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US4773928A Expired / Lapsed US ⏱️ 0.0 years remaining

Plasma spray powders and process for producing same

Assignee: Osram Sylvania Inc
•
Filing: 1987-08-03
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Granted: 1988-09-27
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Expires: 2007-08-03
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Abstract

Abstract A process is disclosed for producing plasma type spray powders. The process involves forming, an admixture of a base metal, chromium, aluminum, and yttrium or master alloy powders containing these elements, and dry milling the admixture by high shearing to produce a homogeneous mixture. A slurry of this mixture and an aqueous solution of a binder is then spray dried to produce agglomerates, the major portion of which has a particle size of from about 20 to about 53 microns. This major portion is then separated from the remainder of the agglomerates and sintered in a reducing atmosphere to remove the binder and form a sintered powder. The sintered powder is then passed through a high temperature plasma reactor to melt the powder and produce a homogeneous plasma spray powder. A plasma spray powder is disclosed which consists essentially of substantially spherical, melt solidified particles of from about 15 to about 44 microns in size, and having a weight composition of from about 14% to about 19% chromium, from about 10% to about 14% aluminum, from about 0.5% to about 1.0% yttrium and the balance a base metal selected from the group consisting of nickel, cobalt, iron and mixtures thereof.

Inventors

  • 👤 David L. Houck
  • 👤 Richard F. Cheney
  • 👤 James O. Steigelman

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 15:09
CPC Classifications
C; C23; C23C; C23C4/00; C23C4/04; C23C4/06; C23C4/073; B; B22; B22F; B22F1/00; B22F1/14; B22F1/148

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 130 words
A process for producing plasma type spray powders, said process comprising: a. forming an admixture of a base metal and chromium, aluminum, and yttrium powders; b. milling said admixture by high shearing to produce a homogeneous mixture, or conventional blending if fine starting materials are used; c. forming a slurry of said homogeneous mixture and an aqueous solution of a binder; d. spray drying said slurry to produce spray dried agglomerates having a major portion of a particle size of from about 20 to about 53 microns, and a minor portion of the remainder of the agglomerates; e. separating said major portion of said agglomerates from said minor portion; f. sintering said major portion in a reducing atmosphere to remove said binder and to produce a homogeneous plasma spray powder.
Claim 2
Dependent Claim 130 words
A process for producing plasma type spray powders, said process comprising: a. forming an admixture of a base metal and chromium, aluminum, and yttrium powders; b. milling said admixture by high shearing to produce a homogeneous mixture, or conventional blending if fine starting materials are used; c. forming a slurry of said homogeneous mixture and an aqueous solution of a binder; d. spray drying said slurry to produce spray dried agglomerates having a major portion of a particle size of from about 20 to about 53 microns, and a minor portion of the remainder of the agglomerates; e. separating said major portion of said agglomerates from said minor portion; f. sintering said major portion in a reducing atmosphere to remove said binder and to produce a homogeneous plasma spray powder.
Claim 3
Dependent Claim 23 words
A process according to claim 1 wherein said base metal is selected from the group consisting of nickel, cobalt, iron and mixtures thereof.
Claim 4
Dependent Claim 40 words
A process according to claim 2 wherein said admixture consists essentially of, be weight, from about 10% to about 50% chromium, from about 1% to about 20% aluminum, from about 0.2% to about 1.5% yttrium, and the balance base metal.
Claim 5
Dependent Claim 24 words
A process according to claim 3 wherein the major portion of said spray dried agglomerates comprises from about 60% to about 90% by weight.
Claim 6
Dependent Claim 21 words
A process according to claim 4 wherein said binder is selected from the group consisting of polyvinyl alcohol and polyethylene glycol.
Claim 7
Dependent Claim 19 words
A process according to claim 5 wherein the sintering temperature is from about 750° C. to about 900° C.
Claim 8
Dependent Claim 25 words
A process according to claim 6 wherein the sintered powder is passed through a plasma reactor and each particle is melted, alloyed, densified and speroidized.

References Cited (Backward Citations)

US3639151A Cited
US3865722A Cited
US3877930A Cited
US4025334A Cited
US4156053A Cited
US4070184A Cited
US4507189A Cited
US4390368A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1991-09-27 1992-03-28 1992-09-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1995-09-27 1996-03-28 1996-09-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1999-09-27 2000-03-28 2000-09-27 $7700.00 Window Closed / Lapsed

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