简介:Althoughhigh-performancebasicrefractorymaterialsplayanessentialroleinstate-of-the-artsteel-making,magnesiacastableshavenotbeenwidelyuseduntilnow.Amajorchallengeisthatbruciteformation(Mg(OH)2)duringMgOhydrationcausesvolumeexpansionandsubsequentcracking—aphenomenoncommonlycalled"slaking".Toovercomeproblemsrelatedtoslaking,anewspecialtyproduct,SioxX-Mag,hasrecentlybeendevelopedforcement-freeMgOcastablesbasedonMgO-SiO2-H2Obond.Specimensfromindustrial-scale-sizedblocksafterdry-outwerecharacterisedbySEMandXRDtechniques.UsingSioxX-Magincombinationwithmicrosilica,crackingcausedbybruciteformationissuppressed.Theresultsdemonstratethatthedosageofmicrosilicaplaysessentialrolesinthecrackformationinlargesamples.Furthermore,thecompatibilityofSioxX-Magwithdifferenttypesofbasicaggregates,mediumtohigh-gradedead-burnedmagnesiaandolivine,hasalsobeenevaluated.High-performance,self-flowingcement-freeMgOcastableshavebeendeveloped.
简介:Apreliminaryapplicationofthedigitalimagecorrelation(DIC)ispresentedaimingtodetectandanalyzecracknetworkswhichareinducedbystressesarisingduringcuringanddrying(CD)ofMgOcontainingrefractorycastableslabs.SurfaceimagesofcastablesamplesplacedinaspeciallydesignedclimaticchamberwererecordedovertheCDstageswithadigitalcameraandprocessedbytheDICtechniquetomeasurethedisplacementfields.Post-processingDICresultswerecarriedouttoestimatethelength,orientationandopeningofcracksinthenetworks.Themethodologyishighlightedandthefirstexperimentalresultsareshownpointingoutitsfuturepotentialtobetterunderstandtheeffectofthephysicalaspects(particlesize,chemicalanalysis,temperature,etc.)andthestructuralones(slabshapeandsize)onprocessingandperformanceofadvancedrefractorycastables.
简介:Thestabilizationofγ-aluminiumoxyni-tridespinel(γ-AlON)hasbeeninvestigatedbyadditionofMgO,MgAl2O4,etc.,inreactionprocess.Theresultsindicatedthattherearewidersolidsolutionareasnear,Al2O3-richsideinAlN-Al2O3-MgOternarysystems,ThecontentofstabilizedAlONphaseinsamplesisrelatedtoheatingtemperatures,additives,etc.ThelatticeparametersoftheirAlONphasescouldbewelldescribedbytheequation:a0=0.7900+0.0375[MgO]+0.015[AlN](nm)