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Abstract In this study, multifibrillar carbon and carbon/ceramic (C/SiCON) fibers consisting of thousands of single nanofibers are continuously manufactured. The process starts with electrospinning of polyacrylonitrile (PAN) and PAN/oligosilazane precursors resulting in poorly aligned polymer fibers. Subsequent stretching leads to parallel aligned multifibrillar fibers, which are continuously stabilized and pyrolyzed to C or C/SiCON hybrid fibers. The multifibrillar carbon fibers show a high tensile strength of 911 MPa and Young’s modulus of 154 GPa, whereas the multifibrillar C/SiCON fibers initially have only tensile strengths of 407 MPa and Young’s modulus of 77 GPa, due to sticking of the nanofibers during the stabilization in air. Additional curing with electron beam radiation, results in a remarkable increase in tensile strength of 707 MPa and Young's modulus of 98 GPa. The good mechanical properties are highlighted by the low linear density of the multifibrillar C/SiCON fibers (~ 1 tex) compared to conventional C and SiC fiber bundles (~ 200 tex). In combination with the large surface area of the fibers better mechanical properties of respective composites with a reduced fiber content can be achieved. In addition, the developed approach offers high potential to produce advanced endless multifibrillar carbon and C/SiCON nanofibers in an industrial scale.

Polysilazane-based coatings exhibit excellent mechanical properties and chemical resistance, but thermal curing limits their range of applications. Therefore, the aim of the study was to evaluate the more resource-efficient curing of polyorganosilazane-based coatings on a stainless-steel substrate by photo-induced thiol-ene “click” reaction at room temperature compared to the conventional thermally induced polymerization using a radical initiator. As expected crosslinking at higher temperatures led to the formation of a pronounced Si-O-Si network. However, crosslinking via UV radiation at room temperature suppressed the incorporation of oxygen remarkably also after a subsequent additional treatment at 135 °C in air. Both the chemical stability of the layers cured by means of UV radiation and the mechanical properties are comparable to those of the thermally crosslinked coatings. Therefore, curing using UV radiation at low temperatures is a suitable alternative method for producing protective coatings on substrates with limited thermal stability.