Patent US3850733A successfully refreshed from Google Patents.
US3850733A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming foundry moulds
Assignee: Canadian Patents and Development Ltd
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Filing: 1972-09-11
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Granted: 1974-11-26
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Expires: 1992-09-11
Abstract
Abstract A method of forming foundry moulds by the electrophoretic deposition of refractory particles from a suspension, wherein refractory particles which are substantially free from ionic contamination are initially treated, for example by milling or vacuum heat treatment to expose fresh uncontaminated surfaces of the particles to render them electrophoretically mobile when in suspension. A mould former with an electrically conductive surface, for example, a wax or plastic mould with a conductive surface, is dipped into a suspension of the treated particles containing a metal sol binder, and which is substantially free from ionic contamination, and a direct potential is applied between the mould former and the suspension to electrophoretically deposit refractory particles from the suspension as a coating on the electrically conductive surface.
Inventors
- 👤 E Szabo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:19
CPC Classifications
C; C25; C25D; C25D1/00; C25D1/12; C25D1/14
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
148 words
A METHOD OF FORMING FOUNDRY MOULDS COMPRISING TREATING PARTICLES OF A REFRACTORY MATERIAL WHICH ARE SUBSTANTIALLY FREE FROM IONIC CONTAMINATION TO EXPOSE GFRESH, UNCONTAMINATED SURFACES OF THE PARTICLES AND RENDER THEPARTICLES ELECTROPHORETICALLY MOBILE WHEN IN SUSPENSION, DIPPING A MOULD FORMER WITH AN ELECTRICALLY CONDUCTIVE SURFACE IN A SUSPENSION OF THE TREATED PARTICLES CONTAINING A METAL SOL BINDER SELECTED FROM THE GROUP COLLOIDAL SILICA, COLLIDAL ALUMINA, COLLOIDAL ZIRCONIA, COLLOIDAL HAFNIA, COLLOIDAL THORIA AND COLLOIDAL TITANI AND WHICH IS SUBSTANTIALLY FREE FROM IONIC CONTAMINATION, APPLYING A DIRECT ELECTRICAL POTENTIAL BETWEEN THE MOULD FORMER ELECTRICALLY CONDUCTIVE SURFACE AND THE SUSPENSION TO ELECTROPHORETICALLY DEPOSITE REFRACTORY PARTICLES FROM THE SUSPENSION AS A COATING ON TO THE ELECTRICALLY CONDUCTIVE SURFACE, REMOVING THE MOULD FORMER WITH THE COATING THEREON FROM THE SUSPENSION APPLYING FURTHER REFRACTORY PARTICLES TO THE COATING TO FORM A FOUNDRY MOULD THEREFROM, AND THEN SEPARATING THE FOUNDRY MOULD FROM THE MOULD FORMER.
Claim 2
Independent Claim
148 words
A METHOD OF FORMING FOUNDRY MOULDS COMPRISING TREATING PARTICLES OF A REFRACTORY MATERIAL WHICH ARE SUBSTANTIALLY FREE FROM IONIC CONTAMINATION TO EXPOSE GFRESH, UNCONTAMINATED SURFACES OF THE PARTICLES AND RENDER THEPARTICLES ELECTROPHORETICALLY MOBILE WHEN IN SUSPENSION, DIPPING A MOULD FORMER WITH AN ELECTRICALLY CONDUCTIVE SURFACE IN A SUSPENSION OF THE TREATED PARTICLES CONTAINING A METAL SOL BINDER SELECTED FROM THE GROUP COLLOIDAL SILICA, COLLIDAL ALUMINA, COLLOIDAL ZIRCONIA, COLLOIDAL HAFNIA, COLLOIDAL THORIA AND COLLOIDAL TITANI AND WHICH IS SUBSTANTIALLY FREE FROM IONIC CONTAMINATION, APPLYING A DIRECT ELECTRICAL POTENTIAL BETWEEN THE MOULD FORMER ELECTRICALLY CONDUCTIVE SURFACE AND THE SUSPENSION TO ELECTROPHORETICALLY DEPOSITE REFRACTORY PARTICLES FROM THE SUSPENSION AS A COATING ON TO THE ELECTRICALLY CONDUCTIVE SURFACE, REMOVING THE MOULD FORMER WITH THE COATING THEREON FROM THE SUSPENSION APPLYING FURTHER REFRACTORY PARTICLES TO THE COATING TO FORM A FOUNDRY MOULD THEREFROM, AND THEN SEPARATING THE FOUNDRY MOULD FROM THE MOULD FORMER.
Claim 3
Dependent Claim
58 words
A method according to claim 1, wherein the particles are in a suspension which is substantially free from ionic contamination, prior to being treated, and then the particles are treated by being comminuted in suspension to expose fresh, uncontaminated surfaces of the particles to render the particles electrophoretically mobile prior to the addition of the metal sol binder.
Claim 4
Dependent Claim
27 words
A method according to claim 2, wherein the particles are comminuted in suspension in a liquid selected from the group distilled, de-ionized, and distilled and deionized water.
Claim 5
Dependent Claim
23 words
A method according to claim 1, wherein the further refractory particles are applied as a relatively coarser stucco coatings between electrophoretically applied coatings.
Claim 6
Dependent Claim
20 words
A method according to claim 1, wherein the refractory material is selected from the group refractory oxides and refractory silicates.
Claim 7
Dependent Claim
85 words
A method according to claim 1, wherein the support member is a pattern of a material selected from the group wax or a plastic provided with an electrically conductive outer coating, and the electrophoretically deposited refractory particles thereon are an investment casting shell, and the pattern together with the electrically conductive coating are removed from the investment casting shell by melting a major portion of the pattern material by placement in a furnace at 250* to 550*C, or leaching, and then burning off the residue.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |