以NH_4HCO_3为沉淀剂通过共沉淀法制备2Y-TZP纳米粉体

Preparing 2Y-TZP Nanopowder by a Coprecipitation Method with NH_4HCO_3 as the Precipitant

以NH_4HCO_3,ZrOCl_2·9H_2O和Y(NO_3)_3为原料,在乙醇溶液中通过共沉淀法制备2Y-TZP纳米粉体,并对其中的反应机理进行研究.在沉淀过程中,NH_4HCO_3和ZrOCl_2通过两步反应生成(NH_4)_3ZrOH(CO_3)_3·2H_2O对沉淀.首先NH_4HCO_3和ZrOCl_2反应生成Zr(OH)_4,其后Zr(OH)_4和NH_4HCO_3进一步反应生成(NH_4)_3ZrOH(CO_3)_3·2H_2O.(NH_4)_3ZrOH(CO_3)_3·2H_2O不稳定,在130℃即可分解生成ZrO_2,并放出氨气、水和二氧化碳.沉淀产物经300和450℃煅烧后得到的ZY-TZP粉体颗粒尺寸细小,不存在大的硬团聚,具有良好的烧结性,在1225℃即可实现高度致密化.

2Y-TZP nanopowder was prepared by a coprecipitation method, using NH4HCO3, ZrOCl(2.)9H(2)O and Y(NO3)(3) as the starting materials. During the precipitating process, (NH4)(3)ZrOH (CO3)(3).2H(2)O was formed through a two-step reaction. First, NH4HCO3 reacted with ZrOCl2.9H(2)O to form Zr(OH)(4), then NH4HCO3 further reacted with Zr(OH)(4) to form (NH4)(3)ZrOH(CO3)(3).2H(2)O. The resulting (NH4)(3)ZrOH(CO3)(3).2H(2)O was unstable and decomposed into ZrO2, NH3, H2O and CO2 at about 130degreesC. The 2Y-TZP powders obtained by calcining the precipitate mixture at 300degreesC and 450degreesC showed very fine particle sizes and were almost free of large hard aggregates. Furthermore, these powders showed good sinterability and could be highly densified at a low temperature of 1225degreesC.