SiC纤维烧结陶瓷的制备及其性能研究  

Preparation and Performance of Sintered SiC Fiber-bonded Ceramics

作　　者：李伟[1] 许志明 苟燕子[1] 尹森虎 余艺平 王松[1] LI Wei;XU Zhiming;GOU Yanzi;YIN Senhu;YU Yiping;WANG Song(Science and Technology on Advanced Ceramic Fiber and Composites Laboratory,College of Aerospace Science and Engineering,National University of Defense Technology,Changsha 410073,China)

机构地区：[1]国防科技大学空天科学学院,新型陶瓷纤维及其复合材料重点实验室,长沙410073

出　　处：《无机材料学报》2025年第2期177-183,共7页Journal of Inorganic Materials

基　　金：湖南省自然科学基金(2023JJ30634)。

摘　　要：SiC纤维烧结陶瓷(Fiber-bonded ceramics,FBCs)是由SiC纤维直接烧结而成的一种新型SiC材料,材料中不存在基体相,其孔隙率小于3%且纤维体积分数超过90%,具有耐高温、高强度、抗氧化与耐辐照等优异性能,是未来航空发动机和先进核能领域的重要候选材料。本工作在国内率先开展SiC FBCs的制备以及性能研究,以国产KD-SA型第三代含铝SiC纤维为原料,通过预处理在纤维表面原位构筑石墨(in-situ graphite,iG)层,采用热压烧结工艺直接烧结纤维,制备SiC(Al)FBCs。实验表征了纤维及材料的宏/微观结构,测试了材料的力学与氧化性能。结果表明:通过预处理SiC(Al)纤维,iG/SiC(Al)纤维表面可生成厚度为300~400 nm的碳层,且iG层与纤维结合较好。采用热压烧结工艺制备的iG/SiC(Al)FBCs密度为3.15 g/cm^(3),气孔率仅为0.52%,基体完全致密,纤维发生变形呈六棱柱状,且纤维之间有明显的界面;材料弯曲强度、断裂韧性与断裂功分别为320 MPa、9.5 MPa·m^(1/2)与1169 J·m^(-2);经1500、1600℃空气氧化100 h,材料弯曲强度保留率分别高达86%与72%,且维持伪塑性断裂模式。SiC fiber-bonded ceramics(FBCs),representing a novel class of SiC materials,synthesized via direct sintering of SiC fibers and characterized by lack of a matrix phase,porosity below 3%and fiber volume fraction exceeding 90%,exhibit remarkable properties,including high-temperature resistance,high strength,and robust resistance to oxidation and irradiation.Consequently,they are a promising contender for future aero-engine and advanced nuclear energy applications.Herein,SiC(Al)FBCs were prepared by pre-treating the fibers to form in-situ graphite(iG)layers on their surface,followed by direct sintering the fibers using a hot-press sintering process.Then,macroscopic/microscopic structures,mechanical properties and oxidative properties of the fibers and bulk ceramics were characterized.The results show that pre-treatment of SiC(Al)fibers leads to forming a 300-400 nm thick carbon layer,adhering well to the fibers.Density of the hot-press sintered iG/SiC(Al)FBCs is 3.15 g/cm^(3),with a porosity of only 0.52%.Meanwhile,the matrix is completely dense,the fibers are deformed in a new form of hexagonal prisms,and the well-defined interfaces are present between the fibers.Furthermore,bending strength,fracture toughness,and work of fracture of the bulk ceramics are 320 MPa,9.5 MPa·m1/2 and 1169 J·m^(-2),respectively.After oxidation at 1500 and 1600℃for 100 h in air,the retention rates of the flexural strength remain as high as 86%and 72%,respectively,while maintaining a quasi-plastic fracture mode.

关 键 词：SIC纤维 SiC纤维烧结陶瓷 力学性能 氧化性能 

分 类 号：TB35[一般工业技术—材料科学与工程]