以高炉渣为助烧剂制备ZTA陶瓷及其性能研究

发布时间：2018-05-02 07:59

  本文选题：ZTA陶瓷 + 高炉渣　； 参考：《郑州大学》2017年硕士论文

【摘要】：ZTA陶瓷由于其高强度、高韧性、耐腐蚀、耐磨损及高性价比等特点,是目前使用广泛的一种工程陶瓷材料,同时,高的烧结温度是影响ZTA陶瓷成本及制约其应用领域的重要因素。常用的助烧剂中,固相添加剂降低烧结温度不明显且仍难有效使ZTA陶瓷低温致密化,液相添加剂导致室温下ZTA陶瓷中存在玻璃相而降低了材料力学性能。本文将使用具有析晶特性的玻璃态工业废弃物高炉渣为烧结助剂,既降低了ZTA陶瓷的烧结温度,又提高了陶瓷的力学性能,具有工艺简单、节能环保、实用性高等优点。为了更加全面地探究添加高炉渣作为助烧剂对ZTA陶瓷的物理性能、力学性能、显微结构的影响,文中首先利用X荧光光谱仪(XRF)、X射线衍射仪(XRD),差示扫描量热分析(DSC)、激光粒度分析仪和扫描电镜(SEM)等对高炉渣及炉渣微粉的化学组成、物化特性、热学特性及微观结构进行了研究和分析。结果表明,水淬高炉渣主要为玻璃态物质,其化学组成为CaO、SiO_2、Al_2O_3、MgO等,为制备陶瓷及其烧结助剂的主要成分;DSC和XRD分析表明,在不添加晶核剂的情况下,炉渣玻璃体的析晶温度在850~950℃左右,晶化后的主晶相为钙黄长石,微晶粒径为1μm左右,表明高炉渣具有较高的析晶活性。其次,依次研究了ZrO_2与Al_2O_3配比、传统固相添加剂TiO_2、液相复合添加剂SiO_2/CaO,以及高炉渣的添加量在不同温度下对ZTA陶瓷性能的影响。研究表明,含30wt%ZrO_2,1600℃烧结2小时后,ZTA陶瓷的抗弯强度为225MPa、断裂韧性为2.63MPa·m1/2,但SEM分析表明,无助烧剂时,该烧结温度下材料难以致密;引入2wt%TiO_2固相添加剂1600℃烧结2小时,ZTA抗弯强度为330MPa,但是相对密度也仅有90%,表明固相添加剂助烧结作用有限;引入液相复合添加剂SiO_2/CaO达5wt%时,经1600℃烧结2小时,ZTA陶瓷相对密度可达94%,但抗弯强度有所下降(300MPa),这是由于液相添加剂的引入在晶界处形成玻璃相,影响了材料的力学性能;添加5wt%高炉渣,1550℃烧结2小时,降温到950℃保温1h热处理,ZTA陶瓷相对密度达到97%,抗弯强度达到375MPa、断裂韧性为3.97MPa·m1/2,通过XRD与SEM分析表明,此时ZTA晶界玻璃相中析出钙黄长石微晶,形成的微晶玻璃能有效的提高陶瓷的力学性能。最后,研究了原料Al_2O_3粒度和成型压力对ZTA陶瓷性能的影响。研究表明,高能球磨能明显降低Al_2O_3粉体粒度,高能球磨40min,粉体粒度达0.43μm,时间继续延长,微粉开始团聚;配方固定时,成型压力对ZTA致密度有一定影响,成型压力过大在坯体中应力集中,不利于致密烧结;当Al_2O_3粒度为0.43μm,成型压力为120MPa,1550℃烧结2小时,ZTA陶瓷的体积密度达4.36g/cm3,抗弯强度为430MPa,断裂韧性为4.81MPa·m1/2,硬度为10.20GPa,采用大比表面积的原料微粉,可提高ZTA陶瓷的烧结活性。
[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，

本文编号：1833048