Presentation on theme: "Metallography Lab. 0 Effects of target current on the mechanical properties of Cr-C coatings by using the Unbalanced Magnetron Sputtering Professor ： Dr."— Presentation transcript:
Metallography Lab. 0 Effects of target current on the mechanical properties of Cr-C coatings by using the Unbalanced Magnetron Sputtering Professor ： Dr. Yu-Sen Yang Speaker ： Jia-Hau Lin Date ：
Metallography Lab. 2 Introduction 1.The chromium carbide (Cr-C) films have excellent properties including chemical stability, oxidation resistance, low coefficient of friction and wear resistance. 2. The excellent anti-wear performance of Cr-C films can be attributed to the large content of carbide. 3. Cr-C coatings have been known to protected tools which may be damaged by high thermal load (high cutting speed).
Metallography Lab. 6 Experiment (Properties test ) 5.Wear rate estimation: Calculated after measuring wear track by Alpha-step (1)Alpha-Step 量測磨痕斷面面積 (2) 計算磨耗體積及磨耗率 V: 體積， R: 質心半徑， A: 不規則形狀面積
Metallography Lab. 7 Results and discuss (Component Analysis) Cr 靶電流 Cr( at.%)C ( at.%) 1 A A A A A A
Metallography Lab. 8 Results and discuss ( Friction coefficient test) Against ballLoadingRotation diameterRotation rateLength Cr ball0.5kg20mm286rpm1000m 1A2A3A4A5A6A
Metallography Lab. 9 1A2A3A4A5A6A 6* * * * * *10 -6 單位 :mm 3 ‧ N -1 ‧ m -1 Results and discuss (Wear rate)
Metallography Lab. 10 Results and discuss (friction coefficient)
Metallography Lab. 11 Results and discuss (Wear rate)
Metallography Lab. 12 Results and discuss 1A 6A
Metallography Lab. 13 Results and discuss(Raman) D band ： 1350 cm-1 G band ： 1580 cm-1 材料及其結構拉曼波峰位置 (cm -1 ) 天然鑽石 1332~1334 天然鑽石 (C 12 ) 1323 石墨 ~1600 合成鑽石 (C 13 ) 1290 合成鑽石膜 1332 非晶質碳 (a-C) 及類鑽碳膜 1350 附近 1580 附近
Metallography Lab. 14 Conclusions The experimental results show the carbon content in Cr-C films increase with decreasing target current when target current decrease from 6A to 1A,the carbon content increase from31.1 at.% to at 94.2 at.%. The friction coefficient of films decrease from 0.66 to 0.22 and the wear rate is reduced from 423 ‧ (mm 3 ‧ N -1 ‧ m -1 ) to 6 ‧ (mm 3 ‧ N -1 ‧ m -1 ) when the current reduced from 6A to 1A. The lowest wear rate is 6 ‧ (mm 3 ‧ N -1 ‧ m -1 ) at traget current 1A The lowest friction coefficient is 0.22 at traget current 2A The excellent anti-wear performance of Cr-C films can be attributed to the large content of carbide.
Metallography Lab. 15 The reasons for a low coefficient of friction is the formation of solid solution carbon in the diamond- like carbon film in the crystal structure, which could effectively reduce wear and promote the wear resistance characteristics.