【作者】 赵运才；

【导师】 肖汉宁；

【作者基本信息】 湖南大学 ， 材料学， 2003， 博士

【摘要】 铝硅酸盐微晶玻璃具有机械强度高、耐磨损、化学稳定性好等特性，它在航天航空、机械、建筑和化学工程上具有广阔的应用前景，且组成该系统的氧化物原料资源丰富，因此，近年来该系统微晶玻璃的开发研究十分活跃。有关该系统玻璃的组成与性能、分相与析晶方面已开展了一定的研究，但在如何提高其耐磨性能，进一步扩大其在耐磨、耐腐蚀结构件上的使用范围，目前尚缺乏深入研究。本文旨在开发一种新型耐磨、耐腐蚀微晶玻璃材料，以更好地满足工程领域对高性能结构材料应用的需求。 本文对微晶玻璃的发展历史、制备技术及其失效特性作了较系统的综述。以石英、长石、白云石、方解石和滑石等天然矿物为主要原料，CaF₂、Cr₂O₃和ZrO₂作为复合晶核剂，采用熔融法制备了一种新型耐磨、耐蚀材料——耐磨铝硅酸盐微晶玻璃（简称为耐磨微晶玻璃）。用X射线衍射仪测定了材料的物相组成，其主晶相为透辉石，并含有少量硅灰石；用扫描电子显微镜观察了材料的显微结构，其中大部分晶粒尺寸在100nm左右。 实验表明：晶核剂CaF₂有利于降低玻璃系统的晶化温度和析晶活化能，当加入4wt％（以下简写为％）的CaF₂时，晶化温度和析晶活化能分别为936℃和172.75KJ／mol，而加入6％的CaF₂时，晶化温度和析晶活化能为890℃和88.81KJ／mol。复合晶核剂（CaF₂、Cr₂O₃和ZrO₂）可以进一步降低界面能，使成核活化能降低，有利于玻璃的分相和析晶，从而易得到组织致密、晶粒细小的耐磨微晶玻璃。经正交实验优化，复合晶核剂中CaF₂、Cr₂O₃和ZrO₂含量分别为6％、1.2％和6％时材料耐磨性能最佳。 稀土氧化物CeO₂的引入有利于改善玻璃液的澄清效果，消除气泡，使微晶玻璃材料晶体颗粒更细小，组织更致密，性能有所改善，同时微晶玻璃的耐碱性得到明显的改善，其含量以1.5％为好。系统中MgO含量的变化对微晶玻璃的性能有较大的影响，当MgO含量在6～15％时，随着MgO含量的增加，微晶玻璃的抗弯强度逐渐增加。当MgO含量为15％时，抗弯强度达到最大值，为275MPa。当MgO含量超过15％时，由于组织中玻璃相的增加，导致材料性能有所下降。同时随着MgO含量的增加，微晶玻璃的显微硬度逐渐增加，MgO含量为15％的试样硬度最高，达到7.98GPa。 微晶玻璃晶化工艺参数对材料的耐磨性和抗弯强度影响显著，对于受多种因湖南大学博士学位论文素影响的玻璃晶化过程，采用正交试验方法可较快找出各因素对微晶玻璃性能的影响规律，并使工艺参数得到优化。所得工艺参数为:T。二790℃、:。=l .sh;T晶=930℃、T晶=o.sh和升温速率小于5℃/min。所制得耐磨微晶玻璃的性能指标为:抗弯强度为278MPa;显微硬度为7.98GPa;相对耐磨性为90%A12O3瓷球的（l/0 .665）1 .5倍。 摩擦与磨损是工程材料的重要服役性能之一。在制备耐磨微晶玻璃的基础上，对该材料的摩擦学特性进行了评价，特别探讨了载荷、转速对耐磨微晶玻璃摩擦磨损性能的影响，应用现代微观表面测试分析技术和摩擦学原理研究了该材料的磨损机理。结果表明:耐磨微晶玻璃在摩擦过程中，表层产生晶粒滑移和犁沟，出现疲劳脆性断裂和微裂纹，并发现有对偶件材料的转移和表面膜的形成。载荷和转速的变化对材料磨损特性影响显著，随着载荷的增加耐磨微晶玻璃的磨损量明显的增大，当载荷在20⁴0N时，磨损量随载荷增加较快，40N时的磨损量大约为20N时的1 .8倍。当载荷继续增加时，磨损量增长较缓慢。耐磨微晶玻璃的磨损量在转速为400印m时最大，其值为1.2一1.4mg，转速增大或减小，磨损量有所降低，当转速为100印m时，材料的磨损量最小，其值为0.8一1.Omg。 耐磨微晶玻璃的磨损率随温度的变化规律如下:从室温至500℃，磨损率随温度升高而增加，在500℃时达到最大。在500一800℃之间，磨损率显著降低，降幅可接近两个数量级，表明该材料具有良好的高温自润滑性。更多还原

【Abstract】 Glass-ceramics composed of aluminous silicate have excellent characteristics such as high mechanical strength, abrasion-resistance and chemical stability, which make it have wide broad applications in space and aircraft, mechinery, architecture and chemical engineering. The raw materials of the system is abundant, therefore the research about the system has become a focus of glass-ceramics. The compositions and properties, nucleation and crystallization of the system have been made considerable research, however, It has not been reported much to improve the abrasion-resistance so as to widen its applications as structure parts in abrasion and erosion environments, here we would like to develop a glass-ceramics with good abrasion and erosion resistance to meet better needs for structural engineering applications.The development, fabrication technology and failure characteristics of glass-ceramics were systematically reviewed. A new type of glass-ceramics with good abrasion and erosion resistance was prepared by melting method using quartz, feldspar, dolomite and calcite et al as the starting materials. CaF2, Cr2O3 and ZrO2 were used together as multi-nucleating agents. The phase compositions of the glass-ceramics were analyzed by x-ray diffractory. Results show that the main crystalline phases are diopside [CaMg(SiO3)2] and wollastonite [ -CaSiO3]. Microstructure of the glass-ceramics were observed by scanning electronic microscopy. It has a uniform structure with crystal particles about 100nm.CaF2 can decrease the temperature and activation energy of the base-glass for crystallization. When 4 wt% CaF2 was added in the glass, the crystallization temperature and activation energy is 936 and 172.75 KJ/mol respectively. When CaF2 was increased to 6 wt%, the temperature and activation energy decreased to 890 癈 and 88.81 KJ/mol. CaF2is an efficient nucleation agent for the abrasion resistant glass-ceramics, the optimal content of CaF2 is about 6 wt%. Multi-nucleating agents composed of CaF2, Cr2O3 and ZrO2 can further decrease interface energy of the glass system for crystallization so as to get a glass-ceramics with homogeneous, dense and fine microstructure. The optimal contents of CaF2, Cr2O3 and ZrO2 arecorrespondingly 6 wt %, 1.2 wt % and 6 wt %, which were determined by orthogonal tests.The addition of CeO2 can improve the clarifying degree of glass melt by elimination of the residual bubble, increase the alkali resistance and mechanical properties of the glass-ceramics. The optimal amount of CeO2 is about 1.5 wt%. The change of MgO content in the system has obvious effects on properties of the glass-ceramics. When the content of MgO increased from 6 wt % to 15 wt %, the bending strength and the Vikes-hardness of the glass-ceramics gradually increased, at 15 wt % MgO, up to 275MPa and 7.98Gpa respectively. When MgO contents over 15 wt %, the properties of the material decreased owing to the increase of glass phase.Crystallization parameters have remarkable influence on the abrasion resistance and bending strength of the glass-ceramics. The optimal parameters for this system are Tn=790 , Tn=1.5h; TC=930 , T c=0.8h and heating rate is less than 5癈/min, which were obtained by orthogonal tests. The glass-ceramics show a bending strength of 278MPa and a Viker-hardness of 7.98GPa. The wear resistance of the glass-ceramics is 1.5 times as that of 90% AbOs ceramics.Friction and wear are important application performance for engineering materials. Tribological characteristics of the glass-ceramic was evaluated, especially in the effects of load, sliding speed on friction and wear performance. The wear mechanism was analyzed by the technology of surface micro-analysis and principles of tribology. Experimental results show that the sliding between crystalline particles, and plough groove, fracture stripping and micro-cracks in the surface layer are the main mechanism for the wear loss. When the load were increased from 20N to 40N, the wear loss quickly increased with the load, and the wear loss at 4更多还原