Low Temperature Preparation And Properties Of Corundum-Based Porous Ceramics

Porous ceramics are widely used in water purification,industrial product decontamination,high-temperature flue gas filtration and other fields due to their high efficiency,greenness,stability and other characteristics,showing excellent application reliability.Traditional porous ceramic products are always sintered.under high temperature conditions,so the energy consumption of the products is high,and the manufacturing cost remains high,which limits their widespread application.In this paper,corundum particles with different size are used as aggregates,and phosphate and resin are used as binders to prepare porous ceramics at low temperature(<1000?).The main contents are as follows:The preparation and water resistance of corundum-based porous ceramics combined by phosphate were studied.In order to overcome the strength attenuation of phosphate-bonded porous ceramics,caused by reacting with water,the influence of molding process and kinds of water-resistant modifiers on physical and chemical properties of corundum-based porous ceramics combined by phosphate were systematically studied.The results found that corundum-based porous ceramics modified by silica sol-boric acid have better comprehensive performance,and have higher flexural strength retention rate of 94.23%after immersion in water.The introduction of submicron SiO2 results in a more uniformly dispersed water-resistant phase,which strengthens the hydrophobic effect.The B2O3 glass phase formed by boric acid pyrolysis after heat treatment makes up the gap caused by the change of phosphate binding phase and reduces the number of water permeation channels caused by the growth of the particles of the binding phase.When plastic molding is used,the material has the best comprehensive performance when the water content is 12%.The unidirectional press moulding will cause the orientation deflection of irregular corundum aggregate,which is beneficial to the improvement of the testing strength,but affects the uniformity of the pores of the material,so the molding pressure should not exceed 14 MPa.The corundum-based porous ceramics combined by epoxy resin was studied,mainly to investigate the effects of resin type,adding amount,corundum particle size and modifier on material properties.The study found that corundum-based porous ceramics combined by oily epoxy resin has higher strength than those combined by water-based resin.The corundum-based porous ceramic containing 5%weight of oily bisphenol F epoxy resin has higher strength of 20.98 MPa when the porosity is 36.81%.However,after immersion in water.at room temperature for 48 h,the strength of the sample decreased significantly.The main reason for the strength loss was the fracture of the bonding phase.After adding 1.2%weight of KH-560 coupling agent to modify the material,the immersion strength of the sample is greatly improved,and the strength retention rate is increased to 80%.