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US3766040A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of detecting and locating corrosion sites

Assignee: Individual
•
Filing: 1972-11-24
•
Granted: 1973-10-16
•
Expires: 1992-11-24
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Abstract

Abstract Method of detecting and locating areas responsible for incipient galvanic corrosion on a metallic surface. Localized electrochemical cells which occur on metallic surfaces as a result of anodic and cathodic sites in contact with an electrolytic solution and which results in corrosion at such locations are detected by immersing the surface in an aqueous electrolytic solution containing a suspension of particles bearing an electrical charge of opposite polarity to the charge carried by the localized site. Particles in the suspension are attracted by the opposite polarity of the localized sites, if any, on the metallic surfaces, causing such particles to accumulate at the locations of the sites. These accumulations of particles remain on the metallic surface following withdrawal from the aqueous solution. Coated metallic surfaces can be examined for the existence of pinholes, cracks, and other penetrating surface discontinuities by subjecting the metallic surface to an electrical charge of polarity opposite that of the particles suspended in solution.

Inventors

  • 👤 H Wellborn

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 14:05
CPC Classifications
G; G01; G01N; G01N17/00

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 22 words
The method of claim 1, wherein said metallic surface is subjected to an aqueous electrolytic suspension of particles of amorphous (fused) silica.
Claim 2
Dependent Claim 42 words
The method of claim 1, wherein said step of subjecting comprises immersing the surface in said aqueous electrolytic suspension, subsequently removing the surface from the aqueous suspension, and observing the location on the surface of any accumulation of said particles adhering tHereto.
Claim 3
Dependent Claim 29 words
The method of claim 3, further comprising the step of removing the residual quantity of said suspension which remains on the surface after removal from the aqueous electrolytic suspension.
Claim 4
Dependent Claim 41 words
The method of claim 1, for detecting penetrating discontinuities in the coating of a coated metallic surface, additionally comprising the steps of charging the metallic surface with an electromotive force of polarity opposite the polarity of said charged particles in suspension.
Claim 5
Dependent Claim 46 words
The method of claim 5, wherein said step of subjecting comprises immersing the coated charged surface in said aqueous suspension, subsequently removing the coated charged surface from the aqueous suspension, and marking the location on the coated surface of any accumulation of said particles adhering thereto.
Claim 6
Dependent Claim 29 words
The method of claim 6, further comprising the step of removing the residual quantity of said aqueous suspension which remains on the coated surface after removal from said solution.
Claim 7
Dependent Claim 31 words
The method of claim 1, wherein the corrosion sites being detected have an electrically positive charge, and wherein said aqueous solution contains a suspension of particles having an electrically negative charge.

References Cited (Backward Citations)

US2762767A Cited
US2857320A Cited
US2897126A Cited
US2900320A Cited
US2869003A Cited
US3168455A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1976-10-15 1977-04-16 1977-10-16 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1980-10-15 1981-04-16 1981-10-16 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1984-10-15 1985-04-16 1985-10-16 $7700.00 Window Closed / Lapsed

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