Composite Thermistor Sintered Body for Low B-Constant Sensing
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Solution Overview
Problem
Thermistors used in high temperature ranges face challenges in accurately detecting temperature due to the limitations of their B constant, which needs to be controlled to cope with higher temperature ranges.
Innovation Solution
A thermistor sintered body with a composite structure including the Y2O3 phase and the Y(Cr, Mn)O3 phase or the YMnO3 phase, where the composition is controlled such that 0 ≤ Cr/Mn < 1.0, effectively lowering the B constant to 2400 K or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermistor is designed for wide temperature range detection, then the temperature range expands, but the B constant becomes too large causing inaccurate detection
Solution Approach 1:
The patent changes the chemical composition parameters of the thermistor material by controlling the Cr/Mn ratio to be less than 1.0 and adding CaO (3-10 mol%), which fundamentally alters the electrical resistance characteristics and reduces the B constant to enable accurate detection across the expanded temperature range
Solution Approach 2:
The patent creates a composite oxide material system combining multiple metal oxides (Cr2O3, MnO2, CaO, and other metal oxides) with specific compositional ratios, where the interaction between different oxide components produces synergistic effects that optimize both the temperature range and detection accuracy
2Temperature
If the B constant is reduced for high temperature operation, then high temperature detection becomes possible, but the composition control becomes more difficult
Solution Approach 1:
The patent establishes specific parameter ranges for composition control (Cr/Mn ratio < 1.0, CaO content 3-10 mol%) that provide a manufacturing window balancing high temperature performance with compositional controllability, making the complex composition manageable through defined specifications
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 configuration allows for accurate temperature detection in a wide temperature range from -50°C to 1200°C, ensuring the thermistor sintered body can effectively operate in high temperature applications.
Implementation Method 1
The thermistor is a substance which detects a temperature based on a change in the resistance value, and when the resistance value becomes too low, cannot accurately detect the temperature. The thermistor has an NTC (Negative Temperature Coefficient: negative temperature coefficient of resistance) characteristics
Data Source
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AI summary
The present invention provides a thermistor sintered body that is capable of suppressing a B-constant at 1000°C to a level comparable to that of a conventional wide range-type product. This thermistor sintered body is formed of a composite structure provided with a Y2O3 phase, and a Y(Cr, Mn)O3 phase or a YMnO3 phase. The thermistor sintered body according to one embodiment of the present invention has a chemical composition, excluding oxygen, of 3-9 mol% of Cr, 5-15 mol% of Mn, 1-8 mol% of Ca (wherein Cr/Mn<1.0), with the remainder being Y