Coated Particle Group for Thermal Expansion Control and Electrical Insulation
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Solution Overview
Problem
Existing materials with negative thermal expansion coefficients, such as tungsten zirconium phosphate and manganese nitride, fail to provide adequate electrical insulation and controlled thermal expansion, making them unsuitable for electronic device applications like semiconductor sealing and circuit boards.
Innovation Solution
A particle group comprising coated particles with a core of a first inorganic compound and a shell of a second inorganic compound, where the shell has higher volume resistivity and specific thermal expansion characteristics, ensuring excellent thermal expansion control and electrical insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If tungsten zirconium phosphate or manganese nitride is used as an additive to reduce linear thermal expansion coefficient, then thermal expansion control is improved, but electrical insulation properties deteriorate
Solution Approach 1:
The invention uses a composite particle structure with a core made of first inorganic compound (e.g., TiO2) and a shell made of second inorganic compound (e.g., Al2O3, SiO2, ZrO2). This composite structure allows the core to provide negative thermal expansion while the shell provides electrical insulation, resolving the contradiction between thermal expansion control and electrical insulation properties.
Solution Approach 2:
The invention applies different material properties to different parts of the particle: the core region provides thermal expansion control functionality while the shell region provides electrical insulation functionality. This local differentiation of material properties allows simultaneous achievement of both requirements.
2Temperature
If materials with negative thermal expansion coefficient are used, then thermal expansion control is improved, but controlled thermal expansion characteristics deteriorate
Solution Approach 1:
The invention controls the ratio of shell to core by adjusting the amount of second inorganic compound (4-50 wt% based on total particle weight) and the particle size (0.1-100 μm). This parameter optimization ensures that the thermal expansion control characteristic is maintained while achieving controlled and reproducible results for manufacturing precision.
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 particle group achieves reduced linear thermal expansion coefficients and enhanced electrical insulation, making it suitable for applications in electronic devices and components sensitive to thermal changes.
Implementation Method 1
The volume resistivity of the second inorganic compound is higher than the volume resistivity of the first inorganic compound
Implementation Method 2
Requirement 1: |dA(T)/dT| is 10 ppm/°C or more at at least one temperature T1 in a range of -200° C. to 1,200° C.
Data Source
AI summary
A coated particle having excellent thermal expansion control and electrical insulation properties includes a core of a first inorganic compound containing a metal or semimetal element P; and a shell of a second inorganic compound containing a metal or semimetal element Q. The first inorganic compound satisfies 1, and the coated particles satisfy 2 and 3. 1: |dA(T)/dT| is ≥10 ppm/°C at T1 of -200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the first inorganic compound)/(a c-axis lattice constant of a crystal in the first inorganic compound). 2: in XPS of a surface of each of the coated particles, a ratio of a number of atoms of Q contained in the shell to a number of atoms of P contained in the core t is 45 to 300. 3: an average particle diameter of each coated particle is 0.1 to 100 µm.