共沉淀工艺对NiO-YSZ粉料制备及组成的影响

Effect of coprecipitation technologies on synthesis and composition of NiO-ZrO_2 powder

以NH3·H2O、NH3·H2O NH4HCO3缓冲溶液、NaOH溶液为沉淀剂,通过共沉淀法制备了NiO YSZ固体氧化物燃料电池阳极粉料;通过对比原始配方和最终粉料的质量,分析组成的准确性。由热重分析确定粉料的煅烧工艺,分别在600℃、800℃、1000℃煅烧1h后,进行X射线衍射(XRD)分析和透射电子显微镜(TEM)微观结构观察。研究结果表明,煅烧后的粉料中得到了立方晶型NiO和YSZ(由Y2O3稳定的ZrO2),颗粒大小呈阶梯状分布。对以NH3·H2O为沉淀剂制得的粉料进行组成分析,发现NiO YSZ粉料严重偏离了原组成,镍含量较低,这是因为Ni2+以[Ni(NH3)4]2+形式流失,可见氨水不宜作为沉淀剂制备阳极基体的粉料。以NH3·H2O NH4HCO3缓冲液为沉淀剂,在一定程度上提高了NiO的收率;利用NaOH溶液为沉淀剂可以完全避免Ni2+流失,能够较准确地控制粉料组成。

NiOZrO2 anode powder for solid oxide fuel cell(SOFC) was synthesized by coprecipitation method with NH3·H2O, NH3·H2ONH4HCO3 buffer solution and NaOH solution as the coprecipitation agents. The composition accuracy was analyzed by comparing the mass of the original composition with the eventual powder. The calcining technlogy for the powder was determined by thermogravimetric analysis, and the powder was then calcined at 600 ℃, 800 ℃ and 1000 ℃ for 1 h respectively, followed by XRD analysis and TEM microstructure observation. The results show that cubic NiO and cubic YSZ with a cascade particle distribution are obtained after calcining. Composition analysis of the powder synthesized with NH3·H2O as the coprecipitation agent shows that the composite powder has a high deviation from its original composition. The Ni content in the powder is low due to the loss of Ni in the form of 2+, thereby aqua ammonia is not suitable as a coprecipitation agent for preparing the anode substrate powder. The productive output of nickel is increased by using NH3·H2ONH4HCO3 buffer solution. The loss of nickel can be completely averted and the powder composition can be controlled by using NaOH as the coprecipitation agent.