INFLUENCE OF METAL CATION VALENCE STATE ON ELECTRICALLY REGULATED FRICTION BEHAVIOR

Abstract

Abstract: This study investigates the influence of metal cation valence state on electrically regulated friction behavior using three inorganic salts with distinct valence state—NaCl, MgCl₂, and LaCl₃—as lubricant additives. Friction tests reveal that the monovalent Na⁺-based lubricant exhibits significant friction modulation under negative electrical stimulation, with the friction coefficient decreasing from 0.085 (at 0 V) to 0.028 (under negative voltage), representing a 67% reduction. In contrast, divalent Mg²⁺ and trivalent La³⁺ ions show no comparable friction-regulation capability. The morphological features, surface roughness, and chemical states of wear scars were analyzed using white light interferometry, scanning electron microscopy, and X-ray photoelectron spectroscopy. The results demonstrate that the friction-regulation mechanism of monovalent Na⁺ ions under negative voltage arises from enhanced adsorption on the steel ball surface, thereby improving anti-friction performance. Conversely, the adsorption capacities of Mg²⁺ and La³⁺ ions remain unaffected by electrical signals, leading to negligible changes in their friction-reduction properties.

Key words: electrically regulated friction, metal cation, valence state, friction and wear

References

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