Ni-Based Resistor Alloy Balancing Resistivity and Workability
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Solution Overview
Problem
Existing resistance materials struggle to achieve a balance of appropriate hardness, volume resistivity, and temperature coefficient of resistance, with Ni—Cr—Al-based alloys often having issues with excessive temperature coefficient increases or decreased workability when manufacturing conditions are inappropriate.
Innovation Solution
A Ni-based alloy with specific composition ranges (15% ≤ Cr ≤ 25%, 1% ≤ Al ≤ 4%, 1% ≤ Cu ≤ 3%, 0% ≤ Si ≤ 1.5%, 0% ≤ Mn ≤ 1.5%, with the balance being Ni and inevitable impurities, undergoing a manufacturing process involving melting and casting, homogenization heat treatment, hot working, cold working, and optimized heat treatment to control the precipitation of γ′ phase and short-range ordered phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ni—Cr—Al-based alloy is used to achieve high volume resistivity, then volume resistivity is improved, but temperature coefficient of resistance increases excessively and hardness increases causing decreased workability
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters (Cr: 15-25%, Al: 1-4%, Cu: 1-3%, Si: 0-1.5%, Mn: 0-1.5%) and heat treatment parameters (solution treatment temperature, time, and cooling rate) to achieve the optimal balance between volume resistivity and workability. This systematic parameter optimization resolves the contradiction by finding the specific parameter range where both high volume resistivity and acceptable workability coexist.
Solution Approach 2:
The patent employs composite material principles by creating a multi-element Ni-based alloy system that combines Cr, Al, Cu, Si, and Mn in specific proportions. This composite alloy structure allows the material to simultaneously achieve high volume resistivity through Cr and Al content while maintaining workability through the balancing effects of Cu, Si, and Mn, thus resolving the technical contradiction between these properties.
2Reliability
If Ni—Cr—Al-based alloy is used to achieve high volume resistivity, then volume resistivity is improved, but temperature coefficient of resistance increases excessively
Solution Approach 1:
The patent uses parameter changes by optimizing the Al content (1-4%) and Cr content (15-25%) ratio, along with adding Cu (1-3%), Si (0-1.5%), and Mn (0-1.5%), to achieve high volume resistivity while controlling the temperature coefficient of resistance within -50 to 10 ppm/°C. The solution treatment parameters (temperature, time, cooling rate) are also optimized to achieve the desired electrical properties.
Solution Approach 2:
The patent applies composite material principles by formulating a multi-element alloy where Cr and Al provide high volume resistivity, while Cu, Si, and Mn work synergistically to stabilize the temperature coefficient of resistance. This composite alloy composition resolves the contradiction between achieving high volume resistivity and maintaining stable temperature coefficient of resistance.
3Reliability
If solution treatment is performed to control electrical characteristics, then electrical characteristics are improved, but hardness increases excessively
Solution Approach 1:
The patent applies parameter changes by optimizing the solution treatment parameters (temperature, time, and cooling rate) combined with the specific alloy composition to achieve the desired balance between electrical characteristics and hardness. The controlled cooling rate after solution treatment is particularly important in preventing excessive hardness while maintaining good electrical 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 solution achieves a resistor with Vickers hardness of 160 Hv or more and 230 Hv or less, volume resistivity of 125 μΩ·cm or more and 150 μΩ·cm or less, and a temperature coefficient of resistance between −50 ppm/°C and 10 ppm/°C, ensuring high workability and thermal stability.
Implementation Method 1
a homogenization heat treatment step of performing a homogenization heat treatment on the ingot to obtain a heat-treated body
Implementation Method 2
a heat treatment step of performing a heat treatment for removing strain and controlling a precipitation amount of a γ′ phase and a formation amount of a short-range ordered phase
Implementation Method 3
a heat treatment step of performing a heat treatment for removing strain and controlling a precipitation amount of a γ′ phase
Data Source
AI summary
The present invention relates to a resistor including a Ni-based alloy that consists of 15.0 mass %≤Cr≤25.0 mass %, 1.0 mass %≤Al≤4.0 mass %, 1.0 mass %≤Cu≤3.0 mass %, 0 mass %≤Si≤1.5 mass %, and 0 mass %≤Mn≤1.5 mass %, with the balance being Ni and inevitable impurities, in which the resistor has a Vickers hardness at 20° C. of 160 Hv or more and 230 Hv or less, a volume resistivity at 20° C. of 125 μΩ·cm or more and 150 μΩ·cm or less, and a temperature coefficient of resistance at 20° C. to 155° C. of −50 ppm/° C. or more and 10 ppm/° C. or less, and relates to a manufacturing method thereof.