Please use this identifier to cite or link to this item:
Diffusion barrier characteristics of CrTaN thin film on cobalt cemented tungsten carbide
|Authors: ||Yu-Ting Lin|
|Contributors: ||NTOU:Institute of Materials Engineering|
|Issue Date: ||2011-11-23T03:13:09Z
|Abstract: ||為了防止在模造過程中的高溫環境下，碳化鎢中的鈷結合劑擴散的問題。希望藉由CrTaN作為擴散阻障層來阻擋鈷擴散，藉由DC磁控濺鍍系統，在氬氣以及氮氣的混和氣氛下沉積CrTaN薄膜。CrTaN薄膜在含有6 wt.%鈷的碳化鎢基材上，氮氣的流量比率N2/(Ar+N2)固定在0.4，Ta靶和Cr靶的總濺鍍功率為300 W，CrTaN薄膜沉積速率隨著Cr的功率上升而逐漸上升，從23到27 nm/min。沉積出來的CrTaN薄膜為柱狀晶結構，硬度和楊氏係數分別為16-27 GPa和211-383 GPa。沉積出的CrTaN薄膜，在500oC和600oC大氣下和模擬玻璃模造環境在600oC氧含量50 ppm氮氣下分別進行四小時退火。藉由AES和XRD來分析擴散阻障層經過退火後的成分和晶相變化，在500oC和600oC大氣下退火四小時的擴散阻障層會產生Ta2O5 和Cr2O3氧化物，使表面粗糙度上升，硬度和楊氏係數下降。反之，在600oC氧含量50 ppm氮氣下進行四小時退火的擴散阻障層則沒有氧化層生成，硬度和楊氏係數上升。在500oC和600oC大氣下和600oC氧含量50 ppm氮氣下進行四小時退火後的試片，並未發現鈷向外擴散，所以CrTaN在玻璃模造的環境下，可以有效的阻抗鈷向外擴散。|
To prevent the diffusion out of cobalt from cemented tungsten carbides at high working temperatures, CrTaN coating were prepared as a diffusion barrier by reactive direct current magnetron co-sputtering onto 6 wt.% cobalt cemented tungsten carbide substrates, using Ta and Cr targets in an argon-nitrogen atmosphere. The nitrogen flow ratio, N2/(Ar+N2), during the sputtering process was set at 0.4. The deposition rates of CrTaN coatings varied from 23 to 27 nm/min. The CrTaN coatings crystallized into a columnar structure, without heating the substrates during the sputtering process and exhibited surface hardness and Young's modulus values of 16–27 and 211–383 GPa, respectively. The annealing treatments were conducted at 500 and 600oC for 4 hours in air and 600oC for 4 hours in 50 ppm oxygen with balanced nitrogen gas. The diffusion barrier performance was evaluated by Auger electron spectroscopy depth profiles (AES), and X-ray diffraction (XRD). Oxidation resistance of the CrTaN coatings was also investigated. Orthorhombic L-Ta2O5 and rhombohedral Cr2O3 was observed after annealing at 500 and 600oC for 4 hours in air. When the oxide appeared, the thin film surface become more rough, the surface hardness and Young's modulus values decreased. Annealing in 600oC for 4 hours in a 50 ppm O2-N2 atmosphere, surface not oxide phase was observed. The hardness and Young's modulus values was increased. We also investigated oxidation resistance of the CrTaN coatings under a 50 ppm O2-N2 atmosphere, to assess the fabricated layers effectiveness as a protective coating for glass molding dies. Next carbon nitride films were deposited on the CrTaN films, to increase the surface wear property, because carbon nitride film has a batter wear resistance. The films were annealing in 50 ppm O2-N2 environment to simulate the glass molding environment, to observe the adhesion of CrTaN, surface roughness and hardness.
|Appears in Collections:||[材料工程研究所] 博碩士論文|
Files in This Item:
All items in NTOUR are protected by copyright, with all rights reserved.