Ceramic Fibers Based on SiC and SiCN Systems: Current Research, Development, and Commercial Status (original) (raw)

Characterization of nearly stoichiometric SiC ceramic fibres

Journal of Materials Science, 2001

A comparative study of the chemical composition and microstructure of Hi-Nicalon, Hi-Nicalon type S, Tyranno SA, Sylramic and Carborundum fibres has been conducted. This analysis has confirmed results already published but has also evidenced some original features. The Hi-Nicalon type S fibre has a near stoichiometric composition but it still contains some oxygen (˜1 at. %) and free carbon (˜2

Research Progress in SiC-Based Ceramic Matrix Composites

Journal of the Korean Ceramic Society, 2012

SiC-based ceramic matrix composites show many advantages over their monolithic ceramic counterparts, which makes them potential candidates for applications in various fields. Depending strongly on the chemical composition and microstructure of the fiber reinforcement, matrix as well as the fiber/matrix interphase in the material, the properties of ceramic matrix composites(CMCs) are highly tailorable. In this paper, the latest progresses in the interphase design, matrix modification and fiber reinforcement decoration of CMCs are reviewed, their effects on the properties of the CMCs are introduced.

Behaviors of SiC fibers up to high temperature

Owing to progress in the manufacturing on SiC fibers, the mechanical and thermal behaviors of SiCf/SiCm composites have been sharply improved. Besides, regarding their physical and chemical properties and their stability under irradiation, SiC/SiC composites are potential candidates for nuclear applications in advanced fission (Generation IV) and fusion reactors (ITER). CEA must characterize and optimize them before their uses in reactors. In order to study these materials, CEA is developing a multi-scale modeling from fibers to bulk composite specimens. In this approach, the fiber behaviors must firstly be well known. The purpose of this paper is to present a review of the studies led by the CEA about the behaviors of SiC fibers. Thus, CEA has developed a specific device, named MecaSiC, for tensile testing single fibers up to high temperature.

Synthesis of SiC fibre with low oxygen content and high tensile strength using a polyblend precursor

Journal of Materials Science, 1991

SiC fibre with low oxygen content and high tensile strength was first synthesized in our laboratory. The SiC fibre was obtained by using a polyblend of polycarbosilane (PC) and hydroxy-terminated-polybutadiene (HTPB) as a precursor. It was found that PC could react with HTPB to form cross-linked polymers at temperatures around 260 ° C, so the HTPB can be used as a curing agent. Consequently, the need for oxygen to be introduced in the air-curing process is reduced and SiC fibre with low oxygen content and higher tensile strength can be made. The chemical compositions, the oxidation resistance and chemical stability of the SiC fibre were also studied here.

Thermal behaviour of advanced composite materials based on SiC fibres

Journal of thermal …, 2003

Emanation thermal analysis (ETA) was used for characterization of thermal behaviour of SiC f /SiC composites on heating in argon and air, respectively. Effect of gas environment (argon, air) and helium ions implantation on the microstructure development of the SiC f /SiC composite prepared by chemical vapour infiltration (CVI) from Nicalon CG fibres was investigated under in situ conditions of heating. The annealing of near surface structure irregularities was observed in the range 280-700°C and evaluated by means of the mathematical model, assuming that the structure irregularities served as diffusion paths for radon. The ETA reflected the formation of amorphous silica and its subsequent crystallization to crystoballite. Morphology of the SiC f /SiC samples before and after the heat treatments was characterized by means of SEM.

Characterization and application of a novel low viscosity polysilazane for the manufacture of C- and SiC-fiber reinforced SiCN ceramic matrix composites by PIP process

Journal of the European Ceramic Society

Four unidirectional fiber reinforced SiCN ceramic matrix composites were manufactured by means of polymer infiltration and pyrolysis. Two carbon fibers (T800H and Granoc XN90) as well as two silicon carbide fibers (Tyranno ZMI and SA3) without fiber coating were chosen. As matrix precursor, a poly(methylvinyl)silazane was investigated and utilized. The composites with the SA3 and the XN90 fiber had the highest tensile strengths of 478 and 288 MPa, respectively. It is considered that these high modulus fibers with the low modulus SiCN matrix create weak matrix composites. After exposure to air (T = 1200°C, 10 h), a significant decrease of the mechanical properties was found, caused by the burnout of carbon fibers and the oxidation through open pores stemming from the PIP process and SiCN/SiCN interfaces in case of the SiC fiber based composites. CMCs at 1200°C is investigated. For the application in jet engines, such CMCs are equipped with additional environmental barrier coatings . Since CVD-SiC coatings have proven to successfully protect in-house manufactured C/C-SiC composites under re-entry conditions, combustion chamber conditions or utilized as nozzle extension, half of the manufactured SiCN based composites were coated with CVD-SiC and compared to those without coating .

Are short Hi-Nicalon SiC fibers a secondary or a toughening phase for ultra-high temperature ceramics?

2014

This paper deals with the effect of the addition of Hi-Nicalon SiC fibers to Zr-and Hf-borides. The main scope is to understand the fiber/matrix chemical interaction and correlate it to the fracture toughness. Transmission electron microscopy (TEM) was used as key investigation tool to disclose the microstructural features at nanoscale level. Several sintering additives were used to enable densification in the temperature range 1600-1850°C. It was observed that the fiber strongly reacts with the matrix at the same temperature at which the sintering additive starts to be effective. At this point, the fibers themselves locally behave as sintering aid promoting a strong fiber/matrix bonding which prevents any possibility of fiber pullout. Fiber modification was correlated with the fracture toughness and it was at last deduced that these fibers exert a toughening action only when the sintering temperature is kept below 1700°C. Above this temperature fibers start to significantly degrade and can be considered just as a secondary phase.