导　　师： 张玉军

学科专业： 080502

授予学位： 硕士

作　　者： ;

机构地区： 山东大学

摘　　要： 随着熔模铸件品种的日趋多样化，陶瓷型芯的使用量逐渐增加，对其性能要求也不断提高。但是，目前现有的陶瓷型芯性能较差，致使熔模铸件生产滞后。因此，提高陶瓷型芯的综合性能是熔模铸件生产的关键。目前，常用的陶瓷型芯主要有氧化硅和氧化铝两大系列。氧化硅陶瓷型芯高温活性大，在陶瓷与金属的界面上易产生气孔和粘砂；氧化铝型芯则难以从铸件中脱出。Al/_2O/_3／SiO/_2复合陶瓷型芯具有耐高温、抗热腐蚀、高强度等优良性能，很大程度上克服了氧化铝、氧化硅等陶瓷型芯强度低、高温变形大及脱芯困难等缺点。 本文研究了陶瓷型芯原料配方组成、成型、干燥工艺和烧成制度等对型芯性能的影响，制备了综合性能优良的Al/_2O/_3／SiO/_2陶瓷型芯，得出以下结论： 1、通过原料矿物组成及化学成分对型芯性能的影响研究认为：制备Al/_2O/_3／SiO/_2陶瓷型芯的原料最佳配比为莫来石：蓝晶石：α-Al/_2O/_3粉：石英粉=14：4：2：1。 2、不同粘结剂对样品性能有较大的影响，CMC是采用挤出成型工艺制备Al/_2O/_3／SiO/_2陶瓷型芯合适的粘结剂。采用CMC作为粘结剂时，型芯吸水率、显气孔率、体积密度及抗弯强度等性能可以满足应用要求。 3、通过不同烧成温度下烧成试样性能的研究发现，烧成温度为1500℃时型芯试样的性能最佳。此时，型芯的吸水率达到20．9％、显气孔率达到36％、体积密度达到1．96g//cm~3、弯曲强度达到28．2MPa。本实验制备Al/_2O/_3／SiO/_2陶瓷型芯的烧成制度为：室温经120分钟升至300℃，经90分钟升至600℃保温60分钟，再经90分钟升至1200℃保温60分钟，经90分钟升至1500℃保温30分钟。 4、烧成试样的X射线衍射分析结果说明，随着烧成温度的升高，试样中Al/_2O/_3相、SiO/_2相和蓝晶石相逐渐消失，1500℃� With the diversification of the investment casting, the demands of the quantity and performance of ceramic core are improving increasingly. However, at present, the ceramic core can't satisfy the need of development because of the bad performance and production lag. Therefore, the key of the production of the investment casting is to enhance the performance of ceramic core. The ceramic core that was commonly used mainly contain silicon and aluminum. Silicon ceramic cores have the property of high-temperature activity, so the interface of the ceramic and metal had stick and sand porosity. Alumina cores are difficult to remove from the samples. Al/_2O/_3//SiO/_2 composite ceramic materials have many excellent performances, such as high temperature resistant, high-intensity and so on. The difficulties and shortcomings of alumina, silicon oxide and other ceramic core are overcome. In this paper, Al/_2O/_3//SiO/_2 composite ceramic cores with excellent performances are obtained by the extrusion molding processing. The amount of the raw materials, the sintering processing and the applications of the ceramic core are studied. The conclusions are as follows. 1、The proper proportion of Al/_2O/_3//SiO/_2 ceramic core is mullite:kyannite:α-Al/_2O/_3: SiO/_2=14:4:2:1 by studying the raw material and chemical component. 2、CMC is the favorable adhesive to prepare Al/_2O/_3//SiO/_2 ceramic core by contrasting and testing property of different adhesives in the study. 3、The sintering system of the study is as follows: Heating up to 300℃from room temperature by 120 minutes, continuously sintering up to 600℃by 90 minutes and standing for 60 minutes, then sintering up to 1200℃by 90 minutes and standing for 60 minutes, finally sintering up to 1500℃by 90 minutes and standing for 30 minutes. When the sintering temperature is 1500℃, the proportion of water absorption reached 20.9/%, the rate of porosity reached 36/%, the volume density reached 1.96 g//cm~3, the bending strength reached 28.2 MPa.

关 键 词： 陶瓷型芯 原料配比 烧成温度 应用

领　　域： [金属学及工艺]