高压合成B-C-N化合物的结构表征

STRUCTURE CHARACTERIZATION OF HIGH-PRESSURE-SYNTHESIZED B-C-N COMPOUNDS

将三聚氰胺和硼酸的混合物进行高温处理 ,制备出成分为B0 .54 C0 .2 8N0 .1 8的B -C -N前驱物 .这种前驱物与Ca3B2 N4触媒混合后在 5 .5GPa,16 0 0℃条件下获得平均成分为B0 .47C0 .2 3N0 .3 0 的化合物 .采用X射线衍射和选区电子衍射分析了高压合成产物的晶体结构 ,发现合成的B -C -N化合物由 3种相组成 ,主晶相为正交相 ,其余为六方相和立方相 .

Due to the structural similarity of graphite and hexagonal boron nitride (h-BN), the ternary B-C-N compounds were expected to have semiconducting properties, as well as intercalation and lubrication properties. The B-C-N precursor was prepared by using boric acid and melamine as starting materials. After mixing the B-C-N precursor and Ca 3B 2N 4 catalyst, B 0.47 C 0.23 N 0.30 compounds were obtained under the pressure of 5.5 GPa and at temperature of 1 600 ℃. Three phases of B-C-N compound in the synthesis were identified by XRD and SAD analyses. The main phase in the synthesis is of orthorhombic structure. The other two residual phases are hexagonal and cubic B-C-N. The lattice parameters for the orthorhombisc B 2CN crystal are a =0.477 6 nm, b = 0.458 5 nm and c =0.362 9 nm. For the hexagonal crystal, a =0.250 6 nm and c =0.665 7 nm and for the cubic crystal, a =0.359 6 nm. The bond states of the B-C-N compounds are characterized by XPS and IR.