Translucent Piezoelectric Glass Ceramic Crystal Control
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Solution Overview
Problem
Current piezoelectric glass ceramics are either opaque or lack translucency in the visible and infrared ranges, limiting their applications, and existing methods for achieving translucency often compromise piezoelectric performance.
Innovation Solution
A method to prepare translucent piezoelectric glass ceramics by controlling the average crystal size of non-ferroelectric piezo-active crystallites to less than 1 micrometer, using a temperature gradient during the ceramization process, and subsequent poling of ferroelectric crystallites to ensure preferred orientation and maintain piezoelectric behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crystal size is increased to improve piezoelectric performance, then the piezoelectric characteristics are enhanced, but the translucency deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystal size parameter within a specific range (0.1-1 micrometer) to simultaneously achieve both piezoelectric performance and translucency. The ceramization process parameters (temperature, time, atmosphere) are optimized to produce crystals of this critical size range that balances optical transparency with piezoelectric activity.
Solution Approach 2:
The patent implements local quality by creating a heterogeneous structure where crystalline phases with piezoelectric properties are distributed within a glass matrix. This composite structure allows different regions to serve different functions: the glass matrix provides translucency while the embedded micro-crystals provide piezoelectric response, resolving the contradiction between the two properties.
2Reliability
If a temperature gradient is applied during ceramization to achieve crystal orientation, then piezoelectric functionality is enabled, but the manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating orientation-promoting agents or nucleating particles into the glass matrix before ceramization. These pre-added components create preferred nucleation sites that guide crystal growth orientation during the subsequent heating process, eliminating the need for complex external temperature gradient applications while still achieving the necessary crystal alignment for piezoelectric functionality.
3Illumination intensity
If the crystal size is reduced below 1 micrometer to achieve translucency, then the translucency is improved, but the piezoelectric response may be compromised
Solution Approach 1:
The patent employs composite materials by creating a glass-ceramic composite where the glass phase provides optical transparency and the crystalline phase provides piezoelectric properties. The specific composition (containing BaO, TiO2, SiO2, and other oxides) is designed to form a two-phase composite structure where nanocrystals are embedded in a glass matrix, allowing both translucency and piezoelectric response to coexist despite the small crystal size.
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 approach achieves both good translucency and piezoelectric characteristics in the visible and infrared ranges, with crystal sizes controlled to be smaller than 100 nm for optimal results, allowing for up to 30% transmission in the visible range and IR range.
Implementation Method 1
Piezoelectric materials are intensively used worldwide, due to their unique material's performance. Piezoelectric glass ceramic materials provide an interesting and promising alternative to conventional piezoelectric materials such as PZT ceramics.
Implementation Method 2
the converse—an applied electrical charge (field) results in a change of shape of the material)
Implementation Method 3
Halliyal et al. used a crystallization in a temperature gradient which was generated by positioning polished glass samples on a microscope hot stage. Thereby piezoelectric samples could be prepared from non-ferroelectric piezo-active materials by effecting a preferred direction of orientation of the precipitated crystallites.
Implementation Method 4
internal domain alignment via the application of an electric field (so-called 'poling') which is only available for ferroelectric materials
Data Source
AI summary
A translucent piezoelectric glass ceramic is disclosed. The glass ceramic is prepared from a precursor glass by a ceraming process, using a temperature gradient to effect the precipitation of non-ferroelectric piezo-active crystallites from the precursor glass with a preferred direction of orientation and having an average crystal size of less than 1 micrometer. Alternatively, a translucent piezoelectric glass ceramic comprising ferroelectric crystallites may be prepared by poling. In this case the crystal size is controlled to be smaller than 90 nanometers but preferably larger than 10 nanometers.