Magnetoceramic nanocrystals from the bulk pyrolysis of novel hyperbranched polyferrocenyl(boro)-carbosilanes

作者：Kong, Jie^*; Schmalz, Thomas; Motz, Guenter; Mueller, Axel H. E.

来源：Journal of Materials Chemistry C, 2013, 1(7): 1507-1514.

DOI：10.1039/c2tc00193d

• POLYMER-DERIVED CERAMICS
• C-N CERAMICS
• SILICON-CARBIDE
• ORGANOMETALLIC POLYMERS
• BLOCK-COPOLYMERS
• THIN-FILMS
• TEMPERATURE
• FABRICATION
• PRECURSORS
• PROCESSABILITY

We report a novel strategy to synthesize nanostructured magnetoceramics via a direct bulk pyrolysis of hyperbranched polycarbosilanes without any assistance of nanoscaled templates. The hyperbranched polyferrocenyl(boro)carbosilanes (hb-PBCS) were synthesized via a convenient A(2)+B-3 strategy. After the pyrolysis of hb-PBCS under a nitrogen atmosphere at 1100 degrees C, iron silicide nanocrystal enriched ceramics with a grain size of 20-60 nm were formed. The regular architecture and quite higher ceramic yield of polymeric precursors are superior in retaining iron and silicon that give a possibility to aggregate into regular nanocrystals during the bulk pyrolysis in comparison to their linear counterparts. Furthermore, if the mixed precursor of hb-PBCS with regular architecture and a silylene-diacetylene polymer with high ceramic yield was employed, a hierarchical structure of uniform nanorods with diameters of 20-30 nm and aspect ratios of similar to 5 together with microspheres with diameters of 4-8 mm could be obtained under the same pyrolytic conditions. A vibrating sample magnetometer measurement demonstrated that the generated iron silicide nanocrystal enriched ceramics possessed weak ferromagnetism with an ultralow hysteresis loss.

• 出版日期2013
• 单位西北工业大学