Ceramic Sheet Sintering Process for Uniform Densification
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Solution Overview
Problem
The existing sintering processes for ceramic sheets often result in fragility, low qualified rates, high production costs, and limited thickness due to inhomogeneous densification and improper temperature control, leading to cracks and breakage, especially in thin sheets with uneven thickness.
Innovation Solution
A controlled sintering process with specific temperature ramping sequences (slow, rapid, and slow heating) and cooling rates, combined with biscuit firing and glazing, using a water-reducing agent and petuntze-based slurry with precise composition, to form a ceramic sheet with a bumpy outer surface and thin, transparent design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid heating is used to reduce sintering time, then productivity increases, but inhomogeneous densification occurs causing cracks and breakage
Solution Approach 1:
The sintering process is divided into multiple heating stages with different rates: slow heating (100-400°C at 1-2 hours), rapid heating (400-900°C at 2-3 hours), and very slow heating (900-1100°C at >3 hours), followed by controlled temperature maintenance (1100-1350°C at 3-4 hours). This segmentation allows different parts of the temperature range to be optimized for different purposes, resolving the contradiction between speed and quality.
Solution Approach 2:
The sintering process employs periodic temperature adjustments including multiple heating phases, a cooling phase, and a reheating phase (1230-1270°C to 1290-1310°C). This periodic action ensures uniform densification throughout the ceramic sheet while maintaining high productivity through optimized cycle timing.
2Reliability
If slow heating is used to ensure uniform densification, then qualified rate increases, but production time and cost increase
Solution Approach 1:
The heating process is segmented into phases with different rates matched to specific temperature ranges and material states. Slow heating is applied only where necessary (100-400°C for dehydration, 900-1100°C for densification), while rapid heating is used in intermediate ranges (400-900°C), optimizing both quality and time.
Solution Approach 2:
The sintering process maintains continuous useful action through optimized temperature maintenance (1100-1350°C for 3-4 hours) and reheating (1230-1270°C to 1290-1310°C) phases, ensuring complete densification without unnecessary delays, thus reducing total time while maintaining high qualified rates.
3Strength
If high sintering temperature is used to achieve densification, then ceramic strength increases, but thermal stress causes cracks and breakage
Solution Approach 1:
The process applies different heating rates to different temperature ranges based on the material's state at each stage. Very slow heating is used at 900-1100°C where densification occurs, reducing thermal stress, while rapid heating is used at 400-900°C where the material is more tolerant of thermal gradients.
Solution Approach 2:
The temperature profile includes periodic cooling and reheating phases: cooling with very slow rate after reaching 1350°C, then reheating from 1230-1270°C to 1290-1310°C. This periodic action relieves accumulated thermal stress while achieving complete densification and high strength.
4Quantity of substance
If thin ceramic sheets are produced to reduce material usage, then cost decreases, but fragility and breakage increase
Solution Approach 1:
The process uses precise control of temperature parameters including maintenance at 1100-1350°C for 3-4 hours and reheating from 1230-1270°C to 1290-1310°C, along with very slow cooling rates. These parameter changes ensure uniform densification throughout thin sheets, achieving high strength and transparency while maintaining thin dimensions (1.0-4.0 mm).
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 process significantly increases the success rate of ceramic sheet sintering, achieving smooth, bright glazes, and allows for larger, thinner sheets with a three-dimensional effect, enhancing transparency and aesthetic appeal.
Implementation Method 1
heating up slowly when the temperature of the kiln ranges from 100 to 400° C., the temperature rise duration ranges from 1 to 2 hours; heating up rapidly when the temperature of the kiln ranges from 400 to 900° C., the temperature rise duration ranges from 2 to 3 hours; heating up very slowly when the temperature of the kiln ranges from 900 to 1100° C., the temperature rise duration should be longer than 3 hours
Implementation Method 2
when the temperature of the kiln reaches 1350° C., cooling with a very slow cooling rate
Implementation Method 3
a light source may be set on the ceramic sheet, consequently a three-dimensional effect of shadow carving with soft, bright and transparent effects is achieved
Data Source
AI summary
Disclosed is a sintering process for ceramic sheets. After biscuit firing and glazing, a green body is placed in a kiln, wherein the temperature of the kiln is controlled such that: when the kiln temperature is 100-400° C., the temperature rise duration is 1-2 hours when the kiln temperature is 400-900° C., the temperature rise duration is 2-3 hours; when the kiln temperature is 900-1100° C., the temperature rise duration must reach 3 hours or more; when the kiln temperature is 1100-1350° C. the temperature rise duration is controlled to be 3-4 hours; and after the temperature reaches 1350° C., heat-preservation cooling is conducted; when the temperature drops to 1230-1270° C., the temperature is raised again to 1290-1310° C.; when the temperature drops again to 880-920° C., the kiln cover is opened for cooling, and the finished product is taken out.