MoS2/WS2 Nanosheet-Based Composite Films Irradiated by Atomic Oxygen: Implications for Lubrication in Space
MoS2/WS2 Nanosheet-Based Composite Films Irradiated by Atomic Oxygen: Implications for Lubrication in Space
复制标题
原子氧辐照的 MoS2/WS2 纳米片复合薄膜：对太空润滑的影响
DOI：
10.1021/acsanm.1c01816
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发表时间：
2021-08-30
影响因子：
5.9
通讯作者：
Pu, Jibin
中科院分区：
文献类型：
--
作者：
Fan, Xin;Shi, Yanbin;Pu, Jibin
低地球轨道（LEO）上的原子氧（AO）对广泛应用于空间的MoS 2润滑膜的摩擦学性能具有不可逆的劣化影响。在这里，我们证明了高的耐辐照性与低摩擦和磨损相结合，可以实现在一个复合材料，包括二硫化钼基质与少量的WS 2。通过综合使用微观结构表征和分子动力学（MD）计算，我们发现，纯二硫化钼薄膜的非晶结构是最容易被氧化，由于其松散和无序的结构。相比之下，具有平行于衬底的高度有序的（002）晶面的膜可以显著抑制AO的扩散，例如，添加3.9原子%WS 2的MoS 2/WS 2复合膜的氧化深度在5.4 × 10（19）的剂量辐照后低于20 nm。atoms.cm具体地说，在长期AO照射过程中，复合膜的结构经历了从MoS 2晶体到MoOx晶体再到非晶的转变过程。与纯MoS 2膜的摩擦学性能的快速劣化相比，MoS 2/WS 2复合膜在5.4 × 10（19）atoms.cm（-2）剂量的辐照后保持0.015的低摩擦系数和2.03 × 10（-7）mm（3）.N-1.m（-1）的磨损率，与未辐照样品几乎相同。
The atomic oxygen (AO) in the low earth orbit (LEO) has an irreversible degradation impact on the tribological properties of MoS2 lubricating films widely used in space. Here, we demonstrate that high irradiation tolerance combined with low friction and wear can be realized at a composite comprising the MoS2 matrix with a small amount of WS2. By comprehensively using microstructure characterization and molecular dynamics (MD) calculations, we reveal that the amorphous structure of a pure MoS2 film is the most susceptible to be oxidized due to its loose and disordered structure. In comparison, films with a highly ordered (002) crystal plane parallel to the substrate can significantly inhibit the diffusion of AO, e.g., the oxidation depth of a MoS2/WS2 composite film with an addition of 3.9 atom % WS2 is below 20 nm after a dose of 5.4 x 10(19) atoms.cm(-2) irradiation. Specifically, the structure of composite films during long-term AO irradiation experiences a transformation process from the MoS2 crystal to the MoOx nanocrystal to amorphous. Compared with the rapid deterioration of tribological properties for the pure MoS2 film, the MoS2/WS2 composite film maintains a low friction coefficient of 0.015 and wear rate of 2.03 x 10(-7) mm(3).N-1.m(-1) after a dose of 5.4 x 10(19) atoms.cm(-2) irradiation, almost identical to the unirradiated samples.