Slip casting is a common method for producing ceramic products with complex shapes, and good slip flowability is crucial to ensuring forming quality. However, factors such as high solids content and interparticle attraction can increase slip viscosity and reduce flowability. Plasticizers, as an effective aid, can significantly improve flowability by adjusting the physicochemical properties of the slip. This article details the mechanisms and applications of plasticizers improving slip casting flowability.
I. Mechanisms of Plasticizers Improving Slip Casting Flowability
The main mechanisms by which plasticizers improve slip casting flowability include:
Reducing Electrostatic Attraction: Ceramic particles typically carry electrostatic charges, causing interparticle attraction and increasing slip viscosity. Plasticizers can adsorb onto the particle surface, shielding the electrostatic charge, and reducing the electrostatic attraction between particles. Reducing Surface Tension: Plasticizers can reduce the surface tension of the liquid phase (usually water), improve its wetting of solid particles, promote particle dispersion, and reduce slip viscosity. Improving Interparticle Lubricity: Plasticizers form a lubricating layer between particles, reducing interparticle friction and making particles easier to slide, reducing the plastic viscosity of the slip. |  |
Changing Particle Dispersion State: Plasticizers can promote particle dispersion, prevent particle agglomeration, and form a more uniform and stable slip system.
II. Common Types of Slip Casting Plasticizers and Applications
Polyethylene Glycol (PEG): A commonly used water-soluble plasticizer that can effectively reduce slip viscosity and improve flowability, suitable for various ceramic systems. The usual concentration is 0.1%-1.0%.
Polyacrylic Acid Sodium (PAAS): A high molecular weight polymer with good dispersion and plasticizing effects, especially suitable for high-solids slips. The usual concentration is 0.05%-0.5%.
Sodium Citrate: An environmentally friendly plasticizer with good biodegradability that can effectively improve slip flowability while reducing environmental pollution. The usual concentration is 0.5%-2.0%.
Carboxymethyl Cellulose (CMC): A natural polysaccharide derivative with good thickening and stabilizing effects, which can also improve slip flowability. The usual concentration is 0.1%-0.5%.
Sodium Tripolyphosphate (STPP): Has a dispersing effect, can effectively reduce slip viscosity and improve flowability, but the dosage should be noted, excessive amount may lead to a decrease in slip stability. The usual concentration is 0.1%-0.3%.
TopTime Ceramics Technical Services:
TopTime Ceramics has a professional ceramic slip formulation R&D team that can provide customized plasticizer solutions based on customer-specific needs, helping customers optimize slip formulations, improve slip casting flowability, and enhance product performance.