Abradable Coating Powder Blend for Turbine Engine Reliability
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Solution Overview
Problem
Existing abradable coatings for turbine engines face reliability and high cost issues due to the limitations of previous powders and processes used in thermal spraying, which affect the consistency and durability of the coatings.
Innovation Solution
A composite thermal spray powder blend comprising a first component of metal particles and a second component of mechanically or chemically clad solid lubricant, specifically hexagonal boron nitride, with a binder to enhance mechanical integrity and reproducibility, allowing for improved entrapment and distribution of the solid lubricant and polymer phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal spray powders (metal plus non-metal blends) are used, then the coating can be applied, but the coating microstructure is inconsistent and reliability is poor
Solution Approach 1:
The invention segments the powder into distinct component types: (1) metal particles, (2) solid lubricant particles, and (3) polymer-coated particles. Each component is separately controlled and blended in specific ratios (metal: 40-70 wt%, solid lubricant: 20-50 wt%, polymer: 10-30 wt%), allowing precise control over the final coating microstructure and eliminating the inconsistency found in conventional single-blend approaches.
Solution Approach 2:
The invention applies local quality by providing different functional characteristics to different regions of the coating: metal particles provide structural strength, solid lubricant particles provide low friction properties, and polymer-coated particles provide toughness and crack resistance. This localized functional distribution creates a composite microstructure that is both consistent and reliable.
2Strength
If conventional powder blends are used, then coating can be formed, but mechanical integrity is insufficient and polymer phase decomposes
Solution Approach 1:
The invention uses polymer coating as an intermediary layer on the metal particles. This polymer coating acts as a protective mediator that prevents direct contact between the metal particles and the harsh thermal spray environment, thereby preventing polymer phase decomposition while maintaining mechanical integrity through the composite structure.
Solution Approach 2:
The invention creates a multi-phase composite material system combining metal particles, solid lubricant particles, and polymer-coated particles. This composite structure provides both mechanical strength from the metal phase and polymer phase stability through the coated particle structure, resolving the contradiction between strength and polymer stability.
3Ease of manufacture
If simple powder blends are used, then manufacturing is easier, but coating reproducibility is poor
Solution Approach 1:
The invention performs preliminary classification and coating of particles before final blending. Metal particles are pre-coated with polymer, solid lubricant particles are pre-surfactant treated, and then both are blended in controlled ratios. This preliminary preparation ensures consistent particle properties that lead to reproducible coating microstructures while maintaining manufacturing feasibility through automated classification and coating processes.
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 solution results in more reproducible and consistent coating microstructures, improved mechanical integrity, and reduced decomposition of the polymer phase, leading to enhanced performance and reliability of abradable coatings with better flowability and reduced manufacturing challenges.
Implementation Method 1
the solid lubricant comprises hexagonal boron nitride
Implementation Method 2
sprayed onto a surface using plasma or low velocity combustion processes
Implementation Method 3
sprayed onto a surface using plasma or low velocity combustion processes
Implementation Method 4
the spraying of a slurry of very fine powdered constituents with a binder to form droplets, and drying the droplets into a powder
Data Source
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AI summary
A thermal spray powder having a first component A mechanically blended with a second component B, wherein the first component A is a metal or metal composite, preferably at least one of Ni -Cr- Al clad ABN, Ni-Cr-Al clad HBN, Ni-Cr-Al clad agglomerated hexagonal boron nitride powder with organic binder, Ni-Cr-Al agglomerated hexagonal boron nitride powder with inorganic binder, an MCrAlY type powder where M is at least one of Ni, Co, Fe, and wherein component B is a polymer clad with at least one of nickel, nickel alloys, nickel chrome alloys, nickel chrome aluminum alloys, nickel aluminum alloys, cobalt and cobalt alloys. The result is a thermal spray powder of four distinctly different phases making the powder a four-phase blend.