GB2142935A - Seamless sintered iridium crucibles - Google Patents
Seamless sintered iridium crucibles Download PDFInfo
- Publication number
- GB2142935A GB2142935A GB08312805A GB8312805A GB2142935A GB 2142935 A GB2142935 A GB 2142935A GB 08312805 A GB08312805 A GB 08312805A GB 8312805 A GB8312805 A GB 8312805A GB 2142935 A GB2142935 A GB 2142935A
- Authority
- GB
- United Kingdom
- Prior art keywords
- iridium
- sintering
- lying
- range
- stage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/0466—Alloys based on noble metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/1003—Use of special medium during sintering, e.g. sintering aid
- B22F3/1007—Atmosphere
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/10—Sintering only
- B22F3/1017—Multiple heating or additional steps
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B35/00—Apparatus not otherwise provided for, specially adapted for the growth, production or after-treatment of single crystals or of a homogeneous polycrystalline material with defined structure
- C30B35/002—Crucibles or containers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2201/00—Treatment under specific atmosphere
- B22F2201/20—Use of vacuum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Powder Metallurgy (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
Seamless iridium crucibles are made by cold isostatically compacting iridium powder on a mandrel, sintering the blank in stages at successively higher temperatures while screening the blank from the heating elements using iridium sheet or plate. The sintered blank is then isostatically hot compacted.
Description
SPECIFICATION
Seamless iridium crucibles
The invention relates to the manufacture of seamless iridium crucibles.
Hitherto, seamless iridium crucibles have been manufactured by starting with a cast or sintered bar or billet of iridium which was reshaped into a crucible by hot forging, hot rolling and deep drawing in the hot state. It was possible to produce crucibles of a diameter of approximately 80 mms by means of such hot upsetting actions. However, crucibles manufactured from cast billets are coarsegrained. Such crucibles produced by hot upsetting processes commonly have a short service life and tend to bulge out if a galliumgadolinium garnet material is fused thereinto.
It has been desired for a long time to manufacture iridium crucibles with considerably greater diameters than those producible in accordance with the hot upsetting process, but hitherto this problem had been resolved by welding iridium plates together to form the crucibles. However, where such crucibles include a welding seam there is a grave risk that they may fracture along the seam.
It is therefore an object of the invention to establish a method of manufacturing seamless iridium crucibles which is not restricted as regards the crucible size.
The invention consists in a method of manufacturing seamless iridium crucible, in which fine-grained iridium powder is pressed cold and isostatically on a mandrel at a pressure of 1000 to 3000 bar, is stripped from the mandrel in the form of crucible blank and is subsequently sintered in a furnace in stages at successively increasing temperatures at a pressure of 10-3 to 10-6 mbar, the crucible blank being screened from the heating elements of the sintering furnace by means of iridium sheet or plate during at least the sintering operation in the highest temperature stage, and the sintered iridium crucible being subsequently compacted by isostatic hot pressing.
Iridium crucibles manufactured in accordance with the invention have a fine-grained and amorphous structure. They may be machined subsequently if this is required and can be produced economically in any desired size. These crucibles are preferentially utilised for growing mono-crystals.
Fine-grained iridium powder is utilised as the starting material for the iridium crucibles to be manufactured according to the invention. This powder is pressed isostatically in the cold state under a pressure of say 2300 bar, on a mandrel which preferably consists of stainless steel. After stripping the crucible blank thus produced from the mandrel, it is placed in a vacuum sintering plant and subjected to a sintering operation in four stages at successively increasing temperatures. The pressure amounts to say 10-5 mbar during the sintering operation. The initial sintering action is appropriately performed at a temperature of approximately 1 000 C. The sintering period then amounts to say 1 7 hours.This sintering period may be shortened considerably however if the fine grained iridium powder utilised as the initial material is degassed before being isostatically pressed into the crucible blank in the cold state.
A temperature of approximately 11 50 C is selected for the second sintering stage, the sintering period amounting to say 3 hours.
Impurities, preferably deriving from the same substance, such as iridium oxide, are vapourised during this time. The third sintering stage has a temperature of approximately 1 900 C, and the sintering period amounts to approximately 4 hours. This third stage is then also followed by a fourth sintering stage which has an approximate temperature of 2100"C and a sintering period of approximately 1 hour.It proved to be appropriate during the fourth sintering stage in particular, to screen the crucible blank from the heating elements of the sintering furnace by means of iridium plates to prevent precipitation of vapourised heating conductor material such as tantalum or tungsten on the iridium crucible, because precipitates of this nature give rise to brittle intermetallic phases which prevent hermetic sintering of the iridium crucible surface. It is appropriate for the iridium plates however to be inserted between the crucible blank which is to be sintered and the heating elements, even before the onset of the first sintering stage. The iridium plates then remain within the sintering furnace as a screen, throughout the four sintering stages.The completion of the crucible sintering action is then also followed by a subsequent compacting operation on the sintered crucible by isostatic hot pressing. This subsequent compacting operation is preferably performed at a temperature of say 1 380 C and a pressure of say 1 800 bar. The subsequent compacting operation period amounts to approximately 3 hours, but this period may be shortened when making crucibles of small diameter. The residual pores still present in the crucible after sintering are closed by the subsequent compacting operation which is performed without encapsulation, so that a practically poreless, seamless iridium crucible having a vary fine-grained structure is available as an end product. Iridium crucibles were produced by means of the method according to the invention, which had a diameter of 62 mms and a height of 62 mms and a wall thickness of 1.4 mm. They proved to be very satisfactory for growing monocrystals, without the appearance of shortcomings like bulging or surface roughnesses.
In a modification, where degassed iridium powder is utilised the first sintering stage above referred to is omitted and only stages 2 to 4 carried out.
Claims (9)
1. A method of manufacturing a seamless iridium crucible, in which fine-grained iridium powder is pressed cold and isostatically on a mandrel at a pressure of 1000 to 3000 bar, is stripped from the mandrel in the form of a crucible blank and is subsequently sintered in a furnace in stages at successively increasing temperatures at a pressure of 10-3 to 10-6 mbar, the crucible blank being screened from the heating elements of the sintering furnace by means of iridium sheet or plate during at least the sintering operation in the highest temperature stage, and the sintered iridium crucible being subsequently compacted by isostatic hot pressing.
2. A method according to claim 1, wherein a temperature lying within the range from 800 to 1 000 C is selected as the temperature of the first sintering stage, the second selected stage lying within the range from 1100" to 1200"C, the third selected stage lying within the range from 1700 to 1 900 C and the fourth selected stage lying within the range from 1950 to 2200"C, sintering being performed for at least 20 minutes during the fourth stage and for at least 60 minutes during each of the other temperature stages.
3. A method according to claim 1 of 2, wherein the subsequent compacting operation is performed at a temperature of 1 200 C to 1 500 C and at a pressure of 900 to 2000 bar.
4. A method according to claim 3, wherein the subsequent compacting operation is performed without encapsulation.
5. A method according to any of the preceding claims 1 to 4, wherein iridium powder is degassed before the isostatic cold pressing operation.
6. A method according to claim 5, wherein degassed iridium powder is utilised, the sintering operation being performed in three stages only, the first lying within the range from 1100" to 1 200 C the second lying within the range from 1700 to 1 900 C and the third lying within the range from 1950 to 2200"C, sintering being performed for at least 20 minutes during the third stage and for at least 60 minutes during each of the other stages.
7. A method according to any of the preceding claims, wherein the mandrel utilised is of stainless steel.
8. A method of manufacturing a seamless iridium crucible, substantially as hereinbefore described.
9. A seamless iridium crucible whenever produced according to a method claimed in any of the preceding claims.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3230389A DE3230389C1 (en) | 1982-08-14 | 1982-08-14 | Process for the production of a seamless crucible made of iridium |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8312805D0 GB8312805D0 (en) | 1983-06-15 |
| GB2142935A true GB2142935A (en) | 1985-01-30 |
| GB2142935B GB2142935B (en) | 1985-09-18 |
Family
ID=6170961
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08312805A Expired GB2142935B (en) | 1982-08-14 | 1983-05-10 | Seamless sintered iridium crucibles |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE3230389C1 (en) |
| GB (1) | GB2142935B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5993545A (en) * | 1997-01-24 | 1999-11-30 | W.C. Heraeus Gmbh & Co. Kg | Crucible for growing single crystals, process for making the same and use of the same |
| WO2013180965A3 (en) * | 2012-05-29 | 2014-05-08 | H.C. Starck Inc. | Metallic crucibles and methods of forming the same |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2633203C2 (en) * | 2015-12-09 | 2017-10-11 | Общество С Ограниченной Ответственностью Научно-Производственное Объединение "Металлы Урала" | Metallic iridium articles production method |
| CN105728708B (en) * | 2016-03-10 | 2018-02-06 | 洛阳爱科麦钨钼科技股份有限公司 | A kind of production method of high density long-life tungsten-molybdenum alloy crucible |
| CN112605387B (en) * | 2020-11-29 | 2022-08-23 | 西北工业大学 | Integrated precise forming method for metal iridium ventilation window assembly |
-
1982
- 1982-08-14 DE DE3230389A patent/DE3230389C1/en not_active Expired
-
1983
- 1983-05-10 GB GB08312805A patent/GB2142935B/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5993545A (en) * | 1997-01-24 | 1999-11-30 | W.C. Heraeus Gmbh & Co. Kg | Crucible for growing single crystals, process for making the same and use of the same |
| WO2013180965A3 (en) * | 2012-05-29 | 2014-05-08 | H.C. Starck Inc. | Metallic crucibles and methods of forming the same |
| US9457405B2 (en) | 2012-05-29 | 2016-10-04 | H.C. Starck, Inc. | Metallic crucibles and methods of forming the same |
| US10100438B2 (en) | 2012-05-29 | 2018-10-16 | H.C. Starck Inc. | Metallic crucibles and methods of forming the same |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2142935B (en) | 1985-09-18 |
| DE3230389C1 (en) | 1984-03-15 |
| GB8312805D0 (en) | 1983-06-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |