Preparaetion of Precursor Fiber for SiC Fiber Reinforced Ni-Cr-Al Alloy Composites

Abstract:

SiC_f/Ni-Cr-Al precursor wire has been obtained by deposition of (Al+Al₂O₃) diffusion barrier layers and Ni-Cr-Al alloy coating on the surface of SiC fiber via magnetron sputtering. The morphology, composition and the phase of coatings were studied, and the influence of the coatings on the mechanical property of SiC fiber was investigated. The precursor wires were treated in vacuum at 850℃ and 900℃ for 150 hours. The results show that (Al+Al₂O₃) coating is uniform and dense, the Al₂O₃ coating is in the form of amorphous,and the composition of Ni-Cr-Al alloy coating is close to that of Ni alloy target. The (Al+Al₂O₃) layer and Ni-Cr-Al layer combine well with SiC fiber and have extremely slight negative effect on the tensile strength. After heat treatment in vacuum, the Ni-Cr-Al alloy coating remains intact, and Al₂O₃ coating effectively blocks the element diffusion and restricts the reaction between SiC fiber and Ni-Cr-Al alloy, which can ensure the preparation of high performance of SiC_f/Ni-Cr-Al composites.

Key words:magnetron sputtering; SiC fiber; composite; diffusion barrier coating; precursor wire