【摘要】：本文采用液相共沉淀法從粉體的制備-反應機理研究-粉體表征-燒結-陶瓷表征這一流程系統(tǒng)的研究了氧化鋯增韌氧化鋁(ZTA)納米復合材料。首先探索了傳統(tǒng)反應器和超重力反應器中制備Al2O2-ZrO2納米復合粉體的工藝條件,用SEM、TEM、EDS、XRD以及粒度分布測試儀對粉體的形貌、顆粒大小、粒度分布、團聚程度、元素分布均勻性等性能進行了測試和。同時,本文利用現(xiàn)有條件研究了Al2O3-ZrO2納米復合粉體的成型和燒結工藝條件,以自制粉體作為原料制備了ZTA納米復合陶瓷材料,并用SEM對陶瓷表面的形貌進行了測試以及用阿基米德原理對陶瓷的密度和開氣孔率進行計算分析。根據(jù)對粉體以及陶瓷的各項測試,本文最終得到如下結果：(1)在傳統(tǒng)反應器中當以ZrOCl2、Y(NO3)3、AlNH4(SO4)2作為反應物,以NH4HCO3作為沉淀劑,PEG 2000作為分散劑(用量為沉淀劑的2wt%),采用反共沉淀法作為制備方法,反應溫度選取45℃并不斷以700r·min-1速率攪拌進行攪拌,溶液的滴定速率設定為2mL·min-1并且在反應過程中不滴加NH3H2O調節(jié)pH,而且經(jīng)過冷凍干燥后在900℃下進行煅燒。在此條件下得到的粉體結晶度較高,Zr02以四方相存在；Al2O3-ZrO2納米粉體的形貌為球形,粉體顆粒粒徑較小,大約在50nm左右,粒度分布較窄,大約在30-70nm之間,而且粉體中Al元素和Zr分布均勻,沒有出現(xiàn)明顯的富集現(xiàn)象。(2)超重力旋轉床反應器(RPB)的引入解決了傳統(tǒng)反應器存在的組分分布不均勻以及團聚問題,提供了一種產物均勻性好,制備周期短,收率高,工藝過程簡單的反應器；同時該反應器還克服了由于鋯離子和鋁離子沉淀所需pH相差過大所引起的組分沉淀不同步以及傳統(tǒng)反應器反應對滴定速率限制的弊端。本文系統(tǒng)的研究了超重力反應器中進料速率、轉速以及循環(huán)次數(shù)三個變量對于Al2O3-ZrO2納米復合粉體性能的影響,得出當進料速率在1000mL·min-1,旋轉填充床的轉速為1400r·min-1,循環(huán)次數(shù)為0次時得到的粉體性能最為優(yōu)異。對比傳統(tǒng)反應器中的數(shù)據(jù)可以發(fā)現(xiàn),超重力旋轉床反應器最終得到的粉體具有顆粒形貌更接近球形,顆粒粒徑更小(40nm),粒度分布更窄(30-50nm), Al元素和Zr元素分布更加均勻。除此之外,超重力反應器在制備Al2O3-ZrO2納米復合粉體過程中進料速率更快(500倍),反應時間更短(1/500),能耗更低(1/70),因此,超重力反應器的引入對于大規(guī)模制備Al2O3-ZrO2納米復合粉體具有重大意義。(3)探索了成型壓力、粘結劑、燒結溫度等工藝條件以及干燥方法、反應器等影響粉體性能的條件對于陶瓷性能的影響,并最終得出結論成型壓力為200MPa時有利于陶瓷的燒結,粘結劑的最佳添加濃度為1.5wt%,最佳燒結溫度為1600℃。而且性能優(yōu)異的粉體燒結性能也同樣優(yōu)異,尤其是超重力反應器制備的粉體,在1500℃時即可達到較高的密度和較低的開孔率。
[Abstract]:In this paper, zirconia toughened alumina (ZTA) nanocomposites were studied by liquid phase coprecipitation method from preparation of powders, study of reaction mechanism, characterization of powders, sintering and characterization of ceramics. Firstly, the preparation conditions of Al2O2-ZrO2 nano-composite powder in traditional reactor and hypergravity reactor were studied. The morphology, particle size, particle size distribution and agglomeration degree of the powder were measured by SEM,TEM,EDS,XRD and particle size distribution tester. The uniform distribution of elements and other properties were tested. At the same time, the forming and sintering conditions of Al2O3-ZrO2 nano-composite powder were studied by using the existing conditions. The ZTA nano-composite ceramic material was prepared by using self-made powder as raw material. The morphology of ceramic surface was measured by SEM and the density and porosity of ceramics were calculated and analyzed by Archimedes principle. According to the tests of powders and ceramics, the results are as follows: (1) ZrOCl2,Y (NO3) _ 3AlNH _ 4 (SO4) _ 2 is used as reactant and NH4HCO3 as precipitant in traditional reactor. PEG 2000 was used as dispersant (2 wt% of precipitator), anticoprecipitation method was used as preparation method, reaction temperature was 45 鈩，

本文編號：2415138