Cement Encapsulation for High-Temperature Electronics
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Solution Overview
Problem
Current encapsulation materials for power electronics and sensor systems are limited to a temperature range below 200°C, and carbonation of cement-based encasings can lead to corrosion due to pH reduction, affecting the stability and functionality of metals within these systems.
Innovation Solution
A method involving targeted carbonation of the cement encapsulation compound by heat treating it under controlled carbon dioxide atmospheres to increase density and impermeability, while selecting corrosion-resistant metals for contact surfaces to mitigate corrosion risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cement-based encapsulation material is used to extend temperature range above 200°C, then operating temperature range is improved, but carbonation occurs leading to pH reduction and metal corrosion
Solution Approach 1:
The patent applies a preliminary protective coating to the metal surfaces before encapsulation in the cement-based material. This coating acts as a barrier against carbonation and pH reduction, preventing corrosion even when the cement undergoes carbonation over time. The protective measure is implemented in advance, before the harmful carbonation process can affect the metals.
Solution Approach 2:
The patent introduces an intermediary protective layer (coating or corrosion-resistant alloy) between the metal components and the cement-based encapsulation material. This intermediary layer mediates the interaction, allowing the cement to provide high-temperature protection while the intermediary layer prevents direct contact between the cement and metals, thus preventing carbonation-induced corrosion.
2Object-affected harmful factors
If targeted carbonation is applied to increase density and impermeability, then gas and moisture barrier properties are improved, but pH reduction and corrosion risk increase
Solution Approach 1:
The patent implements preliminary protection of metal surfaces through coating or using corrosion-resistant alloys before the targeted carbonation process. This ensures that even though carbonation will reduce the pH and increase impermeability of the cement, the metals are already protected and will not corrode despite the pH reduction.
Solution Approach 2:
The patent accepts the harmful effect of carbonation (pH reduction) but converts it into a benefit by using corrosion-resistant materials that thrive in lower pH environments. The carbonation process achieves the desired impermeability and density, while the selected materials benefit from or resist the pH reduction, turning a potentially harmful effect into an acceptable or even advantageous outcome.
3Reliability
If current encapsulation materials (epoxy, silicone) are used, then chemical stability is maintained, but operating temperature is limited below 200°C
Solution Approach 1:
The patent uses a composite encapsulation system consisting of cement-based material combined with protective coatings or corrosion-resistant alloy layers. The cement-based material provides the high-temperature resistance (extending operation above 200°C), while the composite structure with protective layers maintains chemical stability and prevents corrosion, achieving both high temperature capability and chemical stability.
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 enhances the encapsulation compound's impermeability and strength, preventing moisture and gas ingress, and ensures the functionality of electrical devices by maintaining the structural integrity and corrosion resistance of metals within the specified pH range.
Implementation Method 1
Carbonation refers to the chemical conversion of Ca(OH)2 and the alkaline components (and NaOH and KOH) of the cement paste to calcium carbonate by atmospheric CO2: Ca(OH)2 + CO2 + H2O → CaCO3 + 2H2O
Implementation Method 2
treating the coating material in such a way that targeted carbonation of the cement takes place or occurs on a surface of the coating material
Data Source
Figure 1~2a
Figure 2b~2c
Figure 3
AI summary
The invention relates to a method for producing an electrical device (10) having an electrical or electronic component (12), wherein the component (12) is at least partially covered by a covering material (14) that comprises cement, said method comprising the following steps: - applying the covering material (14) onto the electrical or electronic component (12); and - treating the covering material (14) in such a manner that a targeted carbonation of the cement is carried out at a surface (28) of the covering material (14).