Formation mechanism of toxic-element-free oxide layer on Tiー6Alー4V alloy in d.c. glow discharge plasma with pure oxygen gas
Formation mechanism of toxic-element-free oxide layer on Tiー6Alー4V alloy in d.c. glow discharge plasma with pure oxygen gas
复制标题
纯氧气直流辉光放电等离子体中Ti-6Al-4V合金无毒元素氧化层的形成机理
DOI：
10.1016/j.surfcoat.2016.05.080
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
K. Wagatsuma
中科院分区：
文献类型：
--
作者：
K. Satoh;S. Sato;K. Wagatsuma
本研究的目的是阐明在纯氧气氛下，利用直流辉光放电等离子体在Ti-6Al-4V合金表面形成无有毒元素氧化层的机理。通过监测等离子体辐照的发射光谱，对表面进行了处理，以确定激发态，结果表明，激发态主要存在三种激发态氧。我们的研究报告说，氧等离子体使有毒元素，如Al和V，大部分从合金的最外层去除；在这种情况下，这种效应可能是由于带正电荷的等离子体物质（如O+和O2+）以数百伏的速度向样品表面加速而导致的优先溅射。为了研究等离子体条件对生成的表面层特性的影响，本研究利用x射线光电子能谱对合金在三种不同条件下形成的氧化层进行了表征。然而，无论等离子体条件如何，都观察到样品表面有毒元素的缺陷，氧化层的生长速度有显著差异。
The purpose of this study is to elucidate the formation mechanism of a toxic-element-free oxide layer on a Ti–6Al–4V alloy by using d.c. glow discharge plasma in pure oxygen atmosphere, which has been found in our previous study. The surface treatment was conducted with monitoring emission spectra irradiated from the plasma to identify the excited species, which revealed that three kinds of excited oxygen species were primarily present there. Our investigation has reported that the oxygen plasma enabled toxic elements, such as Al and V, to be largely removed from the outermost surface of the alloy; in this case, this effect would be attributed to preferential sputtering caused by positively-charged plasma species such as O+and O2+which were accelerated toward the sample surface by hundreds of volts. To investigate the effect of the plasma condition on characteristics of the resultant surface layer, this study characterized the oxide layers formed on the alloy under three different conditions by using X-ray photoelectron spectroscopy. Whereas a deficit in the toxic elements on the sample surface was observed regardless of the plasma conditions, there was a significant difference in the growth rate of the oxide layers.