Introduction
The testing methods for the dispersibility of ceramic slurries include particle size analysis, rheological measurements (viscosity and viscoelasticity), sedimentation tests, and more advanced techniques such as ultrasonic attenuation, multiple light scattering, and dielectric microscopy based on energy-dispersive X-ray spectroscopy. The appropriate method depends on the specific slurry and the required information, as certain methods (such as hydrostatic pressure measurements) can better reflect the relationship between dispersibility and the performance of the final product.
Common testing methods
• Particle size analysis: Measure the particle size distribution in the slurry to evaluate the dispersion degree. • Rheological measurements: ◇ Viscosity: Measure the flow resistance of the slurry. Changes in viscosity over time can indicate aggregation. ◇ Dynamic viscoelasticity: Evaluate characteristics such as relative viscosity and yield stress, which are related to the dispersion state. • Sedimentation tests: Monitor the settling of particles over time to assess stability. The lower the final settling height, the better the dispersion. • Hydrostatic pressure measurement: A new technology that can evaluate the dispersion state of the slurry, especially when the particle concentration increases, and has shown good correlation with the packing rate of sheets made from the slurry. |  |
Advanced and professional testing methods
• Ultrasonic technology: An online monitoring method that utilizes ultrasonic echo signals to quantify the uniformity during the mixing process of suspensions. • Multi-angle light scattering: A method specifically designed for evaluating the dispersion stability of colloidal ceramic slurries, detailed in the draft standard of the International Organization for Standardization (ISO). • Scanning Electron-Assisted Dielectric Microscopy (SE-ADM): A technique that can directly observe and analyze the elemental composition of nanoparticles in solutions, providing detailed information on dispersion and binder distribution. • Differential Centrifugal Sedimentation (DCS): Evaluates the adsorption interaction between ceramic particles and polymer binders by measuring the viscous resistance during the separation of adsorbed binders under centrifugal force. • Nuclear Magnetic Resonance (NMR): Measures relaxation time to assess the dispersion of slurries. The variation in relaxation time can be correlated with the degree of dispersion. |  |
Accurately evaluating the dispersion of ceramic slurries is crucial for ensuring the final product quality. From basic particle size analysis and rheological measurements to advanced ultrasonic monitoring and multiple light scattering techniques, various testing methods reveal the dispersion state and stability of the slurry from different dimensions. In practical applications, appropriate combinations of testing methods should be selected based on the specific characteristics of the slurry and process requirements, and multi-dimensional data cross-validation is used to provide reliable technical support for optimizing dispersion processes and improving product consistency.