摘要
采用柠檬酸-硝酸盐溶胶-凝胶法工艺制备的La10Si5.8Mg0.2O26.8粉末与NiO粉末按40%:60%的质量比混合后,将其按不同的质量比分别添加NH4HCO3和淀粉做造孔剂,通过球磨混合后压制烧结成NiO/Ni-La10Si5.8Mg0.2O26.8阳极片。再用自组装的还原装置在600℃还原5h。用XRD、SEM和排水法等方法对阳极片进行物相、表面形貌和孔隙率的分析观察。试验结果表明:600℃还原5h可以将NiO完全还原为Ni,还原前后磷灰石相La9.33Si6O26的衍射峰位没有发生明显变化,也没有出现新的相,说明两相形成了复相陶瓷而不是固溶体,加入不同质量比的NH4HCO3和淀粉均可得到纯的磷灰石相和NiO。所以两种造孔剂均可制备阳极。看出两种造孔剂制备的阳极片的表面形貌均外观平整未出现明显开裂现象,说明1400℃烧结温度工艺合适。NH4HCO3形成的孔洞均匀细小、淀粉形成的孔洞比较大。加入不同质量比的淀粉形成的孔隙率为50%~75%,加入不同质量比的NH4HCO3形成的孔隙率为30%~45%。加入相同质量比的淀粉比NH4HCO3的孔隙率高。综合考虑阳极片物相、表面形貌和孔隙率,添加30%NH4HCO3制备的阳极片符合要求。
Powder of La10 Si5. 8 Mg 0.2 O26. 8 was prepared by using sol-gel method. The powder was mixed with NiO powder in the ratio4:6. NH4 HCO3 and starch powder with a different weight ratio were added as pore forming agents to the mixture separately. The powder mixtures were ball milled,pressed into disks and sintered to form NiO / La10 Si5. 8 Mg 0.2 O26. 8 disks. The disks were then reduced in H2 atmosphere at600℃ for5 h. The disks were characterized by using XRD,SEM and porosities of the disks were measured by using Archimedes method. The results releaved that NiO were reduced to Ni completely. The peak positions of diffraction of La 9.33 Si6 O26 in XRD patterns are not obviously changed and no new phases are confirmed after the reduction. This means that there are NiO and apatite phase in the composite but not the solid solution. NiO and apatite phase can be obtained with addition of a different weight ratio of NH4 HCO3 and starch powder. Therefore both of NH4 HCO3 and starch can be used for preparing anode. The surfaces of the dicks made with the two pore forming agents are in a good flatness and no cracks are found. This indicates that the sintering temperature of1400℃ is suitable. The pores formed with NH4 HCO3 are homogeneous and fine. The pores formed with starch powder are bigger. The porosities of disks made with starch and with NH4 HCO3 in a different weight ratio are50% ~75% and34% ~45% respectively. When the weight ratio was the same,we got higher porosity with starch than with NH4 HCO3. Considering phase formation,surface morphology and porosity we conclude that the disk prepared with the addition of30% NH4 HCO3 can meet the requirements for anode.
出处
《材料保护》
CAS
CSCD
北大核心
2013年第S2期96-99,共4页
Materials Protection
基金
大连市科技计划项目(2010A17GX094)
