DLC Film Dimple Formation via Low-Velocity Particle Ejection
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Solution Overview
Problem
Existing methods for forming dimples on diamond-like carbon (DLC) coated surfaces either result in uneven film thickness, damage to the DLC film, or limited coverage ratios, preventing the achievement of improved slidability and wear resistance.
Innovation Solution
A surface treatment method involving the ejection of substantially spherical particles with a median diameter of 1 μm to 20 μm at an ejection pressure of 0.01 MPa to 0.7 MPa to form dimples on the DLC film without exposing the base material, achieving a total projected area of at least 50% and maintaining the DLC film's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If dimples are formed by ejecting fine particles at high velocity onto a DLC film surface, then dimples can be formed on the DLC film, but the DLC film undergoes partial detachment and the base material is exposed
Solution Approach 1:
The invention changes the parameter of particle velocity from high velocity to low velocity (not more than 10 m/s). This parameter change allows dimples to be formed on the DLC film surface while preventing the film from detaching and the base material from being exposed, thus resolving the contradiction between dimple formation and film integrity
Solution Approach 2:
The invention replaces the high-velocity impact mechanism with a low-velocity impact mechanism. Instead of using high kinetic energy particles that cause film detachment, low-velocity particles are used to gently form dimples without damaging the DLC film, substituting the mechanical action to achieve both dimple formation and film preservation
2Shape
If high velocity particles are used to form dimples, then dimple formation is achieved, but the impact stress damages the DLC film structure
Solution Approach 1:
The invention changes the velocity parameter of the ejection particles to not more than 10 m/s. This parameter adjustment ensures that the impact stress is sufficient to form dimples with the desired profile while being low enough to prevent damage to the DLC film structure, thereby resolving the contradiction between shape formation and strength preservation
3Productivity
If the ejection particle velocity is increased to form dimples efficiently, then productivity improves, but the DLC film detaches and base material is exposed
Solution Approach 1:
The invention optimizes the ejection particle velocity parameter to not more than 10 m/s, which is the optimal value that allows dimple formation to proceed efficiently while maintaining coating integrity. This parameter setting resolves the contradiction by finding the velocity threshold that balances productivity with reliability
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 method effectively forms dimples on the DLC film without causing detachment, enabling improved slidability and wear resistance by concentrating impact stress locally and maintaining the DLC film's integrity, thus preventing exposure of the base material.
Implementation Method 1
ejecting substantially spherical ejection particles having a median diameter D50 of from 1 μm to 20 μm and a falling time through air of not less than 10 s/m against a surface of the DLC film of the DLC coated member at an ejection pressure of from 0.01 MPa to 0.7 MPa
Implementation Method 2
concentrating impact stress locally
Data Source
AI summary
A method for surface treatment of a DLC coated member that includes: taking as a treatment subject a DLC coated member having a DLC film coated on a base material surface; ejecting substantially spherical ejection particles having a median diameter of from 1 μm to 20 μm and a falling time through air of not less than 10 s/m against a surface of the film of the member at an ejection pressure of from 0.01 MPa to 0.7 MPa; and forming dimples on the surface of the film without exposing the base material so that a total projected area of the dimples is 50% or more of a treated region and so that the surface of the DLC film is processed to an arithmetic mean height (Sa) of from 0.01 μm to 0.1 μm and a texture aspect ratio (Str) of 0.4 or more.