【摘要】 先驱体聚铝碳硅烷经熔融纺丝、空气预氧化处理、1300℃烧成可制得SiC((OAl)纤维(称为KD—A),该纤维再经1800℃烧结转变为SiC(Al)纤维(称为KD-SA)．采用了元素分析、AES、SEM、XRD、RMS以及29Si、13C、27Al魔角自旋固体核磁共振等测试方法对纤维的组成和结构进行了研究．元素分析结果表明KD—A的化学组成为SiC1／31O0．25Al0．018, KD-SA为SiC1．03O0.013Al0．024．AES表明,KD-A和KD-SA的表面和内部组成不同． SEM 表明KD-A、KD—SA表面光滑平坦,没出现孔洞、裂纹、沟槽等表面缺陷．XRD、RMS以及29 Si、13C、27Al核磁共振的分析结果表明:KD—A包含较多的不定形游离C,O以不定形SiCxOy复合相的形式存在,Al与复合相中的O相连存在于复合相中,复合相在纤维中是连续相,少量的β-SiC微晶分散在其中,是非晶SiC纤维;KD-SA含有大量的β-SiC晶粒, 少量的α-SiC和Al2O3,是近化学计量比的多晶SiC纤维．更多还原

【Abstract】 A ceramic fiber with the SiC(OAl) composition, named KD-A, was prepared by the melt-spinning of precursor polyaluminocarbosilane, air-curing, and pyrolizing at 1300 ℃. The KD-A fiber was converted into SiC(Al) fiber, named KD-SA, by sintering at 1800 ℃. The composition and structure of the two kinds of fibers were characterized by chemical element analysis, AES, SEM, XRD, RMS, and 29Si, 13C, 27A1 MAS NMR. The compositions of KD-A and KD-SA fibers are in the formula SiC1.31O0.25Al0.018 and SiC1.03O0.013Al0.024, respectively. The compositions of KD-A and KD-SA fibers on the surface are different from that of inside of the fibers. The surfaces of KD-A and KD-SA fibers are smooth and even, and there are no hole, crack and groove. KD-A fiber contains free carbon, small amount of β-SiC micro-crystal and aluminium embedded in an intergranular phase SiCxOy, which is ascribed to a non-crystalline SiC fiber. KD-SA fiber contains a large number of β-SiC, a small amount of α-SiC and Al2O3, which is ascribed to a crystalline SiC fiber with a nearly stoichiometric composition.更多还原