电子陶瓷教学课件01_introduction

1、电子陶瓷,Electroceramics,Electroceramics,Research activities of Y.J. Wu,放电等离子烧结(Spark plasma sintering) 难烧结陶瓷的制备 亚稳材料的制备 铁电与介电材料(Ferroelectric and dielectric new materials) 传感陶瓷材料 （唐氏基金，200万元，20122016） 多铁性材料（国家自然科学基金, 77万，20162019） 磁性电介质（教育部博士点基金，12万，20142016） 能源新材料(Energy Materials ) 高储能密度电介质 (973计划，60

2、万，20152019) 超级电容器材料（美都能源，48万，20152017） 巨介电常数材料 微图案铁电薄膜,Electroceramics,References,Electroceramics: Materials, Properties, Applications. Third Edition, A.J. Moulson as a result, they have valuable use in high-performance applications, such as industrial cutting tools for milling and grinding metals.

3、A materials hardness is determined by measuring the size of an indentation made by a sharp diamond pressed strongly onto a material specimen. The hardness of alumina ceramics is nearly three times that of stainless steel; silicon carbide is more than four times harder than stainless steel. This extr

4、eme hardness is one of many unique properties that makes Fine Ceramics super materials for modern technology,Electroceramics,1.7 Structural ceramics,The strength of Fine Ceramic materials may be influenced by the presence of physical defects within the material, such as scratches, internal foreign s

5、ubstances and crystals with abnormal grain growth. Because larger Fine Ceramic components tend to have larger internal defects, larger specimens display less strength compared to smaller ones. A major difference between metals / plastics and Fine Ceramics is that the strength of Fine Ceramics is sig

6、nificantly influenced by variations in their fabrication and manufacturing processes, whereas the strength of metals and plastics is determined by their intrinsic material characteristics,Electroceramics,1.7 Structural ceramics,1. High hardness，high strength,Wear Resistance,Fine Ceramics that exhibi

7、t excellent hardness also greatly surpass most metals in wear resistance. During wear resistance tests, small glass beads were continuously sprayed at high speeds onto Fine Ceramics and metals for extended periods of time. The Fine Ceramics displayed only about 10 percent of the abrasion observed in

8、 the stainless steel samples. Additionally, during a test in which disks with Fine Ceramics and metals attached were continuously rotated in wet sand for eight hours, the Fine Ceramics displayed considerably less abrasion,Electroceramics,1.7 Structural ceramics,耐磨陶瓷衬,陶瓷切割刀片,陶瓷研磨材,Electroceramics,1.7

9、 Structural ceramics,2. High rigidity,Electroceramics,1.7 Structural ceramics,2. High rigidity,Fine Ceramics possess high rigidity, which is measured by inspecting the elasticity of a specimen after applying a load. Materials that display less elastic deformation under load possess higher levels of

10、rigidity. The coefficient of extension with respect to a load is called Youngs modulus. Using Youngs modulus to measure rigidity, alumina and silicon carbide display nearly double the values of stainless steel. Why is high rigidity advantageous? It allows ceramic components to be manufactured to muc

11、h higher levels of precision with regard to size and shape. In some cases, large mechanical stresses are generated on a material while it is being ground to final specifications. The less deformation that occurs during this process, the more precisely the parts can be processed,Electroceramics,1.7 S

12、tructural ceramics,2. High rigidity,Rigidity, also known as stiffness, is generally measured using Youngs modulus. It can be defined as the force necessary to bend a material to a given degree. As shown in the graph above, Fine Ceramics are highly rigid materials, according to Youngs modulus. This m

13、akes their machining accuracy high enough to enable them to be used for high-precision parts,Youngs Moduluses,Electroceramics,1.7 Structural ceramics,Why High Rigidity Yields High Machining Accuracy,2. High rigidity,Electroceramics,1.4 Structural ceramics,精密陶瓷构件,纳米陶瓷轴,陶瓷轴承,Electroceramics,1.7 Struct

14、ural ceramics,3. (High) toughness,Overcoming Fragility: Zirconia Ceramics,Typically, ceramics are characterized by hardness as well as a lack of toughness. The toughness of a material is measured by its resistance to fracturing. Among Fine Ceramics, zirconia possesses relatively high levels of tough

15、ness. As a result, it is used for products such as blades, scissors and knives,Electroceramics,1.7 Structural ceramics,3. (High) toughness,Overcoming Fragility: Zirconia Ceramics,Fracture Toughness,Electroceramics,1.7 Structural ceramics,陶瓷刀片,高尔夫球杆陶瓷镀层,Electroceramics,1.7 Structural ceramics,4. Stro

16、ng but Light,Fine Ceramics are lighter than high-strength metals. Within the same volume, many Fine Ceramic materials weigh only half as much as metal counterparts,Electroceramics,1.7 Structural ceramics,4. Strong but Light,Density refers to a materials mass per cubic centimeter, while specific grav

17、ity refers to the density ratio between a given material and water, where water is assigned a value of 1. Many Fine Ceramic materials have specific gravities less than half those of ferrous metals,Specific Gravities,Electroceramics,1.7 Structural ceramics,燃油泵陶瓷,航空陶瓷,航空陶瓷,Electroceramics,1.7 Structur

18、al ceramics,AlN ceramics High thermal conductivity Susceptors,Al2O3 ceramics Translucency Sodium vapour lamps,Quartz glass High thermal resistance Crucibles,Amorphite glassy carbon High stability CVD and epitaxial processes,Electroceramics,1.7 Structural ceramics,SiCceramics High hardness Protect tube；Cutting tool Microwave absorber,Porous ceramics Flotation of impurities Flow control filter,Quartz glass photomask Low thermal expansion Liquid crystal displays,Titanium diboride cera