文档介绍：Classified Index:TG155
.:
Dissertation for the Master Degree in Engineering
STRUCTURE AND PROPERTIES OF Ni-W-TS COATINGS DEPOSITED ON AL-Li ALLOY
Candidate:
Liang yan hui
Supervisor: Associate Prof.
Academic Degree Applied for: Master of Engi
Specialty: Materials Physi
Affiliation: School of Mat Engineering
Date of Defence: July,2007
Degree-Conferring-Institution: Harbin Institute
Sun mingren neering
cs and Chemistry
erials
Science And
of Technology
摘要
本文用化学复合镀的技术在 2195 型铝锂合金上成功地沉积了不同成分的 Ni-W-B 及 Ni-W-Ts 薄膜。系统研究了 Ni-W-B 及 Ni-W-Ts 薄膜的成分、结构、腐蚀及摩擦学性能。
利用 X 射线光电子能谱(XPS)研究了 Ni-W-B 及 Ni-W-Ts 薄膜成分和化学结构;以原子力显微镜(AFM)和电子扫描电镜(SEM)观察了 Ni-W-B 及 Ni-W-Ts 薄膜的表面形貌和粗糙度。利用纳米力学探针测量了 Ni- W-B 及 Ni-W-Ts 膜的纳米硬度和弹性模量,系统研究了 Ni-W-B 及 Ni-
W-Ts 膜的摩擦学性能及电化学腐蚀行为。研究结果表明:随着工艺参数的不同,样品表面的形态和粗糙度值有明
显的变化。当镀液中Na2WO4 的含量较低时,样品表面呈无规则的微凸体生长特征,随着Na2WO4含量的进一步增加,样品表面呈现致密的胞状和絮状生长特征,膜层趋于致密、光滑,空洞较小,且粗糙度和表面最大高度的值降低;当改变镀液中DMAB含量,样品表面的粗糙度值呈非单调规律变化。镀液中Na2WO4含量较少时,镀层成分主要以元素Ni为主,这因为Na2WO4含量对镀层成分影响呈现出阈值效应。在Ni-W-B膜中,W和B含量的最高值分别是 .%和 .%,W和Ni以金属态为主,而B主要以W2B5态存在;在 Ni-W-Ts膜中C与W和Ni结合形成了WC和Ni3C键结构;不同工艺配比的Ni-W-B膜和Ni-W-Ts膜腐蚀机理均为点蚀,而基体试样的腐蚀机理是均匀地面蚀;Ni-W-B膜本身具有高的耐蚀性,但显微裂纹的存在是点蚀的发生源,严重影响其耐蚀性能;在Ni-W-Ts膜中由于碳纳米管的强化作用,有效地抑制了显微裂纹的产生,耐蚀性能明显提高。从磨痕轮廓及形貌分析显示,Ni-W-B膜和Ni-W-Ts膜的磨损是粘着磨损和磨粒磨损, 与基体试样相比,Ni-W-B膜和Ni-W-Ts膜的耐磨性显著提高。与Ni-W- B膜相比,Ni-W-Ts膜在摩擦过程中持久性和承载能力明显增强。
关键词化学复合镀;组织结构;摩擦学性能;耐腐蚀性
Abstract
In this paper the Ni-W-B and Ni-W-Ts coatings with positions were deposited on the 2195 aluminium alloy posite electro- less plating technique essfully. position, microstructrue, corrosion and frictional behaviors were studied systematically.
position and chemical states of Ni-W-B and Ni-W-Ts coatings were characterized by X-ray photoelectron spectroscopy (XPS). The nanohardness and modulus of Ni-W-B and Ni-W-Ts coatings were measured by mechanical properties microprobe. To observe surface morphology and roughness, atomic force microscope and scanning electric microscope were also used. Moreover, t