Study Gelcasting Prepared MoSi₂-Sialon Composite Ceramic Material Properties

Sialon have excellent mechanical properties,thermal properties and chemical stability,etc,is considered by most researchers is one of the most promising high temperature structure material.Widely used in metallurgy,traffic,transportation,chemical machinery,building materials,medical,aerospace and other fields.Due to the brittleness of ceramic material defect limits its application.Aiming at this problem,this paper USES the added Mo powder added to the Sialon substrate,adopt the method of condensed type injection,the preparation of high strength,uniform green.Through sintering in matrix in situ generated intermetallic compound,induced phase transformation at the same time,the growth columnar beta Sialon phase,to achieve the effect of synergistic toughening.Note condensed type parameters is studied in detail,should instead of sintering process,microstructure and mechanical properties,obtained the following innovative results:?1?Condensed type injection method and the success of the preparation of good intensity,even raw material dispersion,Mo-Sialon ceramics green,according to the injection molding of time needed for large-scale production in the future and the temperature after the ball mill,got the optimization of process parameters,monomer adding amount was 4.0wt%,the ratio of monomers and crosslinking agent is 5:1,the initiator of the adding amount was 0.2wt%,the catalyst for the 6 drops set to 40 ?water bath temperature.?2?Studied under different sintering temperature,MoSi₂-Sialon ceramics should be to the contrary,in the process of in situ generated in Mo powder sintering process to promote the decomposition of Si3N4,generated by the elemental reaction with Mo Si in sintering temperatures generated silicon molybdenum compounds?Mo₅Si₃ and MoSi₂?,with the increase of sintering temperature,the decomposition rate of Si3N4 speeding up,the elemental content of Si increases,silicon molybdenum compounds gradually to a more stable,higher silicon content conversion generated MoSi₂ direction.Mo is summarized in the transformation process of Sialon ceramics substrate for: :Mo?Mo₅Si₃?MoSi₂??3?Under different sintering temperature are analyzed,MoSi₂ ?Sialon ceramics the microstructure and mechanical properties of the sample.In the sintering temperature is 1750?,uniform grain size distribution of the material,length to diameter ratio is big,the generated intermetallic compound MoSi₂ particle size distribution and uniform.1700 to achieve the required hardness requirements,density of 3.601 g/cm3 and fracture toughness of 9.6 Mpa· m1/2 maximum.