Mg-Si Inorganic Compound Particle Synthesis via Melt Infiltration

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Solution Overview

Problem

Conventional methods for producing Mg-Si-based inorganic compound particles face challenges such as composition variation, contamination, and oxidation due to high boiling points and melting points, making it difficult to achieve large particle sizes with homogeneity, and require cumbersome processes that increase production costs.

Innovation Solution

A method involving heating Si and Mg raw-material particles at a temperature between 650°C and 945.6°C, where the Mg melt liquid infiltrates the Si particles, allowing for a synthesis reaction within the Si particles to form Mg-Si compound particles with specific dopant elements, eliminating the need for crushing and enabling control over particle size and structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the atomizing method or centrifugal splaying method is used to synthesize Mg2Si by melting and mixing Mg and Si, then particles can be obtained, but composition variation, contamination, and oxidation occur due to Mg vaporization at high temperatures

Engineering Contradiction:
Improvecomposition uniformityVSAvoidMg vaporization, contamination, oxidation
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The invention changes the temperature parameter from conventional high-temperature melting (above Mg boiling point of 1090°C) to a lower temperature range (650-945.6°C) that is above the eutectic point but below the Mg boiling point. This parameter change allows the melt to infiltrate Si particles and form Mg2Si without significant Mg vaporization, thereby suppressing composition variation, contamination, and oxidation while maintaining manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention performs preliminary mixing of Mg and Si particles in specific size ratios before heating. The Si particles (53-500 μm) are prepared in advance as porous structures that will absorb the Mg melt during heating. This preliminary preparation ensures uniform distribution and prevents Mg vaporization by confining it within the Si particle structure from the beginning of the process.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If the mechanical alloying method is used with large particle size raw materials, then homogeneity is difficult to achieve, but if small particle size raw materials are used, dust explosion hazards increase

Engineering Contradiction:
ImprovehomogeneityVSAvoiddust explosion hazard
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention changes the particle size parameter of raw materials to a specific range (Si: 53-500 μm, Mg: 3-8 mm or 1-3 mm) that is larger than conventional mechanical alloying sizes. This parameter change eliminates dust explosion hazards while achieving homogeneity through the melt infiltration mechanism rather than mechanical mixing, as the Mg melt naturally penetrates the Si particle structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical alloying process (ball milling, high-speed mixing) with a thermal process where Mg melt infiltrates Si particles. This substitution eliminates the need for intensive mechanical mixing that creates dust hazards, while achieving uniform composition distribution through the natural capillary infiltration of the melt into the porous Si particle structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If the conventional method of directly melting multiple raw materials and crushing the ingot is used, then inorganic compound particles can be produced, but the process is cumbersome and production cost increases

Engineering Contradiction:
Improveparticle yieldVSAvoidprocess complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the crushing step from the conventional process sequence. By directly producing particles through melt infiltration at lower temperatures, the method removes the need for subsequent size reduction and separation operations, thereby simplifying the overall process while maintaining high particle yield.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention performs preliminary size classification of raw materials to the appropriate ranges before heating. This preliminary action ensures that the final product achieves the desired particle size distribution (25-1000 μm) directly from the infiltration process, eliminating the need for post-processing crushing and size separation operations.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If heating temperature is increased to ensure complete reaction, then synthesis speed improves, but Mg vaporization and composition variation worsen

Engineering Contradiction:
Improvesynthesis speedVSAvoidcomposition uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention optimizes the temperature parameter to the specific range of 650-945.6°C, which is above the eutectic point (650°C) ensuring complete reaction and good infiltration, but below the Mg boiling point (1090°C) preventing vaporization. This optimized parameter range simultaneously achieves high synthesis speed through complete reaction while maintaining composition uniformity by preventing Mg loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs a two-stage heating approach: first heating to the eutectic point (650°C) to initiate melt formation and infiltration, then maintaining or slightly increasing temperature to complete the synthesis reaction. This periodic temperature control ensures complete reaction for high productivity while limiting peak temperature exposure to prevent Mg vaporization and composition variation.

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

This method reduces production costs, suppresses composition variation and contamination, and allows for the production of inorganic compound particles with enhanced mechanical strength and surface area due to nano-size protuberances, achieving desired particle sizes with high yield and uniform composition.

Implementation Method 1

heating a raw material comprising (i) first raw-material particles comprising Si as a major element, and (ii) second raw-material particles comprising Mg as a major element, at a temperature equal to or higher than 650°C and lower than 945.6°C, thereby impregnating a melt liquid of the second raw-material particles into the first raw-material particles

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

impregnating a melt liquid of the second raw-material particles into the first raw-material particles

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

synthesizing the inorganic compound particles through a synthesis reaction between the elements comprised in said first and second raw-materials particles which takes place in the first raw-material particles

Methodology Applied
Scientific EffectSynthesis reaction: Chemical Bonding

Data Source

PatentEP2690064B1Inorganic-compound particles and process for producing same
Publication Date: 2019.05.15 MITSUBA CORP
  • EP2690064B1 patent drawingFigure 1~2
  • EP2690064B1 patent drawingFigure 3
  • EP2690064B1 patent drawingFigure 4~5

AI summary

A method of producing inorganic compound particles is provided. It includes a step of impregnating a melt liquid of second raw particles into first raw particles by heating a raw material including them at a temperature, which equals to or higher than an eutectic temperature between a region-II (solid-liquid phase range) and a region-I (solid phase range) in a phase diagram and lower than the melting temperature of the inorganic compound. The first raw particles contain an element with a melting point equals to or higher than a melting point of the inorganic compound. The second raw particles contain an element with a melting point lower than the melting point of the inorganic compound. The method also includes a step of synthesizing inorganic compound particles by a synthetic reaction in the first raw particles between the elements contained in the first and second raw particles