Effect of surface roughness on the strength of sapphire fiber

Abstract

In this work, sapphire fibers formed using the modified Stepanov/EFG method were tested for strength. A study of the surface of sapphire fibers obtained from the melt shows that the roughness of the fibers arises mainly due to its fluctuation in ascending gas flows during the growth process. The paper investigates the effect of fiber surface roughness on its strength. To reduce the roughness, the fiber diameter stabilization system was used, which enable to reduce the roughness parameters to tens of nanometers. When testing according to the original method, it was found that a decrease in the surface roughness of the fiber leads to an increase in its strength. And the strength of the fibers decreases with length in a power law.