Abstract: A crack self-healing functionally gradient material for ceramic cutting tools and a preparation method thereof. The material for ceramic cutting tools has a symmetrical gradient structure, and based on the percentage by mass, components of each layer include 50%-80% of Ti(C7,N3), 25%-5% of (W7,Ti3)C and 20%-0% of TiSi2; contents of components of layers that are symmetrical relative to a central layer are the same and a thickness is symmetrically distributed; a content of Ti(C7,N3) gradually increases from the surface layer to the central layer, contents of (W7,Ti3)C and TiSi2 gradually decrease by 5% from the surface layer to the central layer, and the contents of Ni and Mo gradually increase from the surface layer to the central layer.

Abstract: This invention relates to an three-constituent adduct of a metallocene.an ether.an metal halide having the general formula of Cp'MQ.sub.2.RXR'.nM'Q.sub.2/n, where Cp' is a substituted or an unsubstituted dicyclopentadienyl, M is zirconium or titanium, RXR' is tetrahydrofuran or diethylether, M' is alkali metal or alkali earth metal, n=1 or 2. The adduct can be exposed to air for several hours or stored in nitrogen atmosphere for a long period of time, which is prepared by means of a simple and convenient process without further separation and purification and used directly as a catalyst for polymerization of olefins.