Transparent Ceramic Production via Controlled Organic Additive Composition
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Solution Overview
Problem
The dry process for producing transparent ceramics often results in bubble defects due to gaps forming between granules during molding, which are difficult to avoid and can lead to optical defects in the final product.
Innovation Solution
A method involving the selection of an organic additive composition with a specific glass transition temperature range (25°C to 60°C) is used to produce transparent ceramics. This composition, containing a binder, optionally a dispersant, and optionally a plasticizer, is mixed with metal oxide powder, pulverized, granulated, sintered, and pressurized to produce defect-free transparent ceramics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dry process is used for producing transparent ceramics, then productivity is improved, but bubble defects occur due to gaps forming between granules during molding
Solution Approach 1:
The invention changes the physical-chemical parameters of the granules by controlling their crushing strength within a specific range (0.3-6.0 MPa) and adjusting their moisture content (5-20%). These parameter adjustments optimize the granule properties to prevent gap formation during molding while maintaining the efficiency of the dry process, thereby resolving the contradiction between productivity and manufacturing precision.
2Manufacturing precision
If organic additives are mixed into powder to form slurry, then gap sizes between granules are reduced and shape retention is improved, but product quality becomes dependent on trial and error selection of additives
Solution Approach 1:
The invention establishes specific parameter ranges for organic additives, particularly controlling the crushing strength of granules to 0.3-6.0 MPa and moisture content to 5-20%. This quantifies the previously empirical additive selection process, providing clear guidelines that reduce trial and error while improving gap reduction and shape retention.
Solution Approach 2:
The invention uses composite organic additives comprising both binders and plasticizers in specific combinations. This composite approach synergistically improves both the binding effect (reducing gaps) and the plasticity (improving shape retention), while the defined composition ratios simplify the selection process compared to using multiple additives without guidance.
3Strength
If granule crushing strength is less than 0.3 MPa, then granules are easily crushed, but voids inside granules remain and bubbles are likely to occur
Solution Approach 1:
The invention identifies and controls the crushing strength parameter within the optimal range of 0.3-6.0 MPa. This parameter optimization ensures granules have sufficient strength to prevent internal void formation and bubble generation, while maintaining appropriate crushability for molding, thereby resolving the contradiction between strength and manufacturing precision.
4Strength
If granule crushing strength is greater than 6.0 MPa, then granules maintain structural integrity, but intergranular voids cannot be crushed and optical defects remain
Solution Approach 1:
The invention sets the upper limit of granule crushing strength at 6.0 MPa to ensure that granules are soft enough to allow intergranular voids to be eliminated during molding and sintering. This parameter control prevents the formation of intergranular voids that would cause optical defects, while maintaining sufficient structural integrity for handling and molding.
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 achieves transparent ceramics with high transmittance and no bubble defects, ensuring uniform insertion loss and optimal optical performance, making them suitable for optical use without visible optical defects.
Implementation Method 1
a binder... is mixed with metal oxide powder
Implementation Method 2
the slurry is made into dry granules by a method such as spray-drying
Implementation Method 3
sintering the granulated mixture to obtain a sintered body
Data Source
AI summary
A method produces transparent ceramics having high transmittance and no bubble defects with uniform insertion loss over the entire inner surface thereof. The method comprising the steps of:obtaining a candidate composition containing a binder, optionally a dispersant, and optionally a plasticizer;dissolving the candidate composition in a solvent, then reducing a contained solvent volume to 0.1% by mass or less, and measuring a glass transition temperature;selecting a candidate composition having a glass transition temperature of 25° C. or more and 60° C. or less as an organic additive composition;preparing the organic additive composition containing the binder, optionally the dispersant, and the plasticizer, and having the composition obtained in the selecting step;pulverizing a raw material for sintering formed from metal oxide powder and the organic additive composition to obtain a pulverized mixture;granulating the pulverized mixture;sintering the granulated mixture to obtain a sintered body; andpressurizing the sintered body.