Introduction
In comparative studies of ceramic slurry viscosity, the performance of different dispersants varies significantly due to factors such as their stabilization mechanisms (electrostatic, spatial, or electrokinetic), specific ceramic raw materials, and processing conditions like pH value and dispersant concentration. High-performance polymer dispersants are often more effective than small-molecule alternatives such as phosphates.
Comparison of common dispersant performance:
Factors Affecting the Efficacy of Dispersants
The viscosity of ceramic slurries is not determined solely by dispersants. Comparative studies must consider several key factors:
• Optimal Concentration: All dispersants have an optimal concentration range, within which the lowest slurry viscosity is achieved. Excessive addition leads to an excess of free polymers in the solution, resulting in depletion of flocculation and increased viscosity.
• Dispersant Mechanism: The fundamental mechanism (spatial, electrostatic, or electrokinetic) must be compatible with the liquid medium. For example, electrostatic stabilization is most effective in aqueous systems, while spatial stabilization is effective in both aqueous and non-aqueous systems.
• Ceramic Powder Characteristics: The type, particle size distribution, and surface chemical properties of ceramic powders all affect the performance of dispersants.
• Interactions with Other Additives: Dispersants may have compatibility issues with other additives (e.g., binders and flocculants). Their interactions may neutralize or interfere with each other, thereby affecting viscosity.
• Mixing Parameters: The stirring time and shear rate during the mixing process also affect the efficacy of dispersants and the viscosity of the slurry.
By systematically comparing the effects of different dispersants on the viscosity of ceramic slurries, it has been confirmed that high-performance polymer dispersants significantly outperform traditional small-molecule dispersants in reducing viscosity and maintaining stability. The efficacy of dispersants is jointly constrained by multiple factors such as their stabilization mechanisms, optimal concentrations, powder characteristics, and additive compatibility. A deep understanding of the interactions between these variables, and determining the optimal dispersing solution for specific systems through experiments, is crucial for achieving the ideal rheological properties of ceramic slurries and subsequent forming processes.