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用射频磁控溅射法制备了AlN,BN单层膜及AlN/BN纳米多层膜.采用X射线衍射仪、高分辨率透射电子显微镜和纳米压痕仪对薄膜结构进行表征.分析表明:单层膜AlN为w-AlN结构,BN为非晶相.AlN/BN多层膜中BN的结构与BN层厚有关.当BN层厚小于0.55nm时,由于AlN层模板的作用,BN发生了外延生长,BN与AlN的结构相同;当BN层厚大于0.74nm时,BN为非晶.AlN/BN多层膜的硬度也与BN层的厚度有关.当BN层厚为1—2个分子层时,AlN/BN多层膜具有超硬效应;当BN层厚增加到0.74nm时,AlN/BN多层膜的超硬效应消失.计算了多层膜中BN结构转变的临界厚度.讨论了AlN/BN多层膜的硬化机理,晶态BN与AlN层之间的界面协调应力和模量差异是多层膜硬度提高的主要原因.
AlN, BN single layer films and AlN / BN multilayered films were prepared by RF magnetron sputtering.The structures of the films were characterized by X-ray diffraction, high resolution transmission electron microscopy and nanoindentation.The results show that: The structure of BN in AlN / BN multilayers is related to the thickness of BN.When the thickness of BN is less than 0.55nm, BN is generated due to the action of AlN layer template BN is the same as AlN structure; when BN layer thickness is greater than 0.74nm, BN is amorphous.The hardness of AlN / BN multilayers is also related to the thickness of BN layer.When BN layer thickness is 1-2 AlN / BN multilayers have super-hard effect when the thickness of the AlN / BN multilayers increases, and the superhardness of the AlN / BN multilayers disappears when the BN thickness increases to 0.74nm. The hardening mechanism of AlN / BN multilayers was discussed. The interfacial coordination stress and modulus difference between BN and AlN layers were the main reasons for the increase of hardness of multilayers.