Triboplasma Generation and Triboluminescence: Influence of Stationary Sliding Partner
Triboplasma Generation and Triboluminescence: Influence of Stationary Sliding Partner
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DOI：
10.1007/s11249-009-9516-5
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发表时间：
2010-02-01
影响因子：
3.2
通讯作者：
Nakayama, Keiji
中科院分区：
文献类型：
--
作者：
Nakayama, Keiji
本文从静止伙伴的种类对光子能量和等离子体分布的影响的角度研究了摩擦等离子体的特性。测量了针尖半径为1.5和3 mm的金刚石探针在空气中干滑动时，在Al_2O_3、MgO和SiO_2三种不同材料的圆盘上所发射光子的能谱和二维图像。结果表明，三种绝缘固体在紫外区都有较窄的空气放电等离子体谱带，说明摩擦等离子体的产生与绝缘固体的种类无关。在三种固体Al 2 O3、MgO和SiO2中，摩擦等离子体均呈环状分布，且有一个或两个尾部。紫外，可见光和红外光子发射的机制进行了讨论。紫外光子是由空气放电产生的电离等离子体气体发射的，而可见光子是由摩擦等离子体光子、摩擦等离子体电子和摩擦温升与来自等离子体本身的光子一起激发的缺陷和杂质中心发射的。一个696 nm的窄带出现只有与Al 2 O3，它是由于Cr 3+离子激发的紫外光子和电子从摩擦等离子体。红外光子应该是由热释光和黑体辐射组成的热发射从滑动接触发射的，以及从摩擦等离子体。可见光光子发射在Al 2 O3和MgO中的摩擦轨迹对面的对点处最强。为了解释成对点处的光子发射，提出了一个新的模型，即可见光子是由电子轰击金刚石表面产生的带负电荷的斑片引起的反向电场加速的背电子激发的表面缺陷和/或杂质中心发射的。摩擦轨道上的负电荷排斥背电子，因此背电子就在摩擦轨道之外攻击。
In this work, the characteristics of triboplasma have been investigated from the point of view of how the kinds of the stationary partner influence the photon energy and the plasma distribution. The energy spectrum and two-dimensional images of the emitted photons were measured during the sliding of a diamond pin with a tip radius of 1.5 and 3 mm on the three kinds of disk made of Al2O3, MgO, and SiO2 in dry sliding in air. The results showed that all the three kinds of solid tested had narrow bands of air-discharge plasma in the ultraviolet region, demonstrating that the triboplasma generation does not depend on the kinds of insulating solids. Triboplasma was distributed having a ring with one or two tails in all the three kinds of solid Al2O3, MgO, and SiO2. The mechanisms of UV, visible, and IR photon emissions are discussed. The UV photons are emitted from the ionized plasma gas produced by discharging of air, while the visible photons are emitted from the defect and impurity centers excited by the triboplasma-photons, triboplasma-electrons, and frictional temperature rise together with the photons from the plasma itself. A 696-nm narrow band appeared only with Al2O3, and it was attributed to the Cr3+ ions excited by the UV photons and electrons from the triboplasma. The IR photons should be emitted from the sliding contact by the thermal emissions consisting of thermoluminescence and blackbody radiation, as well as from the triboplasma. The visible photon emission was strongest at the pair points facing across the frictional track in Al2O3 and MgO. To explain the photon emission at the pair points, a new model has been proposed, in which the visible photons are emitted from the surface defect and/or impurity centers excited by the back electrons accelerated with the inverse electric field caused by the negatively charged patches produced by the electron bombardment to the diamond surface. The negative charges on the frictional track repelled the back electrons, so that the back-electrons attack just outside the frictional track.