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

【摘要】：氧化鎂克服了傳統(tǒng)材質(zhì)泡沫陶瓷過(guò)濾器與鎂熔體反應(yīng)的問(wèn)題,MgO泡沫陶瓷是鎂合金液熔煉凈化的理想材料。本文針對(duì)MgO燒結(jié)溫度和熱膨脹系數(shù)高導(dǎo)致其燒結(jié)困難和抗熱震性較差的問(wèn)題,采用漿料注模成型方法制備MgO實(shí)體陶瓷,研究了Al_2O_3的添加量和燒結(jié)溫度對(duì)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(jī)理;采用有機(jī)泡沫浸漬法制備MgO泡沫陶瓷,比較了實(shí)驗(yàn)室制備的MgO泡沫陶瓷與鐵絲網(wǎng)對(duì)鎂廢料的過(guò)濾效果,并對(duì)MgO泡沫陶瓷過(guò)濾器的過(guò)濾機(jī)理進(jìn)行了理論分析。Al_2O_3的添加改善了MgO陶瓷的燒結(jié)性能;Al_2O_3與MgO反應(yīng)生成MgAl2O4分布在MgO陶瓷晶粒的周圍,使顆粒間結(jié)合緊密并填充孔隙,從而降低氣孔率,提升致密度;當(dāng)Al_2O_3添加量為20%時(shí),在1500℃燒結(jié)2h的樣品綜合性能最好,此時(shí)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(qiáng)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(shí),MgO陶瓷的抗熱震性最好。隨著燒結(jié)溫度的升高,Al_2O_3添加量為10%的MgO陶瓷孔隙數(shù)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(jié)合越來(lái)越緊密;燒結(jié)溫度從1400℃增加到1550℃時(shí),MgO陶瓷的體積密度、體積收縮率和抗彎強(qiáng)度出現(xiàn)增大的趨勢(shì),與氣孔率的變化趨勢(shì)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(jié)構(gòu)相比,氣孔較少,致密度提高,阻止了鎂熔體進(jìn)一步向陶瓷材料內(nèi)部的滲入;沒(méi)有添加Al_2O_3的MgO陶瓷長(zhǎng)時(shí)間侵蝕易出現(xiàn)出現(xiàn)裂紋和破碎現(xiàn)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(duì)氯化物具有很好的吸附效應(yīng),侵蝕過(guò)程中鎂熔體中的氯化物也會(huì)侵入陶瓷內(nèi)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(shí)間無(wú)關(guān),鋁合金熔體不會(huì)侵入陶瓷材料內(nèi)部,沒(méi)有毛細(xì)現(xiàn)象和化學(xué)反應(yīng)發(fā)生。聚氨脂泡沫塑料經(jīng)過(guò)堿液處理后,隔膜減少,有效地避免了堵孔現(xiàn)象,表面粗糙度增加,有利于漿料的粘附。實(shí)驗(yàn)制得的MgO泡沫陶瓷其氣孔率為83%,容重為0.4 g/cm3、抗彎強(qiáng)度為1.08 Mpa、抗熱震性較好,可以滿足鎂合金熔體的過(guò)濾。利用MgO泡沫陶瓷過(guò)濾實(shí)驗(yàn)室鎂廢料發(fā)現(xiàn),MgO泡沫陶瓷不但對(duì)大尺寸雜質(zhì)具有很好的攔截效果,對(duì)尺寸較小的雜質(zhì)和液態(tài)熔劑夾雜和具有很好的過(guò)濾和吸附效應(yīng)。
[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(hào)：1818917