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US 4,357,222 AGranted
Electrolphoretic casting process
AssigneeNorton Company
InventorJohn W. Lucek
Life of this patent
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Abstract
The invention is an electrophoretic casting process which produces highly dense green castings with residual liquid e.g. water below 7%, and which eliminates excessive liquid and electrode degradation. This is accomplished by careful selection of slip viscosity, utilization of an impervious casting mold set-up in which only a minor part of the mold is conducting, application of a varying voltage cycle, and moving one electrode relative to the other.
Claims26
An electrophoretic casting method comprising the steps of:
- preparing a casting slip by mixing a liquid vehicle and an inorganic powder in such proportions that said casting slip has a viscosity of from 0.5 to 100,000 centipoises;
- casting the slip into an electrophoretic mold set-up including a depository and a non-depository electrode, and wherein said depository electrode makes up less than the entire surface area of the shape defining element of the mold set-up;
- applying a voltage between said electrodes thereby causing migration of the inorganic particles in said slip toward the depository electrode;
- maintaining a potential until the desired degree of particle deposition has occurred;
- terminating said potential;
- removing the excess slip liquid;
- removing the green casting from the mold set-up;
- and firing the green casting.
5 more elements
An electrophoretic casting method for the formation of thick walled tubes and plates, comprising the steps of:
- preparing a casting slip by mixing a liquid vehicle and an inorganic powder in such proportions that said casting slip has a viscosity of from 0.5 to 100,000 centipoises;
- casting the slip into an electrophoretic mold set-up containing multiple electrodes, said electrodes having a configuration conforming to the cross-sectional shape of the green article being cast, and wherein said electrodes are of such a size that any pair of electrodes constitutes only a minor amount of the total surface area of the shape being cast;
- applying a voltage across a first pair of said multiple electrodes thereby causing migration of said inorganic particles toward the anode of said first electrode pair;
- maintaining a voltage across said first pair of electrodes while monitoring the voltage between one of said first pair and an adjacent electrode;
- terminating the voltage between said first electrode pair when the voltage between one of said first electrode pair and the adjacent electrodes drops to less than one volt, and reapplying the voltage to a second electrode pair adjacent to the first electrode pair;
- applying a voltage across said second electrode pair and repeating the process steps utilized with said first electrode pair;
- repeating the steps utilized with said first and second electrode pairs with subsequent adjacent electrode pairs until the desired green casting has been completely formed;
- terminating said voltage;
- removing the excess slip;
- removing the green casting from the mold set-up;
- and firing the green casting.
8 more elements
Dependencies are inferred from the claim text.