Highly loaded, pourable suspensions of particulate materials
AssigneeCeramics Process Systems Corporation
InventorsBruce E. Novich, Mark A. Occhionero, Richard L. Pober
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Abstract
Slurries or suspensions for forming sintered ceramic or metallic articles are described as having a high volume fraction of sinterable particles, at least 55% by volume. while the slurries maintain a pourable viscosity, such as not more that 2000 cPs at 100 s.sup.-1 ; the slurries can be dilatant and/or pseudoplastic. The slurries are prepared by using specific families of dispersants; namely acrylic acid-based polymeric polyelectrolytes, polyethylene imine-based polyelectrolytes, and coupling agents from the subfamilies of oxy-silane esters and phosphate esters. Fabrication of the compositions includes milling under high energy and the addition of at least a portion of the particles in a step-wise manner.
Claims13
A pourable slurry composition for the fabrication of sintered articles, comprising:
- (i) narrow size range, colloidal sinterable particles selected from the group consisting of ceramics, metals, and mixtures thereof;
- (ii) a solvent system;
- and
- (iii) a dispersant polyethylene imine-based polyelectrolytes, the dispersant present in an amount effective to achieve a solids loading of at least 55% by volume and to provide a slurry viscosity of less than 7,500 cPs at 100 sec.sup.-1.
A process for forming a slurry having a pourable viscosity for fabricating sintered articles, comprising:
- (i) admixing
- (a) a solvent system,
- (b) a dispersant polyethylene imine-based polyelectrolytes, and
- (c) at least 55% by volume of sinterable particles of narrow size range selected from the group consisting of ceramics, metals, and mixtures thereof, and consisting essentially of those having a submicron average particle size, those having a colloidal average particle size, or mixtures thereof, at least a portion of the particulates admixed in a staged order of addition;
- and
- (ii) agitating the mixture under high energy to provide a slurry having a viscosity of less than 7,500 cPs at 100 sec..sup.-1.
Dependencies are inferred from the claim text.