Thermal Hood for EB-PVD Substrate Temperature Control

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Solution Overview

Problem

Conventional Electron Beam Physical Vapor Deposition (EB-PVD) systems for coating gas turbine engine airfoils face issues with temperature control, leading to undesirable oxidation phases due to source material coating heaters, which reduces their effectiveness in maintaining substrate temperature.

Innovation Solution

A deposition apparatus with a semi-cylindrical thermal hood within the coating chamber that surrounds the coating zone, utilizing a heating source and electron beam sources to generate radiant heat, providing enhanced temperature control and uniform heating of the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional heaters are used to heat the substrate in EB-PVD systems, then the substrate temperature can be maintained, but the source material coats the heaters over time reducing their capacity to control temperature

Engineering Contradiction:

Improvesubstrate temperature controlVSAvoidheater capacity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

A thermal hood is introduced as an intermediary component between the heating source and substrate. The thermal hood absorbs radiant heat from the electron beam heating source and re-radiates it uniformly to the substrate, preventing direct contact between source material and heating elements while maintaining effective temperature control

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The conventional direct-contact heater system is replaced with a radiant heating system using electron beam sources and a thermal hood. This substitution eliminates the mechanical contact issue where source material coats traditional heaters, replacing it with a non-contact radiant heat transfer mechanism

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If source material coats the heaters, then the heaters' capacity to control temperature is reduced, but temperature variation still occurs leading to undesirable oxidation phases

Engineering Contradiction:

Improvesubstrate temperatureVSAvoidoxidation phase control

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The thermal hood acts as a heat distribution intermediary that receives concentrated radiant energy from the electron beam and redistributes it uniformly across the substrate surface, ensuring consistent temperature control that prevents localized oxidation phases

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the heat transfer parameter from direct radiant heating to indirect heating through the thermal hood, which modifies the temperature distribution profile and achieves more uniform heating that prevents oxidation phase formation

Inventive Principle:

Principle #35Parameter changes

3Temperature

If electron beam sources are used to heat the substrate directly, then temperature can be maintained, but the burden on electron beam sources increases and operating expenses rise

Engineering Contradiction:

Improvesubstrate temperature controlVSAvoidelectron beam energy consumption

Core Design Contradiction:

TemperatureVSUse of energy by moving object

Solution Approach 1:

The thermal hood serves as a heat transfer intermediary that decouples the high-energy electron beam source from the substrate heating function, allowing the electron beam to efficiently heat the hood which then gently heats the substrate, reducing overall energy consumption

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces direct electron beam heating of the substrate with indirect heating through the thermal hood, substituting a high-energy direct heating mechanism with a more energy-efficient indirect radiant heating approach

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 thermal hood ensures temperature stability within 1% of the target temperature, reducing the burden on electron beam sources and improving coating consistency, while also reducing operating expenses by compensating for higher operating pressures.

Implementation Method 1

at least one electron beam source is operative for emitting an electron beam onto the media to generate radiant heat

Methodology Applied

Scientific EffectElectron beam: Electron Beam

Implementation Method 2

a thermal hood within the coating chamber is located adjacent to the coating zone for controlling the temperature of the coating zone

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS8709160B2Deposition apparatus having thermal hood

Publication Date: 2014.04.29 RTX CORP

AI summary

A deposition apparatus includes a coating chamber and a coating zone within the coating chamber for coating work pieces. A heating source heats the coating zone, and a thermal hood within the coating chamber is located adjacent to the coating zone for controlling a temperature of the coating zone.