Resistive Paste Composition for High Resistance and Stable TCR
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Solution Overview
Problem
Existing resistive pastes face a challenge in achieving both high specific resistance and low temperature coefficient of resistance (TCR) for chip resistors, as increasing the addition of resistance value adjusting components tends to excessively reduce the TCR.
Innovation Solution
A resistive paste comprising metal particles (copper and nickel), insulating particles (alumina, zirconia, or boron nitride), and glass particles (including boric oxide and aluminum oxide) with a metal silicide, which produces nickel silicide and nickel aluminum boride upon baking, effectively balancing specific resistance and TCR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the addition amount of resistance value adjusting component (insulating particles) is increased to further increase the specific resistance, then the specific resistance is improved, but the temperature coefficient of resistance (TCR) is excessively reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the glass particles, specifically incorporating boric oxide and aluminum oxide in controlled proportions. This parameter change allows the glass particles to form nickel boride and nickel aluminum boride compounds that simultaneously increase specific resistance and maintain TCR within the target range of -50 to +50 ppm/°C.
Solution Approach 2:
The patent creates a composite material system where glass particles containing boric oxide and aluminum oxide interact with nickel to form multiple compounds (nickel boride, nickel aluminum boride, and nickel silicide). This composite approach allows the resistive paste to achieve both high specific resistance and appropriate TCR by combining the effects of multiple compounds with different electrical properties.
2Quantity of substance
If the addition amount of insulating particles is increased to achieve high specific resistance, then the specific resistance is improved, but the TCR decreases excessively
Solution Approach 1:
The patent modifies the chemical composition of the glass particles by incorporating boric oxide (40-70 wt%) and aluminum oxide (5-20 wt%) in specific proportions. This parameter change enables the glass particles to form nickel boride and nickel aluminum boride compounds that provide both high resistance and stable TCR characteristics.
Solution Approach 2:
The patent employs a composite material approach where the glass particles contain multiple oxide components that react with nickel to form a mixture of compounds. The nickel boride provides high resistance, while the nickel aluminum boride and nickel silicide components work together to maintain TCR within the desired range, achieving a balance between the two properties.
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 resistive paste achieves high specific resistance while maintaining a low TCR, preventing excessive decrease due to increased insulating particle content, thus optimizing the electrical properties of the resistive element.
Implementation Method 1
Glass particles including at least boric oxide and aluminum oxide, wherein nickel boride and nickel aluminum boride are produced when a resistive element of a chip resistor is formed from the resistive paste
Data Source
AI summary
A resistive paste according to the present disclosure includes metal particles, insulating particles, glass particles, and a metal silicide. The metal particles include copper and nickel. The insulating particles include at least one of alumina, zirconia, zinc oxide, or boron nitride. A chip resistor according to the present disclosure includes a resistive element and a substrate. The resistive element includes the resistive paste as a material and is disposed on the substrate.