Preparation And Characterization Of Ti-Si Intermetallic Compound Membrane Materials

Ti-Si intermetallic compound has excellent high temperature resistance and corrosion resistance,which can meet the requirements of most harsh working conditions.It has been continuously studied and paid attention to in many research fields.The preparation and characterization of porous membrane materials for Ti-Si intermetallic compound has certain theoretical significance and practical application value.With the preparation of new filtration membrane materials as the research background,Ti-Si porous intermetallic compound membrane was successfully prepared using high-purity Ti powder and high-purity quartz sheet（Si O₂）as raw materials by pressurized in-situ reaction sintering technology:The pore size of the gradient membrane was 0.5-2μm,the particle size was 0.5-3μm,and the thickness was 3-5μm.The main phase of the gradient membrane was Ti₅Si₃,and the secondary phase were Ti O₂and Ti;Sintering pressure,sintering temperature and particle size of matrix powder did not affect the material composition of the membrane.The smaller the particle size of matrix powder,the higher the sintering temperature and the higher the sintering pressure,the higher the relative content of Ti_xSi_y compounds and Ti O₂ in the membrane.With the decrease of titanium powder particle size and the increase of sintering pressure,the maximum bubble pore size and permeability of the gradient membrane decrease,and the minimum bubble pore size can reach 6.1μm;Sintering temperature did not affect the maximum pore size of the gradient membrane,but the higher the sintering temperature,the lower the permeability of the gradient membrane.There were two distinct particle regions on the surface of Ti-Si intermetallic compound gradient membranes:large particle region and small particle region.The large particle region was the overreaction region and the small particle region was the long-distance diffusion reaction region.If there was an overreaction during the in-situ reaction,the membrane layer formed between Ti and Si atoms will block the mutual diffusion between them and delay the in-situ reaction,resulting in Ti and Si-rich regions in the membrane finally.When the gradient membrane layer was formed,Si O₂ was heated and decomposed into O atoms and Si atoms,and most of the O atoms were dissolved in the porous titanium matrix to form Ti-O solid solution.With the increase of the decomposition amount,the undissolved O atoms react with Ti atoms at high temperature to form Ti O_x compound layer on the surface of the porous titanium matrix;Ti atoms provided by porous titanium matrix react with Si atoms generated by thermal decomposition at high temperature,and finally Ti_xSi_y compound membrane is formed on top of Ti O_x compound layer.In this study,by changing the size of sintering compressive stress,Ti-Si intermetallic compound porous membrane samples were prepared according to the preparation conditions of tubular samples through pressure sintering process,which realized the simulation of confined in-situ reaction sintering process.This work can provide theoretical and technical reference for the subsequent preparation of tubular Ti-Si intermetallic porous membrane samples by localized in-situ reaction.