Zirconyldichloride Modified Polycarbosilazane as Precursors for SiZrCNO Ceramics

Abstract

Zirconyldichloride modified polycarbosilazane (PZrSZO) has been synthesized from two-component dichlorosilanes (methyldichlorosilane and methylvinyldichlorosilane), zirconyldichloride, and ethylenediamine using triethylamine as acid-absorbing agent and tetrahydrofuran as solvent. 1H nuclear magnetic resonance analysis of the as-synthesized PZrSZO suggest a structure of ethylene-bridged polycarbosilazane having –Si–N–C–C–N– as backbone chain with –CH=CH2, –H and –CH3 attached to Si as side groups, which is similar to that of non-modified PSZO precursor. Fourier transform infrared spectroscopy shows Zr–N stretching vibration peak appears at 532 cm-1 suggesting the incorporation of Zr into PSZO through aminolysis reaction between zirconyldichloride and ethylendiamine. SiZrCNO ceramic with the ceramic yield of 63 wt% is obtained through subsequent pyrolysis treatment at 1000 °C for 1 h under argon flow. EDS analysis shows its composition of SiZr0.01C1.03N0.25O0.84 with the Zr percentage of 1.45 wt%. X-ray diffraction analysis shows SiZrCNO ceramics are of mixed amorphous silicon carbonitride oxygen phase embraced with SiO2 nanocrystalline.