New class of funCtionAl silicon caRBOnitride-based ceramic FIBErs from oRganometal compound-modified polySilazanes

无氧化物陶瓷纤维已广泛应用于陶瓷基复合材料的增强。尽管在过去的几年里，人们在开发新的无氧化物陶瓷纤维方面做出了相当大的努力，但它们在工业水平上的应用仅限于碳化硅（SiC）纤维。但SiC纤维非常昂贵（从1.5欧元到10欧元/公斤），这取决于纤维的质量，主要是因为生产由日本公司主导，没有其他国家的替代产品。为了降低纤维的成本并在这个专题上具有竞争力，本项目建议调动欧洲学术研究人员，特别是法国和德国的研究人员的活动和资源。该项目涉及设计、加工和研究一类具有额外功能特性的具有成本效益的新型聚合物衍生的非氧化物陶瓷纤维的性能。所提出的材料有望用作具有电和磁性能的热结构应用的增强材料。为了满足上述应用的要求，所获得的纤维需要结合在侵略性和恶劣环境中的耐久性，同时实现功能特性，如导电性和磁性。这些性能可以通过用金属有机化合物修饰（Si-(B/Al)- c - n）聚合物来实现，导致功能纳米相的原位生长，同时在热解过程中形成相应的陶瓷SiCN（B/Al）基体。为了达到我们的目标，这个项目被分为五个相互关联的科学任务。第一个任务（Ta1）集中于金属修饰预陶瓷聚合物的合成和表征（通过核磁共振、红外光谱、分子量测量和元素分析）。第二个任务（Ta2）涉及聚合物纤维的熔融纺丝和固化，通过对合成的预陶瓷聚合物的流变学研究来优化纺丝工艺。任务3 （Ta3）的重点是将Ta2中制备的固化聚合物纤维转化为所需的含金属功能化陶瓷纤维。将通过FTIR， TG-GC/MS和固态核磁共振对聚合物到陶瓷的转化进行详细的研究。任务4 （Ta4）致力于陶瓷纤维的表征，涉及机械和（纳米）结构性能以及含金属SiCN（B/Al）纤维的功能，特别是其电气和磁性能。Ta5处理陶瓷纤维转化的过程建模。

Non-oxide ceramic fibers have been widely used for the reinforcement of ceramic matrix composites (CMCs). Despite considerable efforts to develop new non-oxide ceramic fibers in the last few years, their use at industrial level exclusively concern silicon carbide (SiC) fibers. But SiC fibers are very expensive (from 1.5 to 10 kEuro/kg) depending on the quality of the fibers, mainly because the production is dominated by companies from Japan with no alternative products from other countries. To reduce the costs of the fibers and to be competitive on this topic, a mobilization of activities and resources of the academic European researchers, especially from France and Germany, is proposed in the present project. This project concerns the design, processing and investigation of the properties of a new class of cost-effective polymer derived non-oxide ceramic fibers with additional functional properties. The proposed materials are expected to be used as reinforcement for thermostructural applications with electrical and magnetic properties. To meet the requirements for the applications mentioned above the obtained fibers need to combine durability in aggressive and harsh environments while achieving functional properties, such as electrical conductivity and magnetic properties. These properties can be achieved through the modification of (Si-(B/Al)-C-N) polymers with metal-organic compounds, leading to the in-situ growth of the functional nanophase simultaneously with the formation of the respective ceramic SiCN(B/Al) matrix during pyrolysis. To reach our objectives, the project is divided into five interconnected scientific tasks. The first task (Ta1) is focused on the synthesis and characterization (through NMR, FTIR, molecular weight measurements and elemental analyses) of the metal-modified preceramic polymers. The second task (Ta2) deals with the melt-spinning and curing of the polymer fibers, as the optimization of the spinning process by means of rheological investigation of the synthesized preceramic polymers. Task 3 (Ta3) is focused on the conversion of the cured polymer fibers prepared in Ta2 into the desired metal containing functionalized ceramic fibers. Detailed investigation of the polymer-to-ceramic conversion will be achieved through FTIR, TG-GC/MS and solid-state NMR. Task 4 (Ta4) is dedicated to the characterization of ceramic fibers, concerning the mechanical and (nano)structural properties and the functionalities of the metal-containing SiCN(B/Al) fibers, in particular their electrical and magnetic properties. Ta5 deals with the process modeling of the ceramic fiber transformation.