Ceramic Coating Overspray Removal via Intermittent Dry Ice

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Solution Overview

Problem

Thermal barrier coatings (TBCs) applied using suspension plasma spraying (SPS) often result in overspray byproduct accumulation, leading to reduced erosion resistance and increased susceptibility to thermal spalling due to inadequate adherence and non-uniform thickness, which is challenging to address in continuous fabrication processes.

Innovation Solution

Intermittent removal of overspray byproduct using a removal agent, such as dry ice, during the SPS process, specifically targeting areas prone to overspray deposition before completing the coating layer, ensuring superior adherence and uniformity of the TBC.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If continuous SPS coating operation is performed, then productivity is improved, but overspray byproduct accumulates and deteriorates coating quality

Engineering Contradiction:

Improvecontinuous coating operationVSAvoidcoating uniformity and adherence

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The continuous coating operation is segmented into multiple passes with intermediate removal steps. The coating process is divided into sequential stages where overspray is removed between passes, preventing accumulation while maintaining continuous production flow.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The harmful overspray byproduct is converted into a beneficial control mechanism. By intentionally allowing controlled overspray during each pass and then removing it systematically, the process uses the overspray itself as a marker to identify areas needing attention, transforming the harmful accumulation into a controllable process parameter.

Inventive Principle:

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

2Manufacturing precision

If overspray byproduct is removed continuously, then coating quality is improved, but process complexity increases

Engineering Contradiction:

Improvecoating uniformity and adherenceVSAvoidprocess system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The overspray removal function is merged with the existing plasma spray system. The same plasma spray apparatus is used for both depositing coating and removing overspray, eliminating the need for separate removal equipment and reducing overall system complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The plasma spray torch is given multiple functions: it serves both as the coating deposition tool and as the overspray removal tool. This multi-functionality reduces the number of components needed and simplifies the overall process system while maintaining coating quality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If traditional SPS process is used without removal, then ease of manufacture is improved, but erosion resistance and spalling resistance deteriorate

Engineering Contradiction:

Improveprocess simplicityVSAvoiderosion resistance and spalling resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Instead of continuous removal or no removal, the process uses periodic removal actions at specific intervals between coating passes. This periodic intervention maintains coating quality and reliability while keeping the overall process simple and manageable.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

Overspray is removed in advance before the next coating pass begins. This preliminary action prevents overspray from interfering with subsequent coating deposition, ensuring consistent coating quality and improved erosion and spalling resistance without complicating the manufacturing process.

Inventive Principle:

Principle #10Preliminary action

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 prevents overspray byproduct buildup, enhancing the erosion resistance and thermal spalling resistance of the TBC, allowing for continuous coating operations with improved component durability and reliability.

Implementation Method 1

The particles are fed to a plasma spray torch in a controlled manner and injected into the plasma plume for deposition onto a substrate

Methodology Applied

Scientific EffectPlasma spray: Plasma Spray

Implementation Method 2

the removal agent is dry ice that is sprayed onto the second portion of the component

Methodology Applied

Scientific EffectSublimation: Sublimation

Data Source

PatentUS10196929B2Process for depositing a ceramic coating and product formed thereof

Publication Date: 2019.02.05 GENERAL ELECTRIC CO

AI summary

A system and methods for applying a ceramic coating to a component that includes first applying a coating material to a first portion of a component. A removal agent is then applied to a second portion of the component that has an overspray byproduct thereon, and then the ceramic coating material is applied to at least the second portion of the component.