Composite Thermistor Bonding Layer for Low-Temperature Sintering
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Solution Overview
Problem
Conventional thermistors face challenges in achieving high bonding strength between the thermistor layer and electrodes due to differences in thermal expansion coefficients and the need for high-temperature sintering, which can degrade bonding strength and thermistor characteristics.
Innovation Solution
A thermistor design utilizing a composite thermistor layer containing metal oxide particles with Mn and Ni, an amorphous phase, and electrodes made from Cu, Al, Ag, or Ni, with a bonding layer formed by diffusing these elements into the composite, allowing for high bonding strength and improved electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal oxide thermistor layer is formed by conventional sintering at high temperature (900°C or higher), then the thermistor layer can be formed, but bonding strength between the thermistor layer and electrode deteriorates due to difference in thermal expansion coefficient
Solution Approach 1:
The invention changes the sintering temperature parameter from conventional high temperature (900°C or higher) to low temperature (600°C or lower), which resolves the thermal expansion mismatch problem between the thermistor layer and electrode, thereby maintaining high bonding strength while still forming a functional thermistor layer
Solution Approach 2:
The invention uses a composite material containing metal oxide particles (with Mn and Ni) and an amorphous phase, which enables low-temperature sintering while maintaining the necessary thermistor characteristics and bonding strength, overcoming the limitation of conventional single-phase metal oxide materials
2Temperature
If metal nitride thermistor layer is formed by sputtering at room temperature, then formation temperature is reduced, but bonding strength between the thermistor layer and electrode is not sufficient
Solution Approach 1:
The invention employs a composite material consisting of metal oxide particles and an amorphous phase that contains Mn and Ni, which provides both low-temperature formability (similar to sputtering advantages) and high bonding strength (overcoming the weakness of metal nitride), achieving a balance between formation temperature and bonding strength
3Temperature
If high-temperature sintering is applied to metal oxide thermistor layer, then thermistor layer formation is achieved, but thermistor characteristics deteriorate
Solution Approach 1:
The invention changes the sintering temperature parameter to low temperature (600°C or lower), which prevents the deterioration of thermistor characteristics that occurs at high temperatures, while still achieving proper densification and electrical properties through the unique composite material composition
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 design achieves high bonding strength and stability of thermistor characteristics, ensuring reliable performance under environmental changes while maintaining flexibility and thermal responsiveness, suitable for small and flexible applications.
Implementation Method 1
the metal oxide requires sintering at a high temperature of 900° C. or higher in a conventional general forming method
Implementation Method 2
due to a difference in thermal expansion coefficient between the thermistor layer (metal oxide) and the electrode, it is difficult to obtain high bonding strength
Implementation Method 3
a bonding layer formed by diffusing these elements into the composite
Data Source
AI summary
A thermistor that includes: a base layer containing a resin component; a thermistor layer on the base layer, wherein the thermistor layer is a composite which includes a plurality of particles including a metal oxide containing at least one first metal element that is at least one of Mn and Ni, and an amorphous phase between the plurality of particles and which contains the same metal element as the first metal element; two electrodes, wherein the two electrodes include at least one second metal element selected from the group consisting of Cu, Al, Ag, and Ni; and a bonding layer between the two electrodes and the thermistor layer, the bonding layer comprising the composite, the second metal element, and the resin component.