Preparation, thermal cure and ceramization of liquid precursors of SiC–ZrC

Abstract

Liquid PEPSI–PZO, as precursor of SiC–ZrC multi-component ceramic, was prepared by facile reactive blending method, using phenylethynylpolysilane (PEPSI) as silicon and carbon source and polyzirconoxanesal (PZO) as zirconium source. The processing capability of PEPSI–PZO met the demands of Precursor-infiltration–pyrolysis technique (PIP) in ceramic composites fabrication. The thermal cure was realized at 130–330°C by ethynyl polymerization and condensations. The thermal cure of PEPSI–PZO precursor was promoted by catalyst Ni(acac)2, and the curing initiation and curing peak temperatures decreased by 25 and 70°C, respectively. Evidenced by ceramic yields and XRD results, the thermal pyrolysis was catalyzed by Ni(acac)2, (ceramic yield was improved by 5–10%). XRD and SEM-EDS results showed that SiC–ZrC by 1600°C pyrolysis was highly crystalline, due to the occurrence of carbothermal reduction reaction. The liquid precursor of SiC–ZrC is an ideal candidate of low cost precursors for high-temperature ceramics and ceramic matrix composites.