本文選題：顯微組織 + 力學性能　； 參考：《南京航空航天大學》2017年碩士論文

【摘要】：氧化鎂克服了傳統(tǒng)材質泡沫陶瓷過濾器與鎂熔體反應的問題,MgO泡沫陶瓷是鎂合金液熔煉凈化的理想材料。本文針對MgO燒結溫度和熱膨脹系數高導致其燒結困難和抗熱震性較差的問題,采用漿料注模成型方法制備MgO實體陶瓷,研究了Al_2O_3的添加量和燒結溫度對MgO陶瓷組織和性能的影響;研究了不同Al_2O_3添加量MgO陶瓷抗鎂/鋁合金熔體的侵蝕機理;采用有機泡沫浸漬法制備MgO泡沫陶瓷,比較了實驗室制備的MgO泡沫陶瓷與鐵絲網對鎂廢料的過濾效果,并對MgO泡沫陶瓷過濾器的過濾機理進行了理論分析。Al_2O_3的添加改善了MgO陶瓷的燒結性能;Al_2O_3與MgO反應生成MgAl2O4分布在MgO陶瓷晶粒的周圍,使顆粒間結合緊密并填充孔隙,從而降低氣孔率,提升致密度;當Al_2O_3添加量為20%時,在1500℃燒結2h的樣品綜合性能最好,此時樣品的線收縮率為20.93%,體積密度為2.422g·cm 3,氣孔率為12.41%,抗彎強度為45.6 MPa;Al_2O_3加入提高了MgO陶瓷的抗熱震性,Al_2O_3添加量為10%時,MgO陶瓷的抗熱震性最好。隨著燒結溫度的升高,Al_2O_3添加量為10%的MgO陶瓷孔隙數量和孔隙尺寸下降,陶瓷材料的晶粒尺寸明顯增大,且晶粒間結合越來越緊密;燒結溫度從1400℃增加到1550℃時,MgO陶瓷的體積密度、體積收縮率和抗彎強度出現增大的趨勢,與氣孔率的變化趨勢相反。不同Al_2O_3添加量的MgO陶瓷材料在鎂熔體中是穩(wěn)定的,侵蝕層與陶瓷材料的原始組織結構相比,氣孔較少,致密度提高,阻止了鎂熔體進一步向陶瓷材料內部的滲入;沒有添加Al_2O_3的MgO陶瓷長時間侵蝕易出現出現裂紋和破碎現象,而Al_2O_3添加量為10%和20%的MgO陶瓷則能保持完整的形態(tài),抗鎂熔體侵蝕性能較好。MgO陶瓷材料對氯化物具有很好的吸附效應,侵蝕過程中鎂熔體中的氯化物也會侵入陶瓷內部。MgO陶瓷材料在ADC12鋁合金熔體中是穩(wěn)定的,MgO陶瓷材料抗鋁合金熔體的侵蝕性能與Al_2O_3添加量和侵蝕時間無關,鋁合金熔體不會侵入陶瓷材料內部,沒有毛細現象和化學反應發(fā)生。聚氨脂泡沫塑料經過堿液處理后,隔膜減少,有效地避免了堵孔現象,表面粗糙度增加,有利于漿料的粘附。實驗制得的MgO泡沫陶瓷其氣孔率為83%,容重為0.4 g/cm3、抗彎強度為1.08 Mpa、抗熱震性較好,可以滿足鎂合金熔體的過濾。利用MgO泡沫陶瓷過濾實驗室鎂廢料發(fā)現,MgO泡沫陶瓷不但對大尺寸雜質具有很好的攔截效果,對尺寸較小的雜質和液態(tài)熔劑夾雜和具有很好的過濾和吸附效應。
[Abstract]:Magnesium oxide overcomes the problem of the reaction between the traditional ceramic filter and the magnesium melt. MgO foam ceramic is an ideal material for the purification of magnesium alloy melt. In order to solve the problem that the high sintering temperature and thermal expansion coefficient of MgO lead to the difficulty of sintering and poor thermal shock resistance, MgO solid ceramics were prepared by slurry injection molding method. The effects of Al_2O_3 addition and sintering temperature on the microstructure and properties of MgO ceramics were studied, and the corrosion resistance mechanism of MgO ceramics with different Al_2O_3 contents against melt corrosion of mg / Al alloy was studied, and the MgO foam ceramics were prepared by organic foam impregnation method. The filtration effect of MgO foam ceramics prepared in laboratory on magnesium waste was compared with that of barbed wire. The filtration mechanism of MgO foam ceramic filter was theoretically analyzed. The addition of Al2O3 improved the sintering performance of MgO ceramics. Al2OS3 reacted with MgO to form MgAl2O4 distributed around the grains of MgO ceramics, which made the particles close and filled with pores. When the amount of Al_2O_3 was 20%, the sample sintered at 1500 鈩，

本文編號：1818917