摘要
热膨胀系数是材料的重要参数之一,自然界中,绝大多数物质都具有较高的热膨胀系数,热胀冷缩的情况较为严重,因此,这类物质通常具有较差的抗热冲击性,不能在温度变化巨大的环境下使用。如不均匀的温度分布和大的温度变化会引起航空航天器件结构破坏和电子设备的几何热变形,从而造成信号失真。然而自然界中,也存在少数具有负热膨胀系数的物质。这类材料的体积会随着温度的升高而减小。利用热膨胀系数的加和性,可将具有低热膨胀系数或负热膨胀系数的材料与高热膨胀系数的材料复合,得到热膨胀系数可调的复合材料,可显著提高其抗热震性。负热膨胀材料分为各向同性负热膨胀材料和各向异性负热膨胀材料。各向同性负热膨胀材料主要是ZrV 2-x P x O 7和ZrW 2O 8系列,各向异性负热膨胀材料主要包括β-锂霞石、钙钛矿系列、A 2M 3O 12系列、M(CN)2(M=Zn,Cd)系列、氧化物、沸石系列和金属有机框架结构材料(MOFs)等。其中,β-锂霞石因其具有较大的负热膨胀系数(α=-6.1×10-6 K-1)、较低的密度(2.67 g/cm 3)、良好的抗热震性、介电性能及红外辐射,常被用作调节复合材料热膨胀系数的材料。β-锂霞石可与其他材料复合,制备出具有负热膨胀或接近“零膨胀”的复合材料,极大地提高材料的抗热震性和尺寸稳定性,进而提高材料的使用寿命。因此,β-锂霞石常被用来制备一些低膨胀陶瓷、微晶玻璃、金属基等复合材料,用于电气设备、电子元件、导弹天线罩涂层材料、激光陀螺仪和天文望远镜等领域。同时,由于β-锂霞石的各向异性热膨胀特性,复合材料中存在较多的残余应力从而使其机械强度下降。为了解决这个问题,可在复合材料中继续引入机械强度较高的纤维或晶须来提高其机械强度,形成三相复合的低膨胀、高机械强度的复合材料。这将进一步拓展此复合材料在惯性导弹、光纤陀螺等航空航天中的应用。本文主要综述了β-锂霞石在金属、玻璃以及陶瓷低膨胀两相或三相复合材料领域的研究现状及进展,概述了这几类低膨胀系数复合材料的制备工艺、热学性能、力学性能及应用领域,对β-锂霞石基复合材料未来的发展趋势及应用前景进行了展望。
Thermal expansion coefficient is one of the important parameters of materials.In nature,most materials exhibit high thermal expansion coefficient which would lead to the phenomenon of thermal-expansion and cold-contraction.Therefore,these materials usually have poor thermal shock resistance and cannot be used in the environment with great temperature changes.The signal distortion usually occurs because of the destruction of aerospace components and the deformation of electronic device resulted from the uneven temperature distribution.It is exciting that there are a few materials with negative thermal expansion coefficient,and their volume decreases with the increase of temperature.Based on the additivity of the expansion coefficient,the compounds with low coefficient of thermal expansion can be obtained by introducing the material with low or negative coefficient of thermal expansion into the high ones,which can remarkably improve their thermal shock resistance.Negative thermal expansion materials include isotropic negative thermal expansion materials and anisotropic negative thermal expansion mate-rials.Isotropic negative thermal expansion materials are mainly ZrV 2-x P x O 7 and ZrW 2O 8 series.Anisotropic negative thermal expansion materials mainly includeβ-eucryptite,perovskite series,A 2M 3O 12 series,M(CN)2(M=Zn,Cd)series,oxides,zeolite series and metal organic frameworks(MOFs),etc.Theβ-eucryptite is usually used to adjust the thermal expansion coefficient of composite materials owing to its negative thermal expansion coefficient(α=-6.1×10-6 K-1),low density(2.67 g/cm 3),good thermal shock resistance,dielectric properties and infrared radiation.Composite materials with negative thermal expansion or near zero thermal expansion can be fabricated by compounding with other materials,which can greatly improve the thermal shock resistance and dimensional stability of the materials,and thus prolong the life of the materials.Therefore,β-eucryptite has been used to manufacture low expansion ceramics,glass-ceramics,metal matrix composites applied as fillers for electrical equipment,electronic components,device sealants,aircraft high precision components,humidity sensor sensitive materials and lithium ion battery so-lid electrolytes.At the same time,due to the anisotropic thermal expansion property ofβ-eucryptite,the composites will have more residual stress and lower mechanical strength.In order to solve this problem,fibers or whiskers with high mechanical strength can be introduced to form three-phase composites with low expansion and high mechanical strength,which is beneficial to expand the application of materials in inertial missiles,optic fiber gyro and other aerospace applications.In this paper,the research status and progress of the low expansion two-phase or three-phase composites of metals,glass and ceramics are reviewed.The preparation method,thermal properties and application fields of these low expansion coefficient composites are summarized.The future development trends and application prospects of the composites are also discussed.
作者
薛耀辉
蒋军彪
张辉
文昌秀
苏宗锋
崔晓霞
郭海涛
XUE Yaohui;JIANG Junbiao;ZHANG Hui;WEN Changxiu;SU Zongfeng;CUI Xiaoxia;GUO Haitao(Xi’an Modern Control Technology Research Institute,Xi’an 710065,China;Xi’an Institute of Optics and Precision Mechanics,Chinese Academy of Sciences(CAS),Xi’an 710119,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第5期68-77,共10页
Materials Reports
基金
国家自然科学基金委面上项目(61475189)
中国科学院西部之光基金
陕西省自然科学基金青年科学基金项目(2014JQ8345)
中科院光谱成像重点实验室开放基金~~
关键词
β-锂霞石
负热膨胀
复合材料
β-eucryptite
negative thermal expansion
composites
作者简介
薛耀辉,西安现代控制技术研究所高级工程师。2005年在清华大学获得材料学硕士学位,2012年在西安交通大学获得微电子与固体电子学博士学位。目前主要从事光纤通信与光纤传感技术研究;崔晓霞,博士,中国科学院西安光学精密机械研究所副研究员、硕士生导师。2010年在西安光机所获得光学专业博士学位,同年进入中国科学院西安光机所瞬态光学重点实验室先进光电与生物材料研发中心工作。目前从事纳米功能材料及玻璃复合材料的研究工作,近年来,在纳米材料领域发表学术论文40余篇,包括J.Mater.Chem.,Nanoscale,Opt.Lett.和Opt.Express等,cuixx@opt.ac.cn。
