Patent US3883647A successfully refreshed from Google Patents.
US4339271A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a sintered powder body
Assignee: ABB Norden Holding AB
•
Filing: 1978-06-28
•
Granted: 1982-07-13
•
Expires: 1998-06-28
Abstract
Abstract A shaped body is formed by cold-pressing a powdered material into a desired shape and then providing thereon a surface layer of a material having a lower melting point than the powder of the shaped body. The shaped body is then placed in a furnace connectable to vacuum equipment, wherein the pressure is first lowered to a value lower than atmospheric pressure and then the temperature is increased so that the material of the surface layer melts. Thereafter the body is isostatically hot-pressed under the direct influence of an inert, gaseous pressure medium, the powder particles being thus bound together to high density by pressure sintering.
Inventors
- 👤 Sven-Erik Isaksson
- 👤 Hans Larker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:56
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/12; B22F3/1208; B22F3/1258; B22F3/1266; B22F3/125
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
279 words
A method of manufacturing a sintered body from sinterable powdered material comprising the steps of: (a) cold-pressing the sinterable powdered material to form a shaped body; (b) providing the shaped body with an initially porous surface layer having a thickness of up to about 1 mm., said surface layer being comprised of a coating material having a melting point that is lower than the melting point of the sinterable material of the body, said layer being capable of fusing and thereby becoming non-porous and gas-tight upon being heated to a temperature above the melting point of the coating material; (c) subjecting the shaped body with the porous surface layer thereon simultaneously to vacuum and heating at an elevated first temperature below the melting point of said coating material whereby the evacuation of said shaped body takes place over its whole surface, said evacuation being continued for a time sufficient to degasify the entire shaped body; (d) thereafter heating the body with the surface layer thereon to a second temperature which is above the melting point of said coating material whereby said layer fuses and is rendered non-porous and gas-tight; (e) isostatically hot pressing the shaped body with the gas-tight surface layer thereon at a sintering temperature not higher than that at which the coating material is in a fluid high viscous state, said hot pressing being accomplished utilizing an inert gaseous pressure medium which completely surrounds the body and is in direct contact with the entire outer surface of said gas-tight surface layer whereby the sinterable powdered material of the shaped body is compacted and sintered to high density; (f) said coating material being non-volatile at said second temperature.
Claim 2
Independent Claim
279 words
A method of manufacturing a sintered body from sinterable powdered material comprising the steps of: (a) cold-pressing the sinterable powdered material to form a shaped body; (b) providing the shaped body with an initially porous surface layer having a thickness of up to about 1 mm., said surface layer being comprised of a coating material having a melting point that is lower than the melting point of the sinterable material of the body, said layer being capable of fusing and thereby becoming non-porous and gas-tight upon being heated to a temperature above the melting point of the coating material; (c) subjecting the shaped body with the porous surface layer thereon simultaneously to vacuum and heating at an elevated first temperature below the melting point of said coating material whereby the evacuation of said shaped body takes place over its whole surface, said evacuation being continued for a time sufficient to degasify the entire shaped body; (d) thereafter heating the body with the surface layer thereon to a second temperature which is above the melting point of said coating material whereby said layer fuses and is rendered non-porous and gas-tight; (e) isostatically hot pressing the shaped body with the gas-tight surface layer thereon at a sintering temperature not higher than that at which the coating material is in a fluid high viscous state, said hot pressing being accomplished utilizing an inert gaseous pressure medium which completely surrounds the body and is in direct contact with the entire outer surface of said gas-tight surface layer whereby the sinterable powdered material of the shaped body is compacted and sintered to high density; (f) said coating material being non-volatile at said second temperature.
Claim 3
Dependent Claim
32 words
The method as claimed in claim 1, wherein the coating material during step (d) at least partially penetrates into the pores of the shaped body and seals them in a gas-tight manner.
Claim 4
Dependent Claim
15 words
The method as claimed in claim 2, wherein the coating material consists essentially of enamel.
Claim 5
Dependent Claim
15 words
The method as claimed in claim 2, wherein the coating material consists essentially of glass.
Claim 6
Dependent Claim
33 words
The method as claimed in claim 1, wherein during step (c) the first temperature is maintained at value slightly below the melting point of said coating material for a predetermined period of time.
Claim 7
Dependent Claim
44 words
The method as claimed in claim 4, including between steps (d) and (e) the step of reducing the temperature to which the coated shaped body is subjected to a value below the melting point of said coating material so that the coating layer solidifies.
Claim 8
Dependent Claim
30 words
The method as claimed in claim 1, wherein the step of providing the shaped body with an initially porous surface layer comprises spraying said coating material onto said shaped body.
Claim 9
Dependent Claim
23 words
The method as claimed in claim 4, wherein the pressure medium is selected from the group consisting of argon, helium, nitrogen and hydrogen.
Claim 10
Dependent Claim
27 words
The method as claimed in claim 1, wherein the sinterable powdered material consists essentially of at least one member of the group WC, TaC, TiC and VC.
Claim 11
Dependent Claim
33 words
The method as claimed in claim 1, wherein the step of providing the shaped body with an initially porous surface layer comprises immersing said shaped body into a liquid containing said coating material.
Claim 12
Independent Claim
288 words
A method of manufacturing a sintered body from sinterable powdered material comprising the steps of: (a) cold-pressing the sinterable powdered material to form a shaped body; (b) providing the shaped body with an initially porous surface layer having a thickness of up to about 1 mm., said surface layer being initially comprised of a coating material that is capable of forming, with said sinterable powdered material, a eutectic having a melting point that is lower than the melting point of the sinterable material of the body, said layer being capable of fusing and thereby becoming non-porous and gas-tight upon being heated to a temperature above the melting point of th eutectic; (c) subjecting the shaped body with the porous surface layer thereon simultaneously to vacuum and heating at an elevated first temperature below the melting point of said eutectic whereby the evacuation of said shaped body takes place over its whole surface, said evacuation being continued for a time sufficient to degasify the entire shaped body; (d) thereafter heating the body with the surface layer thereon to a second temperature which is above the melting point of said eutectic whereby said layer fuses and is rendered non-porous and gas-tight; (e) isostatically hot pressing the shaped body with the gas-tight surface layer thereon at a sintering temperature not higher than that at which the eutectic is in a fluid high viscous state, said hot pressing being accomplished utilizing an inert gaseous pressure medium which completely surrounds the body and is in direct contact with the entire outer surface of said gas-tight surface layer whereby the sinterable powdered material of the shaped body is compacted and sintered to high density; and (f) said eutectic being non-volatile at said second temperature.
Claim 13
Independent Claim
288 words
A method of manufacturing a sintered body from sinterable powdered material comprising the steps of: (a) cold-pressing the sinterable powdered material to form a shaped body; (b) providing the shaped body with an initially porous surface layer having a thickness of up to about 1 mm., said surface layer being initially comprised of a coating material that is capable of forming, with said sinterable powdered material, a eutectic having a melting point that is lower than the melting point of the sinterable material of the body, said layer being capable of fusing and thereby becoming non-porous and gas-tight upon being heated to a temperature above the melting point of th eutectic; (c) subjecting the shaped body with the porous surface layer thereon simultaneously to vacuum and heating at an elevated first temperature below the melting point of said eutectic whereby the evacuation of said shaped body takes place over its whole surface, said evacuation being continued for a time sufficient to degasify the entire shaped body; (d) thereafter heating the body with the surface layer thereon to a second temperature which is above the melting point of said eutectic whereby said layer fuses and is rendered non-porous and gas-tight; (e) isostatically hot pressing the shaped body with the gas-tight surface layer thereon at a sintering temperature not higher than that at which the eutectic is in a fluid high viscous state, said hot pressing being accomplished utilizing an inert gaseous pressure medium which completely surrounds the body and is in direct contact with the entire outer surface of said gas-tight surface layer whereby the sinterable powdered material of the shaped body is compacted and sintered to high density; and (f) said eutectic being non-volatile at said second temperature.
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) | 1985-07-12 | 1986-01-11 | 1986-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-12 | 1990-01-11 | 1990-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-12 | 1994-01-11 | 1994-07-13 | $7700.00 | Window Closed / Lapsed |