Dual-Wavelength In Situ Pyrometry During Additive Formation of Fibers by Laser-Induced Deposition

A dual-wavelength pyrometry system has been demonstrated for measuring the reaction zone temperature for a series of carbon and SiC fibers grown additively by hyperbaric-pressure laser-induced chemical vapor deposition. The results demonstrate an inverse relationship between reaction zone size and temperature measurement noise. Though the noise can obscure transient effects associated with unstable growth, use of individual wavelength signals has been demonstrated as a means to deconvolute these features. Consequently, the use of in situ temperature measurements helps to link the final morphology of the fiber to its real-time growth behavior.