Application Study Of MAX Phases Containing Titanium In MgO-C Refractories

How to prepare low-carbon refractories without weakening the performance of carboncontaining refractories has long been the research direction of carbon composite refractories.In this paper,taking MgO-C refractories as an example,the experiment uses magnesia,flake graphite,elemental silicon,four MAX phases(Ti₃AlC₂,Ti₂ Al C,Ti₃SiC₂,Ti₂ Al N)as raw materials,and adds5 wt% of phenolic resin as the combination to prepare a low-carbon MgO-C refractories with a carbon content of 4 wt%.Use MAX phase to replace part of the flake graphite in MgO-C refractories to prepare low-carbon MgO-C refractories,control the replacement amount and particle size of MAX phases,reduce carbon content without significantly reducing the performance of MgO-C refractories,and ensure low The carbon MgO-MAX-C refractories still has high mechanical properties.The innovative approach of adding the MAX phase provides a new idea for the use of low-carbon MgO-C refractories under high temperature conditions.Research indicates:(1)In a buried carbon environment,the phase change of the MAX phase is related to the elements it contains,and with the increase of temperature,the phase will continue to change.The main phases of the MAX phase containing titanium are Ti N and TiO₂.(2)In a buried carbon environment,when MAX phase replaces 3 wt% graphite content in MgO-C refractories,it can effectively improve its physical properties at room temperature.The MgO-MAX-C refractory forms plate-like or fibrous carbides or nitrides and deposits in the pore matrix,reducing the apparent porosity of the MgO-C refractories and improving its compressive strength;it is improved by the special chemical bond of the MAX phase The elastic modulus and flexural strength of MgO-C refractories;through the overflow reaction of active atoms,oxides are formed to block pores,and the high-temperature volume stability and oxidation resistance of MgOC refractories are improved.And MgO-Ti₃AlC₂-C refractories has the highest strength,and MgOTi₃SiC₂-C refractories has the best oxidation resistance.(3)When the MAX phase particle size is changed,only Ti₃SiC₂ is sensitive to the particle size,and the mechanical properties and oxidation resistance are further enhanced,while Ti₃AlC₂ and Ti₂ Al N are only sensitive to the particle size in terms of oxidation resistance,and the oxidation resistance is enhanced.(4)In the dynamic slag resistance experiment,the MgO-C refractories with Ti₂ Al N added to form an oxidation protective layer of TiO₂ and Al2O3,and the magnesium-aluminum spinel which increases the viscosity of the slag and prevents the erosion of the slag,which improves the slag resistance of the MgO-C refractories.Corrosion performance.