摘要
聚硅碳硅烷 (PSCS)与乙酰丙酮铝 (Al(AcAc) 3 )在一定条件反应制备了耐高温SiC(Al)纤维先驱体聚铝碳硅烷 (PACS)。PACS通过熔融纺丝、预氧化处理、低温烧成、高温烧结等一系列工艺过程制备了耐高温SiC (Al)纤维。SiC (Al)纤维的化学组成为Si1C1 15O0 0 2 6Al0 0 13 ,主要结构是平均晶粒为 95nm的 β SiC ,O和游离C含量均大大低于Nicalon纤维 (O >10wt% ,游离C >10wt% ) ,同时含有微量的Al和少量的 α SiC。纤维表层O含量和Si含量略高于纤维内部 ,表面光滑平坦 ,没有明显表面缺陷。SiC (Al)纤维的平均直径为 13μm ,平均强度为 2 3GPa ,14 0 0℃氩气中处理 1h ,强度保留率 95 %以上 ;180 0℃氩气中处理 1h ,强度保留率为 71%。纤维的高温稳定性高于Nicalon纤维 。
The precursor, Polyalumicarbosilane (PACS) of super-high temperature resistance SiC(Al) fibers was synthesized by the reaction of polysilocarbosilane, or PSCS, with Al(AcAc)_3. The process to prepare SiC(Al) fibers by PACS is in four steps: (1)Melt-spinning of PACS into “green fibers”, (2) Curing the fibers to make fibers infusible, (3) Pyrolysis of the cured fibers at 1300℃ in inert atmosphere, (4) Sintering of the pyrolyzed fibers. The composition of SiC(Al) fibers is described in the formula Si_1C_(1.15)O_(0.026)Al_(0.013), in which there are mainly β-SiC grains in size of 95nm, 0.87wt% aluminum, small amount of α-SiC, SiC_xO_y phase and free carbon. The content of SiC_xO_y phase and free carbon is much lower than that of Nicalon fibers. The content of oxygen and silicon on the surface of the fibers is some higher than inside; while Si, C, O and Al are uniformly distributed inside the fibers. The average tensile strength of SiC(Al) fibers is 2.3 GPa, with the average diameter 13 μm. The initial tensile strength of the fibers remains 95% after the treatment at 1400℃ for 1h in argon. After sintering at 1800℃ for 1h in argon, SiC(Al) fibers remain the initial tensile strength by 71%. The high temperature stability of the fibers is better than that of Nicalon, but inferior to that of Tyranno SA.
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2004年第5期79-82,共4页
Acta Materiae Compositae Sinica
基金
国家自然科学基金资助项目 ( 5 9972 0 42 )
关键词
SiC(Al)纤维
耐高温
性能
SiC(Al)fibers
high-temperature resistance
performance
