喷雾造粒粉末ZrO_2(Y_2O_3)烧结行为的研究

Study on the sintering behavior of zirconia spray granualation ZrO_2(Y_2O_3)

研究了喷雾造粒粉末ZrO2 (Y2 O3 )的烧结行为。在坯体烧结过程中形成的新团聚体主要由 5 0 0℃之前的升温速度所决定 ,当升温速度大于 2 .5℃ /min时 ,造粒粉中有机物燃烧放出的热量将导致颗粒间的紧密粘连 ,形成团聚体。新生团聚体将影响整个烧结过程 ,实验结果表明 :新生团聚体不仅阻碍烧结 ,同时使坯体的烧结方式发生了变化。即在较低密度下 ,烧结体的致密化速率大幅度减小 ,而主要呈现为以晶粒长大为主的烧结 ,致使坯体内部气孔难以消除 ,并且出现晶粒异常长大。通过研究烧结行为 ,获得了致密烧结、结构均匀氧化锆陶瓷的烧成曲线。

Sintering behavior of zirconia spray granulation ZrO 2(Y 2O 3) was investigated. Agglomeration formed during sintering in the green compact was controlled by the heating rate from room temperature to 500℃. When the heating rate is above 3.5℃/min, the quantity of heat given out by sintering the polymer in zirconia spray granulation made the particles strongly interconnected, and induced to the formation of agglomeration. Agglomeration has shown to affect to different extents the sintering behavior over the entire sintering schedule. Such agglomerate-induced inhibition not only reduces the sinterability of the powder compacts, but also promotes the onset of the transition of sintering mechanism from densification kinetics to coarsening kinetics at lower sintered density. As generally realized that under such circumstance, the voids within the sintered compacts may frequently be retained and larger grains developed, which would accordingly largely reduce a desired performance of the final products. The sintering schedule of zirconia spray granulation ZrO 2(Y 2O 3) that gave small grain size and high relative density was obtained.