Piston Ring Coating Abrasion Trade-off
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Solution Overview
Problem
The increased ceramic content in thermal spray coatings for piston rings leads to higher abrasion loss of the engine liner, which is the opposite member sliding with the piston ring, necessitating a solution that enhances abrasion resistance while minimizing wear on this component.
Innovation Solution
A thermal spray coating for piston rings comprising molybdenum particles, nickel chromium alloy particles, and chromium carbide particles, with specific diameter ranges and mass percentages, applied via plasma spraying to achieve excellent abrasion resistance and reduced abrasion of the opposite member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ceramic component content in the thermal spray coating is increased to enhance abrasion resistance, then the abrasion resistance of the piston ring is improved, but the abrasion loss of the engine liner (opposite member) increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the median diameter of chromium carbide particles to 5 to 25 μm and adjusting the mass percentages of molybdenum particles (40 to 60%) and chromium carbide particles (20 to 40%). This optimization balances the hardness needed for abrasion resistance with the particle size that minimizes damage to the opposite member, resolving the contradiction between coating durability and counterface wear.
Solution Approach 2:
The patent uses composite materials by combining molybdenum particles, nickel chromium alloy particles, and chromium carbide particles in specific proportions. This multi-component composite coating provides both the hardness from chromium carbide for abrasion resistance and the toughness from molybdenum to reduce impact damage to the engine liner, thereby addressing the technical contradiction.
2Reliability
If a thermal spray coating is applied to the outer peripheral sliding surface of the piston ring, then the burning resistance is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing the powder composition with specific particle size distributions and material compositions before spraying. The chromium carbide particles are prepared in advance with a median diameter of 5 to 25 μm, and the powder mixture is formulated with precise mass percentages of each component, allowing the thermal spray process to directly produce the optimized coating without additional processing steps.
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 coating provides enhanced abrasion resistance for both the piston ring and the engine liner, suppressing abrasion loss and maintaining a smooth sliding surface, thereby improving the durability and performance of the piston ring.
Implementation Method 1
the powder composition is thermally sprayed on the outer peripheral sliding surface of the piston ring base material by a plasma spraying method
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
A thermal spray coating for piston ring having excellent abrasion resistance, and capable of suppressing abrasion of the opposite member is provided. The thermal spray coating for piston ring according to the invention is a thermal spray coating for piston ring obtained by thermally spraying a powder composition on the outer peripheral sliding surface of a piston ring base material, and the powder composition contains molybdenum particles, nickel chromium alloy particles and chromium carbide particles, and the median diameter of the chromium carbide particles is 5 to 25 µm.