英语翻译The important thermal properties to materials are:.Heat

英语翻译
The important thermal properties to materials are:
.Heat resistance ,the ability of a material to remain atable with changes in temperature .Ceramic materials have high resistance ratings .
.Thermal conductivity ,the ability of a material to transfer heat energy along its lwngth ,width ,or thickness .The rate of heat transfer for a material is called its coefficient of thermal conductivity.Metals have high coefficients of themal conductivity.Ceramics and polymers have low conductivity rates .they are therefore good heat insulators .
Thermal expansion,the rate of size change per unit of heat applied.Almost all engineering materials expand as they are heated .The rate of expansion is called the coefficient of linear expansion .The rate of expansion varies greatly among materials.
The varying rates of thermal expansion are the basis of the bimetal thermostat .The metal stripe of the thermostat have greatly different thermal expansion coefficients .When they are the other strip .This causes the strips to bend and touch the contact point .This action closes an electric circuit which could start a furnace ,turn on a cooling fan ,or light a warning light.
Electric and magnetic properties
Electrical and magnetic properties are similar .The electrical properties describe the behavior of a material carrying an electrical current .Magnetic properties involve the behavior of materials in an electromagnetic field .These properties include :
.Electrical conductivity the ability to conduct an electric current .Engineering materials are classified as conductors and insulators .Other materials are called semiconductors and are the foundation of the computer and data processing industry.
The opposite of electrical conductivity is electrical resistivity .If resistivity is an important property ,it is often discussed as the dielectric property or strength.The dielectric strength is a specific measure of a material's electrical insulating qualities .Metals generally are considered considered conductors of electricity while ceramics and polymers are insulators .
.Magnetic properties the ability to be magnetized by an external electromagnetic force .Materials with high magnetic properties are said to be permeable or have high permeability .Iron ,nickel ,and cobalt which are called ferromagnetic materials have high permeability.They are easily magnetized .

对材料的重要热性能：
.耐热性,一个物质的能力保持atable与温度的变化.陶瓷材料具有高电阻率.
.热导率,材料的传热能力的能源沿lwngth,宽度,或厚度.在传热率的材料被称为它的导热系数.具有金属热传导系数高.陶瓷和聚合物的导电率低.因此,他们良好的热绝缘体.
热膨胀,热面积每单位变化率应用.几乎所有的工程材料扩大,因为它们被加热.扩张速度被称为线膨胀系数.扩张速度参差不齐材料.
热膨胀的速率是不同的双金属温控器的基础.恒温的金属条带,大大不同的热膨胀系数.当他们在其他地带.这将导致带弯曲,接触的联络点.这一行动结束通电可以开始冷却风扇,或轻警告灯一炉,转.
电场和磁场特性
电磁特性是相似的.电性能的描述一个携带电流材料的行为.磁学性质涉及的材料的电磁场的行为.这些属性包括：
.导电能力进行电流.工程材料被列为导体和绝缘体.其他材料被称为半导体,是计算机和数据处理产业的基础.
在相反的是电导率电阻率.如果电阻是一个重要的属性,它往往是作为电介质强度财产或讨论.电介质强度是一个材料的电绝缘特性的具体措施.金属通常被认为认为,电力导线,而陶瓷和聚合物绝缘体.
.磁学性质的能力被磁化由外部电磁力.高磁性材料说成是渗透或高渗透.铁,镍,钴和被称为铁磁材料具有高渗透性.他们容易被磁化