简介:碱性体系中以水玻璃和硅溶胶为双硅源,硫酸铝为铝源,在硅铝酸盐凝胶形成过程中加入氧氯化锆,用水热晶化法成功合成了Zr-ZSM-5分子筛。通过XRD、Raman、UV-VIS、BET、SEM、NH3-TPD、Py-IR等手段对其进行表征。研究结果表明:Zr成功进入ZSM-5分子筛骨架,且随着锆摩尔含量的增加,分子筛的比表面积减小,孔径和孔体积增大,势必会影响到分子筛的择形催化性能;此外,分子筛的酸类型重新分布,L酸比例增大,总酸量和酸强度有所减小,势必会影响其酸催化性能;同时分子筛的生长方式也发生了改变,晶体结构由三维棺状变为二维层片状,相对结晶度有所降低,但其骨架结构依然保持完整。
简介:TheeffectoftitaniumadditiononthemicrostructureandmechanicalpropertiesofbrassCu40Znhasbeenstudiedviathepowdermetallurgy(P/M)route.Thewater-atomizedCu40Zn—1.0wt%Tialloypowderwasconsolidatedatdifferenttemperaturesintherangeof400—600℃usingsparkplasmasintering(SPS)andhotextrusionsubsequently.Resultsshowthatthesuper-saturatedsolidsolutiontitaniumelementinrapidlycooledbrassCu40Znpowdercreatedhighchemicalpotentialforaprecipitatereaction,showingsignificantgrainrefinementeffectsontheconsolidatedCu40Znmatrix.Consequently,excellentmechanicalpropertieswereobtainedbyprecipitationhardeningandworkhardeningaftersinteringandextrusion,withyieldstrengthof390MPa,ultimatetensilestrengthof617MPa,andVickersmicro-hardnessof192HV,whichare28.7%,23.4%,and23.9%highervaluesthanthoseofextrudedCu40Znbrass,respectively.