DE1558636C

DE1558636C - Process for the production of dispersion-hardened lead or dispersion-hardened lead alloys

Info

Publication number: DE1558636C
Application number: DE19671558636
Authority: DE
Inventors: Michael V Edgeworth Sewickley Bowman Robert S Pittsburgh Kanzelmeyer James H Ahquippa Pa Rose (V St A)
Original assignee: Associated Lead Manufacturers Ltd , London
Priority date: 1966-02-10
Filing date: 1967-02-06
Publication date: 1973-06-20

Description

punkt des Bleis. Das Molverhältnis zwischen Sauerstoff- und Schwefeloxyd kann in der Oxydationsatmosphäre in einem Bereich von 5 : 50, vorzugsweise zwischen^;10_;: 30, liegen.point of lead. The molar ratio between oxygen and sulfur oxide can be in the oxidizing atmosphere in a range of 5:50, preferably between ^; 10 _; : 30, lie.

Bereits oxydierte Bleipartikeln, die zwecks Entfernung des Kohlendioxyds in bekannter Weise erhitzt worden sind, können mit einem Schwefeloxyd bei Temperaturen zwischen 100 und 350⁰C behandelt werden.Already oxidized lead particles, which for the removal of carbon dioxide have been heated in a known manner, can be treated with a sulfur oxide at temperatures between 100 and 350 ⁰ C.

Folgendes Beispiel zeigt die Herstellung von dispersionsgehärtetem Blei aus Pulver nach einem Verfahren gemäß der Erfindung:The following example shows the production of dispersion hardened Powder lead by a method according to the invention:

Bleipulver mit einer durchschnittlichen Partikelgröße von 10 Mikron und einem Oberfiächen-Oxydgehalt von 2,8 % wird 2 Stunden lang unter einem Vakuum von 10~³ mm Hg auf eine Temperatur von 300 bis 31O⁰C erhitzt, um das Kohlendioxyd zu beseitigen. Nach dem Abkühlen auf 100° C im Vakuum wird das Pulver 30 Minuten lang und bei einer Temperatur von 100° C der Wirkung von trockener, kohlendioxydfreier Luft, die aber Schwefeldioxyd mit einem Partialdruck von 20 mm Hg enthält, ausgesetzt. Ungefähr 0,08 cm³ Gas wird pro Gramm Pulver absorbiert. Eine Probe des behandelten Pulvers zeigt, daß bei einer Erhitzung auf 335⁰C unter einem Vakuum von 10~³ mm Hg keine wesentliche Gasbildung auftritt. Das Molverhältnis zwischen dem Sauerstoff im Bleioxyd und dem Schwefeldioxyd in der Oxydhaut ist ungefähr 18. Enthält beispielsweise die Behandlungsatmosphäre Wasserdampf mit einem Partialdruck von 4 mm Hg, dann ist die Absorption des Schwefeldioxyds etwas höher. In jedem Fall tritt bei einer nachfolgenden Behandlung des Pulvers bei 100⁰C keine wesentliche Absorption von Kohlendioxyd ein, weder bei trockener noch bei mit Feuchtigkeit angereicherter Luft, die Kohlendioxyd mit einemLead powder having an average particle size of 10 microns and a Oberfiächen-oxide content of 2.8% is heated for 2 hours under a vacuum of 10 ^-3 mm Hg at a temperature of 300 to 31o ⁰ C to eliminate the carbon dioxide. After cooling to 100 ° C in vacuo, the powder is exposed to the action of dry, carbon dioxide-free air for 30 minutes and at a temperature of 100 ° C, but which contains sulfur dioxide with a partial pressure of 20 mm Hg. Approximately 0.08 cm ^{3 of} gas is absorbed per gram of powder. A sample of the treated powder shows that when heated to 335 ^° C. under a vacuum of 10 ^-3 mm Hg, no significant gas formation occurs. The molar ratio between the oxygen in the lead oxide and the sulfur dioxide in the oxide skin is about 18. If, for example, the treatment atmosphere contains water vapor with a partial pressure of 4 mm Hg, the absorption of the sulfur dioxide is somewhat higher. In any case, when the powder is subsequently treated at 100 ^° C., no significant absorption of carbon dioxide occurs, neither with dry air nor with air enriched with moisture, which carbon dioxide with a

ίο Partialdruck von 15 bis 20 mm Hg enthält. Daraus erweist sich die Stabilität des mit einem Schwefeloxyd behandelten Pulvers unter normalen Behandlungsund- Lagerverhältnissen.
Werden die durch die vorerwähnte Behandlung gewonnenen Partikeln im Vakuum unter Druck von etwa 4200 kg/cm² zu einem Barren gepreßt, dann kann dieses dispersionsgehärtete Blei auf herkömmliche Weise gut verschweißt werden, während die ähnlich verdichteten und stranggepreßten Originalpartikeln wegen der Gasbildung an der Verbindungsstelle keine zufriedenstellenden Schweißverbindungen ergeben.ίο Contains partial pressure of 15 to 20 mm Hg. This shows the stability of the powder treated with a sulfur oxide under normal treatment and storage conditions.
If the particles obtained by the aforementioned treatment are pressed into a bar in a vacuum under a pressure of about 4200 kg / cm ² , then this dispersion-hardened lead can be welded well in the conventional way, while the similarly compressed and extruded original particles do not have any due to the formation of gas at the connection point result in satisfactory welded joints.

Das Bleipulver kann aus reinem oder im wesentlichen reinem Blei bestehen, oder es kann in kleinen Mengen, z. B. bis zu 0,25 Gewichtsprozent, die üblichen Legierungsbestandteile, wie Antimon, Kupfer, Tellur und Silber, von denen bekannt ist, daß sie auf Blei eine härtende Wirkung ausüben, aufweisen.The lead powder can consist of pure or substantially pure lead, or it can be in small amounts Quantities, e.g. B. up to 0.25 percent by weight, the usual alloy components such as antimony, copper, tellurium and silver known to have a hardening effect on lead.

Claims

1 2 caused by gases. These gases arise from patent claims: due to expansion of the enclosed air and the dissolution of lead compounds - besides that

1. Process for producing particles from lead oxide - under the influence of heat. This Lead or lead alloys with an oxide skin that causes 5 phenomena when subjected to heat treatment, are free of moisture and carbon dioxide, e.g. B. rolling, forging or extrusion, Schwied through marked that the in riche, also with a preheating before the lead particles material obtained in a known manner is processed, and - what else afterwards Oxide skin during or after the formation of the partial - it results in the usual welded oxide skin In an oxygen and sulfur oxide io ßen of dispersion hardened lead considerable containing, but carbon dioxide-free defects. Heating leads to the to be connected Atmosphere to be treated. 'Areas to a bubble formation and thus' to one

2. The method as claimed in claim 1, characterized in that the connection is incomplete. Marked by such a deficiency, that the lead particles can stick by atomization compound under certain circumstances the finished part by molten lead in the oxygen and 15 are completely destroyed, e.g. B. if a dispersion sulfur oxide containing but carbon-hardened lead plate as a battery plate in a Swedish oxide a free atmosphere. Acid electrolyte is used.

3. The method according to claim 2, characterized in that it has already been recognized that heating of the draws that sulfur dioxide is used and that dispersion hardened lead is used at over 200 ° C Molar ratio of oxygen to sulfur dioxide 20 swell the particles, a sharp decrease in their in the oxidizing atmosphere is 5:50. Hardness and a progressive decrease in its strength

4. The method according to claim 3, characterized in that these phenomena are characterized by the fact that the molar ratio of oxygen to decomposition of the lead carbonate, whereby CO ₂ gas is formed, originate from sulfur dioxide in the oxidizing atmosphere and that a heat pretreatment of 10:30. 25 lead powder at 250 ° C before extrusion this

5. The method according to claim 1, characterized in that it almost completely excludes swelling. This method shows that lead having an oxide skin is not always satisfactory in practice, in particular particles after the removal of the carbonate, it sets an immediate further processing of the disperse necessary Heating in the carbon dioxide-free ion-hardened lead precedes the inclusion of Atmosphere at a temperature of 100 to 30 humidity or carbon dioxide during a La-350 ° C treated with a sulfur oxide. to prevent irritation.

Lead particles are also free of carbon dioxide ; if it is produced in a known manner

be that liquid lead in dilute sulfuric acid

35 is initiated. The action of the sulfuric acid takes place during the formation of the oxide skin.

The invention relates to a method for producing the lead particles obtained in this way, however, combine of lead particles with an oxide skin by dispersing, if they are then by extrusion sion. For this purpose, finely divided lead will be further processed under influences, but they remain, discarded, among which on the surface of the 4 ° see from those that form the outer shell, separating lead particles forms an oxide skin, e.g. on the bar. Pieces of lead made in this way are used for many purposes Atomization of molten lead in an oxy - but not usable. "

In contrast, the object of the invention is lead particles

Exposure of an oxidizing gas to the lead with an oxide skin, which is essentially particles under controlled conditions, e.g. B. 45 are free of moisture and carbon dioxide and the by mixing the lead particles in the air against each other during further processing into a lead form warden a certain amount of moisture in one piece, in which the surface oxide in Pan mixer, a double cone mixer or the like. Finest distribution is present.

The main part of the lead particles treated in this way becomes: To achieve this object, the method according to

then a plastic deformation, e.g. B. by rollers 50 of the invention, characterized in that the in or extrusion, subjected to the oxide skin into lead particles obtained in a manner known per se and crush the crushed lead oxide with the oxide skin during or after the formation of the Spread lead mass. 'Oxide skin in an oxygen' and sulfur oxide

For best results, use a sustained but carbon dioxide-free atmosphere average particle size of the oxide-coated lead 55 are treated.

particles do not exceed 150 microns, if possible This method gives the surprising advantage of

but not exceeding 20 microns. The lead oxide content that treating the particles in a gas can up to 16 percent by weight. atmosphere has a stabilizing "effect on the sun

In the known process for the preparation of treated particles exerts so that they are before the With dispersion-hardened lead, it is inevitable that 60 extraction of the dispersion-hardened lead also occurs a more or less large amount of carbon dioxide can be stored without carbon dioxide from the Oxide and water vapor is absorbed, what atmosphere absorb.

turn to carbon- and water-containing compounds. It is particularly useful to use the lead particles

bonds on the surface of the lead particles. by atomizing molten lead in such a way The dispersion-hardened lead formed in this way can be obtained in a gas atmosphere created in this way. Included heated to a certain critical temperature, so can form the treatment temperature of the surrounding Bubbles were found to emerge from the atmosphere in which the lead was atomized to speak of arising and included inside, namely from 25 ° C to above the melting point