重力分离SHS陶瓷衬管合成过程的研究

Study on Sythesis Process of Ceramic lined Composite Pipes Using Gravitational Separation SHS Method

本文在采用重力分离ＳＨＳ法制备陶瓷内衬复合钢管的基础上，分析了ＳｉＯ２添加剂在复合钢管制备过程中对燃烧过程、液相重力分离过程及陶瓷层致密度的影响。研究发现：在Ｆｅ２Ｏ３Ａｌ体系中，燃烧过程以扩散为主要机制，ＳｉＯ２在燃烧过程中起稀释剂作用；陶瓷层主要由构成枝晶的αＡｌ２Ｏ３基体相和分布于枝晶晶界的ＦｅＯ·Ａｌ２Ｏ３尖晶石相组成，ＳｉＯ２在陶瓷中以石英相结构存在；ＳｉＯ２通过增加熔体粘度而显著影响熔体中Ａｌ２Ｏ３Ｆｅ液相重力分离过程；ＳｉＯ２通过提高熔体中ＦｅＯ组分的含量和Ａｌ２Ｏ３熔体的粘度对陶瓷致密过程具有双重影响。实验表明，合理的ＳｉＯ２添加量（质量分数）为２％。

Abstract Based on ceramic lined composite pipes produced by gravitational separation SHS method,the effect of SiO_2 additions on combustion process,liquid liquid phases gravitational separation process and ceramic densification during synthesis of the composite pipes has been investigated.It was found that the combustion process for SHS method is mainly controlled by diffusion mechanism,in Fe_2O_3 Al system SiO 2 is present as a diluent during combustion process.Ceramic layers are mainly composed of matrix phase of α Al_2O_3 dendritic crystals and FeO·Al 2O_3 spinel phases distributed in the dendritic boundary,the SiO_2 in ceramic exis ted in the form of quartz phases.SiO_2 addition would have marked influence on the gravitational separation of Al_2O_3 Fe liquid liquid phases through increasing melt viscosity,SiO_2 possesses dual effects on the ceramic densification through increasing FeO contents in melt and increasing viscosity of Al 2O_3 melt.The results of experiments showed that the suitable content of SiO_2 in mixture is about 2 per cent for gravitational separation SHS method.