An open-atmosphere nitriding process for titanium using a watt-level pulsed Nd:YAG laser
An open-atmosphere nitriding process for titanium using a watt-level pulsed Nd:YAG laser
复制标题
使用瓦特级脉冲 Nd:YAG 激光器对钛进行开放式气氛氮化工艺
DOI：
10.1016/j.surfcoat.2022.128362
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发表时间：
2022
影响因子：
5.4
通讯作者：
Kobayashi Kosei
中科院分区：
文献类型：
--
作者：
Ohtsu Naofumi;Endo Ryo;Takeda Shinya;Miura Koyo;Kobayashi Kosei
一般来说，金属表面氮化应在没有氧气的氮气气氛中进行。在开放气氛中处理被认为导致氧化物形成。在本文中，我们提出的实验结果，推翻了这种传统的理解，通过创建一个氮化钛层，没有氧化物，使用脉冲Nd：YAG激光照射在一个特定的设置在开放的气氛中。实现这种开放式气氛氮化的关键事件是由等离子体产生引发的Ti表面的瞬时熔化。聚焦激光束的使用对于这一过程至关重要。通过功率大于1W的脉冲Nd：YAG激光照射的照射导致形成包含TiN和Ti2N而没有Ti氧化物的氮化钛层，而使用未聚焦光束的照射导致氧化物层，即使使用4W激光。氮化层的厚度在几微米的范围内，并且厚度随着激光功率的增加而增加。此外，表面硬度也相应提高，其中使用4W激光获得的硬度是未经处理的表面的3倍。这种开放式气氛激光氮化工艺是一种创新的、前所未有的发现，可以很容易地应用于自动机器人。
In general, metal surface nitriding should be performed in a nitrogen atmosphere without oxygen. Treatment in an open atmosphere is believed to result in oxide formation. In this paper, we present experimental results that overturn this conventional understanding by creating a Ti nitride layer without oxides using pulsed Nd:YAG laser irradiation under a specific setting in an open atmosphere. The key event in the achievement of this open-atmosphere nitriding was the instantaneous melting of the Ti surface initiated by plasma generation. The use of a focused laser beam is essential for this process. Irradiation by pulsed Nd:YAG laser irradiation with a power greater than 1 W led to the formation of a Ti nitride layer comprising TiN and Ti2N without Ti oxides, whereas irradiation using an unfocused beam resulted in an oxide layer, even with a 4 W laser. The thickness of the nitride layer was in the range of several micrometers, and the thickness increased with increasing laser power. In addition, the surface hardness was enhanced correspondingly, where the hardness obtained using the 4 W laser was three times that of the untreated surface. This open-atmosphere laser nitriding process is an innovative and unprecedented finding that can be easily applied to automatic robots.