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采用TG/DSC、XRD和SEM系统考察了K2CO3、NaOH、KOH和氨水等不同pH调节剂调节前驱物溶液pH值,对燃烧法制备的纳米LaMnO3粉体的晶相组成和微观形貌的影响。结果表明:不同的pH调节剂和前驱物溶液pH值对燃烧产物的晶相组成、晶粒大小和微观形貌都有显著的影响。其中以KOH作pH调节剂,pH=13的碱性环境中产物多为立方体的钙钛矿型纳米LaMnO3晶粒,以氨水作pH调节剂,pH=10时产物为蓬松多孔的结构。而以K2CO3和NaOH为调节剂,制得产物为无规则颗粒的聚集体。
The effects of different pH regulators, such as K2CO3, NaOH, KOH and ammonia, on the crystal phase composition and morphology of LaMnO3 nano-powders prepared by combustion method were investigated by TG / DSC, XRD and SEM. The results show that different pH regulators and precursor solution pH have significant effects on the crystalline composition, grain size and microstructure of the products. Among them, KOH was used as pH modifier, pH = 13. The products of alkaline environment were mostly cubic perovskite LaMnO3 crystal grains. Ammonia was used as pH modifier. When pH = 10, the product was fluffy porous structure. With K2CO3 and NaOH as regulators, the product was obtained as irregular aggregates of particles.