Cu-Ni Resistor Protective Layer for Stable TCR and Heat Dissipation
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Solution Overview
Problem
Conventional resistor components face issues with increased resistance value change rates and reduced reliability due to nickel and copper diffusion during the sintering process, and lower rated power due to inadequate heat dissipation from glass-based protective layers.
Innovation Solution
A resistor component design featuring a substrate with a resistive layer made of a Cu—Ni alloy and a protective layer including copper or nickel, which diffuses into the resistive layer to maintain a low temperature coefficient of resistivity and enhance heat dissipation, thereby reducing resistance value change rates and improving reliability and rated power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass-based protective layer is used to protect the resistive layer, then the resistive layer is protected from separation, but the heat dissipation capability is reduced leading to lower rated power
Solution Approach 1:
The protective layer material is changed from glass to metal (Ni or Cu), fundamentally altering the thermal conductivity parameter. Metal materials have significantly higher thermal conductivity than glass, enabling effective heat dissipation while maintaining protective functions. This parameter change resolves the contradiction by selecting a material that simultaneously provides protection and superior heat dissipation.
Solution Approach 2:
The protective layer is designed as a composite structure containing metal particles (Ni or Cu) embedded in a glass matrix. This composite approach combines the protective properties of glass with the heat dissipation capabilities of metal, achieving both protection and effective thermal management in a single integrated layer.
2Power
If nickel or copper is used in the electrode, then good conductivity is achieved, but diffusion into the resistive layer during sintering increases the temperature coefficient of resistivity
Solution Approach 1:
The harmful diffusion of Ni or Cu from the electrode into the resistive layer is converted into a beneficial effect. By intentionally adding the same metal elements to the protective layer, the patent creates a controlled diffusion source that compensates for unwanted diffusion, maintaining stable TCR while preserving electrode conductivity.
Solution Approach 2:
The protective layer is formulated with the same metal elements (Ni or Cu) as the electrode, creating compositional homogeneity. This ensures that the protective layer and electrode work synergistically, with the protective layer's metal content matching the electrode's metal content to maintain consistent diffusion characteristics and stable TCR throughout the component.
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 solution effectively maintains a low temperature coefficient of resistivity and resistance value change rate, enhancing the reliability and rated power of the resistor component by controlling the diffusion of metals and improving heat dissipation.
Implementation Method 1
nickel (Ni) or copper (Cu) contained in an electrode may diffuse into the resistive layer
Implementation Method 2
glass or the like included in the conventional protective layer may have lower heat dissipation than metal
Data Source
AI summary
A resistor component includes a substrate having a first surface and a second surface, opposing each other; an external electrode disposed outside of the substrate; a resistive layer disposed on the first surface of the substrate, connected to the external electrode, and including an alloy of a first metal and a second metal; and a first protective layer disposed on the resistive layer and including any one of the first and second metals.