Oxide Deposition on Porous Components Preventing Pore Clogging
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Solution Overview
Problem
Existing methods for depositing thermal barriers on components with open pores, such as turbine blades and combustion chambers, often result in clogging of cooling channels, leading to hot spots, cracks, and degradation, and require expensive and complex unblocking processes.
Innovation Solution
A method involving controlled double injection of a carrier gas loaded with oxide precursors in a low-pressure plasma, combined with a fluid injected in the gaseous state opposing the carrier gas flow, to prevent clogging of open pores by maintaining a higher pressure and flow rate upstream of the component, ensuring the oxide is deposited only on the surface while preserving the pore structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermal barrier is deposited on a porous component by conventional methods (plasma projection, CVD, PVD), then the surface is coated with protective oxide layer, but the open pores become clogged, leading to hot spots, cracks, and component degradation
Solution Approach 1:
The patent applies preliminary anti-action by injecting a protective gas (argon or nitrogen) through the porous component before oxide precursor introduction. This creates a pressure differential that prevents oxide deposition in pores while allowing surface coating, thereby preemptively avoiding the harmful effect of pore clogging before it occurs
Solution Approach 2:
The patent uses an intermediary gas (argon or nitrogen) that serves as a mediator between the oxide precursors and the porous component. This intermediary gas flows through the pores, creating a protective barrier that prevents oxide deposition in the pores while allowing the oxide coating to form on the external surface
2Manufacturing precision
If conventional deposition methods are used to coat porous components, then oxide layer is formed on surface, but expensive and complex unblocking operations are required to restore pore functionality
Solution Approach 1:
The patent performs preliminary action by establishing gas flow through the pores before oxide deposition begins. This preliminary gas flow setup prevents pore clogging from occurring in the first place, eliminating the need for subsequent unblocking operations and expensive laser equipment
Solution Approach 2:
The patent extracts the harmful oxide deposition process from the pore interior by using differential gas flow. The protective gas flows through the pores while oxide precursors are prevented from entering, effectively separating the coating function from the pore structure
3Ease of operation
If high pressure and high flow rate gas injection is used to prevent pore clogging, then pore patency is maintained, but energy consumption increases significantly
Solution Approach 1:
The patent applies parameter changes by optimizing the protective gas flow rate to a moderate range (1-100 sccm) rather than using high flow rates. The method also controls oxide precursor concentration (0.1-10 sccm) and adjusts these parameters based on pore characteristics, achieving effective pore protection with minimal energy consumption
Solution Approach 2:
The patent applies local quality by tailoring the gas flow parameters to the specific pore characteristics of the component. The method adjusts flow rates and precursor concentrations based on local pore density, size, and distribution, ensuring effective pore patency maintenance with optimized energy usage for each specific application
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 prevents pore clogging, maintains the structural integrity of open pores, and allows for a high-quality oxide coating on components with substantial open pores, reducing energy consumption and avoiding the need for expensive unblocking operations.
Implementation Method 1
injecting a carrier gas loaded with droplets of at least one precursor of the oxide in a low-pressure plasma
Implementation Method 2
depositing a thermal barrier on the surface... by physical deposit in the vapor phase i.e. by evaporation (particularly by EB-PVD, Electron Beam Physical Vapor Deposition)
Implementation Method 3
the pressure and the mass flow rate of said fluid upstream of the permeable component being such that the pressure of the gas at the outlet of the at least one pore is greater than the pressure in the plasma chamber
Data Source
AI summary
The invention relates to a method and system for forming a layer of oxide on a pervious component made of a material or a stack of materials that are stable at 400° C., said component including an outer surface to be coated and at least one pore with a diameter of 50 to 1000 μm leading onto said outer surface. Said method includes the following steps: a) injecting a carrier gas loaded with droplets of at least one precursor of the oxide into a low-pressure plasma inside an enclosure of a plasma reactor housing the component to be coated, and injecting a fluid passing through the pervious component and flowing in gaseous state through said at least one pore with a flow opposite to that of the carrier gas in the plasma chamber in order to avoid the clogging of the pore, the pressure and the mass flow of said fluid upstream of the pervious component being such that the pressure of the gas at the outlet of the at least one pore is higher than the pressure in the plasma chamber, and the injection mass flow of the fluid passing through the pervious component is: α) less than or equal to the mass low of the carrier gas loaded with precursor of the oxide injected into the plasma chamber, and β) greater than or equal to the product of the mass flow of the carrier gas loaded with precursors of the oxide injected into the plasma chamber by the ration between the total surface of the open pores of the pervious component and the surface of the passage section of the plasma chamber, thus, the speed of the gas at the outlet of the at least one pore is no lower than the intake speed of the carrier gas loaded with at least one precursor of the oxide in, non-preferentially, the liquid, gel or solid state thereof, on the outer surface of the component; b) injecting a carrier gas not loaded with a precursor of the oxide into a plasma inside the plasma chamber, wherein the injection of the fluid passing through the pervious component is maintained and steps a) and b) are repeated, such as to form said oxide on the outer surface, the diameter of the at least one pore being preserved.