Composite-Coated Piston Seal for Low Friction and Wear Resistance

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Solution Overview

Problem

Piston rings made from nickel-based superalloys experience significant wear and increased friction due to chromia and alumina formation at high temperatures, leading to excessive wear and reduced creep resistance in gas turbine engines.

Innovation Solution

A piston seal assembly with a coating comprising a metal alloy binder phase and distributed hard particles, such as Cr2O3, applied to the seal body, providing enhanced wear resistance and reduced friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If nickel-based superalloy is used for piston rings to improve creep resistance, then creep resistance is improved, but wear resistance deteriorates due to chromia and alumina formation at high temperatures

Engineering Contradiction:
Improvecreep resistanceVSAvoidwear resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention applies a composite coating comprising a metal alloy binder phase with distributed hard particles (such as Cr2O3, Al2O3, carbides, or silicon carbides) on the piston ring surface. This composite structure combines the creep resistance of the nickel-based superalloy substrate with the wear resistance of the hard particle coating, resolving the contradiction between creep resistance and wear resistance.

Inventive Principle:
Principle #40Composite materials

2Reliability

If chromia and alumina form on the piston ring surface at high temperatures, then oxidation resistance is improved, but friction increases leading to additional wear

Engineering Contradiction:
Improveoxidation resistanceVSAvoidfriction
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the surface composition parameters by applying a coating with specific hard particles and binder phase ratios. The coating contains between 60-80 volume percent metal alloy binder phase and 20-40 volume percent hard particle phase, creating a surface layer with optimized friction characteristics while maintaining oxidation resistance.

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces wear and friction, increasing the endurance life of engine components and reducing overhaul costs by minimizing wear on counterface parts.

Implementation Method 1

A piston seal assembly for a gas turbine engine... low friction, wear resistant piston seal... The coating significantly reduces wear and friction

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3719357B1Low friction, wear resistant piston seal
Publication Date: 2025.12.10 RTX CORP
  • EP3719357B1 patent drawingFigure 1
  • EP3719357B1 patent drawingFigure 2~3

AI summary

A piston seal assembly (10) for a gas turbine engine includes a seal (20) composed of a nickel-based superalloy, a component (14, 16) in contact with the seal (20) and defining a seal-counterface (18), and a coating (24) on the seal (20) at the seal-counterface (18), wherein the coating (24) is a metal alloy binder phase (26) and a hard particle phase (28) distributed through the binder phase (26).