Stepwise synthesis of a Zr–C–Si main chain polymer precursor for ZrC/SiC/C composite ceramics

Abstract

Novel polymers containing a refractory metal in the main chain are highly desired as ultra-high temperature ceramic precursors. Herein, a low oxidation state active species Cp₂Zr(II) with two semi-filled outer orbits was firstly obtained using Cp₂ZrCl₂ with Mg. This active species of Cp₂Zr(II) was subsequently copolymerized with (CH₃)₂Si(CH₂Cl)₂ to form a PZCS precursor with a Zr–C–Si main chain. The pathways of constructing the Zr–C–Si main chain were proposed based on the active species Cp₂Zr(II) polymerization combined with the auxiliary function of ·MgCl, quite different from the conventional understanding of using the Grignard reaction mechanism to explain the synthesis of metal-containing polymer precursors. The ceramic yield of the PZCS precursor at 900 °C is 43.9 wt%, and the ZrC/SiC/C composite preceramic powder was prepared by the pyrolysis of the PZCS precursor, which has important application prospects in ultra-high sonic aircraft and aero rocket engines. It is expected that this stepwise method of using refractory metal-containing active species to synthesize main-chain metallopolymers would provide significant guidance for preparing novel UHTCs precursors.