Zirconia Particle Shape Control via Molybdenum Surface Distribution
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Solution Overview
Problem
Existing methods for producing zirconia particles do not effectively control the particle shape or consider the hydrolysis and condensation behavior, leading to unstable particle shapes.
Innovation Solution
The production of zirconia particles with a polyhedron shape is achieved by mixing a zirconium compound with a molybdenum compound, followed by firing, which allows for stable control of particle shape and distribution of molybdenum in the surface layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods (PTL 1 and PTL 2) are used to produce zirconia particles by adding metal additives to water-containing slurry, then zirconia particles can be produced, but the particle shape cannot be stably controlled
Solution Approach 1:
The invention changes the chemical composition parameter by introducing molybdenum compound as an additive to the zirconium compound slurry. This parameter change (adding Mo) fundamentally alters the particle formation mechanism during firing, enabling stable polyhedral shape control that was not achievable with conventional additives alone.
Solution Approach 2:
The invention creates a composite system by combining zirconium compound with molybdenum compound in specific proportions. This composite approach allows the synergistic interaction between the two elements during hydrolysis and condensation, resulting in zirconia particles with controlled polyhedral shapes that maintain stability.
2Manufacturing precision
If conventional production methods are used without considering hydrolysis and condensation behavior, then production process is simpler, but particle shape becomes unstable
Solution Approach 1:
The invention applies preliminary action by controlling the hydrolysis and condensation behavior during the slurry preparation and drying stages. By pre-establishing the chemical environment and reaction conditions before firing, the particle shape is determined and stabilized early in the process, making the subsequent firing step more predictable and effective.
Solution Approach 2:
The invention systematically controls multiple parameters including the molybdenum content (0.1-10 mass%), slurry composition, drying conditions, and firing temperature. These parameter changes work together to control the hydrolysis and condensation kinetics, enabling stable particle shape formation through a manageable but optimized process.
3Shape
If molybdenum is added to control particle shape, then polyhedron shape is achieved, but molybdenum distribution in surface layers becomes uneven
Solution Approach 1:
The invention accepts and utilizes the local quality variation of molybdenum distribution in surface layers. Rather than seeking uniform distribution throughout, the patent recognizes that uneven surface distribution (with higher Mo concentration at surfaces) is a natural consequence of the formation mechanism and can be controlled to achieve the desired polyhedral shape with appropriate surface properties.
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 method produces zirconia particles with a stably controllable polyhedron shape, improved dispersion stability, and adjustable particle size, shape, and physical properties.
Implementation Method 1
The present invention is premised on control of properties of particles through addition of a different metal, such as yttria, to a water-containing slurry containing zirconium hydrate... either method does not take the hydrolysis and condensation behavior into consideration
Implementation Method 2
either method does not take the hydrolysis and condensation behavior into consideration
Implementation Method 3
mixing a zirconium compound and a molybdenum compound to form a mixture; and firing the mixture
Implementation Method 4
heating the composite in a temperature range of 1100° C. to 1400° C. to form zirconia
Data Source
AI summary
It relates to zirconia particles containing molybdenum and each having a polyhedron shape. The molybdenum is preferably unevenly distributed in surface layers of the zirconia particles. It also relates to a method for producing the zirconia particles. The method includes mixing a zirconium compound and a molybdenum compound to form a mixture and firing the mixture.