NiCr Alloy Surface Heating Element Thermal Stress Reduction
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Solution Overview
Problem
Conventional surface type heating elements face issues with low output due to high resistivity, poor mechanical properties, thermal stress, and challenges in joining dissimilar materials, particularly with ceramic and metal substrates, and metal materials have limitations in high-temperature applications due to low melting points and component diffusion.
Innovation Solution
A surface type heating element made from a NiCr alloy with a Ni content ranging from 60 to 95 wt%, which has low temperature coefficient of resistance, high ductility, and resistance to thermal stress, is developed, using a photonic sintering method to ensure stable output and adhesion without increasing thickness, and is designed to have a small coefficient of thermal expansion for reduced thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If ceramic materials are used for surface type heating element, then high resistivity is achieved, but output and operating temperature are limited
Solution Approach 1:
The patent changes the material parameter from ceramic to metal (specifically NiCr alloy), fundamentally altering the electrical resistivity characteristic. This parameter change enables lower resistivity and higher output while maintaining heating functionality.
2Loss of energy
If ceramic materials are used for surface type heating element, then high resistivity is achieved, but mechanical properties and toughness are poor
Solution Approach 1:
The patent changes the material parameter from ceramic to metal (NiCr alloy), fundamentally altering the mechanical properties. This enables improved ductility and toughness while maintaining the heating element functionality.
3Loss of energy
If ceramic materials are used for surface type heating element, then high resistivity is achieved, but thermal stress and thermal shock resistance are poor
Solution Approach 1:
The patent changes the material parameter from ceramic to metal (NiCr alloy), fundamentally altering the thermal stress characteristics. This enables better resistance to thermal deformation and thermal shock while maintaining heating element functionality.
4Strength
If glass frit is added to paste to improve adhesion, then bonding function is enhanced, but resistivity increases
Solution Approach 1:
The patent changes the material parameter from ceramic-based paste to metal-based paste (NiCr alloy), fundamentally altering both adhesion and resistivity characteristics. This enables simultaneous improvement in adhesion while maintaining low resistivity.
5Power
If metal materials are used for surface type heating element, then low resistivity and high output are achieved, but melting point and high-temperature stability are limited
Solution Approach 1:
The patent uses a composite alloy material (NiCr alloy) that combines nickel and chromium in specific proportions. This composite structure provides both low resistivity for high output and high melting point for high-temperature stability.
6Power
If NiCr alloy is used for surface type heating element, then low resistivity and high output are achieved, but adhesion to substrate may be poor
Solution Approach 1:
The patent optimizes the paste composition parameters including NiCr alloy particle size distribution, organic vehicle content, and glass frit content. These parameter changes enable good adhesion while maintaining low resistivity and high output.
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 NiCr alloy surface type heating element achieves stable output, improved mechanical properties, enhanced adhesion, and resistance to thermal stress, extending the product's lifetime and reliability while preventing metal component diffusion at high temperatures.
Implementation Method 1
surface type heating element which generates heat using electricity
Implementation Method 2
a method of sintering a paste including ceramic powder by irradiating the paste with light energy using white light
Data Source
AI summary
Discussed is a surface type heating element which generates heat using electricity and a method of manufacturing the surface type heating element. The surface type heating element includes a NiCr alloy and has an adhesive strength of 3 N or more with respect to a substrate or an insulating layer and an electrical resistivity of 10−4 to 10−2 Ωcm, and thus it can be used even at a high operating temperature of 400° C. or more, suppresses the elution of the material itself, and has high fracture toughness, a low coefficient of thermal expansion, and heat resistance, resulting in improvement of the reliability and lifetime of the product.