Abstract: Diamond and ceramic whiskers 712 are grown on diamond, ceramic, or metal coated 714 fibers 710 (e.g. carbon, glass, ceramic or metal fibers) and used in composites 700. The whiskers 712 1) increase fiber-matrix bonding, 2) maintain fiber separation and 3) provide uniform fiber distribution. The coating 714 1) improves the mechanical properties of the fiber and 2) protects the fiber 710 from corrosive attack by the matrix material 720. A catalytic process for growing whiskers 712 allows fiber strength to be maintained during the whisker growth process. Composite materials made with whiskered or coated and whiskered fibers are useful whenever light-weight and high strength materials are required.