本文選題：ZTA陶瓷 + 高爐渣��； 參考：《鄭州大學》2017年碩士論文

【摘要】：ZTA陶瓷由于其高強度、高韌性、耐腐蝕、耐磨損及高性價比等特點,是目前使用廣泛的一種工程陶瓷材料,同時,高的燒結溫度是影響ZTA陶瓷成本及制約其應用領域的重要因素。常用的助燒劑中,固相添加劑降低燒結溫度不明顯且仍難有效使ZTA陶瓷低溫致密化,液相添加劑導致室溫下ZTA陶瓷中存在玻璃相而降低了材料力學性能。本文將使用具有析晶特性的玻璃態(tài)工業(yè)廢棄物高爐渣為燒結助劑,既降低了ZTA陶瓷的燒結溫度,又提高了陶瓷的力學性能,具有工藝簡單、節(jié)能環(huán)保、實用性高等優(yōu)點。為了更加全面地探究添加高爐渣作為助燒劑對ZTA陶瓷的物理性能、力學性能、顯微結構的影響,文中首先利用X熒光光譜儀(XRF)、X射線衍射儀(XRD),差示掃描量熱分析(DSC)、激光粒度分析儀和掃描電鏡(SEM)等對高爐渣及爐渣微粉的化學組成、物化特性、熱學特性及微觀結構進行了研究和分析。結果表明,水淬高爐渣主要為玻璃態(tài)物質,其化學組成為CaO、SiO_2、Al_2O_3、MgO等,為制備陶瓷及其燒結助劑的主要成分;DSC和XRD分析表明,在不添加晶核劑的情況下,爐渣玻璃體的析晶溫度在850~950℃左右,晶化后的主晶相為鈣黃長石,微晶粒徑為1μm左右,表明高爐渣具有較高的析晶活性。其次,依次研究了ZrO_2與Al_2O_3配比、傳統固相添加劑TiO_2、液相復合添加劑SiO_2/CaO,以及高爐渣的添加量在不同溫度下對ZTA陶瓷性能的影響。研究表明,含30wt%ZrO_2,1600℃燒結2小時后,ZTA陶瓷的抗彎強度為225MPa、斷裂韌性為2.63MPa·m1/2,但SEM分析表明,無助燒劑時,該燒結溫度下材料難以致密;引入2wt%TiO_2固相添加劑1600℃燒結2小時,ZTA抗彎強度為330MPa,但是相對密度也僅有90%,表明固相添加劑助燒結作用有限;引入液相復合添加劑SiO_2/CaO達5wt%時,經1600℃燒結2小時,ZTA陶瓷相對密度可達94%,但抗彎強度有所下降(300MPa),這是由于液相添加劑的引入在晶界處形成玻璃相,影響了材料的力學性能;添加5wt%高爐渣,1550℃燒結2小時,降溫到950℃保溫1h熱處理,ZTA陶瓷相對密度達到97%,抗彎強度達到375MPa、斷裂韌性為3.97MPa·m1/2,通過XRD與SEM分析表明,此時ZTA晶界玻璃相中析出鈣黃長石微晶,形成的微晶玻璃能有效的提高陶瓷的力學性能。最后,研究了原料Al_2O_3粒度和成型壓力對ZTA陶瓷性能的影響。研究表明,高能球磨能明顯降低Al_2O_3粉體粒度,高能球磨40min,粉體粒度達0.43μm,時間繼續(xù)延長,微粉開始團聚;配方固定時,成型壓力對ZTA致密度有一定影響,成型壓力過大在坯體中應力集中,不利于致密燒結;當Al_2O_3粒度為0.43μm,成型壓力為120MPa,1550℃燒結2小時,ZTA陶瓷的體積密度達4.36g/cm3,抗彎強度為430MPa,斷裂韌性為4.81MPa·m1/2,硬度為10.20GPa,采用大比表面積的原料微粉,可提高ZTA陶瓷的燒結活性。
[Abstract]:Because of its high strength, high toughness, corrosion resistance, wear resistance and high performance-to-price ratio, ZTA ceramics are widely used in engineering ceramics, at the same time, High sintering temperature is an important factor that affects the cost of ZTA ceramics and restricts its application field. Among the commonly used sintering aids, the solid phase additives are not obvious in lowering sintering temperature and are still difficult to effectively densify ZTA ceramics at low temperature. Liquid phase additives lead to the existence of glass phase in ZTA ceramics at room temperature and decrease the mechanical properties of the materials. In this paper, the glassy industrial waste blast furnace slag with crystallization property is used as sintering assistant, which not only reduces the sintering temperature of ZTA ceramics, but also improves the mechanical properties of the ceramics. It has the advantages of simple process, energy saving and environmental protection, high practicability and so on. In order to investigate the effect of adding blast furnace slag as sintering aid on the physical properties, mechanical properties and microstructure of ZTA ceramics, In this paper, the chemical composition, physicochemical properties of blast furnace slag and slag powder were analyzed by X-ray diffractometer, differential scanning calorimetry (DSC), laser particle size analyzer and scanning electron microscope (SEM). Thermal properties and microstructure were studied and analyzed. The results show that the slag of water-quenched blast furnace is mainly glassy, and its chemical composition is CaOOSiO2Al2O3MgO, etc. The results of DSC and XRD analysis for the preparation of ceramics and its sintering auxiliaries show that, without the addition of nucleating agents, The crystallization temperature of slag vitreous is about 850 ~ 950 鈩，

本文編號：1833048