Boron-Silicon Coating Composition for High-Temperature Alloy Brazing

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Solution Overview

Problem

The existing processes for joining high-temperature alloys, such as welding, brazing, and diffusion brazing, are complex and costly due to the need for multiple steps and specialized filler materials, particularly in preparing braze fillers that match the composition of the parent materials, which complicates the coating and application processes.

Innovation Solution

A coating composition comprising a mechanical blend of boron and silicon sources with specific weight ratios, combined with particles having wear resistance, surface-enhancing, or catalytic properties, applied as a paste or paint to substrates, which can be heated to a brazing temperature to form a braze alloy that matches the parent material's composition, reducing the number of necessary filler coatings and simplifying the coating process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional brazing methods are used with specialized filler materials matching parent material composition, then joining quality is improved, but process complexity and cost increase

Engineering Contradiction:
Improvejoining qualityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the chemical composition parameters of the coating material by incorporating reactive elements (Al, Ti, B, Si) that transform during heating to form the desired braze alloy composition in situ, eliminating the need for pre-matched filler materials

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention extracts and removes the complex requirement for specialized filler material selection and preparation, simplifying the process to a standard coating application followed by heating treatment

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If multiple filler coatings are applied to match parent material properties, then joining performance is improved, but manufacturing steps and time increase

Engineering Contradiction:
Improvejoining performanceVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention merges multiple coating applications into a single coating layer containing all necessary reactive elements, which then transforms during one heating cycle to produce the desired braze alloy composition

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention performs preliminary preparation by incorporating all necessary alloying elements and reactive components into the initial coating formulation, so that subsequent heating automatically produces the correct braze alloy composition without additional steps

Inventive Principle:
Principle #10Preliminary action

3Reliability

If complex braze filler preparation is performed to match parent material composition, then wetting and flow characteristics are improved, but coating process complexity increases

Engineering Contradiction:
Improvewetting and flow characteristicsVSAvoidcoating process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the approach by formulating the coating with reactive elements that transform during heating to create the desired braze alloy composition, simplifying the coating application process while maintaining wetting and flow characteristics

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coating material performs self-service by automatically transforming into the correct braze alloy composition through in situ reactions during heating, eliminating the need for complex pre-preparation of filler materials

Inventive Principle:
Principle #25Self-service

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 approach reduces the complexity and cost of the coating process by allowing a single coating composition to match the parent material's properties, improving wetting and flow characteristics, and forming a braze alloy that integrates well with the substrate, thereby enhancing the joining process while minimizing thermal stresses and corrosion risks.

Implementation Method 1

the braze filler is melted during the process at a temperature above 450 °C, i.e. forming a liquid interface

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The physical stage includes wetting and flowing of the braze filler

Methodology Applied
Scientific EffectWetting: Wetting

Implementation Method 3

During this stage there is solid-liquid interaction, which is accompanied by substantial mass transfer. The base material volume that immediately adjoins the liquid filler metal either dissolves or is reacted with the filler metal in this stage. At the same time a small amount of elements from the liquid phases penetrates into the solid base material

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 4

a liquid must be formed and become active in the joint area

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2830816B1A novel coating concept
Publication Date: 2019.11.13 ALFA LAVAL CORP AB
  • EP2830816B1 patent drawingFigure 1~2
  • EP2830816B1 patent drawingFigure 3~4
  • EP2830816B1 patent drawingFigure 5~6

AI summary

The present invention relates to composition comprising a blend of at least one boron source and at least one silicon source, and the composition further comprises particles selected from particles having wear resistance properties, particles having surface enhancing properties, particles having catalytic properties or combinations thereof, wherein the blend comprises boron and silicon in a weight ratio boron to silicon within a range from about 3:100 wt:wt to about 100:3 wt:wt, wherein silicon and boron are present in the blend in at least 25 wt%, and wherein the at least one boron source and the at least one silicon source are oxygen free except for inevitable amounts of contaminating oxygen, and wherein the blend is a mechanical blend of particles in and the particles have an average particle size less than 250 µm. The present invention relates further to a method for providing a coated product and a coated product obtained by the method.