Ca_3B_2N_4-hBN系中立方氮化硼的膜生长机制

GROWTH MECHANISM OF cBN BY METAL FILMS

以Ca_3B_2N_4为触媒,在高温高压下对六角氮化硼进行处理,在六角氮化硼与触媒的交界处得到了被金属膜包覆的立方氮化硼晶体。这表明六角氮化硼到立方氮化硼的转变与人造金刚石的膜生长机制类似,立方氯化硼晶体在触媒与六角氮化硼接触处择优成核,在生长着的立方氮化硼与六角氮化硼之间存在着金属薄膜,该膜对立方氮化硼“基元”有输运作用。随着该金属膜向六角氮化硼区的推进,在其后留下生长的立方氮化硼晶体。

By using Ca3B2N4 as catalyst and treating hBN-Ca3B2N4 under high pressure andhigh temperature,we obtained cBN crystals covered with metal films at the junction of hBN and tcatalyst layer. This shows that the formation mechanism of cBN is similar to that of diamond. In this way, nuclei of cBN formed first at the contact face between hBN and catalyst wherein exist- ed,the metal films between the cBN and solvent. The 'cBN cells' moves through the films and precipitate on the nuclei of cBN. As the films move toward the solvent,the cBN crystals become larger and larger. The films play an importent role in the transfer of 'cBN cells'.