多層氮化鋁鉻/氮化鈦釩硬質薄膜之機械性質與高溫氧化研究

Mechanical Performance and Thermal Oxidation of Multilayered AlCrN/TiVN Hard Coatings Synthesized by Cathodic Arc Evaporation

陳俊孝(Chun-Hsiao Chen)

指導教授 ： 張銀祐

國立虎尾科技大學/工程學院/機械與電腦輔助工程系碩士班/碩士(2016年)

摘要

過渡金屬氮化物，像是TiVN和AlCrN，由於具有優異的抗磨損性能、硬度、抗腐蝕能力，所以被沉積在基材表面，來當作保護層；本實驗使用陰極電弧蒸鍍系統來鍍製單層AlCrN、TiVN薄膜、多層硬質AlCrN/TiVN薄膜，在鍍製多層硬質AlCrN/TiVN薄膜時，將TiN當作介層可有效的提升鍍層跟基材間附著力的強度、藉由薄膜相互堆疊，抑制差排移動、細化晶粒，進而提升薄膜的機械性質；而TiV和AlCr靶材的陰極電流及偏壓是控制在70A和120V來沉積硬質氮化膜、轉架速度設定為2rpm。透過不同鋁含量的Cr50Al50與Al70Cr30靶材來改變薄膜鋁含量，並探討其機械性質與微結構上的差異，最後在進行實際切削測試。

在薄膜結構方面，使用場發射掃描式電子顯微鏡(FE-SEM)來拍攝薄膜在常溫及高溫時表面及截面微結構形貌、使用高解析穿透式電子顯微鏡(TEM)針對更微小的區域進行內部結構、晶體結構及顯微影像的分析並搭配能量分散光譜儀(EDS)來進行定性半定量的元素分析；利用X射線繞射分析儀來進行化學組成與相位的判別；使用ESCA進行高溫時的氧化分析，觀察氧化深度、鍵結，並研究氧化物的分布情況；在機械性質方面則是透過微小試驗機來量測硬度、在常溫及高溫下利用Ball-On-Disk磨耗試驗機來分析薄膜的抗磨損能力、利用衝擊試驗機來評估受到連續衝擊後，薄膜抗衝擊疲勞的性能；在刀具切削方面，設定主軸轉速為16000rpm，總切削距離為65公尺，比較未鍍層刀具與多層硬質AlCrN/TiVN薄膜刀具磨耗情況。

實驗結果顯示隨著鋁含量增加與多層薄膜結構的產生，硬度、抗磨損能力等都有效的提升，其中又以多層硬質AlCrN/TiVN薄膜週期厚度為13.54nm具有最高的硬度38.97GPa，與最低的磨損率1.93×10-7mm3/NM，而在抗衝擊疲勞性能方面也表現出優良的結果，這是因為多層AlCrN/TiVN薄膜藉由AlCrN、TiVN兩種薄膜相互堆疊的設計有效抑制差排行為產生，並抑制晶粒成長，與單層TiVN薄膜相比，藉由多層結構與鋁的加入後，抗氧化性明顯的提升，且高鋁含量的多層AlCrN/TiVN薄膜表現出比多層CrAlN/TiVN薄膜更優異的抗氧化性；而在實際切削7003鋁合金測試中，多層硬質AlCrN/TiVN薄膜也提供刀具最佳的保護效果，有效提升刀具壽命。

關鍵字

硬質膜 ； 機械性質 ； 多層膜 ； 氧化行為 ； TiVN ； AlCrN

並列摘要

Transition metal nitrides, such as TiVN and AlCrN, have been used as protective hard coatings due to their excellent tribological properties. In this study, AlCrN, TiVN and multilayered AlCrN/TiVN coatings were synthesized by cathodic-arc evaporation. During the coating process of AlCrN/TiVN, TiN was deposited as an interlayer to enhance adhesion strength between the coatings and substrates. The cathode current of both TiV and AlCr cathodes were controlled to produce hard nitride coatings.
The microstructure of the thin films was characterized by using a field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM), equipped with an energy-dispersive x-ray analysis spectrometer (EDS). Glancing angle X-ray diffraction (XRD) was used to characterize the microstructure and phase identification of the films. The chemical composition and bonding structures were also evaluated. The multilayer thickness and alloy content of the deposited coating were correlated with the evaporation rate of cathode materials. Mechanical properties, such as the hardness, were measured by means of Vickers indentation. A Ball-on-disc wear test at room temperature and high temperature was conducted to evaluate the tribological properties of the deposited coatings. To evaluate the cutting performance, end milling tests of 7003 Al alloys of the deposited tools were conducted at a rotational speed of 16000rpm.
The results showed that the multilayered AlCrN/TiVN with the highest Al content possessed the highest hardness and wear resistance. The AlCrN / TiVN multilayer film with the period of 13.54nm possessed the highest hardness 38.97GPa and the lowest wear rate 1.93×10-7. Besides, the AlCrN/TiVN showed good impact resistance ,No obvious damage was found after 500,000.impacts.AlCrN/TiVN multilayer film overlap are designed to effectively inhibit grain growth. After oxidation at 500℃and 700℃,the TiVN showed serious oxidation and oxides of TiO2,V2O5 and VO2 were observed. The introduction of AlCrN and CrAlN can improve the oxidation resistance of TiVN. For the end milling of 7003Al alloys. The TiVN coated tool showed improved tool life as compared to CrAlN and AlCrN because the effect of solid lubrication of TiVN. The multilayered AlCrN/TiVN possessed the lowest wear scale among the studied tools.

並列關鍵字

hard coating ； mechanical ； multilayer ； oxidation ； TiVN ； AlCrN

參考文獻

[12] 曾麟詠，2011，”以反應性直流磁控濺鍍製備氮化鉻硼鎢奈米複合薄膜之製程與性質研究”，國立台北科技大學材料科學與工程研究所碩士學位論文。

[19] 汪大永，張銀祐，洪志穎，2005，”陰極電弧沉積氮化鋁鈦/氮化鉻奈米多層薄膜之開發與應用”，科學與工程技術期刊，1卷，2期，頁1~6。

[67] 洪瑞彬，2015，”硬質多層薄膜AlCrSiN/TiVN之機械性質與氧化行為研究”，國立虎尾科技大學機械與電腦輔助工程系研究所碩士論文。

[1] Q.H. Kong, L. Ji, H.X. Li, X.H. Liu, Y.J. Wang, J.M. Chen, H.D. Zhou, 2011, “Composition, microstructure, and properties of CrNx films deposited using medium frequency magnetron sputtering ”, Applied Surface Science ,257, pp. 2269–2274.

[2] F. Zhou, K.M. Chen, M.L. Wang, X.J. Xu, H. Meng, M. Yu, Z.D. Dai, 2008, “Friction and wear properties of CrN coatings sliding against Si3N4 balls in water and air ” , Wear,265 , pp.1029–1037.