Lanthanum Hexaboride Composite Particles Coating
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Solution Overview
Problem
Existing methods for producing lanthanum hexaboride-containing composite particles result in products with low transparency and poor weather resistance due to high calcination temperatures and complex production processes, which also lead to a decrease in infrared shielding performance over time.
Innovation Solution
A method involving the reaction of lanthanum hexaboride particles with a silica precursor and an organic solvent, followed by a silicon compound, to form composite particles without high-temperature calcination, achieving a silica coating that enhances weather resistance and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If calcination at high temperature (at least 500°C) is performed to form a dense silica coating for water resistance, then water resistance is improved, but particle size increases to several μm resulting in high haze and low transparency
Solution Approach 1:
The patent changes the reaction parameters by conducting silica formation at lower temperatures (room temperature to 100°C) instead of high-temperature calcination (500°C+). This is achieved by controlling pH, reaction time, and silica precursor concentration to form a dense coating without thermal sintering that would increase particle size and reduce transparency.
Solution Approach 2:
The patent performs preliminary surface treatment of lanthanum hexaboride particles with silane coupling agents before silica formation. This preliminary action creates surface groups that facilitate uniform silica nucleation and growth at lower temperatures, ensuring dense coating formation without requiring high-temperature calcination that would compromise transparency.
2Illumination intensity
If particles are pulverized to smaller size to improve transparency, then transparency is improved, but specific surface area increases and lanthanum hexaboride particles are exposed resulting in decreased water resistance
Solution Approach 1:
The patent changes the approach from mechanical size reduction to chemical coating formation. By controlling silica precursor hydrolysis and condensation reactions at lower temperatures with controlled pH, a dense protective coating is formed that maintains water resistance even on fine particles, eliminating the need for pulverization that would expose fresh surfaces.
3Manufacturing precision
If complex production steps with multiple reagents are used to achieve uniform coating, then coating uniformity is improved, but device complexity and production difficulty increase
Solution Approach 1:
The patent extracts and eliminates unnecessary production steps from complex prior art methods. Instead of using multiple reagents including ammonia water, hydrochloric acid, and extended calcination steps, the invention uses a simplified one-step or two-step process with silane coupling agent and silica precursor in controlled aqueous or alcoholic solution, achieving uniform coating without complex equipment or multiple processing stages.
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 produces composite particles that result in a formed product with high transparency and sustained infrared shielding performance, while simplifying the production process and avoiding the need for high-temperature calcination.
Implementation Method 1
reacting at least one silica precursor selected from the group consisting of a tetraalkoxysilane, its hydrolysate and its condensate, in the presence of lanthanum hexaboride particles, a base having a boiling point of at most 200° C., water and an organic solvent
Implementation Method 2
reacting the first reaction mixture with at least one silicon compound selected from the group consisting of an amino-modified silicone, an alkylsilane and an aminosilane, or with the silicon compound and the silica precursor added, to obtain a second reaction mixture containing lanthanum hexaboride-containing composite particles
Data Source
AI summary
To provide a method for producing lanthanum hexaboride-containing composite particles which are capable of forming a formed product having sufficiently high transparency and which are excellent in weather resistance, by a simple operation without calcination treatment at high temperature, and a method for producing a formed product using it. Also provided is a method for producing composite particles, which involves: reacting at least one silica precursor selected from a tetraalkoxysilane, its hydrolysate and its condensate, in the presence of lanthanum hexaboride particles, a volatile base, water and an organic solvent to obtain a first reaction mixture, and reacting the first reaction mixture with at least one silicon compound selected from an amino-modified silicone, an alkylsilane and an aminosilane, or the silicon compound and the silica precursor added, to obtain a second reaction mixture containing lanthanum hexaboride-containing composite particles.