Ceramic Heater Metal Coating Prevents Carbonization During Sintering
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Solution Overview
Problem
Conventional ceramic heaters experience conductivity deterioration and non-uniform temperature distribution due to the reaction of buried metal with carbon content during sintering, requiring time-consuming winding of metal members in a non-conduction state.
Innovation Solution
A method involving the formation of a metal coating film with a standard free energy of formation lower than the heat-resistant metal material on a heat-resistant metal material, which is then press-molded into a ceramic green body and sintered, prioritizing the reaction of the coating film with carbon to prevent conductivity deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal heating element is buried in a ceramic base and sintered at high temperature, then the ceramic heater achieves high temperature resistance and structural integrity, but the metal reacts with carbon content in the powder causing carbonization and conductivity deterioration
Solution Approach 1:
A metal coating film made of a metal different from the heating element is applied as an intermediary layer between the metal heating element and the ceramic powder. This coating film acts as a mediator that reacts with carbon content during sintering, preventing direct carbonization of the heating element metal and maintaining its conductivity while still allowing the sintering process to proceed at high temperatures.
2Shape
If a metal member is used to wind a heating element in a non-conduction state before sintering, then the heating element can be properly positioned and shaped, but great time and efforts are required for the winding process
Solution Approach 1:
The metal coating film is applied to the heating element in advance before the sintering process. This preliminary coating action prepares the heating element for controlled carbonization during sintering, eliminating the need for time-consuming winding operations with metal members while ensuring proper positioning and shape are maintained throughout the sintering process.
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
This approach stabilizes the carbonization reaction, preventing conductivity non-uniformity and maintaining the integrity of the heat-resistant metal material's conductivity, even during high-temperature sintering.
Implementation Method 1
the metal coating film reacts with carbon in ceramic on a priority basis... there is an effect in that deterioration in conductivity is prevented by suppressing carbonization of the heat-resistant metal material
Implementation Method 2
a sintering step of generating a ceramic sintered body by sintering the ceramic green body molded in the molding step
Data Source
AI summary
A method of manufacturing a ceramic sintered body, includes: a film forming step of forming, on a surface of a heat-resistant metal material, a metal coating film made of a metal material having a standard free energy of formation of metal carbides lower than that of the heat-resistant metal material; a molding step of disposing the heat-resistant metal material provided with the coating film in the film forming step at a predetermined position in powder that serves as a starting material of a ceramic base, and molding a ceramic green body by press-molding the powder; and a sintering step of generating a ceramic sintered body by sintering the ceramic green body molded in the molding step.