Hi-Nicalon™ SiC Fiber

HI-NICALON™ ceramic fiber is primarily designed to be used as reinforcements for high temperature ceramic composites. It can also be used as a reinforcement for plastic, and metal matrix composites. Surface treatments are normally recommended to facilitate processing and maximize composite properties. The fiber can also be used to form fibrous products such as high temperature insulation, filters, etc. Its resistance to chemical attack allows it to be used in harsh environments. Typical fiber properties are shown in Table 1.

HI-NICALON™ fiber can be incorporated as the reinforcement for a variety of ceramic composites. Standard CMC processing techniques, such as sol-gel, chemical vapor infiltration, melt infiltration, or polymer infiltration can be used, depending on the user’s needs and capabilities. Candidate matrix materials include silicon carbide, silicon nitride, alumina, glasses, and others. Fiber surface treatments are generally removed before making CMC’s, such as by heating to 600⁰C for 30 minutes. Fiber interface coatings, such as BN, are generally applied to the fiber to achieve optimum CMC properties. The specific fiber type and the specific CMC processing technique is best determined by the user.

Weaving, Braiding, and Coating As textile grade yarn, HI-NICALON™ fiber can be readily incorporated into a large variety of woven tapes, braids, etc. Specialty interface coatings such as BN (often recommended for optimum CMC mechanical properties) may be applied to the tow or cloth. A network of US contractors exists to respond to customer needs. Contact COI Ceramics to discuss specific needs and receive further information.

CMC’s reinforced with HI-NICALON™ ceramic fiber offer distinct advantages over other materials. Oxide fiber and super alloys generally lose mechanical properties above 800⁰C. SiCO fiber generally loses properties above 1000⁰C. 100 micron diameter monofilament SiC fiber is generally not possible to weave