Silicon carbide fibers

Question 1

What are the characteristics of silicon carbide fibers?

Answer 1

~ SiC fibers have high tensile strength, high elastic modulus, and good thermal stability

Question 2

What is the Yajima process?

Answer 2

~ liquid polyme is injected through a spinneret to produce solidified green fibers

~ significant time in high temp furnaces converts the polymer (cross-linking, pyrolysis, and sintering) to Si-C-O

~ then typical temp limit is ~1200C, with degrading properties starting at 1000C

Question 3

What are oxygen free SiC fibers?

Answer 3

~ consist mainly of β-SiC microcrystals and amorphous carbon

~ produced from polycarbosilane by electron beam curing and pyrolysis

~ these fibers have improved thermal stability (long term strength retention to 1500-1600C)

~ fibers are typically smaller than 20um. They are coated with polymer-based sizings. They are supplied as multi-filament (300+) twisted tows on a spool, or as woven cloth