本文關(guān)鍵詞：基于PSD的AlON透明陶瓷快速無(wú)壓燒結(jié)及其機(jī)理研究　出處：《大連海事大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： AlON透明陶瓷 無(wú)壓燒結(jié) 粒度分布 雙峰粉

【摘要】：AlON透明陶瓷是一種新型的功能陶瓷,它不僅具有良好的力學(xué)性能和化學(xué)穩(wěn)定性,而且在紅外到紫外波段均有良好的透光性,因此被廣泛的應(yīng)用于特種儀器制造、紅外探測(cè)等領(lǐng)域,具有非常廣闊的發(fā)展前景。目前世界各國(guó)多采用無(wú)壓、熱壓的方式燒結(jié)AlON透明陶瓷,但無(wú)壓燒結(jié)制備AlON透明陶瓷存在燒結(jié)溫度高、保溫時(shí)間長(zhǎng)的問(wèn)題,因此制備成本仍然較高。本文以碳熱氮化還原法合成的AlON粉體為原料,添加0.5 wt%Y_2O_3為燒結(jié)助劑,以不同球磨工藝對(duì)AlON粉體進(jìn)行球磨,獲得兩種具有不同粒度分布特征的AlON粉體:其一為單峰粉體,D50=1.1μm;其二為雙峰粉體,特征峰位分別為1.1μm和2.2μm。無(wú)壓燒結(jié)試驗(yàn)表明,雙峰AlON粉體具有較好的燒結(jié)活性,其致密化溫度較低,且致密化速率及相同溫度下的致密化程度均高于單峰AlON粉體。雙峰粉在無(wú)壓燒結(jié)過(guò)程中的相轉(zhuǎn)變研究表明:AlON粉體在升溫至1400℃時(shí)轉(zhuǎn)變?yōu)锳l_2O_3和AlN,其中粗顆粒AlON轉(zhuǎn)變?yōu)榱⒎溅?Al_2O_3和h-AlN,而細(xì)顆粒AlON轉(zhuǎn)變?yōu)榱溅?Al_2O_3和h-AlN,且隨燒結(jié)溫度繼續(xù)升高,由于η-Al_2O_3和AlON的結(jié)構(gòu)相似性,η-Al_2O_3和h-AlN在較低溫度(1600～1700℃)重新轉(zhuǎn)變?yōu)锳lON,而 α-Al_2O_3 和 h-AlN 在 1700～1800 ℃轉(zhuǎn)變?yōu)?AlON。進(jìn)一步的微觀結(jié)構(gòu)演化研究表明:快速升溫使樣品中由AlON分解產(chǎn)生的Al_2O_3在重新轉(zhuǎn)變成AlON相之前,顆粒保持近球形的、雙峰分布的粒度分布特征。近球形的顆粒形貌有利于實(shí)現(xiàn)顆粒重排,雙峰顆粒尺寸分布有利于晶粒生長(zhǎng),二者共同促進(jìn)致密化進(jìn)程。在Al_2O_3全部轉(zhuǎn)變?yōu)锳lON相之后,AlON大顆粒與大顆粒,大顆粒與小顆粒,小顆粒與小顆粒之間的傳質(zhì)過(guò)程同時(shí)快速進(jìn)行,從而使得燒結(jié)后期試樣中AlON晶�？焖匍L(zhǎng)大,使氣孔得到有效的排除從而獲得高致密度樣品。具有雙峰粒度分布特征的AlON粉體,以40 ℃/min快速升溫至1880℃保溫150min,制備了高透過(guò)率的AlON透明陶瓷,3mm厚樣品的紅外透過(guò)率達(dá)81.8%,實(shí)現(xiàn)了 AlON透明陶瓷的快速低溫?zé)Y(jié)。
[Abstract]:AlON transparent ceramics is a new type of functional ceramics. It not only has good mechanical properties and chemical stability, but also has good transmittance in infrared and ultraviolet bands. Therefore, it is widely used in the manufacture of special instruments, infrared detection and other fields, and has a very broad development prospects. At present, AlON transparent ceramics are sintered by non-pressure and hot pressing in most countries in the world. However, AlON transparent ceramics prepared by pressureless sintering have the problems of high sintering temperature and long holding time, so the preparation cost is still high. In this paper, the AlON powder synthesized by carbothermal nitridation reduction method is used as raw material. Two kinds of AlON powders with different particle size distribution were obtained by adding 0. 5 wt%Y_2O_3 as sintering aids and different ball milling technology. One was single peak powder. D50C 1.1 渭 m; The second is bimodal powder, the characteristic peak is 1.1 渭 m and 2.2 渭 m respectively. The results of pressureless sintering show that bimodal AlON powder has good sintering activity and low densification temperature. The densification rate and densification degree at the same temperature were higher than that of single peak AlON powder. The phase transition of bimodal powder during pressureless sintering was studied. The AlON powder changed to Al_2O_3 and AlN when it was heated to 1400 鈩，

本文編號(hào)：1433135