微波烧结制备MoSi及SiC/MoSi,纳米复合陶瓷
刘长虹艾云龙何文（南昌航空大学材料科学与工程学院，南昌330063）
文摘采用微波烧结法制备了MaSi,和10vol%SiC/MaSi,纳米复合陶瓷。通过SiC预加热体的混合式加热法和合理的保温结构设计，实现了MoSi,低湿阶段的快速升温，提高了温度均匀性。密度和力学性能测试结果表明，1450℃保温60min烧结工艺下，MoSi,试样的相对密度达到93.4%，断裂韧度4.5MPa*mV2，维氏硬度为10.53CPa，弯曲强度为186MPa。10vol%SiC/MoSi,试样尽管相对密度下降为90.3%，但各项力学性能均优于MoSi,试样。相比1650℃热压烧结，微波烧结温度降低了200℃，MoSi,和SiC/MoSi,试样致密性有所下降，但力学性能有较大提高，光其是MoSi,试样。断口扫描分析表明，徽波烧结试样相对热压烧结试样基体晶粒更细，孔腺细小且分布均匀；SiC/MoSi,试样微波烧结的晶粒细化效果不如MaSi,明显。
关键词微波烧结，力学性能，晶粒细化，SiC,MoSi,陶瓷
MicrowaveSinteringofMoSi,andSiC/MoSiNanocompositeCeramics
Liu ChanghongAi YunlongHeWen
(School of Material Science and Engineering, Nangchang Hangkong University,Nangchang330063)
Abstract MoSi, and SiC/MoSi, nanocomposite ceramics were prepared by microwave sintering.Hybrid heating using SiC as preheating material and reasonable design of heat preservation system realized the fast elevation of tem perature of MoSig on the low temperature stage, and enhanced the temperature unifomity of MoSig.Thedensity and mechanical properties tests showed that under the sintering parameters of 1 400°C and holding 60 min, the properties of pure MoSiz sample achieved relative density of 93.4%, fracture toughness 4.5 MPa·m'?, Vickers hardness 10.53 GPa, and bending strength 186 MPa. All the mechanical properties of 10vol. % SiC-MoSi, were superior to that of pure MoSiz, though the relative density decreased to 90. 3%. The temperature of microwave sintering MoSi, and SiC/ MoSi, samples decreased 200°C lower than hot-pressing sintering temperature (1 650°C ), but the mechanical proper ties are actually enhanced greatly, in particular MoSi,sample. Fracture surfaces indicated that compared to hot-press ing sintered samples, the microwave sintered samples presented refined grain size, fine and uniform pore, However the effect of grain refinement of microwave sintering to SiC/MoSi, is weaken compared to pure MoSi, sample
Key wordsMicrowave sintering,Mechanical property, Grain refining,SiC,MoSi, ceramics
0引言
MoSi,在航空领域中具有广泛的应用前景。复合化是改善其性能的有效途径，而SiC颗粒或晶须被认为是MoSi,基陶瓷材料最有发展前途的复合方法之。已有的研究表明，SiC/MoSi,系复合材料不仅强韧性得到较大改善[!]，而且表现出比MoSi,更好的抗氧化性。先进制备工艺的成熟和应用有助于更好的发挥MoSi,及其复合材料的性能潜力。微波烧结作
收稿日期：2011-09-07
基金项目：江西省自然科学基金资助项目(2009GZC0107）
为一种重要工艺手段，对结构陶瓷显示出巨大的潜力，尤其是对于制备高致密性、超细晶粒结构的高强度高韧性纳米陶瓷材料非常有利。微波烧结可解决常规烧结陶瓷致密性不高，导致材料性能无法充分发挥，热压烧结陶瓷难以满足各种成型，特别是航空航天对高温构件形状的要求等向题。但由于各种材料的微波介电特性不同，可应用微波烧结的网瓷材料种类并不多[2-7]。目前国内外有关MoSi,材料的改性等
作者商介：刘长虹，1978年出生，讲师，主要从事结构陶瓷制备及改性研究。E-mail;chliu29@163.coe
宇航材料工艺htp：//www.yhclgy.com2012年第3期
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