and high cold compressive strength(6.23 MPa).

关 键 词：多孔陶瓷 硼酸铝晶须 凝胶注模 固相反应 隔热材料 

分 类 号：TQ175.79[化学工程—硅酸盐工业]