等离子喷涂超细氧化铝-3wt%氧化钛涂层的电学性能研究  

Electrical Properties of Nanostructured Al_2O_3-3wt% TiO_2 Coating Deposited by Plasma Spraying Deposited by Plasma Spraying

作　　者：林新华[1] 周霞明[1] 黄静琪[1] 丁传贤[1] 

机构地区：[1]中国科学院上海硅酸盐研究所,上海200050

出　　处：《无机材料学报》2004年第3期623-628,共6页Journal of Inorganic Materials

摘　　要：采用大气等离子喷涂系统,制备了常规和超细Al_2O_3-3wt％TiO_2涂层.利用 X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)对涂层相组成和显微结构进行了表征.测量了涂层直流电阻,介电常数和介电损耗.在等离子喷涂过程中,α-Al_2O_3氧化铝大部分转变为γ-Al_2O_3.氧化钛在常规涂层中主要以非计量的Ti_2O_3形式存在;对于超细涂层,氧化钛与氧化铝反应形成固溶体.常规Al_2O_3-3wt％TiO_2涂层呈现典型的板条层结构,而超细Al_2O_3-3wt％TiO_2涂层除了具有板条层外,还含有大量的等轴α-Al_2O_3晶粒,其尺寸在150～800nm之间,在常规涂层中,组成板条层的柱状γ-Al_2O_3晶粒直径约为700nm;而对于超细涂层,其绝大部分<200nm.与常规Al_2O_3-3wt％TiO_2涂层相比,超细Al_2O_3-3wt％TiO_2涂层具有较高的直流电阻;但在相同频率下,超细涂层介电常数和介电损耗都较常规涂层小.Conventional and nanostructured Al2O3-3wt%TiO2 coatings were deposited by plasma spraying with conventional and nanostructured powders, respectively. The phase compositions and microstructure of the as-spraying coatings were characterized by XRD, SEM and TEM. The electrical resistivity, dielectric constant and dielectric loss of coatings were measured. In both conventional and nanostructured Al2O3-3wt%TiO2 coatings, alumina mainly existed in the form of gamma-Al2O3 with some alpha-Al2O3. Non-stoichiometric Ti2O3 was found in the conventional coating; while in the nanostructured coating, titania reacted with alumina to form solid solution. The conventional Al2O3-3wt%TiO2 coating exhibited a typical splat microstructure. For the nanostructured Al2O3-3wt%TiO2 coating, many equiaxed alpha-Al2O3 grains besides splat lamellae were also observed. The size of equiaxed alpha-Al2O3 grains was about 150similar to800nm. Compared to the conventional Al2O3-3wt%TiO2 coating, electrical resistivity of the nanostructured Al2O3-3wt%TiO2 coating increased. But the nanostructured coating exhibited lower dielectric constant and dielectric loss.

关 键 词：等离子喷涂 氧化铝-氧化钛涂层 超细晶粒 电学性能 

分 类 号：TG174[金属学及工艺—金属表面处理]