Synthesis and characterization of zirconium diboride ceramic precursor

In the present study, ZrB 2 precursor which met the requirements of polymer infiltration-pyrolysis process, was synthesized and characterized. ZrB 2 precursor was synthesized with bis(cyclopentadienyl)zirconium dihydride (Cp 2 ZrH 2 ), borane-dimethyl sulfide complex (BH 3 ·S(CH 3 ) 2 ), and vinyltrimethylsilane ((CH 3 ) 3 Si(CH CH 2 ), VTMS). The molecular structure of the precursor, pyrolysis behavior, and the composition of the derived ceramics were investigated. The results showed that, the as-synthesized precursor was an oligomer based on Zr–H–B polycentric bridge bonds. The precursor was stable in an inert atmosphere. The ceramic yield of the precursor at 1200 °C was around 65.5% under N 2 atmosphere. The derived ceramics obtained under 1200 °C were composed of h-ZrB 2 , m-ZrO 2 and t-ZrO 2 . When the temperature was up to 1400 °C, peaks of ZrC emerged due to carbothermic reduction. m-ZrO 2 and t-ZrO 2 disappeared with the pyrolysis temperature above 1600 °C. The derived ceramics pyrolyzed at 1800 °C were composed of h-ZrB 2 and ZrC, and the former was the predominant phase.