Electrophoretic Deposition: A Quantitative Model for Particle Deposition and Binder Formation from Alcohol-Based...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Electrophoretic deposition (EPD) is a technique for forming ceramic layers from a suspension.
• Consolidation of deposited particles is crucial for layer integrity.
• Magnesium hydroxide (Mg(OH)2) can precipitate at electrodes during EPD in specific solutions.

Purpose of the Study:

• To quantitatively model the deposition rates of particles and Mg(OH)2 during EPD.
• To understand the role of Mg(OH)2 precipitation in consolidating electrophoretically deposited layers.
• To investigate the factors influencing Mg(OH)2 formation and its impact on particle deposition.

Main Methods:

• Electrophoretic deposition of LaB6 particles from a suspension containing Mg(NO3)2, isopropanol, and water.
• Controlled variation of current, Mg(NO3)2 concentration, pH, and water content.
• Analysis of Mg(OH)2 content and particle deposition rates.

Main Results:

• Mg(OH)2 precipitation is directly controlled by the charge passed, acting as a binder.
• A minimum current threshold is necessary for both Mg(OH)2 and particle deposition.
• The particle sticking coefficient is 1.0 above the minimum current, indicating efficient layer formation when Mg(OH)2 is present.

Conclusions:

• Mg(OH)2 precipitation is essential for consolidating electrophoretically deposited layers.
• Quantitative models for particle and Mg(OH)2 deposition can be established based on charge passed.
• EPD parameters like current, ion concentration, and pH significantly influence layer formation and consolidation.