CeO_2和Sm_2O_3对方镁石-尖晶石材料烧结性能及显微结构的影响
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摘要
为了研究稀土氧化物掺杂方镁石-尖晶石复相材料的烧结性能及显微结构,以富镁尖晶石细粉与烧结镁砂细粉为主要原料,分别外加质量分数为1%、2%和3%的CeO_2和Sm_2O_3,于1 600、1 650、1 700和1 750℃保温3 h烧成分别测定烧后试样的线收缩率、体积密度、显气孔率,并通过XRD、SEM、EDS等对其物相组成及显微结构进行分析。结果表明:1)引入稀土氧化物CeO_2与Sm_2O_3均有利于镁砂与尖晶石烧结致密化,引入CeO_2未参与反应,呈孤立形态分布于晶粒间;引入Sm_2O_3与原料中杂质反应形成稀土硅酸盐相分布于晶粒间。2)材料的体积密度和线收缩率随稀土氧化物加入量的增加而增加。在加入量相同的情况下,引入CeO_2的材料致密化程度相对较高。添加3%(w) CeO_2的材料体积密度达到3. 29 g·cm-3,显气孔率为10. 3%,烧后线收缩率为7. 79%。3)引入CeO_2和Sm_2O_3都有部分固溶于尖晶石与方镁石晶体内,活化晶格,促进晶粒发育。
This work aims at studying the sintering properties and microstructure of rare earth oxide doped periclase-spinel composite materials. Composites were prepared using magnesium-rich spinel fines and sintered magnesite fines as starting materials,extra-adding rare earth oxides CeO_2 or Sm_2O_3( 1%,2%,and3%,by mass) as additives,firing at different temperatures of 1 600 ℃,1 650 ℃,1 700 ℃,and 1 750 ℃ for3 h. The linear shrinkage,bulk density,and apparent porosity were determined and the phase composition and microstructure of the obtained specimens were analyzed. It is demonstrated that:( 1) the introduction of CeO_2 and Sm_2O_3 are both in favor of the sintering densification of the magnesia and spinel material; the introduced CeO_2 does not participate in the reaction distributing isolatedly among the crystal grains; the introduced Sm_2O_3 reacts with impurities from the starting materials forming rare earth silicates distributing among crystal grains;( 2) the bulk density and linear change increase with the rising amount of rare earth oxides; with the same addition,the CeO_2 doped material has relatively high density; the specimen with3 mass% CeO_2 has density of 3. 29 g·cm~(-3),apparent porosity of 10. 3% and linear shrinkage of 7. 79%;( 3) a part of the introduced CeO_2 and Sm_2O_3 solid-solve into periclase and spinel crystals,activating crystal lattices and promoting the crystal growth.
This work aims at studying the sintering properties and microstructure of rare earth oxide doped periclase-spinel composite materials. Composites were prepared using magnesium-rich spinel fines and sintered magnesite fines as starting materials,extra-adding rare earth oxides CeO_2 or Sm_2O_3( 1%,2%,and3%,by mass) as additives,firing at different temperatures of 1 600 ℃,1 650 ℃,1 700 ℃,and 1 750 ℃ for3 h. The linear shrinkage,bulk density,and apparent porosity were determined and the phase composition and microstructure of the obtained specimens were analyzed. It is demonstrated that:( 1) the introduction of CeO_2 and Sm_2O_3 are both in favor of the sintering densification of the magnesia and spinel material; the introduced CeO_2 does not participate in the reaction distributing isolatedly among the crystal grains; the introduced Sm_2O_3 reacts with impurities from the starting materials forming rare earth silicates distributing among crystal grains;( 2) the bulk density and linear change increase with the rising amount of rare earth oxides; with the same addition,the CeO_2 doped material has relatively high density; the specimen with3 mass% CeO_2 has density of 3. 29 g·cm~(-3),apparent porosity of 10. 3% and linear shrinkage of 7. 79%;( 3) a part of the introduced CeO_2 and Sm_2O_3 solid-solve into periclase and spinel crystals,activating crystal lattices and promoting the crystal growth.
引文
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[9]刘磊,王周福,何俊鹏,等.Y2O3和CeO2对镁砂烧结性能及显微结构的影响[J].耐火材料,2012,46(5):340-343.
[10]LIU J,WANG Z,WANG X,et al.The effects of in situ formation of Y3Al5O12on property improvement of magnesium aluminate spinel refractories[J].Ceram Int,2018,44(7):7416-7420.
[11]SARKAR R,GHOSH A,DAS S K.Reaction sintered magnesia rich magnesium aluminate spinel:effect of alumina reactivity[J].Ceram Int,2003,29(4):407-411.
[2]李静捷,赵惠忠,王立锋,等.尖晶石组成和含量对RH浸渍管用方镁石-尖晶石质耐火材料性能的影响[J].耐火材料,2016,50(3):189-194.
[3]GHOSH A,SARKAR R,MUKHERJEE B,et al.Effect of spinel content on the properties of magnesia-spinel composite refractory[J].J Eur Ceram Soc,2004,24(7):2079-2085.
[4]高振昕.耐火材料显微结构[M].北京:冶金工业出版社,2002:186-190.
[5]AKSEL C,RAND B,RILEY F L,et al.Thermal shock behaviour of magnesia-spinel composites[J].J Eur Ceram Soc,2004,24(9):2839-2845.
[6]BELGACEM S,GALAI H,TISS H.Qualitative and quantitative investigation of post-mortem cement refractory:The case of magnesiaspinel bricks[J].Ceram Int,2016,42(16):19147-19155.
[7]曹林洪,于成铎,刘敏,等.添加剂对方镁石-尖晶石砖性能影响[J].西南工学院学报,2002,17(2):63-65.
[8]田忠凯,王周福,王玺堂,等.稀土氧化物对反应烧结合成镁铝尖晶石的影响[J].耐火材料,2008,42(5):326-329.
[9]刘磊,王周福,何俊鹏,等.Y2O3和CeO2对镁砂烧结性能及显微结构的影响[J].耐火材料,2012,46(5):340-343.
[10]LIU J,WANG Z,WANG X,et al.The effects of in situ formation of Y3Al5O12on property improvement of magnesium aluminate spinel refractories[J].Ceram Int,2018,44(7):7416-7420.
[11]SARKAR R,GHOSH A,DAS S K.Reaction sintered magnesia rich magnesium aluminate spinel:effect of alumina reactivity[J].Ceram Int,2003,29(4):407-411.