Zirconyldichloride Modified Polycarbosilazane as Precursors for SiZrCNO Ceramics

摘要

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=CH_2, -H and -CH_3 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 SiZr_(0.01)C_(1.03)N_(0.25)O_(0.84) 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 SiO_2 nanocrystalline.