Silicon Nitride Ceramic Laminate for Heat Dissipation
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Solution Overview
Problem
Conventional ceramic laminates for insulative heat dissipating bodies, particularly those using silicon nitride, face challenges in achieving dense, fine structures without grain boundary phases, leading to compromised mechanical properties, heat dissipation, insulation, and thermal cycle reliability due to high-temperature sintering processes and residual thermal stress.
Innovation Solution
A ceramic laminate is formed with a silicon nitride film on a metal layer, characterized by a minimum film thickness of 1 μm or more, porosity less than 3%, and average grain sizes of 300 nm or less in the film thickness direction and 500 nm or less in the in-plane direction, without a grain boundary phase derived from sintering aids, using an aerosol deposition method at room temperature to enhance mechanical and thermal properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature sintering is used to produce silicon nitride ceramics, then densification is achieved, but crystal grains grow large and strength decreases
Solution Approach 1:
The invention changes the temperature parameter from high-temperature sintering (1000°C or higher) to low-temperature heating (800°C or lower), which prevents excessive grain growth while achieving sufficient densification through the unique heating method that combines microwave and conventional heating
Solution Approach 2:
The invention employs periodic or multi-stage heating action by combining microwave heating with conventional heating in a controlled sequence, allowing densification to occur in stages without sustained high-temperature exposure that would cause grain growth
2Manufacturing precision
If high-temperature sintering is used to produce silicon nitride ceramics, then densification is achieved, but voids form and serve as crack initiation points
Solution Approach 1:
The invention changes the temperature parameter from high-temperature sintering (1000°C or higher) to low-temperature heating (800°C or lower), which achieves densification while preventing void formation and crack initiation that occur during prolonged high-temperature exposure
Solution Approach 2:
The multi-stage heating process allows progressive densification without the formation of voids, as the controlled heating sequence ensures uniform densification throughout the ceramic body without creating stress concentrations that lead to voids
3Manufacturing precision
If sintering aids are added to promote densification, then densification is improved, but grain boundary phase forms and lowers mechanical properties
Solution Approach 1:
The invention changes the temperature parameter to low-temperature heating (800°C or lower), which eliminates the need for sintering aids that would otherwise be required to achieve densification at high temperatures, thereby preventing grain boundary phase formation
Solution Approach 2:
The invention extracts or removes the need for sintering aids from the process by using low-temperature heating combined with microwave energy, which achieves densification through a different mechanism that does not require additional chemical additives
4Manufacturing precision
If sintering aids are added to promote densification, then densification is improved, but heat dissipation property and insulation property are lowered
Solution Approach 1:
The invention changes the temperature parameter to low-temperature heating (800°C or lower), which achieves densification without introducing sintering aids that would compromise heat dissipation and insulation properties
Solution Approach 2:
The invention extracts or removes sintering aids from the process by using low-temperature microwave-assisted heating, thereby preserving the intrinsic heat dissipation and insulation properties of the silicon nitride ceramic without contamination from grain boundary phases
5Strength
If high-temperature bonding is used to join ceramic substrate and metal plate, then bonding strength is achieved, but thermal stress is generated
Solution Approach 1:
The invention changes the temperature parameter from high-temperature bonding (800°C or higher) to low-temperature bonding (800°C or lower), which reduces thermal stress while maintaining adequate bonding strength through the unique heating method
Solution Approach 2:
The multi-stage heating process allows progressive bonding without generating excessive thermal stress, as the controlled heating sequence ensures uniform temperature distribution and gradual bond formation
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 results in a ceramic laminate with improved mechanical properties, heat dissipation, insulation, and thermal cycle reliability, along with increased withstand voltage, allowing for thinner ceramic films and reduced thermal stress, thus enhancing the performance of insulative heat dissipating bodies.
Implementation Method 1
aerosol deposition method in which ceramic particles are made to collide with a metal plate and a dense ceramic film is formed directly on a metal plate surface at a normal temperature
Implementation Method 2
ceramic particles are made to collide with a metal plate and a dense ceramic film having no grain boundary phase derived from a sintering aid is formed directly on a metal plate surface
Data Source
AI summary
The present invention provides a ceramic laminate having excellent mechanical properties, heat dissipation property, insulating property, heat resistance and anti-reactivity, and particularly an insulative heat dissipating body having an excellent thermal cycle reliability and a high withstand voltage.The ceramic laminate 1 according to the present invention is a ceramic laminate in which a ceramic film 3 is formed on a metal layer 2, wherein the ceramic film 3 has a minimum film thickness of 1 μm or more, contains silicon nitride and inevitable impurities, and has silicon nitride crystal grains having an average grain size of 300 nm or less in the film thickness direction and an average grain size of 500 nm or less in the in-plane direction. As a result, the present invention can provide a ceramic laminate having excellent mechanical properties, heat dissipation property, insulating property, heat resistance and anti-reactivity, and particularly an insulative heat dissipating body having an excellent thermal cycle reliability and a high withstand voltage.