Abstract: This work aims at improving the sintering property of zirconia toughened alumina (ZTA) granulated powder.ZTA slurries were prepared through ball milling using alumina powder with different particle sizes (d₅₀:1.72 μm,3.48 μm and 13 nm) and yttria stabilized zirconia (YSZ) as the main starting materials,adding binders and dispersants.The effect of the YSZ extra-addition (0,5%,10%,15% and 20%,by mass) on the rheological property of the slurries was investigated.ZTA granulated powders were prepared using the spray drying method,and then the powders were pressed into shapes and fired at different temperatures (1 520,1 600,and 1 680 ℃).The linear shrinkage and relative density of the fired samples were determined.The results show that:(1)the ZTA slurries exhibit shear thinning behavior and possess a yield stress;the rheological properties of the slurries are well-described by the Herschel-Bulkley model,with a high correlation coefficient (>0.98);(2)the particle size of the prepared ZTA granulated powders is mainly within the range of 125 to 45 μm,demonstrating a wide distribution;(3)the optimal formulation is 99 mass% activated alumina powder (d₅₀=1.72 μm),1 mass% nano-alumina (d₅₀=13 nm),and 15 mass% YSZ (extra-adding);this formulation results in a Carr coefficient of 8.62%,a water content of 0.22%,and an angle of repose of 25.2°;after firing at 1 600 ℃ for 2 h,the sample exhibits a relative density of 94.8% and a linear shrinkage rate of 18.2%.

Key words: spray drying method, zirconia toughened alumina (ZTA), rheological property, relative density, linear shrinkage

摘要： 为了提高氧化锆增韧氧化铝(ZTA)造粒粉的烧结性能,以不同粒径(d₅₀=1.72 μm,d₅₀=3.48 μm,d₅₀=13 nm)的Al₂O₃粉和氧化钇稳定氧化锆粉(YSZ)为主要原料,并加入黏结剂和分散剂,混合球磨得到ZTA浆料。研究了不同YSZ外加量(外加质量分数分别为0、5%、10%、15%和20%)对浆料流变性能的影响。并采用喷雾干燥法制备了ZTA造粒粉。造粒粉经压样成型后分别在1 520、1 600和1 680 ℃保温2 h烧成,并测试其线收缩率和致密度。结果表明:1)ZTA浆料呈现剪切变稀的特性,并且具有一定的屈服应力,浆料的流变性能符合Herschel-Bulkley模型,拟合的相关系数较高,＞0.98;2)所制备的ZTA造粒粉的粒度分布范围主要在125~45 μm,粒度分布较广;3)以99%(w)活性Al₂O₃粉(d₅₀=1.72 μm)为主要原料,加入1%(w)纳米Al₂O₃(d₅₀=13 nm)、外加15%(w)YSZ时,所制备造粒粉性能较好,其对应的卡尔系数为8.62%,含水率为0.22%,休止角为25.2°,经1 600 ℃保温2 h烧后,其致密度为94.8%,线收缩率为18.2%。

关键词: 喷雾干燥法, 氧化锆增韧氧化铝(ZTA), 流变性能, 致密度, 线收缩率