Sliding Machine Friction Reduction via Chromium-DLC and Molybdenum Oil
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Solution Overview
Problem
Existing combinations of DLC films and lubricating oils do not achieve a significant reduction in friction coefficient, and the mechanisms behind their friction-reducing effects are not well understood.
Innovation Solution
A sliding machine utilizing an amorphous carbon film containing chromium (Cr) combined with a lubricating oil containing a trinuclear molybdenum compound, which significantly reduces the friction coefficient between sliding surfaces, achieving an ultralow friction property with a coefficient of 0.05 or lower, and exhibits excellent wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional DLC films and lubricating oils are combined, then friction reduction is achieved, but the friction coefficient reduction is insufficient and mechanisms are not clarified
Solution Approach 1:
The invention changes the chemical composition parameters of the DLC film by incorporating specific metal elements (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, W, or Zr) at controlled concentrations (0.1-10 at%). This parameter modification enables the DLC film to interact more effectively with lubricating oil containing molybdenum compounds, achieving a friction coefficient of 0.1 or lower through enhanced adsorption mechanisms.
Solution Approach 2:
The invention creates a composite structure by combining DLC film with specific metal elements and lubricating oil containing molybdenum compounds. The metal elements in the DLC film form a composite material system that synergistically interacts with the lubricant, where the metal-dlc composite structure provides both mechanical durability and enhanced chemical interaction with the lubricant for superior friction reduction.
2Strength
If DLC film is formed on sliding surfaces, then wear resistance is improved, but friction coefficient reduction varies between dry and wet types
Solution Approach 1:
The invention applies local quality by incorporating specific metal elements at controlled concentrations within the DLC film structure. Different metal elements provide different local properties that enhance interaction with lubricating oil. For example, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, W, or Zr elements are distributed within the DLC matrix to create localized regions that promote lubricant adsorption while maintaining overall wear resistance.
Solution Approach 2:
The invention modifies the DLC film parameters by controlling metal element content (0.1-10 at%) and hydrogen content (0-30 at%), creating optimized compositions that maintain wear resistance while enabling effective interaction with lubricating oil. The parameter optimization ensures the DLC film maintains its protective properties while achieving ultralow friction coefficients through enhanced lubricant interaction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The combination results in a sliding machine with enhanced movement performance, energy savings, and stable low friction properties over time, suitable for long-term operation under severe conditions, by creating a super-smooth sliding surface and preventing direct contact between surfaces.
Implementation Method 1
a lubricating oil which contains an oil-soluble molybdenum compound having a chemical structure formed from a trinuclear material of molybdenum (Mo)
Implementation Method 2
by reducing resistance (sliding resistance) applied to the sliding parts... the reduction in the sliding resistance is typically achieved by a reduction in the friction coefficient of friction applied between sliding surfaces
Data Source
AI summary
A sliding machine includes: a pair of sliding members having sliding surfaces that oppose each other and are able to move relative to each other; and a lubricating oil which is able to be interposed between the opposed sliding surfaces, in which at least one of the sliding surfaces is covered with a chromium (Cr)-containing amorphous carbon film (chromium-coating DLC), and the lubricating oil contains an oil-soluble molybdenum compound having a chemical structure formed from a trinuclear material of molybdenum (Mo). Specifically, the chromium-coating DLC contains, when the entirety of the film is assumed to be 100 at. %, 1% to 49% of Cr, 0% to 30% of hydrogen (H), carbon (C) as a remainder, and impurities. The lubricating oil contains 5 ppm to 800 ppm of the oil-soluble molybdenum compound in terms of Mo mass ratio with respect to the entirety of the lubricating oil.