Composite hBN Lubricant Powder for Abradable Coating Flow
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Solution Overview
Problem
Conventional crushed hBN in abradable coatings exhibits poor flow and deposition characteristics, leading to inefficient and poorly controlled manufacturing processes due to agglomeration issues with bentonite binder, resulting in low material density and incompatibility with standard processing equipment.
Innovation Solution
A process involving mixing bentonite clay and hexagonal boron nitride (hBN) powder, followed by calcine heat treatment, crushing, and sizing to produce a composite material with improved flowability and controlled particle sizes, suitable for thermal spray, which includes mixing bentonite clay and hexagonal boron nitride (hBN) powder, followed by calcine heat treatment, crushing, and sizing to produce a composite material with improved flowability and controlled particle sizes, suitable for thermal spray applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional crushed hBN is used with bentonite binder, then the material can be processed, but agglomeration occurs leading to poor flow and deposition characteristics
Solution Approach 1:
The patent applies parameter changes by controlling the particle size of hBN through crushing and classification to achieve optimal flow characteristics. By adjusting particle size parameters and using specific binder concentrations, the process eliminates agglomeration while maintaining manufacturability. The classified particle sizes (fine, medium, coarse fractions) are processed separately and recombined, changing the physical parameters of the mixture to achieve desired flow properties.
Solution Approach 2:
The patent segments the hBN particle size into distinct fractions (fine, medium, coarse) through classification processes. Each fraction is processed separately with appropriate binders and then recombined. This segmentation prevents agglomeration by ensuring uniform distribution of particles with different sizes, thereby improving flow and deposition characteristics while maintaining ease of manufacture.
2Ease of manufacture
If spray drying is used to agglomerate hBN with bentonite binder, then the material can be formed, but the process has poor repeatability due to low material density
Solution Approach 1:
The patent changes the physical parameters of the hBN-bentonite mixture by controlling particle size distribution and binder concentration. By adjusting these parameters, the process achieves consistent agglomeration results with high repeatability. The classified particle sizes are processed with controlled binder addition, ensuring uniform density and consistent manufacturing outcomes.
Solution Approach 2:
The patent creates a composite material system combining hBN with specific binder concentrations and controlled particle size distributions. This composite approach ensures uniform mixing and consistent physical properties, improving process repeatability. The composite structure allows for controlled agglomeration while maintaining material density and manufacturing precision.
3Ease of operation
If hBN is crushed to reduce particle size, then flowability improves, but dust generation increases
Solution Approach 1:
The patent segments the crushing process into controlled stages with classification between stages. By processing hBN through multiple classification steps, the system achieves fine particle sizes for improved flowability while capturing and recycling dust particles. The segmented approach allows selective removal of dust fractions while maintaining the beneficial fine particles for flow.
Solution Approach 2:
The patent recovers dust particles generated during crushing and classifies them into useful size fractions. Rather than discarding dust as waste, the system recovers and reprocesses these particles, converting the harmful dust generation into a beneficial resource. This recovery process reduces overall dust emission while maintaining flowability through controlled particle size distribution.
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 process results in a stable and efficient manufacturing of abradable coatings by producing a free-flowing, low-dust composite hBN and calcined bentonite powder, enhancing process repeatability and yield.
Implementation Method 1
applying a calcine heat treatment to the mixture of the bentonite clay and the hexagonal boron nitride powder
Data Source
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AI summary
A process for solid lubricant filler powder used in abradable coating manufacture comprising mixing (12) a bentonite clay and a hexagonal boron nitride powder to form a mixture of the bentonite clay and the hexagonal boron nitride powder; consolidating (14) the bentonite clay and the hexagonal boron nitride powder to form a composite material; heat treating (16) the composite material to at least 500 degrees centigrade; breaking up (18) the composite material into a variety of sizes; and segregating (20) the composite material to produce a final product of free flowing, low dust powder of composite hexagonal boron nitride and calcined bentonite.