Ceramic+Materials

1、The word ceramic, derives its name from the Greek keramo, meaning “pottery”, which in turn is derived from an older Sanskrit （梵文，一种古印度语）root, meaning “to burn”. The Greeks used the term to mean “burnt stuff” or “burned earth”. Thus the word was used to refer to a product obtained through the action

2、of fire upon earthy materials.陶瓷这个词，它的名字来源于希腊凯拉默，意为“陶”，这又是来自一个年长的梵文（梵文，一种古印度语）根，烧“意义”。希腊人用这个词的意思是“烧东西”或“烧土”。因此，这个词被用来指通过通过火烧泥土材料产品。Ceramics make up one of three large classes of solid materials. The other material classes include metals and polymers（聚合物）. The combination of two or more of these mate

3、rials together to produce a new material whose properties would not be attainable by conventional means is called a composite（复合材料）. Examples of composites include steel reinforced（增强） concrete, steel belted（加固） tires, glass or carbon fiber-reinforced plastics (so called fiber-glass resins（树脂）) used

4、 for boats, tennis rackets, skis, and racing bikes.陶瓷组成一对固体材料三大类。其他材料类包括金属和聚合物（聚合物）。两种或两种以上的材料结合在一起产生一个新的材料，其性能将不通过传统的方法得到的组合称为复合（复合材料）。实例的材料包括钢筋混凝土（增强），半钢子午线轮胎（加固），玻璃纤维和碳纤维增强塑料（俗称玻璃纤维树脂（树脂）用于船，网球拍，滑雪板，与赛车。Ceramics can be defined as inorganic, non-metallic materials that are typically produced using

5、 clays and other minerals from the earth or chemically processed powders. Ceramics are typically crystalline in nature and are compounds formed between metallic and non-metallic elements such as aluminium and oxygen (alumina, Al2O3), silicon and nitrogen (silicon nitride, Si3N4) and silicon and carb

6、on (silicon carbide, SiC). Glass is often considered a subset （子集）of ceramics. Glass is somewhat different from ceramics in that it is amorphous（非晶的）, or has no long range crystalline order.陶瓷是无机非金属材料，通常是用粘土和其他矿物从地球或化学处理的粉末。陶瓷的性质通常是晶体和化合物的金属和非金属元素如铝和氧之间形成（氧化铝，氧化铝），硅和氮（氮化硅，氮化硅）和硅碳（碳化硅，碳化硅）。玻璃通常被认为是一个

7、子集（子集）陶瓷。玻璃是有所不同的，它是从陶瓷晶（非晶的），或没有长期的结晶顺序。Most people, when they hear the word ceramics, think of art, dinnerware（餐具）, pottery, tiles, brick and toilets. The above mentioned products are commonly referred to as traditional or silicate-based ceramics. While these traditional products have been, and co

8、ntinue to be, important to society, a new class of ceramics has emerged that most people are unaware of. These advanced or technical ceramics are being used for applications such as space shuttle（航天器） tile, engine components, artificial bones and teeth, computers and other electronic components, and

9、 cutting tools, just to name a few.大多数人，当他们听到这个词想到艺术，陶瓷，餐具（餐具），陶瓷，瓷砖，砖和厕所。上述产品通常被称为传统或硅基陶瓷。而这些传统产品已经，并继续，重要的社会，一个新的类陶瓷已经出现，大部分人都不知道。这些先进技术陶瓷被用于应用程序如航天飞机（航天器）瓦，发动机部件，人工骨骼和牙齿，电脑和其他电子元件，和切割工具，只是仅举几例。1. Advanced Ceramics1。先进陶瓷Advanced ceramics, also known as engineering or technical ceramics refer to ma

10、terials which exhibit superior mechanical properties, corrosion/ oxidation resistance, and thermal, electrical, optical or magnetic properties. Advanced ceramics are generally broken down into the following segments: structural ceramics; electrical and electronic ceramics; ceramics coatings; chemica

11、l processing （化工）& environmental ceramics.先进陶瓷，也被称为工程或技术陶瓷是指具有优越的机械性能的材料，耐腐蚀、耐氧化，热，电，光，磁特性。先进陶瓷一般分为以下几个部分：结构陶瓷；电子陶瓷；陶瓷涂层；化学处理（化工）环保陶瓷。Structural ceramics include applications such as industrial wear parts（耐磨件）, bio-ceramics（生物陶瓷）, cutting tools, and engine components. Electronic ceramics, wh

12、ich has the largest share of the advanced ceramic market, includes capacitors（电容器）, insulators（绝缘体）, substrates（基片）, integrated circuits packages（集成电路封装）, piezoelectrics（压电体）, magnets（磁体） and superconductors. Ceramic coatings find applications under chemical processing and environmental ceramics inc

13、lude filters（过滤器）, membranes（膜片）, catalysts, and catalyst supports（催化剂载体）.结构陶瓷的应用包括如工业耐磨零件（耐磨件），生物陶瓷（生物陶瓷），切削工具，和发动机部件。电子陶瓷，具有先进的陶瓷市场的最大份额，包括电容器（电容器），绝缘体（绝缘体），基板（基片），集成电路封装（集成电路封装），压电材料（压电体），磁铁（磁体）和超导体。陶瓷涂层，发现化学处理和环境下陶瓷材料的应用包括过滤器（过滤器），膜（膜片），催化剂，催化剂载体（催化剂载体）。The beginning of the advanced ceramics era

14、 has been said to have started approximately 50 years ago with the expanding use of chemically prepared powders. For example, the Bayer（拜耳） process for the production of alumina powders initially grew from spark plug （火花塞）production. While these powders would be considered relatively low grade by to

15、days standards, they were more pure and offered more control over the composition, microstructure, and crystal structure over minerals-based ceramics.先进的陶瓷时代开始一直在说大约50年前开始的扩大使用化学制备粉末。例如，拜耳（拜耳）对氧化铝生产过程从最初的火花塞（火花塞）生产的增长。而这些粉末会被认为是相对较低的等级按今天的标准来看，他们更纯净，提供了更多的控制的组成，微观结构和晶体结构，在矿物基陶瓷。Today, the market for

16、 advanced ceramics is large and growing as they continue to replace more traditional materials in many applications while providing the only material solution in other applications. In many cases, ceramics are used with other materials to make up only part of an overall system. This is especially tr

17、ue in the electronics field.今天，先进陶瓷市场越来越庞大，因为他们继续取代传统材料在许多应用中，而在其他应用程序提供的材料解决方案。在许多情况下，陶瓷是用其他材料只占整体系统的一部分。这是在电子领域尤其如此。The future success of both the traditional advanced ceramic markets and developing non-traditional U. S. markets depends on factors such as increasing the quality and reliability of

18、the finished products, improving the cost/benefit ratio （成本效益比）of ceramic components, increasing applied research and development, increased supply of domestic, high-quality raw materials, and overcoming designer and end-user reluctance to use ceramics.既有传统的陶瓷市场和发展的非传统的美国市场未来的成功取决于诸如提高最终产品的质量和可靠性的因素

19、，提高成本/效益比（成本效益比）陶瓷元件，增加应用的研究与开发，国内供应增加，优质的原材料，并克服设计师和最终用户不愿使用陶瓷。Improvements are occurring however, in areas such as powder processing, shape forming, non-destructive evaluation（非破坏性检测）, machining, standardization （标准化）and the development of a materials property database（数据库）. In order to reduce man

20、ufacturing expenses, researchers are looking toward innovation（创新）, “near-net-shape（近净尺寸）” forming methods such as gel-casting（胶铸）, freeze-casting（冰冻铸法）, injection molding, and rapid prototyping（原型制造）. These methods will reduce machining cost, which can be as much as 50% of the total manufacturing c

21、ost.改进的发生但是，在诸如粉加工，成形，无损评价（非破坏性检测），加工，标准化（标准化）和材料性能数据库的发展（数据库）。为了降低制造费用，研究人员正在向创新（创新），“近净成形（近净尺寸）”的方法，如凝胶注模成型（胶铸），冷冻铸造（冰冻铸法），注射成型，快速成型（原型制造）。这种方法会降低加工成本，可高达50%的总制造成本。Advanced structural ceramics are ceramic materials that demonstrate enhanced mechanical properties under demanding conditions. Because

22、 they serve as structural members, often being subjected to mechanical loading, they are given the name structural ceramics. Ordinarily, for structural applications ceramics tend to be expensive replacements for other materials, such as metals, polymers, and composites. For especially erosive, corro

23、sive, or high temperature environment, however, they may be the material of the choice. This is because the strong chemical bonding in ceramics.先进的结构陶瓷是表现出苛刻的条件下增强的机械性能的陶瓷材料。因为它们作为结构构件，往往受到机械加载，它们被赋予名称结构陶瓷。通常，在结构应用陶瓷往往是昂贵的替代其他材料，如金属，聚合物，和复合材料。对于特别侵蚀性，腐蚀性或高温环境中，但是，它们可能是首选材料。这是因为，在陶瓷的强化学键。Chemical bon

24、ds make them exceptionally robust （坚固）in demanding situations. For example, some advanced ceramics display superior wear resistance, making them ideal for tribological (wear) applications such as mineral processing equipment. Others are chemically inert and therefore are used as bone replacements in

25、 the highly corrosive environment of the human body. High bond strengths also make ceramics thermochemically inert（热化学惰性）, this property shows promising areas of application in engines for automobiles, aerospace vehicles（航空航天器）, and power generators（电力发电机）.化学键使他们非常强大（坚固）在要求较高的场合。例如，一些先进陶瓷显示效果出众的耐磨性，

26、使它们非常适合摩擦（穿）的应用，如选矿设备。其它的是化学惰性的，因此，被用作骨替代在人体内的高腐蚀性环境中。高粘结强度也使陶瓷热化学惰性（热化学惰性），此属性会显示应用程序的引擎汽车，航空航天器有前途的领域（航空航天器），以及发电机（电力发电机）A number of technological barriers have to be surmounted in order to make advanced structural ceramics an everyday reality. The most significant challenges are the inherent flaw

27、 sensitivity（固有的裂纹敏感性）, or brittleness, of ceramics and the variability （变化性）of their mechanical properties.一些技术障碍必须克服以先进结构陶瓷的现实生活。最重要的挑战是固有的缺陷灵敏度（固有的裂纹敏感性），或脆性，陶瓷和变异性（变化性）的力学性能。Among the strategies for achieving ceramics with improved mechanical properties, especially toughness, some involve the en

28、gineering of microstructures that either resist the propagation of cracks or absorb energy during the crack propagation process. Both goals can be achieved simultaneously in microstructures with fibrous or interlocked （联锁的）grains. In ceramics produced with such microstructures, cracks are deflected（

29、偏离） from a straight path, leading to a dramatic increase in crack length, at the same time particles behind the advancing crack tip bridge the crack, tending to hold it closed. Crack deflection and crack bridging also occur in whisker（晶须） reinforced fracture surface area and much greater energy abso

30、rption.在策略和改进的机械性能，特别是韧性达到陶瓷，一些涉及结构工程抗裂纹或裂纹扩展过程中吸收能量。双方的目标是可以同时实现的微观结构与纤维或互锁（联锁的）颗粒。在这样的组织生产陶瓷，裂纹偏转（偏离）从直线路径，导致裂纹长度显著增加，在裂纹尖端裂纹桥接同时颗粒，倾向于把它关闭。裂纹偏转和桥联也发生在晶须（晶须）钢筋断口面积和更高的能量吸收。Another mechanism that can lead to increased fracture toughness in ceramics is microcracking, which occurs in single phase pol

31、ycrystalline ceramics whose grains are anisotropic (各向异性，that is, whose mechanical properties vary with direction) or in intentionally biphasic（双相） polycrystalline microstructures. In these materials tiny microcracks open up to either side of the main crack path ahead of the advancing crack tip. Thi

32、s phenomenon has two effects. First, the energy that goes into the opening of the subsidiary（附属的） cracks increases the energy needed for propagation of the main crack. Second, as the main crack propagates, microcracks opening up in the wake（尾随） or process one adjacent to the main crack but behind th

33、e crack front result in an increase in volume, which tends to close the main crack. The resistance to propagation thus increases the farther the crack propagates.另一种机制，可以使陶瓷断裂韧性的增加是微裂纹，它发生在单相多晶陶瓷的晶粒各向异性（各向异性，即，其力学性质随方向）或故意双相（双相）多晶结构。在这些材料中微裂纹开放的主裂纹路径的两侧，在裂纹尖端。这种现象有两方面的影响。第一，能源进入子开（附属的）裂缝增加的主裂纹扩展所需要的

34、能量。其次，作为主要的裂纹，裂纹在唤醒开放（尾随）或过程中的一个相邻的主裂纹，但在成交量的增加裂纹前沿的结果，这往往会关闭主裂纹。为了扩展阻力从而增加更远的裂纹。The most promising toughening mechanism for ceramic materials involves a phase transformation（相变）. The method is referred to as transformation toughening. Although other materials such as alumina can be transformation t

35、oughened, zirconia (zirconium dioxide, ZrO2) is the prototype（原型） material for this process. Pure zirconia, upon cooling below 1150, undergoes a dramatic three percent volume expansion as it transforms from a tetragonal （四方的）form to a monoclinic（单斜的） form. This expansion can be used to advantage by

36、dispersing extremely fine tetragonal particles in a matrix of cubic zirconia or alumina. The small size of the particles (less than 1 micrometer) and their intimate contact with the matrix induce the tetragonal structure to remain stable at room temperature.最有前途的增韧陶瓷材料包括相变（相变）。该方法被称为相变增韧。虽然其他材料，如氧化铝

37、可相变增韧氧化锆（锆，氧化锆，）是原型（原型）对这一过程的材料。纯氧化锆，在冷却到低于1150，经历了一个戏剧性的百分之三的体积膨胀，因为它从四方（四方的）形成单斜（单斜的）形式。这个扩展可以使用极细颗粒在分散四方立方氧化锆、氧化铝基的优势。小尺寸的颗粒（小于1微米）及其与基体紧密接触引起的四方结构在室温下保持稳定。Ahead of an advancing crack, however, a stress field（应力场） triggers the transformation of the embedded tetragonal particles to the monoclinic

38、form. Behind the advancing crack, a process zone forms in which all the tetragonal particles have transformed to the monoclinic form. The cumulative（累积的）increase in volume exerts a closing force on the advancing crack, as well as a corresponding resistance to crack propagation that increases with cr

39、ack length. Ceramics such as transformation toughened zircinia (TTZ) are often referred to as ceramic steel because the strain, or change in dimension, in response to stress behavior resembles that of steel instead of a brittle ceramic. Also, the underlying（基本的） phase transformation is called marten

40、sitic, after a similar transformation in rapidly quenched steel to a phase known as martensite.推进裂缝，然而，一个力场（应力场）触发嵌入式四方颗粒单斜形态的转型。在推进过程中形成裂纹，带所有四方颗粒转变为单斜晶系。累计（累积的）体积增加前进的裂纹施加的关闭力，以及相应的抗裂纹扩展，裂纹长度的增加。如相变增韧陶瓷zircinia（TTZ）通常被称为陶瓷钢由于应变，或尺寸变化，在应激反应中的行为相似，钢代替易碎的陶瓷。同时，底层（基本的）相变为马氏体，经过相似变换在快速淬火钢称为马氏体相。2 Funct

41、ional Ceramics2功能陶瓷Capacitors are devices that store electric energy in the form of an electric field generated in the space between two separated, oppositely charged electrodes. Their capacity to store energy makes them essential components in many electric circuits, and that capacity can be greatl

42、y increased by inserting a solid dielectric material into the space separating the electrodes. Dielectrics are materials that are poor conductors of electricity. The non-conducting properties of ceramics are well known, and some ceramics are made into extremely effective dielectrics. Indeed, more th

43、an 90 percent of all capacitors are produced with ceramic materials serving as the dielectric.电容器装置，将电能储存在电场中产生的形式之间的空间分离的两，带相反电荷的电极。他们储存能量的能力使他们在许多电路的重要组成部分，而能力可以大大增加通过插入一个固体介质材料在空间分离的电极。介质是电的不良导体材料。非导电性的陶瓷是众所周知的，和一些陶瓷制成的极为有效的介质。事实上，超过百分之90的所有电容器陶瓷材料作为介质产生。Piezoelectrics （压电体）are materials that gen

44、erate a voltage when they are subjected to mechanical pressure. Conversely, when subjected to an electromagnetic field, they exhibit a change in dimension. Many piezoelectric devices are made of the same ceramic materials as capacitor dielectrics.（压电体）压电材料产生电压，当受到机械压力。相反，当受到一个电磁场，它们表现出的尺寸变化。许多压电器件是由

45、相同的陶瓷材料作为电容器介质。It can be explained that low electric conductivity is a factor of the chemical bonds that form a material. In dielectrics, unlike in conductive materials such as metals, the strong ionic and covalent bonds holding the atoms together do not leave electrons free to travel through the ma

46、terial under the influence of an electric field. Instead, the material becomes electrically polarized（极化）, its internal positive and negative charges separating somewhat and aligning parallel to the axis of the electric field. When employed in a capacitor, this polarization acts to reduce the streng

47、th of the electric field maintained between the electrodes, which in turn raise the amount of charge that can be stored.它可以解释低电导率的材料的化学键的形成因素。在电介质中，不像在导电材料如金属，强烈的离子键和共价键原子绑在一起不离开的自由电子通过电场的影响下的材料。相反，物质变电极化（极化），其内部正负电荷分离点和对齐平行于电场的方向。当在一个电容器，这种极化作用降低电极之间保持电场强度，从而提高可储存的电荷量。Most ceramic capacitor dielect

48、rics are made of barium titanate (BaTiO3) and related compounds. In the case of BaTiO3, at high temperature (above approximately 120), the crystal structure consists of a tetravalent（四价） ion (Ti4+) sitting at the centre of a cube with the oxygen ions (O2-) on the faces and the divalent（二价） barium io

49、ns (Ba2+) at the corners. Below 120, however, a transition occurs. The Ba2+ and O2- ions shift from their cubic positions, and the Ti4+ ion shifts away from the cube centre. A permanent dipole（永久偶极子） results, and the symmetry of the atomic structure is no longer cubic (all axes identical) but rather

50、 tetragonal (the vertical axis different from the two horizontal axes). There is a permanent concentration of positive and negative charges toward opposite poles of the vertical axis. This spontaneous（自发的） polarization is known as ferroelectricity（铁电性）. The temperature below which the polarity is ex

51、hibited is called the Curie point. Ferroelectricity is the key to the utility of BaTiO3 as a dielectric material.大多数陶瓷电容器介质是由钛酸钡（BaTiO3）和相关化合物。在钛酸钡的情况下，在高温（约120以上），晶体结构由四价（四价）离子（Ti4+）坐在有氧离子（O2-）立方体中心的面和二价（二价）钡离子（Ba2+）在角落。120以下，然而，发生过渡。Ba2+和O2-离子从立方的位置，和Ti4+离子移出立方体的中心。永久偶极（永久偶极子）的结果，和原子结构的对称性不再是立方（所有

52、轴相同）而四方（垂直轴不同于两个水平轴）。有正电荷和负电荷向垂直轴的两极永久的浓度。这种自发极化（自发的）称为铁电性（铁电性）。温度低于该极性表现为居里点。铁电钛酸钡的效用是关键作为介电材料。3. Conductive Ceramics3。导电陶瓷In addition to the well-known physical properties of ceramic materialshardness, compressive strength（抗压强度）, brittlenessthere is the property of electric resistivity（电阻）. Most c

53、eramics resist the flow of electric current, and for this reason ceramic materials such as porcelain have traditionally been made into electric insulators. Some ceramics, however, are excellent conductors of electricity. Most of these conductors are advanced ceramics, modern materials whose properti

54、es are modified through precise control（精确控制） over their fabrication from powders into products.除了陶瓷材料硬度众所周知的物理性能，抗压强度（抗压强度），脆性有电阻率特性（电阻）。大多数陶瓷抵抗电流的流动，因为这个原因，陶瓷材料如瓷器通常被制成绝缘子。然而，一些陶瓷，是电的优良导体。大多数这些导体先进陶瓷，其性质是通过精确控制改进的现代材料（精确控制）在制备粉末产品。Electric conductivity in ceramics, as in most materials, is of two

55、types, electronic and ionic. Electronic conduction is the passage（通过） of free electrons through a material. In ceramics the ionic bonds holding the atoms together do not allow for free electrons. However, in some cases impurities of differing valence (that is, possessing different numbers of bonding

56、 electrons) may be included in the material, and these impurities may act as donors（施主） or acceptors（受主） of electrons. In other cases transition metals or rare earth elements of varying valency may （变价的过渡或稀土金属元素）be included. These impurities may act as centers for polarons（极子）-species of electrons t

57、hat create small regions of local polarization（局域极化） as they move from atom to atom. Electronically conductive ceramics are used as resistors（电阻器）, electrodes, and heating elements.在陶瓷的导电性，在大多数材料，分为两种类型，电子和离子。电子传导的通道（通过）通过材料的自由电子。在陶瓷中的离子键原子绑在一起不允许自由电子。然而，在某些情况下不同价态的杂质（即，具有不同数目的成键电子）可能在材料中，这些杂质可能作为供体

58、或受体（施主）（受主）电子。在其他情况下，过渡金属或稀土元素不同价态（变价的过渡或稀土金属元素）包括。这些杂质可能作为中心的极化子（极子）-种电子，造成局部极化小区域（局域极化）他们从原子到原子。电子导电陶瓷作为电阻（电阻器），电极，加热元件。Ionic conduction consists of the transit（输运） of ions (atoms of positive or negative charge) from one site to another via point defects called vacancies（空穴） in the crystal lattice

59、（晶格）. At normal ambient temperatures very little ion hopping （跃迁）takes place, since the atoms are at relatively low energy states. At high temperatures, however, vacancies become mobile, and certain ceramics exhibit what is known as fast ionic conduction（快离子导体）. These ceramics are especially useful in gas sensors, fuel cells（燃料电池）, and batteries.离子传导的运输（输运）离子（正或负电荷的原子）从一个站点到另一个通过点缺陷称为空位（空穴）晶格中（晶格）。在正常环境温度下很小的离子跳跃（跃迁）发生，由于原子是在相对较低的能量状态。在高温下，然而，空缺成为移动，和某些陶瓷展示了所