Thermal Barrier Coating Resists Sand Penetration

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Solution Overview

Problem

Turbine engine components experience degradation due to sand-related distress, where fluid sand deposits penetrate thermal barrier coatings, leading to spallation and accelerated oxidation of exposed metal, necessitating significant repairs.

Innovation Solution

A thermal barrier coating system comprising zirconates, hafnates, titanates, or mixtures thereof, doped with 20-100 wt% oxide, which reacts with molten sand deposits to form a silicate oxyapatite/garnet barrier phase, inhibiting further penetration, applied using methods like electron beam physical vapor deposition or air plasma spray.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional thermal barrier coatings are used, then the coating provides thermal insulation, but sand deposits penetrate the coating causing spallation and accelerated oxidation

Engineering Contradiction:

Improvecoating durabilityVSAvoidsand penetration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The coating is designed to react with the harmful sand deposits to form a beneficial barrier phase (silicate oxyapatite/garnet) that prevents further penetration. The harmful sand is transformed into a protective reaction product that seals the interface between the coating and substrate.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The coating composition is modified by doping with specific oxides (20-100 wt%) to change its chemical reactivity parameters. This enables the coating to undergo controlled chemical reactions with sand deposits at service temperature, transforming the coating's properties from passive to actively protective.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the coating reacts with sand deposits to form a barrier phase, then penetration is inhibited, but the coating composition becomes more complex

Engineering Contradiction:

Improveresistance to sand penetrationVSAvoidcoating composition

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The thermal barrier coating is formulated as a composite material containing zirconates, hafnates, or titanates combined with 20-100 wt% doping oxides. This composite structure provides both the thermal insulation properties of the base material and the reactive capability of the dopants to form protective barrier phases.

Inventive Principle:

Principle #40Composite materials

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 system effectively reduces sand-related distress by forming a durable, impermeable barrier phase, enhancing the durability of turbine airfoils in desert environments and preventing metal exposure.

Implementation Method 1

reacts with molten sand deposits to form a silicate oxyapatite/garnet barrier phase

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

forming a durable, impermeable barrier phase

Methodology Applied

Scientific EffectPhysical barrier formation: Physical Containment

Data Source

PatentUS8343587B2Process of forming durable reactive thermal barrier coatings

Publication Date: 2013.01.01 RTX CORP

AI summary

A method for providing a component with protection against sand related distress comprises the steps of: providing a substrate; and forming a thermal barrier coating system by depositing at least one layer of a first material selected from the group consisting of a zirconate, a hafnate, a titanate, and mixtures thereof, which first material has been mixed with at least one oxide so that each layer contains from about 25 to 99 wt% of at least one oxide.