High-Temperature Ceramic Components With Sacrificial-Powder Pathways
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Solution Overview
Problem
Producing high temperature ceramic components with complex shapes and internal voids or passages is challenging due to material shrinkage during sintering, making near net-shape products difficult to achieve without extensive post-processing like machining.
Innovation Solution
A method involving additive manufacturing and direct current sintering (DCS) is used to create a green body with a primary and sacrificial powder, accounting for anisotropic shrinkage, followed by sintering and removal of the sacrificial powder to form ceramic components with internal voids and pathways, reducing the need for post-processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If traditional machining processes are used to create complex internal voids and passages in ceramic components, then the desired structure can be achieved, but the manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The patent incorporates sacrificial powder into the green body during additive manufacturing before sintering. This preliminary action allows internal voids and passages to be formed automatically during the sintering process when the sacrificial powder is removed, eliminating the need for complex post-manufacturing machining operations to create these features
Solution Approach 2:
The patent utilizes the parameter change of anisotropic shrinkage during sintering by elongating the green body along the build direction to compensate for expected shrinkage. This ensures that the final sintered component achieves the desired dimensions and complex internal features without requiring extensive machining
2Manufacturing precision
If ceramic components are sintered without accounting for anisotropic shrinkage, then the sintering process is simpler, but the manufacturing precision and dimensional accuracy deteriorate
Solution Approach 1:
The patent performs preliminary calculation and elongation of the green body dimensions to compensate for anisotropic shrinkage before sintering. By pre-adjusting the green body geometry based on expected shrinkage behavior, the final sintered component achieves accurate dimensions without requiring complex real-time control during sintering
Solution Approach 2:
The patent accounts for thermal effects during sintering by incorporating anisotropic shrinkage compensation into the green body design. The elongation along the build direction compensates for the directional shrinkage that occurs during heating and sintering, ensuring dimensional accuracy in the final component
3Shape
If green body is not elongated to account for anisotropic shrinkage, then the manufacturing process is simpler, but the shape and dimensional accuracy of the final component deteriorate
Solution Approach 1:
The patent applies preliminary elongation to the green body in the build direction to compensate for anisotropic shrinkage before sintering. This pre-adjustment ensures that the final sintered component achieves the desired shape and dimensions, with the elongation factor determined by the expected shrinkage behavior
Solution Approach 2:
The patent changes the geometric parameter of the green body by elongating it along the build direction. This parameter adjustment compensates for the anisotropic shrinkage that will occur during sintering, ensuring that the final component maintains the correct shape and dimensions
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 method enables the production of ceramic components with complex internal features and near net shapes, minimizing the need for post-processing such as machining.
Implementation Method 1
performing a direct current sintering (DCS) process on the green body under axial loading along the first axis and at elevated temperatures sufficient to sinter the green body
Implementation Method 2
the green body is elongated relative to a first axis to account for anisotropic shrinkage during sintering thereof
Data Source
AI summary
Methods for forming ceramic components and the component formed thereby are provided. The methods include producing a green body including a primary powder and a sacrificial powder, wherein the green body is elongated relative to a first axis to account for anisotropic shrinkage during sintering thereof, performing a direct current sintering (DCS) process on the green body under axial loading along the first axis and at elevated temperatures sufficient to sinter the green body and produce an intermediate component having a first portion including a sintered ceramic material formed from the primary powder and a second portion including the sacrificial powder or a derivative thereof, and removing the sacrificial powder or the derivative thereof from the intermediate component leaving voids and/or pathways within the first portion and thereby producing the ceramic component.