Aluminium Basecoat Exothermic Coating for Gas Turbines
Solution Overview
Problem
Existing corrosion protective coatings for gas turbine engine components require high-temperature processing, which can compromise the optimum mechanical properties of these components.
Innovation Solution
A method of forming a protective coating by applying a basecoat composition with an aluminium phase on a substrate, followed by heating to a first temperature to cure the basecoat, and then to a second temperature for activating an exothermic reaction with the substrate to form the protective coating, all while keeping the processing temperature below 900°C to preserve mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional high-temperature coating processes (above 900°C) are used to form corrosion protective coatings, then the coating provides effective corrosion resistance, but the mechanical properties of the substrate are compromised
Solution Approach 1:
The invention changes the temperature parameter from traditional high-temperature processes (>900°C) to a lower temperature process (below 900°C, specifically 600-850°C). This is achieved by using a basecoat composition containing aluminium phase that undergoes an exothermic reaction with the substrate to form the protective coating at reduced temperatures, thereby preserving the mechanical properties of the substrate while still providing effective corrosion resistance.
Solution Approach 2:
The basecoat composition contains aluminium phase that self-reacts with the substrate through an exothermic reaction when heated to the second temperature. This self-service mechanism generates the necessary heat for coating formation without requiring external high-temperature heating, enabling the coating process to proceed at lower overall temperatures that preserve substrate mechanical properties.
2Strength
If the processing temperature is kept below 900°C to preserve mechanical properties, then the substrate maintains optimum mechanical properties, but the coating formation process becomes more complex
Solution Approach 1:
The coating process is segmented into distinct temperature stages: a first temperature (600-850°C) for curing the basecoat layer and protecting the aluminium phase, and a second temperature for activating the exothermic reaction. This segmentation allows each stage to be optimized independently, managing process complexity while maintaining substrate mechanical properties.
Solution Approach 2:
The basecoat composition is prepared in advance with the aluminium phase dispersed in a binder material, and the surface of the substrate is pre-treated if necessary. This preliminary preparation simplifies the subsequent coating formation process by having all reactive components ready for the exothermic reaction, reducing the complexity of real-time process control.
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
This method effectively forms a protective coating that provides corrosion resistance without compromising the mechanical properties of the substrate, and can be efficiently implemented in factory environments.
Implementation Method 1
applying a glow discharge plasma on the basecoat layer and heating the basecoat layer to a second temperature greater than the first temperature in order to activate an exothermic reaction
Implementation Method 2
activate an exothermic reaction between at least the aluminium phase of the basecoat layer and the at least one chemical element of the substrate. The exothermic reaction forms the protective coating on the surface of the substrate
Data Source
AI summary
A method of forming a protective coating. The method includes providing a substrate including at least one chemical element and a surface; forming a basecoat composition including an aluminium phase including aluminium; applying the basecoat composition on the surface of the substrate to form a basecoat layer; heating the basecoat layer to a first temperature for a predetermined period of time; applying a glow discharge plasma on the basecoat layer; and heating the basecoat layer to a second temperature greater than the first temperature, in order to activate an exothermic reaction between at least the aluminium phase of the basecoat layer and the at least one chemical element of the substrate, wherein the exothermic reaction forms the protective coating on the surface of the substrate.