Preparation and microstructure of boron-doped isotropic pyrolytic carbons with different boron contents

Boron-doped isotropic pyrolytic carbons were prepared by chemical vapor deposition(CVD) with CH4、H2 and BCl3 as gaseous precursors.The effects of boron on the microstructure and oxidation properties of pyrolytic carbons were investigated.The results show that boron can be doped into pyrolytic carbon,and the concentration increases with the flow rate of BCl3.Boron doping does not change the isotropy of pyrolytic carbons,but remarkably changes the microstructure of pyrolytic carbons.Increasing the flow rate of BCl3,the microstructure of pyrolytic carbon changes gradually from spherical carbon structures to fine wrinkled graphitic sheet structures,while boron changes from substitutional boron into boron carbide.The results from oxidation show that boron can effectively inhibit the oxidation of pyrolytic carbon.