室温固化型Al2O3-SiO2系无机高温黏结剂的制备

Preparation of room temperature curing Al2O3-SiO2 inorganic high temperature adhesive

为解决目前国内无机高温黏结剂存在固化温度高,粘接强度低,脆性大和使用温度不高等问题,以不同粒度的板状刚玉、ρ-Al2O3细粉和硅微粉为主要原料,硅酸盐水泥为结合剂,轻质氧化镁为添加剂制备了一种可室温固化,使用温度在1300℃以上,剪切强度较大的无机高温黏结剂。研究了不同烧成温度和不同原料配比对无机高温黏结剂的微观结构和力学性能的影响。采用XRD、SEM分析烧后试样的物相组成和显微结构,并对试样进行体积密度、显气孔率、常温抗折强度、常温耐压强度和剪切强度等性能测试。结果表明:制备的黏结剂室温下可固化;在1300℃烧后,Al2O3、SiO2质量比为5∶1、5∶2和5∶3的试样中均有α-Al2O3、β-SiO2和3Al2O3·2SiO2物相,Al2O3、SiO2质量比为5∶3的试样在1300℃烧后β-SiO2为主要物相;当Al2O3、SiO2质量比为5∶2、烧成温度为1600℃时,长柱状莫来石生成量增加,试样的力学强度较大,其抗折强度、耐压强度和剪切强度分别为9.40、22.17和1.74 MPa。

An inorganic high temperature adhesive was prepared using tabular corundum with different particle sizes,ρ-Al 2O 3 fine powder and microsilica as main raw materials,silicate cement as the binder and light weight magnesia as the additive in order to solve the problems of high curing temperature,low bonding strength,high brittleness and low service temperature of inorganic high temperature adhesives.The prepared inorganic high temperature adhesive could be cured at room temperature and had the service temperature above 1300℃and high shear strength.Effects of different sintering temperatures and different raw material ratios on the microstructure and mechanical properties of the inorganic high temperature adhesive were investigated.The phase composition and the microstructure of the sintered specimens were analyzed by XRD and SEM,and the bulk density,the apparent porosity,the cold modulus of rupture,the cold crushing strength and the shear strength were tested.The results show that the prepared adhesive can be cured at room temperature.α-Al 2O 3,β-SiO 2 and 3Al 2O 3·2SiO 2 phases present in the specimens with Al 2O 3 SiO 2 mass ratios of 51,52 and 53 after firing at 1300℃,and the main phase of the specimen with the Al 2O 3 SiO 2 mass ratio of 53 isβ-SiO 2.When the mass ratio of Al 2O 3 SiO 2 is 52 and the sintering temperature is 1600℃,the amount of long columnar mullite increases,the mechanical strength of the specimen is higher,its modulus of rupture,crushing strength and shear strength are 9.40,22.17 and 1.74 MPa,respectively.