Preparation And Performance Of Cordierite Transparent Wearable Glaze

In this research,cordierite transparent glazes were prepared by raw glaze method,high-temperature melting and crystallization method and in-situ growth method.The cordierite crystallization temperature and phase transition process,as well as the microstructure development were investigated by Differential Scanning Calorimetry-Thermogravimetric Analysis(DSC-TGA),X-ray diffractometry(XRD),Scanning Electron Microscopy(SEM).The effect of preparation methods,content of nucleation agent and a additive on the phase transition process and the microstructure of cordierite glazes were analyzed,and the effect of cordierite crystal size and crystalline content on the microhardness,transparency and the friction and wearing behavior were also investigated.Raw glaze method is that glaze materials are mixed and milled to get a glaze slip,then clay supports are immersed into it,and finally experience a heating process.The results demonstrate that columnar cordierite generated on the glaze with single firing by raw glaze method.The slenderness ratio of cordierite crystals was 2:1,and the crystal size in radial direction was 10μm,as well as the glaze surface presented part of the milky white area.While in the cooling process for a thermal insulation,the slenderness ratio of cordierite crystals was 2:1,the crystal size in radial direction was 500 nm,the content of nucleation agent and the temperature system should be strictly controlled,as a consequence the glaze surface was transparent,but the cordierite crystalline contend and its crystal size were quite small,and the abrasion resistance can not be enhanced.Therefore,it is not suitable for preparing cordierite transparent glazes by raw glaze method.Cordierite transparent glazes owned excellent properties like high transparency and enhanced abrasion resistance prepared by high-temperature melting and crystallization method,which is processed by heating raw materials at a high temperature and quenching in air,then get a glazed tile.The cordierite crystalline content reached nearly 50%wt.The microhardness of glaze surface was above 8GPa,and it was prepared without the addition of nucleation agents.In addition,cordierite crystallized from the frit in the bulk crystallization mechanism,and the slenderness ratio of cordierite hexagonal prism was 4:1,the crystal size in radial direction was 5μm.By adding adequate amount of phosphorus into the frit,the cordierite crystallization temperature was lowered,and the lowest temperature was 1000°C,the crystallization mechanism was also changed into a surface crystallization manner.Meanwhile,if the cooling process was controlled in an adequate rate cordierite could also crystallized on a bulk crystallization manner using the phase separationmechanism of phosphorus.In-situ growth method is processed by mixing cordierite powder and boron frit to get a glazed tile.Cordierite transparent glazes could also be prepared via in-situ growth method.The slenderness ratio of cordierite was 5:1 and the crystal size in radial direction was 2μm.Using this method the glaze surface presented a uniform distribution of cordierite crystal,and cordierite crystallized in a surface crystallization mechanism.The properties of glaze surface could also be severely affected by the weight fraction of cordierite,if the amount of cordierite is too high,the glaze can not melted easily,if the content is too low,cordierite powders melted prematurely,as a result the glaze surface presented non-crystalline phase.