Synthesis and characterization of a polyborosilazane/Cp₂ZrCl₂ hybrid precursor for the Si–B–C–N–Zr multinary ceramic

Abstract

A novel zirconium-contained polyborosilazane (PBSZ-Zr) was synthesized by chemical modification of a liquid polyborosilazane (LPBSZ) with Cp2ZrCl2. A Si-B-C-N-Zr multinary ceramic was prepared via pyrolysis of PBSZ-Zr. The properties and the ceramization process of PBSZ-Zr, as well as the microstructural development and properties of the derived SiBCN-Zr ceramic, were well studied. The active Si-H and N-H groups in LPBSZ react with Zr-Cl in Cp2ZrCl2 to form PBSZ-Zr polymers. The Zr content of the SiBCN-Zr ceramic was 3.39 wt% when the weight ratio of Cp2ZrCl2 to LPBSZ was 20 : 100. The SiBCN-Zr ceramic remains amorphous when pyrolyzed below 1600 °C, but the crystal phases of Zr2CN, ZrC, BN, SiC, and Si3N4 were detected from a 1600 °C treated sample. Due to the low activity of free carbon at the interface of the SiBCN-Zr ceramic, the oxidation resistance of the SiBCN-Zr ceramic under air was improved compared with the SiBCN ceramic.

Synthesis and processing of silicon nitride and related materials using preceramic polymer and non-oxide sol-gel approaches

“…13b, produced HfSiBCN ceramics that remained amorphous to 1300 °C before segregating during crystallisation [191], and which produced composites with carbon fibres with significantly better resistance to hydrothermal corrosion compared with silicon carbonitride [192]. Reaction of CpZrCl2 with a polyborosilazane polymer led to amorphous ZrSiBCN ceramics up to 1600 °C, where phase segregation during crystallisation was again observed [193].…”

Polymer precursor‐derived HfC–SiC ultrahigh‐temperature ceramic nanocomposites

“…The HfC–SiC composite ceramics are commonly synthesized by milling and sintering of HfC and SiC powder mixtures . However, due to the difficulties in dispersing of raw powders, it is hard to get products with uniform microstructure and distribution . Single‐source precursor synthesis approach has been applied to synthesize nanoscale composites in very recently .…”

“…9,10 However, due to the difficulties in dispersing of raw powders, it is hard to get products with uniform microstructure and distribution. 9,11 Single-source precursor synthesis approach has been applied to synthesize nanoscale composites in very recently. 1,3,11,12 However, in several limited studies it is reported that the compositions of Hf-containing products are complicated, such as HfN x and HfC x N 1Àx , and exist in the obtained products.…”

“…9,11 Single-source precursor synthesis approach has been applied to synthesize nanoscale composites in very recently. 1,3,11,12 However, in several limited studies it is reported that the compositions of Hf-containing products are complicated, such as HfN x and HfC x N 1Àx , and exist in the obtained products. 1,3 The polymeric precursor as an alternative method for preparing nanoscale ceramic powders has drawn much attention recently.…”

Synthesis of soluble and meltable pre‐ceramic polymers for Zr‐containing ceramic nanocomposites

“…In recent years, polymer‐derived method has been extended to synthesize Si‐containing ceramic nanocomposites . In the last decade, ceramic nanocomposites have been shown to be excellent material candidates for applications in high‐temperature or harsh environments because their properties improve upon reduction in the size of the ceramic phases towards the nanoscale . For example, Kong's group has developed magnetic and high‐temperature‐resistant ceramic nanocomposites via the design of novel hyperbranched silicon and metal‐containing polymers .…”