Mechanical properties and oxidation resistance of CrAlN/BN nanocomposite coatings prepared by reactive dc and rf cosputtering
Mechanical properties and oxidation resistance of CrAlN/BN nanocomposite coatings prepared by reactive dc and rf cosputtering
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DOI：
10.1016/j.surfcoat.2011.02.044
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发表时间：
2011-07-25
影响因子：
5.4
通讯作者：
Ikeno, S.
中科院分区：
文献类型：
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作者：
Nose, M.;Kawabata, T.;Ikeno, S.
分别以CrAl靶和h-BN靶为靶材，通过反应共溅射(脉冲直流溅射和射频溅射)制备了CrAlN/BN纳米复合涂层。X射线衍射(XRD)和选区电子衍射(SAED)分析表明，CrAlN/BN涂层由非常细小的B1型CrAlN相组成。当BN体积分数增加到8vol.%以上时，CrAlN/BN涂层中的细小颗粒呈弥散状分布，呈现出纳米晶性质。透射电子显微镜的横截面观察表明，硬度最高的涂层具有纤维状结构，由宽度类似20 nm、长度类似于50 nm的颗粒组成。X射线光电子能谱(XPS)分析表明，涂层主要由CrAlN和h-BN相组成。涂层的压痕硬度(H-IT)和有效杨氏模数(E*)随BN相含量的增加而增加，在BN相体积分数为7%时达到最大值，分别接近46和440 Gpa，然后在BN相体积分数为18%时分别下降到约40和350 Gpa。此外，与CrAlN涂层相比，CrAlN/BN涂层具有更好的抗氧化性能。在800℃空气中热处理1h后，CrAlN涂层的压痕硬度下降到沉积前的50%，而CrAlN/BN纳米复合涂层的硬度要么保持不变，要么增加，达到约46 GPa.在900℃保温1h后，所有涂层的硬度均降至40%左右。(C)2011爱思唯尔B.V.保留所有权利。
CrAlN/BN nanocomposite coatings were deposited through reactive cosputtering, i.e., pulsed dc and rf sputtering, of CrAl and h-BN targets, respectively. X-ray diffraction (XRD) and selected area electron-diffraction (SAED) analysis indicated that the CrAlN/BN coating consists of very fine grains of B1 structured CrAlN phase. With an increasing BN volume fraction of over 8 vol.%, the nanocrystalline nature of the grains is revealed through a dispersion of fine grains in the CrAlN/BN coating. A cross-sectional observation using a transmission electron microscope (TEM) clarified that the coating demonstrating the highest level of hardness has a fiber-like structure consisting of grains that are similar to 20 nm in width and similar to 50 nm in length. X-ray photoelectron spectroscopy (XPS) analysis revealed that the coating consists mainly of CrAlN and h-BN phase. The indentation hardness (H-IT) and effective Young's modulus (E*) of the coatings increased with the BN phase ratio, reaching a maximum value of similar to 46 and similar to 440 GPa at similar to 7 vol.% of BN phase; it then decreased moderately to similar to 40 and similar to 350 GPa at 18 vol.% of BN, respectively. Furthermore, CrAlN/BN coatings showed superior oxidation resistance compared with CrAlN coatings. After annealing at 800 degrees C in air for 1 h, the indentation hardness of CrAlN coatings decreased to 50% of the as-deposited hardness; in contrast, the hardness of CrAlN/BN nanocomposite coatings either stayed the same or increased, attaining a value of about 46 GPa. After annealing at 900 degrees C for 1 h, the hardness of all the coatings decreased to about 40%. (C) 2011 Elsevier B.V. All rights reserved.