Sintering Solid Oxide Cells Using Spacer-Mediated Load
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Solution Overview
Problem
The sintering process of solid oxide cells often results in deformation due to differing thermal expansion coefficients of the layers, leading to contact issues and material waste, making mass production costly and inefficient.
Innovation Solution
A method involving a body in the green or pre-sintered state on a support with a load on spacers that initially do not contact the body, heat-treated at specific temperatures to prevent sticking and allow uniform sintering, ensuring minimal stress and uniform expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional sintering is performed without load application, then the sintering process is simple, but the body deforms due to thermal expansion differences between layers
Solution Approach 1:
A load is placed on the green body before sintering begins. This preliminary application of load ensures that the body is constrained during the sintering process, preventing deformation caused by thermal expansion differences between layers. The load is removed only after sintering is complete, at which point the body has already achieved its desired flat shape.
2Manufacturing precision
If a load is applied directly to the green body during sintering, then deformation is prevented, but the green body sticks to the load causing defects
Solution Approach 1:
A coating layer is applied to the load before placing it on the green body. This coating acts as an intermediary between the load and the green body, preventing direct adhesion while still allowing the load to effectively constrain the body during sintering. The coating prevents sticking and potential defects while maintaining the load's stabilizing function.
3Manufacturing precision
If the load contacts the green body immediately, then deformation is prevented, but the organic components cannot decompose properly
Solution Approach 1:
The load is positioned to contact the green body only after the organic components have decomposed. During the initial heating phase, the load is either not in contact or contacts minimally, allowing organic decomposition to occur without interference. Once decomposition is complete and the body structure is stabilized, the load is applied or increased to prevent deformation during the main sintering phase.
4Stability of the object's composition
If symmetric layer arrangement is used, then thermal stress is reduced, but material selection is restricted
Solution Approach 1:
Instead of requiring symmetric layer arrangements, the invention applies a mechanical load parameter to counteract thermal expansion differences. This approach changes the problem from a material arrangement constraint to a process parameter control, allowing asymmetric layer configurations with different materials to be used while still preventing deformation during sintering.
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 method reduces material waste and deformation, resulting in a more cost-effective and efficient production of solid oxide cells with fewer defects, achieving a uniform and flat sintered body.
Implementation Method 1
heat treating the body in the green state or in the pre-sintered state at a temperature above the softening point or decomposition temperature of the spacer such that the load contacts the body
Implementation Method 2
heat treating the body in the green state or in the pre-sintered state at a temperature above the decomposition temperature of organic components contained in the green body
Implementation Method 3
sintering the body in the green state or pre-sintered state
Implementation Method 4
providing a load on at least one spacer on the support such that the load is located above said body
Data Source
AI summary
The present invention provides a method for sintering, comprising in the following order the steps of: providing a body in the green state or in the pre-sintered state on a support; providing a load on at least one spacer on the support such that the load is located above said body in the green state or in the pre-sintered state without contacting the body; heat treating the body in the green state or in the pre-sintered state at a temperature above the decomposition temperature of organic components contained in the green body and below the softening temperature or decomposition temperature of the spacer; heat treating the body in the green state or in the pre-sintered state at a temperature above the softening point or decomposition temperature of the spacer and below a sintering temperature such that the load contacts the body, and—sintering the body in the green state or pre-sintered state.