Catalysis of nickel acetylacetonate in thermal cure and ceramization of SiC preceramic resin

• The efficiency of catalysis of nickel acetylacetonate in thermal cure and ceramization of SiC precursor was ascertained.
• Catalysis of Ni(acac)2 (2%) lowered curing temperature from >220 °C to 146 °C, and improved ceramic yield from 48% to 70%.
• Catalysis of Ni(acac)2 making polysilane more suitable candidate of SiC precursor of ceramic materials.

In this paper, the efficiency of catalysis of nickel acetylacetonate in the thermal cure and ceramization of a new liquid polymeric precursor (methyl-terminated vinyl-containing oligomethylsilane, PSI) of SiC was investigated. The new liquid PSI was prepared by Wurtz condensation method using lithium as reductant. Under nitrogen atmosphere, the thermal cure was preformed through the mechanism of hydrosilylation, dehydrogen and vinyl polymerization; with the addition of Ni(acac)2 or Co(acac)3 as catalyst, the cure reaction was promoted to proceed at credibly decreased temperature, especially when using Ni(acac)2 as catalyst. With the increase of Ni(acac)2 amount, the thermal curing exotherm of PSI precursor shifted to lower temperatures gradually. Upon pyrolysis, the ceramic yield of PSI precursor was highly improved by catalysis of Ni(acac)2. With the increase of Ni(acac)2 amount, the ceramic yield of PSI precursor was highly increased from 53% to 77%; the growth of crystalline phase was accelerated at the same time. The elements in the pyrolyzed β-SiC were observed to distribute uniformly at micro-scale. The results showed that the catalyst Ni(acac)2 could accelerate thermal cure, promote ceramic crystallization and improve the SiC ceramic yield of PSI precursor.

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