Thermal Spray Slurry Redispersibility via Controlled Rotation

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Solution Overview

Problem

Ceramic thermal spray coatings face issues due to sedimentation of ceramic particles in the slurry, leading to precipitates that are difficult to redisperse, making the slurry unsuitable for practical applications.

Innovation Solution

A thermal spray slurry with ceramic particles of specific size range (200 nm to 5 μm) is stirred at controlled temperatures and rotation speeds to prevent sedimentation, and may include flocculants, viscosity modifiers, and dispersants to enhance redispersibility and fluidity, allowing for effective thermal spraying.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the slurry is stored for practical applications, then the ceramic particles sediment and form precipitates, but the precipitates are difficult to redisperse making the slurry unusable

Engineering Contradiction:
Improveslurry usabilityVSAvoidslurry homogeneity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the particle size parameter of ceramic particles to a specific range (200 nm to 5 μm) to resolve the contradiction. This parameter change affects both the sedimentation behavior and redispersibility of the particles, making the slurry usable after storage despite precipitate formation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a dynamic redispersion process by rotating the container at a specific speed (100 rpm) for a specific time (120 minutes) at controlled temperature (20-30°C). This dynamic action transforms the static precipitated state back into a usable slurry state.

Inventive Principle:
Principle #15Dynamics

2Reliability

If ceramic particles are used for thermal spray coatings, then protective properties are achieved, but sedimentation during storage reduces slurry applicability

Engineering Contradiction:
Improvecoating protective propertiesVSAvoidslurry handling
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent optimizes the ceramic particle size parameter to balance coating performance and handling ease. The specific size range (200 nm to 5 μm) ensures both protective coating properties and manageable sedimentation behavior that allows practical handling through controlled redispersion.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent establishes preliminary storage conditions and redispersion protocols before actual use. By pre-defining the container rotation parameters (100 rpm for 120 minutes at 20-30°C), the slurry is prepared in advance for optimal handling and application performance.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the slurry is allowed to stand still during storage, then sedimentation occurs, but stirring during storage increases energy consumption

Engineering Contradiction:
Improveslurry homogeneityVSAvoidstorage energy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by stationary object

Solution Approach 1:

Instead of continuous stirring during storage, the patent employs periodic action by rotating the container at specific intervals (100 rpm for 120 minutes) at controlled temperature. This periodic redispersion maintains slurry usability while minimizing energy consumption compared to continuous agitation.

Inventive Principle:
Principle #19Periodic action

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 method ensures sufficient redispersibility of precipitated ceramic particles, enabling the slurry to be usable in practical applications and forming dense, efficient thermal spray coatings.

Implementation Method 1

rotating the cylindrical vessel at a rotation speed of 100 rpm for 120 minutes around the central axis of the cylindrical vessel to stir the thermal spray slurry

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

disposing, at a temperature of 20° C. or higher and 30° C. or lower, the cylindrical vessel so as for the central axis of the cylindrical vessel to be horizontal and by rotating the cylindrical vessel

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

the ceramic particles in the slurry are sedimented by gravity and thus precipitates of the ceramic particles are sometimes produced

Methodology Applied
Scientific EffectSedimentation: Sedimentation

Data Source

PatentUS10377905B2Slurry for thermal spraying, thermal sprayed coating, and method for forming thermal sprayed coating
Publication Date: 2019.08.13 FUJIMI INCORPORATED

AI summary

A thermal spray slurry of the present invention contains ceramic particles having an average particle size of 200 nm or more and 5 μm or less. Precipitates formed when 700 mL of the thermal spray slurry is placed in a 16.5-cm-high cylindrical vessel having a volume of 1 L and is allowed to stand still at room temperature for 1 week are made to disappear by disposing, at a temperature of 20° C. or higher and 30° C. or lower, the cylindrical vessel so as for the central axis of the cylindrical vessel to be horizontal and by rotating the cylindrical vessel at a rotation speed of 100 rpm for 120 minutes around the central axis of the cylindrical vessel to stir the thermal spray slurry in the cylindrical vessel.