ISSN   1004-0595

CN  62-1095/O4

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王云峰, 佟瑞庭, 张涛, 杜晶涛, 韩宾, 刘更. 微重力环境下硅基纳米器件碰撞滑动接触问题研究[J]. 摩擦学学报, 2022, 42(5): 863-873. DOI: 10.16078/j.tribology.2021181
引用本文: 王云峰, 佟瑞庭, 张涛, 杜晶涛, 韩宾, 刘更. 微重力环境下硅基纳米器件碰撞滑动接触问题研究[J]. 摩擦学学报, 2022, 42(5): 863-873. DOI: 10.16078/j.tribology.2021181
WANG Yunfeng, TONG Ruiting, ZHANG Tao, DU Jingtao, HAN Bin, LIU Geng. Collision Sliding Contact of Silicon-Based Nanodevices Considering the Influence of Microgravity Environment[J]. TRIBOLOGY, 2022, 42(5): 863-873. DOI: 10.16078/j.tribology.2021181
Citation: WANG Yunfeng, TONG Ruiting, ZHANG Tao, DU Jingtao, HAN Bin, LIU Geng. Collision Sliding Contact of Silicon-Based Nanodevices Considering the Influence of Microgravity Environment[J]. TRIBOLOGY, 2022, 42(5): 863-873. DOI: 10.16078/j.tribology.2021181

微重力环境下硅基纳米器件碰撞滑动接触问题研究

Collision Sliding Contact of Silicon-Based Nanodevices Considering the Influence of Microgravity Environment

  • 摘要: 随着纳米技术的发展,微机电系统被广泛应用于微纳卫星、皮卫星以及各种高精密仪器. 单晶硅广泛应用于微机电系统,考虑微重力环境空间机构无规则碰撞的运动特性,建立刚性金刚石压头与弹性硅基体之间碰撞滑动接触的分子动力学模型,对比研究压头不同振动频率和振幅对平均摩擦力的影响. 结果表明:压头振动频率低于基体固有频率时,平均摩擦力无明显变化,而高于固有频率时,平均摩擦力随振动频率增大呈现先减小后不变的趋势;振幅的增大导致压头和基体的碰撞更加剧烈,剧烈的碰撞导致基体表面更多原子晶格结构破坏,失效原子数增多,降低了平均摩擦力;在基体表面引入纹理,发现纹理表面能够有效降低平均摩擦力.

     

    Abstract: With the development of nanotechnology, nano/micro-electromechanical systems (NEMS/MEMS) have also made significant progress. Because of their small size, low power consumption, and low cost, they are widely used in micro-nano satellites, pico-satellites and various high-precision instruments. Due to the severe size effects, the surface adhesion and friction force are more prominent compared to the volume force in traditional machinery, which greatly affect the performance, stability and service life of NEMS/MEMS devices. In space environment, the microgravity environment induces irregular collisions when components are disturbed, which causes collision friction and further influences their friction performance. Single crystal silicon is widely used in NEMS/MEMS, while its collision friction properties are still unknown. Therefore, studies on collision sliding contact of silicon-based nanodevices considering the influence of microgravity environment are of great significance for the wide application of NEMS/MEMS in the aerospace field. Based on the movement characteristics of random collisions of space mechanisms in microgravity environment, this paper proposed a molecular dynamics model to describe the collision and sliding contact between a rigid diamond indenter and an elastic silicon substrate, and the collision was represented by applying the coupled vibrations in Y and Z directions to the indenter. Besides, a spring was applied at the bottom of the substrate to simulate the response of the substrate to the vibrations of the indenter. The effects of vibration frequencies and amplitudes on the average friction forces were studied. The results showed that the average friction force of collision sliding contact exhibited obvious frequency dependence. When the vibration frequency of the indenter was lower than the natural frequency of the substrate, the average friction force showed little variation with the increase of the vibration frequency of the indenter. When the vibration frequency of the indenter was higher than the natural frequency, there was severe vibration between the indenter and substrate, and the average friction force decreased at the initial stage and then tended to a stable level with the increase of the vibration frequency. Severe vibration led to an increase in the surface temperature of the substrate and the failure of a large number of atomic lattice structure, which made the surface material of the substrate soft and reduced the shear modulus of the substrate. Increasing of the amplitude led to severe collisions between the indenter and the substrate. The increase of the amplitude led to the destruction of the lattice structure of more atoms on the surface of the substrate. As a result, the number of failure atoms increased and the temperature of the substrate surface became higher, which reduced the average friction force significantly. In addition, a large number of studies proved that textured surface with specific structural characteristics exhibited excellent tribological properties. Texture was introduced on the surface of the substrate, and the friction properties of the textured surface and a smooth surface under different working conditions were compared. The results showed that the textured surface reduced the real contact area between the indenter and the substrate. As the vibration frequency increased, the collision caused a great temperature rise in the contact area, which made the substrate material become soft, and the resistance of the indenter was reduced during the sliding process. As a result, the textured surface can reduce the average friction force effectively. In this work, molecular dynamics simulation was used to study the friction mechanism of collision sliding contacts and the anti-friction effects of textured surface, which provided a theoretical basis and scientific guidance for the anti-stick and anti-friction design of micro-nano devices.

     

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