Green Garnet Thin Film Sintering to Prevent Cracking and Sticking
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Solution Overview
Problem
Solid state ion conducting ceramics, such as lithium-stuffed garnets, face issues during film casting and sintering, including sticking to substrates, cracking, warping, and brittleness, which hinder the production of high-density thin films suitable for electrochemical devices.
Innovation Solution
A method involving the preparation of a modified source powder, forming a slurry, casting a green tape, and sintering it to produce a sintered thin film, using specific solvents, binders, and sintering aids to enhance film quality and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional casting and sintering methods are used for solid state ion conducting ceramics, then the films can be produced, but the films stick to the substrate, crack, warp, or become too brittle to handle
Solution Approach 1:
The patent introduces a release layer as an intermediary between the green film and the substrate. This release layer prevents the green film from sticking to the substrate during sintering, allowing the film to be easily removed after sintering without damage. The release layer acts as a mediator that eliminates the harmful sticking effect while maintaining film integrity.
Solution Approach 2:
The patent modifies the sintering process parameters including using a controlled atmosphere (oxygen partial pressure from 1e-1 to 1e-20 atm), specific temperature ranges (700-1200°C), and extended sintering times (1-600 minutes). These parameter changes optimize the sintering process to produce films with reduced cracking, warping, and brittleness while maintaining high density.
2Manufacturing precision
If conventional sintering methods are used, then the films can be sintered, but the films exhibit surface deteriorations, cracking, and warping
Solution Approach 1:
The patent implements precise control of sintering parameters including temperature (700-1200°C), time (1-600 minutes), and oxygen partial pressure (1e-1 to 1e-20 atm). These controlled parameter changes enable the production of high-quality films with minimal surface deterioration, cracking, and warping, achieving superior manufacturing precision.
Solution Approach 2:
The patent employs feedback control during the sintering process by monitoring and adjusting oxygen partial pressure and temperature to maintain optimal conditions. This feedback mechanism ensures consistent film quality by preventing surface deteriorations, cracking, and warping that would occur with uncontrolled sintering processes.
3Quantity of substance
If higher solid loading is used in green tapes, then the sintered films have higher density and lower porosity, but the casting and sintering processes become more difficult
Solution Approach 1:
The patent achieves high solid loading (60-80 wt% or more) in green tapes by modifying slurry composition and using optimized casting parameters. The high solid loading slurry is cast to form green tapes that maintain good flowability and casting characteristics despite the high ceramic content, enabling easier manufacture while achieving high density films after 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
The method results in sintered thin films with lower porosity, higher density, and improved surface quality, suitable for electrochemical devices without further processing, and achieves higher yield and reduced defects.
Implementation Method 1
casting the slurry to form a green tape
Implementation Method 2
sintering the green tape to form a sintered thin film
Implementation Method 3
drying the green tape
Data Source
AI summary
Set forth herein are processes and materials for making ceramic thin films by casting ceramic source powders and precursor reactants, binders, and functional additives into unsintered thin films and subsequently sintering the thin films under controlled atmospheres and on specific substrates.