Li(Na/K)NbO3 Niobate Powder Carbon Stabilization
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Solution Overview
Problem
Existing lead-free alkali metal niobate powders for piezoelectric applications are prone to decomposition in high humidity and water, leading to unsuitable ceramics, and their stabilization methods are complex and sensitive to oxidation or require foreign elements.
Innovation Solution
A niobate powder with a general composition of Li(Na/K)NbO3 and a controlled carbon content of 10 to 100 ppm/(m2/g) is produced using a process that excludes CO2, resulting in a niobium oxide carbonate layer on the surface, enhancing stability and allowing processing in humid conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alkali metal niobate powders are used for piezoelectric applications, then lead-free alternative is achieved, but the powders decompose in high humidity and water leading to electrically conductive compounds
Solution Approach 1:
The patent converts the harmful effect of carbon (which typically causes electrical conductivity and destabilization) into a beneficial protective mechanism. By controlling carbon content to 10-100 ppm/(m2/g), the carbon forms a protective layer on the niobate powder surface that prevents water and moisture from reaching and decomposing the underlying material, thus converting carbon's normally harmful role into a protective function.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the carbon content within a specific range (10-100 ppm/(m2/g)) and the calcination temperature (900-1100°C). This optimization of parameters transforms the niobate powder's surface properties, creating a stable structure that resists decomposition in humid environments while maintaining piezoelectric functionality.
2Reliability
If stabilization methods are applied to improve water resistance, then stability improves, but the production methods become very complicated
Solution Approach 1:
The patent extracts and eliminates harmful impurities (excessive carbon, foreign elements) during the calcination process, retaining only the beneficial controlled carbon content (10-100 ppm/(m2/g)). This extraction approach simplifies the production method by removing the need for complex multi-step stabilization processes while achieving the desired moisture resistance.
Solution Approach 2:
The niobate powder undergoes self-stabilization during calcination at 900-1100°C, where the controlled carbon content automatically forms a protective surface layer. This self-service mechanism eliminates the need for additional complex stabilization steps, foreign element additions, or organic coatings, simplifying the overall production process.
3Reliability
If foreign elements are introduced to achieve stabilization, then resistance to moisture improves, but oxidation sensitivity increases
Solution Approach 1:
The patent changes the chemical composition parameters by controlling carbon content to 10-100 ppm/(m2/g) and avoiding foreign elements. The calcination temperature parameter (900-1100°C) is optimized to create a stable surface structure that provides moisture resistance without introducing oxidation-sensitive foreign elements, thus resolving the contradiction between stability and oxidation sensitivity.
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 niobate powder exhibits significantly improved stability in water and moisture, enabling processing in aqueous environments without the need for organic solvents, thus providing a lead-free alternative for piezoelectric materials with enhanced piezoelectric properties.
Implementation Method 1
A niobate powder with a general composition of Li(Na/K)NbO3 and a controlled carbon content of 10 to 100 ppm/(m2/g) is produced using a process that excludes CO2, resulting in a niobium oxide carbonate layer on the surface
Implementation Method 2
Piezoelectricity describes the change in the electric polarization and thus the occurrence of an electric potential in solid bodies when these are elastically deformed
Data Source
AI summary
A niobate powder for a piezoelectric application. The niobate powder includes a general composition of Li(Na/K)NbO3 and a carbon content per BET surface area of the niobate powder of from 10 to 100 ppm/(m2/g). The BET surface area is determined in accordance with DIN ISO 9277. The carbon content is determined via a non-dispersive infrared absorption.