DE1533353A1 - Process for the production of a finely divided alloy - Google Patents

Description

Dr. Walter Beil "June 28, 1866

Alfred Hoeppener

Dr Uras Joa & im Wolff. 1533353

Dr. Hans Chr. Beil

Ki-cht.senwa.ite

Frankfurt a. M.-Höchst

AdelcmstraiJe 58 - Tel. 312649

Our no. 12 872

CHAS.PFIZER & CO., INO.
Brooklyn, NY, V.8t.A.

Process for the production of a finely divided alloy

The invention relates to a process for the production of copper / iron alloys, in particular of novel iron powders previously permeated with copper.

The term "alloy" used in the description and in the claims denotes a material with metallic properties, which consists of two or more chemical elements, at least one of which is present as an elemental metal. It is already known that the physical properties of the · Iron can be improved by alloying with copper. Since the metals are practically insoluble in one another at building temperature and since their mutual solubility is quite limited even at elevated temperatures, various aids have been used to bring the metals mentioned into close contact.Thus, one has copper and iron powder together

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mixed and manufactured using powder metallurgy methods Objects shaped. One also has the so-called infiltration - method applied, i.e. the pores of one sintered metallic ceramic constituent, in this case iron or steel, filled with a metal or alloy with a lower melting point, e.g. copper.

These known processes for the production of copper / iron alloys are having great difficulty and sharing tied together. Thus segregation can occur during storage and in the presence of powder mixtures of copper and iron. Yet more disadvantageous is the fact, even with the most discriminated Powder mixes are not the ones to guarantee optimal Properties required Hoiaogeri tat achieved »Yird. Farther has the sirterungetar Pul vergemi scha aus / Zupfer and iron cause the composite to expand, thereby an increase in porosity and thus the main cause for insufficient strength, as well as material defects and a high percentage of rejects.

Now it became “a comparatively simple method of manufacture new iron / copper alloys found in powder form, das «compared to conventional infiltration methods offers significant cost advantages. This process gives the powders according to the invention an unusual fine structure ' and ensures a closer intermingling of the elements that make up the thus attributed to attainable, superior physical properties can be. After simple pressing and sintering, the new alloys, which are present in individual particles, shrink into products of great density and high strength.

The metallographic underside characteristics of the new alloys can be seen more clearly on the basis of the attached print of greatly enlarged photomicrographs made with the aid of an electron microscope. Any photographic

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shows part of a single particle of one according to the invention Alloy made in a 3 # Lgen solution of nitric acid was etched in alcohol to wash away the copper-rich areas. These attached photograph! See prints show on the

Fig. 1 with an iron alloy produced according to the invention 7 wt .-? 6 copper in about 100,000 times the diameter enlargement,

Fig. 2 the one reproduced with approximately the same diameter enlargement Alloy of Fig. 1 after the heat treatment described below,

Fig. 3 an iron alloy produced according to the invention with 20 Qe.v.-fo copper in a diameter of about 3,300-f ac th enlargement,

Fig. 4 also with a 3,000-fold increase in diameter reproduced alloy according to Fig. 3 the heat treatment and

Fig. 5 shows a part of the back seen at ¹ Fig. 4 particle, this time 17,700 fold-in about Durchiueaservergrtsserung.

The main features of these representations are described below in Connection with the pain structure of the new products described.

The method according to the invention essentially consists in that a reducible iron compound with copper or a reducible copper compound mixed wi, rd and that this Reactants are reduced to metallic form at elevated temperature · The quantitative proportions «ο chosen that a product with a copper content of about 1 to about 50 wt .- # is obtained.

Copper sinters at about 825 ° C and melts bi3 850 in the pure state at about 1083 ° C and having an iron content τοη 3,2j6 or ■ ore at about 1094 ⁰ C. To the present invention can be achieved, unusually narrow concentration τοη Bisen and copper to it -

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enough, it is essential that the temperature is truer «! the reduction level is at least 10O ⁰ G above the sintering temperature of the copper. In general, at least the melting temperature of the copper is preferred as the reduction temperature. In the case of alloys with more than 20 $ ew .- # copper, however, reduction temperatures at or above the melting temperature of the copper easily lead to an agglomeration of the reduced product to a mass which is then extremely difficult to break into smaller miles. In the production of alloys with such a high Kupfergehelt it therefore holds best the Reduk.tio ns temperature below the copper melting point, but still at least 1OG ⁰ G on the sinter and temperature of the copper and thus to that, preferably at a temperature of 950 to 1050 ⁰ C. for alloys with a copper content of about 1 to $ 20 will result in the biggest advantage if the reduction is at or above the copper melting temperature, preferably at about 1120 - 1135 is carried ° O. In any case, reduction temperatures are unerwünscnt of more than about 1150 ⁰ O since they promote a high degree of agglomeration of the product to a viscous, hard mass, läast grind with useful devices to the metal powder 3i5ft ° ^l,

Under the conditions mentioned, the reaction mixture is reduced to a finely divided alloy of iron with close copper infiltration, without it being necessary to let the copper flow through the iron mass to saturate the pores, as is the case with conventional infiltration of molten copper Iron composites the pail is. In the new method the reduction of the oxide or other reducible iron compound takes place in the solid state "one reduces below 1 094 ⁰ C. jedooh at a temperature which is at least 100 ⁰ C above the sintering temperature of the copper, no liquefaction is carried out of the copper but rather a grain size diffusion of the reduced solids with the achievement of comparable results, as already pointed out, preferred at these lower induction temperatures for the production

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of alloys with high copper yield, and. It is believed, that the fractions uit. high copper content the formation favor infiltrated products.

. If fine-particle alloys of iron with copper infiltration or penetration are spoken of in Besenreib and claims, ao is understood to mean individual particles that contain both copper and iron in close, mutual dispersion and are therefore in front of each other. bloaeen mixtures of copper and iron powder and further distinguish from those particles that consist of only one of these elements and are only coated with the other.

As a result of their nature, the items available in accordance with the invention and available in individual pieces occur during storage or shipping Alloys do not segregate while leaving the individual elements. You can sachgeiaäsa as "pre-infiltrated" · Alloys are called ee as they are using conventional process of powder metallurgy can be molded directly into appropriate hot parts without that a separate penetration of liquid copper into a shaped iron part would be necessary, like the »with the conventional one Infiltration is the case.

In the process of the invention, any reducible compound can be used be used, such as iron eels, or anyea Iron oxide, such as hematite, magnetite, processed magnetite ores * Plug dust, synthetic oxides or reducible Walzainter E.g. also rolling mills. With the mentioned, reducible roll sinter is meant roll slag, which is up to about 99 # or more reducible, such as roll sintering from carbon steel or made of low-alloy steel.

Elemental copper, such as reduced copper powder, finely powdered a copper, electrolytic copper powder or non-metallic copper powder can be used. # & ni ~ However, it is more expensive in general

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or mechanically produced copper oxide, such as copper-I-oxide, Copper (II) oxide, copper Walssirter or Zeiaentkupfer, a by-product des (jrubenabwasser3, which is usually around 50 to 98 $ Contains copper-I-oxide. If copper oxides are used, 30 turns out to be Sometimes it is advantageous to add nitric acid to be added in order to thereby achieve a narrower diffusion cause. However, copper-Ti-ritrate can be used as a source of copper or another water-soluble copper salt in aqueous solution be used.

In addition to copper and iron, nickel, cobalt, molybdenum or Tungsten or reducible compounds of these elements, like nickel-II-oxide, cobalt- (III) ox: yd,!. 'olybdenum trio ^ / d odar Tungstic anhydride. These elements are in general! in smaller ranks to increase the strength used, i.e. bia au about 6 wt .- $ when used one element oiler up to a total of about 12 SEW .- ^ when used multiple elements. "Such elements can be used to achieve an optimal dispersion in the form of soluble oils, such as nitrates or acetates or as compounds together with an acid or baee as a solvent, such as ammonia water or nitric acid can be used.

It is preferred to use reactants whose particle size is less than 250 / u; Particularly preferred are iron compounds with a particle size greater than or equal to about 50 / u and copper compounds of less than about 20 / a, since this is a very close, mutual division of the most favor.

Even if it is not of decisive importance, it is often advantageous to add an aqueous dispersion of an organic adhesive to the reaction participants in order to reduce dusting losses or seigging processes during their handling and subsequent processing to a minimum. Suitable binders include glue from animal protein, methylcallulose, hydroxyethylcelluloae, Oix-

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boxymethyl cellulose and the like. Decompose such compounds sicn quickly at the reduction temperature and should "preferably have a low ash content. In general, adhesive amounts of about 0.5 # of the total weight of the batch are used perfectly adequate, the water content usually accounting for up to about 18% of the total consummation.

When an adhesive is used, the parties know mixed with advantage in the pan mill or "chaser" that the constituents become hard globules with a diameter of up to 25.4 bibs, whereby a second grinding process is not necessary or only necessary to a small extent. These beads can be earthed without drying beforehand Reduction furnace can be entered. If no adhesive is added, the reaction components are mixed thoroughly before they are placed in the oven.

The reduction conditions required in the furnace can be created by a gaseous reduction atmosphere, for example hydrogen or carbon monoxide or substances such as diassociated ammonia, water gas, generator gas and the like. However, finely divided carbon can also be added to the reaction mixture to generate the necessary reduction conditions. Iron black, petroleum coke, anthracite abrasion, Ru33 _f bone black or graphite are suitable for this. The minimum amounts of carbon are based on the respective Raaktie participants and their proportions and can be estimated from the stoichiometry of the reaction. The optimal quantities can be determined ^ edoeh ^ - ^ mH ^ esirexrO ^ ErQiimentQll. Usually one uses the carbon in amounts of wa 8 to 12 ^. Even if a gaseous reducing agent is used, it has proven to be always advantageous to use a small amount of carbon, especially with large loads, so that an effective reduction is ensured. How duktionstechnlk _t known in the R "ea is by using carbon ala Hauptreduktionamittel in

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generally desirable to have a carrier gas through the furnace see below conduct to drive off the volatile reduction products and prevent renewed oxidation. Suitable carrier gases include nitrogen-rich, endothermic gases, exothermic gases, Methane, propane, Brdgaa and der.id. If necessary, of course, artificial gas, generator gas or hydrogen can also be used be used.

The reduction is continued until the realizable connections prkaktisch completely, · ie to about 93 to 98 i "are reduced. During the re-reduction process, the particles produced as a product usually form a lightly sintered sponge, which can be ground or ground to the final particle size determined in terms of ventilation without difficulty. It has been found that a residual oxygen content of 2% or more results in a particularly easily friable sponge which is easier to vomit than all sponges with a lower oxygen content. The time required to carry out the reduction to these "degrees" depends on the reduction conditions and the respective reaction participants. For a practically complete reduction, a period of about 50 minutes to two hours is usually sufficient. It is inexpedient to prolong the reduction unnecessarily, as difficulties in breaking open the gohwan: - mes can occur with reduction times of more than about two hours.

The product can be placed in a hammer mill or at the cooling stage a grinding plant to the specified particle size, are generally ground so finely that ο the powder is a sieve old a light. Mesh size between 0.175 and 0.246 mm happened.

The powder thus obtained may by conventional traverse β η <X * r powder metallurgy to purpose shall Fora en geforat vrtrden, you · done by compacting using about

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1,400 to 8,400 kg / cm and soles sintering under non-oxidizing conditions at elevated temperature, preferably at or above the melting temperature of copper, in order to achieve optimal properties. It should be pointed out that if powder tables made of copper and iron are formed in this way, if the copper content is high, it is necessary to carry out the sintering below the copper melting point with the associated strength and loss of copper to smelt of "blistering. ¹¹ the reason for this let the incoming during sintering agglomeration of the copper-enriched compositions in such mixtures. Furthermore hiESuweisen that the sintering premixed copper and Bisenpulver xu a Auedehnung the composite ale sequence results of Legierungsvorgangea. in contrast, In the case of the alloys according to the invention, which are present in individual particles, any expansion occurs as a result of the refraction process during the hedging stage and not during the sintering of the compacted particles To understand that, the further alloying takes place primarily on the contact surfaces of the particles. This leads to a shrinkage of the integrated composite material, which, as already stated, is more expedient.

The sintered parts which are made from the individual particles in vorlie- ^j constricting alloys of the described reduction process', have good physical properties even without further treatment. The degree of shrinkage and strength mainly depend on the copper content, with shrinkage and steadiness reaching maximum values at a copper content of around 30 ^. ,

Another important feature of the invention is based on the Development of a new type of heat treatment of the alloy

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powder. The heat treatment process results in a surprising, unprecedented increase in the density and strength of the finished, sintered composite. This heat treatment essentially creates a lending curve or "premature shrinkage ¹¹ ", as a result of which the degree of shrinkage in the actual sintering stage is reduced without the undesired expansion mentioned above occurring.

The a-'Z transition temperature of iron is around ^ 10 ⁰ C. In the case of iron with a copper content of less than 3.9 ') Ό , however, this transition takes place at around 835 to Ö50 ° C. It has now been found that the heat treatment of the new alloy powder is most effective within a temperature range between the transition point of the iron-rich phase and a temperature 150 ° C. below it. The best results are obtained when the heat treatment uia less than 50 ⁰ C under the α- 7-transition at a temperature greater, is preferably carried out at about 825 bia 845 ⁰ C. Dax-like Töiaperäturbedingungen lead to the development of highest density, strength and hardness with minimal shrinkage after sintering. Exceeds the Wärmebehanllung temperatures of 845 to 85O ⁰ C, so is an abrupt drop of the properties of a their optimal values.

For best results, the powder should be heat treated for at least about 30 minutes before cooling. The maximum amount of time is not critical and periods of up to 10 hours can be used. However, it remains a heat treatment of more than 4 hours without benefit, cheapest Results are generally achieved in about 1 to 2 hours.

If the reduced powder to which the heat treatment is applied has an oxygen content of more than 2 ^, it takes place the heat treatment is most appropriate with reduction

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conditions so that the oxygen content is reduced to a value below 2 #, preferably below 1 1> «, during this stage. However, if the oxygen content is already $ 2 or less, an inert atmosphere can be used if so desired.

The powder is taken out of the oven as a loosely separated mass. This mass cools down quickly and can be ground again so finely in the same way as after the first reduction ensure that the particles pass through a sieve with a mesh size between 0.175 and 0.246 mm.

The properties of the invention, egierun & powder are largely improved by means of the flat heat treatment. The products have excellent tensile strength after compression and sintering, as can be seen from the following examples. It should be noted that alloys ₀ sn with a copper content of about 1 to 6? 6 tensile strengths of over 3150 kg / cm, while copper contents of 6 to 10 i * result in products with tensile strengths of 4200 kg / ca or more, copper contents of 10 to 40 i> tensile strengths

of 5250 kg / cm or higher and copper contents of 40 to 50 i » to products with tensile strengths above 4550

kg / cm lead. By way of comparison, it can be established that the sintered mile of pre-cut powders has tensile strengths.

wise that only reach up to 2800 - 3150 kg / c »and that is also practical through previous heat treatment of the pulver mixes nothing to change.

In addition, there is the shrinkage occurring during sintering The heat treatment of the new alloys significantly increases the diene and increases the porosity degraded. These advantages are all in the examples presented quantitatively. The nameda ^ present after sintering Properties correspond to or exceed the properties of conventionally infiltrated parts, but are after a fairly simple and economic pres- uad

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Sintering process instead of the more complex and expensive one Infiltration process generated.

A preliminary insight into the fine structure of the new alloys grant their x-ray spectra. An alloy with shows a copper content of 20 # after the first reduction and after the heat treatment practically the same spectrum, namely in both cases a phase enriched with α-iron and a phase enriched in £ -copper. The refractive spectrum of an alloy containing 7 # copper after heat treatment is essentially the same except for the expected evidence of the presence of a smaller one Proportion of the phase enriched with copper. However, the 7 # copper alloy shows after the first reduction an image that corresponds to a single phase enriched in α-iron. For each of these diagrams are the ice maxima relatively flat, the copper maxima schaj & fer educated.

The matsache that one method for this does not receive a second phase as is well surprising and indicates that alloys having a copper content under the Lö'slichkeitsgrenze in iron at the reduction temperature (about 8 # at 1125 ⁰ C), the copper according to the first reduction in have extremely fine dispersion. This can be attributed to the cooling rate after Rarausnahme from the furnace, wherein characteristically the temperature falls within the first minute to about 490 ⁰ C, so that "ie the variation range of the maximum solubility undergoes raach. (The solubility of copper in iron at 500 ⁰ C is only about 0.25 #) »On the other hand, one gets the impression that the subsequent heat treatment within the specified temperature range for a period of 30 minutes or longer results in the separation of a dissolvable, enriched with copper Phase enables.

Through nan gains a better insight into the fine structure microscopic examination of the alloy particles that

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drawn, polished, and etched with nitric acid to use To remove copper-enriched areas and thereby delimit the phases.

According to this, alloys with a copper content of about 1 to 10 # have a very uniform fine structure, the copper content being dispersed in the iron grains up to about 856 in 1 orm of particles with a diameter of less than about 1000 i (0.1 / u) is. At 250 times the powder magnification, no clear grain boundaries can be seen, so that a greater magnification with an electron microscope is necessary for further delimitation. Thus, Fig. 1 shows an iron alloy with 7 tiger copper content after the first reduction and Fig. 2 the same. Alloy after heat treatment, each with a diameter of about 100,000. The copper was removed by the corrosive acid on the areas that appeared as depressions, so that the fineness of the dispersion can be recognized without further ado. If the fields are further ür.teroucnurig one can see that the sample after the reduction has dispersed, copper-enriched and band-shaped accumulated particles with a diameter of about 350 % , whereby the average distance between the copper particles is about 150 % . The distance between these clusters is between only 500 α and values up to about 0.75 / U. Between the clusters one finds particles enriched with copper, whose mean diameter is also about 550 % , but it can be assumed that there are also particles below the dissolution limit of 50 % . Furthermore, cracks with a length of about 0.1 to 0.3 / u and a width of 400 - 900 Ϊ as well as angular cavities with a diameter of 0.1 to 0.9 / u can be found in the fine structure. After the heat treatment and the giants are no longer visible, and the clusters now appear as bands or rings with a length of 10 / u + 5 and a width of 5 / xx ± 1. The copper particles in the rings show an average diameter of about 400 % with a partial height distance

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of about 150 5L The dissolved copper particles between the clusters have a mean diameter of about 175 Si with a particle spacing of about 550 %.

A microscopic examination of alloys of this invention with a Kupfergöhalt of more than 10 and up yields to about 50 wt .- # that these alloys fine unusual tight "packed and angereicüerte with iron grains asc? Is3n _f whose grösaerer or grosster diameter approximately 35 / U with an average distance between adjacent egg grain boundaries of less than about 5 / u. The iron-enriched grains have a very uniform dispersion of finely divided, copper-enriched particles.

Fig. 3 shows an alloy with a single copper content of after, the first reduction and Fig. 4 the same alloy after the heat treatment, both with et, above all 3,600 times the diameter enlargement. The island-like areas that emerge on these images and cover most of the field of vision consist of iron grains in the manner of a plateau, surrounded by "valleys" enriched with copper and removed by the acid. The iron grains here may tend to present themselves as depressions to the eye of the beholder, but this obvious, stereoscopic! See reversal is an optical illusion that can be attributed to the lighting. It can be seen that the iron grains in the sample have an irregular shape after the first reduction, while they appear round or spherical after the heat treatment.

At greater magnification, cracks with a length of about 2500% and a width of 850 % are found in the reduced sample. This can at least «partially explain the higher shrinkage that occurs after sintering. Such cracks are no longer present after the war, -me transformation.

In the following, the average dimensions of a 20 % copper door, determined by Zeis countermeasures, are used.

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the government "" reproduced after the first Beduction at 1125 ⁰ C:

Iron grains

Length 17.50 / rev

Width 13, b9 / U

distance between

the grains 1.76 / rev

Copper particles in the iron grains

Length 0.0423 / u

Width 0.0371 / rev

Distance between

the particle 0.0352 / U

Iron parts in those with copper
enriched bodies

Long 0.0268 / rev

Width 0.0216 ax

distance between

the parts 0.0894 / u

On closer inspection, the iron grains of the ADb. 4 one Much rougher structure than that of Fig. 3. The reason for this can be discovered from the greater growth in size. Fig. 5 shows part of the field of view of Fig. 4 in about 17,700 facner Diameter enlargement. The most prominent feature this rendering is an elongated "valley" or one with Copper-enriched body, the parts of the two adjoining Iron grains separates. The reproduced place within these iron grains is due to the removal of the copper-enriched ones particles attacked with the help of the acid. One recognises, that the copper particles within the iron grains belong to two different size ranges: the primary particles have a diameter of about 0.1 to 0.5 / U, the secondary ones Particles less than about 0.05 / U in diameter.

This unexpected and unusual structure just shows itself after the heat treatment. Probably the atelle

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larger, primary particles agglomeration of ursprüngliahen Kupferteilohen in the reduced sample as a result of the different solubility of copper in iron at the reduction temperature (about $ 8 at 1125 ⁰ C) and in the heat treatment s temp he a door (about 3.5 # at Ö35 ° O). It can be theorized that the primary copper particles represent such copper, the solubility of which is above the heat treatment temperature and which agglomerates during this hardening stage. The theory can also be set up that the smaller, secondary particles represent the copper that is present at the heat treatment temperature up to. dissolved to saturation in the iron and then separated while cooling to room temperature. The fact that these secondary parts are equal in size, the copper parts, to those after the first. \ Reduction in the; If iron grains are present, this hypothesis must be credible. Nevertheless, it should be pointed out that the present definition is not limited by any theory or hypothesis, even if it is credible.

liachstehelid be the average dimensions of a 20 fo entnaltenden copper alloy according Warm is reproduced just andlur ^ at 35 ° & ü:

Oh so bad

Length 20.09 / rev

.width 16.39 / u

Distance between the

CTj 1.6 D Al

iv.ku.iH / vupferteiionen in the
Eisvnkö'r ne rn

Length 0.2713 / rev

Width 0.2404 / rev

Distance between the

Teilchan 0.2865 / U

SAD

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Secondary copper particles in the Iron grains

Length 0.0331 / U,

Width 0

Distance between the

Particle 0.028? / Rev

Iron particles in the areas enriched with copper

Length 0.1238 / rev

Width 0.1122 / rev

Distance between the

Particle 0.4720 ₇ u

The dispersion of a larger amount of copper in the iron grains of the alloys according to the invention can result in their higher strength after sintering compared to conventionally infiltrated alloys with equivalent density, whose copper content appears to be more concentrated between the grains.

It can also be emphasized that, as a microscopic examination showed, the parts enriched with iron and copper enter into a close connection with fusion at the grain boundaries even if the primary reduction is below the melting point of the phase enriched with copper, but still at least 100 is performed 0 above the copper-sintering temperature (for example, the reduction of a 40, 0 Kupierenthaltenden alloy at 95O ⁰ G). This statement applies to the particles after the first reduction as well as after the heat treatment.

There was also a microscopic examination of the novel Alloys set up after compaction and sintering. It was found that the densely sintered alloys resemble the unsintered particles · Sintering only closes the particles into one through grain boundary diffusion Mass together, what from a comparison of the average

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i'Jisen grain sizes as well as that between the grains ν or κ.-and Distance advertising of the heat-treated powder with one of them manufactured, sintered part using a z.L. 20 "ο copper-containing alloy shows:

Length of the width of the distance ζτ / i those üJ.l £ enkö r ner i-Jisenkörner de η ".ι la exi k ö me rn

(/ poor nimble 1st p

Powder 2ü, O9 / U 16.39 / U I, o6, .i

Sintered part 22.09 / U 17.39 A * 1.6B ₇ U

Conventional infiltration 56.66 Ai 27.91 / U 8.3? / U

The above proven resistance to increased grain wax during the sintering appears to reflect the structural stability of the new alloys 40 / o copper containing alloys:

Length of the! Ride the distance from the bisenkörner bisenkörner dei t I'lisenkürnei'n

Sintered part from

a heat treated

Powder 16.28 ax 14.00 , u. 3.41 ax

Conventional infiltration 40.01 22.66 ax ax 12.5 to 1 / U

The known sintered iron composites are usually of such a porosity that the addition of more than 10-15% copper is necessary to achieve sufficient infiltration by the conventional method. In order to have a comparative standard for the alloys according to the invention with a low copper content, sintered parts made of powder mixtures of copper and iron must therefore be drawn down. Öo show Diikrosj & Kopische investigations of sintered, 7% copper-containing rods made from a mixture of copper / iron powder, which passes through a sieve with a mesh size of 0.147 µm,

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large angular pores and massive copper parts with a diameter of 30 / U and my ·. In contrast, the sintered composite material according to the invention, consisting of individual particles of the alloy with a copper content of 7 ^{° C.} , has a very fine, uniform and densely packed structure. The excellent strength properties that can be achieved by alloys can be increased "up to values of 10000 kg / cm" through various procedures. cm. Usually, amounts of graphite of about 0.5 to 2% are sufficient. Pressing and sintering (embossing) again prove to be useful for increasing the density and strength, as are various aftertreatments such as quenching, drawing and normalizing, which are also used in the following examples explained.

The following examples serve to illustrate the invention. Example 1

Alloy with a copper content of 7 % A. Reduction

Rolled iron sinter 1247.1 g

Dried cement copper. 77.0 g

Hydroxyethyl cellulose 5 »3 g
it fiber 285.0 g

The iron mill scale from the above approach, a by-product of a steel roughing mill or -Nachwerk and is so fine that it passes through a sieve having a mesh width of 0.044 mm, with about 50 ° / o £ 5% coarser than 20 / U are. This V / alz sinter has a bulk density of 1.8 to 2.2 g / cm ^ and has the following analytical composition:

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« Dö - 1533353 Fe 74.58% (as FeO 70.50%) O 24.58% Mon <0.05% Mn 0.308% Ni. 0.038% C. 0.006% S. 0.027% P. 0.100% SiO ₂ 0.301% Al ₂ O ₃ 0.010%

The cement copper from the above approach is a by-product of the Mine sewage · Its degree of fineness is less than 20 / U, approximately 85% even below 10 / rev. The cement copper has a bulk weight from 0.8 to 1.5 g / cm * and has the following analytical composition on:

Cu - 90.80% (as Cu: 2.91%, as Cu ₂ O:

96.72%, as CuO: 2.61%)

0 Nitrates 8.03 Zn Chlorides 0.22 Fe Sulfates 0.47 SiO ₂ 0.03 0.26 0.01 0.08 0.10 Other metals Soluble Soluble Soluble

After their union, the components are in a pan mill or chasers, which allow close mixing with minimal milling activity, ground into pellets. These will placed in a reduction furnace at about 1120 to 1135 ° C and for 45 minutes under hydrogen or dissociated Ammonia kept at this temperature. After the reduction, the beads are taken out of the oven and first in a hammer mill to a size of 3.175 mm and less broken up and then crushed in a micro-grinding system so that all the particles are passed through a sieve with a clear mesh

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width of 0.175 mm. The product has a bulk density of 2.3 Ms- 2.5 g / cm 3 and an oxygen content of about 1.6% (after 30 minutes of reduction at 105O ⁰ G under hydrogen) or of 2.37% (correspondingly after treatment the Leco-Yerfahren - melting in Yakuum at 1926 ⁰ C). The weight loss of the hydrogen only provides information about the content of reducible oxygen.

Instead of the iron roll sintering in the above approach, hematite (Pe ₂ O ₃ ) or magnetite (Fe ₂ O 1, FeO) can also be used in sufficient quantities to achieve the same iron content. Likewise, you can replace the cement copper with pure copper-I-oxide.

For the reduction stage, carbon monoxide can be used instead of hydrogen can be used. Gases enriched with carbon monoxide or hydrogen, such as generator gas, can also be used reach.

B. Heat treatment

150 g of the reduced powder are put into the reduction oven brought, kept at 825-845 ° 0 for one hour and then cooled. The powder comes in the form of a loosely sintered mass taken out of the oven and ground again, in the same rfeise as after the first reduction, so finely that the Particles pass through a sieve with a mesh size of 0.175 mmThe calcined powder has an oxygen content of 0.3% (determined by weight loss of hydrogen) or from 1.14% (Leco method) to «

Example 2

Alloys with a copper content of 1 and 2%.

Rolled iron sinter 1314 · »2 g Copper (II) nitrate trihydrate 37.5 "or 76 g Carboxymethyl cellulose 6.2 g

Water 300.0 g

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These approaches are “reduced at II50 CJ and then heat”. acts, where one. proceed according to the working method described in example 1. Instead of iron-V / salt sinter, hematite (Fe ₂ O,) or magnetite (Fe ₂ O ^ FeO) can be used in sufficient quantities to achieve the same iron content.

The copper (II) nitrate can be obtained by equivalent amounts of Cupric oxide and nitric acid or an equivalent Amount of copper (II) acetate to be replaced.

Example 3

Alloy with 14% copper and 1 % hickel.

Bisen roll sinter 1153 »3 g

Dried cement copper 154 »0 g

Animal protein glue 6.0 g

Water 270.0 g

Nickel nitrate (20.3% Wi) 4-9.5-8

This batch is formed into beads as in Example 1, reduced at 1110 ° G and then heat treated. Instead of rolled iron and nickel nitrate, equivalent amounts of hematite (Fe ₂ O ^) and Niekel II acetate tetrahydrate can be used. The cement copper can be replaced by an equivalent amount of pure copper oxide.

Example 4

Alloy with 20% copper

Rolled iron 10-2 g

Dried cement copper 205 »2 g

Copper (II) nitrate trihydrate 37 »1 g

Iron black 105.1 g

Methyl celluiBe 7.9 g

Water 153 g

These components are formed into spheres, in a re-

095 ⁰ O under

ORIGINAL BATHROOM

brought to the induction furnace and heated for 75 minutes at 1095.degree.

209813/0213

pass a weak endothermic carrier gas (about 84 % nitrogen, 10% carbon monoxide, 6 % hydrogen) held. Following the reduction, the feed is milled and heat treated using the procedure of Example 1.

After the reduction and v / heat treatment method of Example 1 an alloy made with, 20% copper and 1% molybdenum:

Rolled iron sintering 1072.8 S. Dried pickled copper 220.5 S. Molybdenum trioxide 15.0 S. Ammonia water (26 Be) 34.0 S. Carboxymethyl cellulose 6.0 S. water 275 G

In the same way, but using 12.6 g of tungstic anhydride (WO,) instead of the molybdenum trioxide in the above approach, a similar alloy with a tungsten content of 1 % is produced. An equivalent cobalt content is achieved with 14.1 g cobalt (III) oxide instead of molybdenum trioxide. The iron whale sinter can be replaced by hematite (FegO,) with the appropriate adjustment of the amount added.

Example 5

Effects of particle size.

The procedure of Example IA is carried out using iron roll sintering repeated with different particle size. the reduced powder pastures compacted at 7,031.5 kg / cm, 45 Sintered minutes at 1120 ° under hydrogen and then an investigation of their physical properties to achieve subjected to the following results:

Roll sintering with a degree of fineness below: 250 / U 44 / U 20 / U

Mean particle size of the

Roll sintering: 80 ai 20 Ai 5 / U.

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2.70 1.81 2.25 6.25 5.96 6.21 2114 2772 1680 1.4 1.0 1.6

Melted products:

Linear shrinkage,% density after sintering, g / cm tensile strength, kg / cm elongation, % ■

Hardness 'B 45', 3 B 34.0 B 48.0

Example 6

Effect of a binder.

The procedure of Example IA is repeated with and without the inclusion of the hydroxyethyl cellulose used as an adhesive. In a second duplicate experiment, this process is repeated once with and once without adhesive, in both cases using cement copper in such an amount that alloys with a copper content of 20 % are formed. The four

ρ reduced powder are all compacted with 7 »031.5 kg / cm-,

Sintered under hydrogen for 45 minutes at 112O ⁰ C and examined for their physical properties with the following results «

7th % Cu 20% Cu

With a bandage Dry With a Dry middle mixture middle mixture 2
Tensile strength, kg / cm 2772 2324 4235 3570 Density after sintering, g / car 5.96 5.67 6.87 6.54 Elongation, % 1.0 0.5 3.0 2.0 Linear shrinkage, % r, 8i (0.25) ^x 3.68 2.65 hardness B 32.3 B 28.0 B 69.6 B 51.2 x) expansion Example 7

Effects of the reduction temperature.

The procedure of Example IA is repeated for a number of batches with the only exception that a few

209813/0213

these charges at 100O ⁰ G rather than at 1120 - 'LL35 ° G are re duced "Every feed is then with 7,031,5 kg / cm compacted, 45 minutes at 1120 ⁰ G under hydrogen gesinter and then below, achieving results a. examined their physical properties:

Reduction temperature:

Reduced powder
Bulk weight, g / cm

Fii it s speed,
sec / 50 g

Powder, the sieve with
clear mesh size of
0.044 mm passed, %

Grew «loss of H ^, % " ⁰ ^
Composite

■ z

First density, g / cnr

(green density) 6.40 6.29 x 6.33 5.76 5.67 5.7

Sintered composite

1000 ⁰ G Coating 3 Complaint 1125 ° G Complaint See 1 occupation 2 1.73 2.35 .1 Employment «2 • 2.4 2.15 1.83 no 30.7 2.39 29.9 35.4 40.0 67.9 32.8 '29, 3 42.8 42.2 59.8 2.07 1.21 36.7 1.2 1.70 1.93 1.22

Dic-hfce after sintering, ■% 6.31 6.20 6.09 5.96 6.02 6, c g / cnr Shrinkage,% 2863 2254 2800 2772 2807 276 Tensile strength in kg / cm 1 * 3 1.4 1.0 1.0 1.1 1.3 Strain, x) expansion (0.90) ^x (0.13) ^X (0.14) ^X - 1.81 1.75 1.8 Linear B 55.3 B 50.7 B 48.0 B 32.3 B 30.7 B 34, hardness xx) 30 minutes at HOO ⁰ G Example 8

Effect of heat treatment.

A portion of the alloy powder with 7% copper from Example IA is divided into a series of charges of 150 g each, in order then to be subjected to the heat treatment of the example, although the temperatures and

QRIGiMÄL INSPECTED., ^

2 0 9813/0213

Heat treatment times can be modified as follows. Each feed is compressed and after the heat treatment according to the method of Example 7 and then tested under sintered ■ obtaining the following _^results:::

1 hour , 39 ,1 9 ι 2 hours 3 hours After heat treatment at 900 ⁰ C , 33 , 83 77 Bulk weight of the powder, g / cnr 2 2961 , 4 0 2.41 2.39 Density after sintering, g / cm 6th 1 6.34 6.29 ^: ' Tensile strength, kg / cm 0 , 44 2912 2737 Elongation, % 42 , 52 1.1 1.0 Linear shrinkage, % 3346 0.80 0.71 ' Hardness B 2, 2, B. 43.1 E. 40.7 After heat treatment at 850 ⁰ O 6, 0, Powder bulk density, g / cm 52, 2.45 2.46 Density after sintering, g / cm 6.59 6.50 Tensile strength, kg / cm 2, 3430 2863 Elongation, % 6, 2.0 1.9 Linear shrinkage, % , 0 0.62 0.54 Hardness B , 80 B. 53.1 B. 49.2- After heat treatment at 835 ⁰ Cf , 7 Bulk weight of the powder, g / cm ⁵ 2.56 2.50 Density after sintering, g / cm , 58 6.89 6.70 Tensile strength, kg / cm , 83 4557 4095 Elongation, % 4431 3.0 2.8 Linear shrinkage, % 3, 0.62 0.53 Hardness -B 0, B. 64.9 B. 59.2 After heat treatment at 800 ⁰ G 63, Bulk weight of the powder, g / cm 2.51 2.47 Density after sintering, g / cm 2, 6.80 6.78 Tensile strength, kg / cm 6, 4200 3633 Elongation, % ,1 3.0 2.9 Linear shrinkage,% , 79 0.70 0.55 Hardness B , 3 B. 61.9 B. 58.8 , 52 , 80 4081 2, O, 61,

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1 hour 2 hours 3 hours

Heat treatment at 700 0 2.36 2.48 2.47 Bulk weight of the powder », g / cm 6.68 6.60 6.51 Density after sintering, g / cm 3500 3584 3185 Tensile strength, kg / cm 2.0 2.1 1.8 Elongation, % 0.77 0.69 0.51 Linear shrinkage,% 60.1 B 61.2 B 58.1 Hardness ■ B Heat treatment at 600 ⁰ O 2.25 2.23 2.21 Bulk weight of the powder, g / cnr 6.30 6.30 6.21 Density after sintering, g / cm 3234- 3101 2716 Tensile strength, kg / cm 1.1 0.8 0.8 Strain, % 0.91 0.87 0.70 Lia & re shrinkage, % 54.2 B 56.2 B 49.1 Hardness B Heat treatment at 500 ⁰ O 2.15 2.11 - Powder bulk density, g / cm 6.09 6.10 5.82 Density after sintering, g / cm 2415 2282 2100 Tensile strength, kg / cm 1.0 0.8 0.8 Strain, % 1.42 1.39 1.12 Linear shrinkage,% 38.0 B 38.2 B 34.5 Hardness "B

Example 9

Effect of heat treatment.

Repeating the procedure of Example 8, but now limited the heat treatment to a time of 60 minutes, with the temperature range 810-850 ⁰ O was further explored with a temperature control of ¥ 20 "From ^ e of Be x * destiny were eeche Samples molded to give the average results:

209813/0213

temperature Tensile strength o strain Line are hardness 60.2 speed kg / cm % shrinkage 59.4 810 ⁰ G 4095 2.0 0.73 B. 62.0 820 ⁰ C 4116 2.0 0.75 B. 63.3 83O ⁰ G 4249 2.9 - '0.69 B. 64.1 835 ° G 4431 3.1 0.79 B. 60.0 840 ⁰ G 4466 3.0 0.82 B. 52.7 845 ⁰ G 4102 2.1 0.84 B. 850 ⁰ G 3437 2.0- 0.80 B.

In this series of experiments, the bulk weights of the powders are between 2.44 and 2.58 g / cm and the density after sintering between 6.52 and 6.84 g / cm

Example 10

Effect of heat treatment

Using the "procedure of Examples 8 and 9" a powder alloy with a copper content of 7% below Heat-treated at a temperature of 835 ° 0 for 30, 45 and 60 minutes to achieve the following results.

Heat treatment for: 30 minutes 45 minutes 60 minutes composite

First density, g / cm ⁵ 5.91 6.40 6.65

Sintered composite

Linear shrinkage, % 1.21 0.97 0.79 Tensile strength, kg / cm ² 3969 4067 4431

Example 11

Effects of reduction temperature and heat treatment.

Samples from each of the reduced powders of Example 7 were made Heat-treated for one hour at 835 ° G. Subsequently compacted and the powders were sintered in the manner described and examined for their physical properties with the following results Properties down: _ ^

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Reduction temperature;

1000 ⁰ G

Besch «! Besch »2 Besch, 3 powder after heat treatment

Bulk density, g / cm ⁵ 2.44 2.12 2.10 flow rate, sec / 50g 33.3 38.6

Powder passing through a sieve with a mesh size of 0.044 mm,% 40.5 r _e loss of H ₉ , % ^x ^ 0.51

1125 ° C
Acc. 1 App. 2 Besc

53.9

0.52

,no

60.0
0.67

2.69
25.3

34.1
0.30

2.58 2.5 25.7 25, C.

40.2
0.22

45, C 0.2

Composite

First density, g / cnr 6.48 6.37 6.30 6, 65 1 6.73 6.6 Sintered composite 79 Density after sintering, g / cm 6.68 6.55 6.52 6, 83 , 3 6.80 6.7 Tensile strength, kg / cm 3745 3430 3325 4431 4277 436 Elongation, % 1.9 2.0 1.8 3, 3.2 2.9 Linear shrinkage,% 1.49 1.31 1.53 O, 0.77 0.6 Hardness B 60.9 B 59.4 B 63.0 B 63 B 58.9 B 60.4

x) HOO ⁰ G for 30 minutes

Example 12

Influence of other metals

Following the procedure of Examples 3 and 4, alloy powders with 7% copper were produced, each of these powders containing no 1% cobalt, nickel or molybdenum. They were compacted and sintered as in the previous examples and examined with the aim of the following results both in the reduced and in the heat-treated state:

209813/0213

% Cobalt Tensile strength
speed, ρ
kg / cm 13th 30 - Density according to
Sintesung,
g / cnr 1533353 hardness • reduced strain
% Linear
Schrum
pfung ^ 1 heat handIt 2226 5.97 E 29.1 % Nickel 3864 1.9 - 6.79 1.43 B 59.7 reduced 4.0 0.72 1 heat treated 2268 5.94 B 33.0 % Molybdenum 4557 1.9 6.77 1.54 B 70.9 reduced 2.3 0.90 1 heat treated 2471 5.99 B 28.1 example 4585 1.8 6.90 1.73 B 74.5 1.9 0.69

Use of elemental copper.

The process of Example 1 was repeated, but instead of the cement copper, an equivalent amount (70 g) of finely powdered copper, which passed through a sieve with a mesh size of 0.147 mm, was used. The reduction was 45 minutes at 1000 ⁰ C, the heat treatment for one hour at 835 ° C carried out Hach completion of compaction and sintering in the manner described "e Weβ the resulting powder had once reduced and then heat-treated in the following state properties:

Reduced heat treated

ρ
Tensile strength, kg / cm 3668 4606 Elongation, % 0.80 1.0 Density after sintering, g / cnr 6.39 6.70 Linear shrinkage,% 0.85 0.09 hardness B 61.3 B 68.4 Example 14

Other sources of copper.

The procedure of Example 1 was repeated using instead

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ϊ - 3

Density according to -, Tensile strenght. Sintering, ff / cm '' kft / cm 6.81 3507 6.80 3584 6.85 4431 6.88 4760 % Gu) 6.75 4844

des Zementkupfers' various other sources of copper were used in amounts equivalent to their copper content. After reduction at 1125 G ⁰ for 45 minutes and heat treatment at 825-845 ° C for one hour, the powders were pressed and sintered in the manner described, after which the following characteristics are determined:

Copper source

Cupric oxide (83.02% Cu)
Rolled copper sinter (88.64% Gu)
Cement copper # 1 (90.80 % Cu)
# 2 cement copper (93.04 % Cu)
Reduced copper powder (99.52% Gu) 6.75

Example 15

Effect of the compression pressure.

A 7 Ί "copper-containing alloy powder that had been produced by the reduction and heat treatment process of Example 1 was added with 0.75 stearic acid and mixed using pressures compacted, after which Jed composite was sintered for 45 minutes at 1120 ⁰ C under hydrogen . The following physical properties could be determined depending on the compression pressure:

Compaction pressure: 4218.9 kg / cm ² 5625.2 kg / cm ² 7031.5 8437.8p

kg / cm ks / cm

Composite

He st density, g / cm ³ 5.94 6.29 6.65 6.76

Initial tensile strength, kg / cm ² 144.06 175.07 251.37 338.03

Sintered composite

Tensile strength, kg / cm ² 3039 3703 4431 5264

Elongation, % 2.9 3.1 3.0 1.8

Density after sintering, g / cm ^ 6.09 6.46 6.83 "6.93

Linear shrinkage,% 0.83-0.80 0.79 0.75

• Hardness B 46.0 B 61.3 B 63.3 B 69.2

COPY 209813/0213

Example 16

Graph! T Influences with Different Compression «.

Example 15 was carried out, with 1% graphite now being added to the heat-treated item powder before compaction and sintering. The following results could be determined:

Compression pressure: Example 17 4218.9 ' 5625.2 7031.5 8437.8 kg / cm ² kff / on kK / cm * kfc / approx Composite Board density, g / cnr 5.96 6.33 6.68 · 6.78 Sintered composite Density after sintering,
Tensile strength, kg / cm g / cm ³ 6.07 6.43 6.80 6.91 Elongation, i> 5039 64o5 7637 9590 Linear shrinkage, # 1.9 2.0 2.0 0.9 hardness 0.86 0.84 0.81 0.80 B 72.3 B 83.2 B 86.9 B 100.2 -

Effect of an imprint.

The procedures of Examples 15 and 16 were repeated, wherein Now the finished, sintered piece is pressed again under the same conditions as in the first pressing and sintering cycle was sintered. As a result, the following properties were achieved!

209813/0219

Compression pressure:

Additivesj

Composite

Initial density, g / cm

7031.5 kg / om

6.65

Sintered composite

Served after sintering, 6.83 g / cm

Density after renewed. Pressure, g / anr

Served after re-sintering, g / om * - Final tensile strength, kg / approx

Final elongation, i » Final hardness

Linear shrinkage, % After the 1st sintering After the 2nd compression After the 2nd sintering

7031.5 84-37.8 8437.8

kff / cm kg / cm k ^ / om

Jt graphite - 1 ^ graphite

6.63

6.79

6.75

6.92

6.74

6.90

6.86 6.81 7.13 7.05 6.93 6.85 7.20 7.11 5404 7791 5803 S652 3.0 2.0 5.1 3.0 B 77.8 B 94.2 B 85.3 B 99.7 0.79 0.91 0.75 0.76 0.06 0.01 0.06 0.01 0.07 0.01 0.05 0.01

Example 18

Effect of graphite with different copper ages.

A number of iron-containing alloy powders with different copper content was prepared according to the procedures of Examples 1 and 2 under reduction at 1125 ⁰ C for 45 Miruten and subsequent heat treatment at 835 ⁰ C for one hour under a Wasseratoffatmosphäre. Each «powder was mixed with 11 ° graphite. N-iCh pressure treatment at 7 31 _β 5 kg / on and 45 minutes sintering at ^ 1120 ° C under hydrogen, the following physical properties were determined:

209813/0213

Copper content 4 * Cu 7Ji Cu 14 * Cu 20 * Cu Composite First density, g / cm ⁵ 6.63 6.68 6.86 6.97 Sintered composite Density after sintering, g / cm ² 6.76 6.80 7.20 7.46 Tensile strength, kg / cm 7259 7637 7840 7903 Strain, * 2.1 2.0 2.0 19th

Linear shrinkage, * 0.77 0.81 1.46 1.96

Hardness B 88.3 B 86.9 B 97.4 B 101.5

Example 19

Post-sintering treatments.

Sintered composites produced according to Example Ib have been used to further improve physical properties subjected to various additional treatments. The following results were achieved:

Copper content: 4 * Cu ^x 7 * Cu ^x 14 * Cu "20 * Cu ³ "

Without graphite

Density after aging,
g / cm 6.76 6.78 7.33 7.59 Tensile strength according to
Aging, kg / cm 5131 6776 5992 5418 Strain, # 2.0 1.9 2.1 2.0 Linear shrinkage
after aging, * 0.76 0.48 1.65 2.47 Hardness B 70.9 B 84.4 B 92.0 B 95.9 With 1 * graphite

• Jt

Density after aging, g / om

6.72 6.74 7.26 7.51

Tensile strength still

Aging, kg / oaT 8267 9331 10290 9604

Elongation, * 1.9 1.9 1 »9. 2.0

Linear shrinkage

after aging, * 0.83 0.63 1.58 1.89

Hardness B 85.4 B 94.4 B 110.8 B 109.4

x) Quenched from the sintering stage in water and aged for 30 minutes at 465 C under hydrogen.

xx) after sintering 60 minutes at 100O ⁰ C under Sfcicketoff * normalized, then cooled in the oven to 370 C, kept 10 minutes under hydrogen at 815 ° C, quenched from this temperature in Wasasr and finally Aged 1 time at 26o ° C in air.

Example 20

Effect of the copper content in reduced powders.

A series of iron-containing alloy powders with different copper ages were produced according to the induction process of Example IA with the appropriate setting of the amount of cement-copper. The reduced powder was mixed with 0.75 # stearic acid as a lubricant, compacted at 7031.5 kg / cm and sintered for 45 minutes at 112o C ⁰ untar hydrogen, the following properties were determined physikall α CNEN :.

copper 0, $
(a) density
after
Sintering, Tensile strength
ability ,,
χ 10 |
kg / cm strain Linear
Schrum
exam, hardness 2 1.22 p, 90 2,646 1.9 1.82 B 27.2 4th 1.20 5, yo 2,660 1.9 1.84 B 29.7 6th 1.26 5.92 2,695 1.1 1.81 B 35.2 7th 1.21 5.96 2.772 1.0 1.81 B 34.0 6th 1.20 5.98 2,779 1.0 1.80 B 35.5 10 1.26 6.08 2.828 1.9 2.20 B 42.2 12th 1.23 6.29 3.213 1.8 2.35 B 49.3 14th 1.26 6.37 3.423 2.0 2.64 a 51.6 16 1.26 6.54 3,612 2.1 3.17 B 55.6 18th 1.20 6.75 3,962 2.0 3.61 B 68.2 20th 1.97 6.87 4,235 3.0 3.68 B 69.6 30 (b) 1.20 6.81 5,579 3.9 8.13 B 90.9 40 (c) 1.84 6.88 4.074 3.8 8.48 B 86.4 50 (d) 1.99 7.27 2.940 4.0 8.44 B 53.8

(a) "flio results from the percentage weight loss of hydrogen over 30 minutes at 1100 ° C.

(b) reducing 30 minutes at 105 ⁰ C, sintered for 10 minutes at 1120 ⁰ C.

(c) Reduced at 95O ⁰ O for ^{30 minutes, sintered at 1120 0} C for 10 minutes.

(d) Reduced at 95O ⁰ C for ^{30 minutes, sintered at 1095 0} C for 10 minutes.

BATH ORIGINAL

209813/0213

Example 21

Effect of the copper content in heat-treated powders.

Following the example 20 produced, reduced powder was 60 minutes at 835 0 "heat-treated under hydrogen," before it is compressed at 7 × Ο'31,5 kg / cm and 45 minutes at 1120 ⁰ C were sintered in hydrogen · The effect of heat treatment the following table shows the physical properties:

copper
ίο 0. %
Ca) density
after
Sinte
tion-
g / cm- ⁷ ■ Porosi
activity, % Tensile strength
ability,
χ 10 "|
kg / cm strain Linea
re
Schrum
exam,
% hardness 2 0.29 6.80 13.8 3.430 4.9 0.77 B 42.2 4, 0.30 6.82 13.8 3,612 4.8 0.80 B 50.0 6th 0.27 6.83 14.0 4.081 3.9 0.75 B 53.9 7th 0.30 6.83 14.1 4,431 3.1 0.79 B 63.3 8th 0.23 6.89 13.4 4.823 4.0 0.93 B 66.1 10 0.28 6.89 13.6 5.796 3.9 1.14 B 77.2 12th 0.31 7.02 12.3 5.859 4.1 1.32 B 80.0 14th 0.30 7.12 11.2 5.936 4.0 1.55 B 80.9 16 0.28 7.23 10.1 6.013 4.0 1.97 B 83.1 18th 0.23 7.38 8.4 6.069 3.9 2.32 B 84.8 20th 0.23 7.46 7.8 6.118 4.1 2.58 B 88.1 30 (b) 0.32 7.48 8.8 6.111 3.0 1.39 B 89.3 40 (c) 0.31 7, $ 5 9.3 5.523 3.1 2.03 B 79.7 50 (d) 0.33 7.75 * 8.1 4,648 3.9 2.18 B 76.5

(a) As shown by the percentage weight loss of hydrogen over 30 minutes at 1100 ° C.

(b) 30 minutes at 1050 ⁰ O reduced, 10 minutes at 112O ⁰ C sintered

(c) Reduced for 30 minutes at 95O ⁰ O, sintered for 10 minutes at 1120 ° C

(d) 30 minutes at 95O ⁰ C reduced, 10 minutes at 1095 ⁰ C sintered

209813/0213

Example 22

Copper / iron powder mix ₀

For comparison purposes, a number of copper alloys were made according to "known processes" by mixing corresponding amounts of reduced powder of elemental copper and iron that passed through a sieve with a mesh size of 0.147 mm for 30 minutes at 7.031.5 kg / cm
compacted and sintered for 45 minutes at 112O ⁰ G under hydrogen. The following properties were then determined:

copper
% density
- according to Sin
tion,
g / cm Porosi
activity, % Tensile strength
ability,
χ ΙΟ "?
kß / cm strain
% Linear
Schrum
exam,
% (a) hardness 2 6.28 20.4 2,492 4.9 (0.01) B 25.5 4th 6.30 20.7 2,800 2.9 (0.92) B 21.4 7th 6.37 20.7 2.94-7 1.6 (1.88) B 39.3 14th 6.40 20.2 3.164 2.3 (2.04) B 20.2 20th 6.49 19.8 3.101 2.5 (2.24) B 19.7

50 (b) 7.02 16.6 1.862 4.5 (0.99) B 3.2

(a) All samples expanded upon sintering

(b) Sintered at 1000 ⁰ O for 30 minutes.

A heat treatment of the powder mixtures according to the process
of Example 21 before the compression stage remained without
significant impact on results.

Example 23
Impact resistance

The impact strength of the new alloys of Example 21 were the corresponding values of the conventional alloys (made from missing copper / iron powders as in Example 22) as well as that with copper in the conventional manner offset iron composites as shown below.

8AD ORIGINAL

209813/0213

ASTM impact strength, m / kg

Copper, % procedure T-K Charpy Izod tension 7th Example 21 2.48 5.9 133.2 7 (+ 1% graphite) Example 21 3.22 5.36 124.8 7th Pulvergemx see 2.34 2.54 58.2 7 O 1% graphite) Powder mix before 2.0 3.82 63.7 14th Example 21 3.08 - - 15th conventional
infiltration 2.14 25th conventional
infiltration _ 3.35 _ 20th Example 21 3.55 - - 30th Example 21 3.42 - -

209813/0213

Claims (24)

PATENT CLAIMS: 1. A process for the production of a finely divided alloy of iron interspersed with about 1 to 50% by weight of copper, characterized in that a reducible iron compound with a corresponding amount of elemental copper or reducible copper compounds and possibly smaller amounts of ITiekel, cobalt, molybdenum , tungsten, or reducible compounds of these elements mixed, this mixture under reductive tion conditions at a temperature up to about 1150 ⁰ C, but at least heated to a about 100 ⁰ C higher than the sintering temperature of copper temperature and holding at this temperature for as long until the reducible compounds are practically completely converted into their metallic state. 2. The method according to claim 1, characterized in that the reactants are mixed in such amounts that an alloy from iron interspersed with about 1 to 20% by weight of copper, and that a temperature is reached during the reduction applies, which is at least the melting temperature of the copper. 3. The method according to claim 1 or 2, characterized in that that a temperature of 1120 up to 1135 ° C. A-. The method according to claim 1, characterized in that one mixes the reactants in such amounts that a Alloy of more than 20 and up to 50 wt .-% copper interspersed Iron is formed and that a temperature below the melting point of copper is used during the reduction. 5. The method according to claim 4-, characterized in that the temperature during the reduction is about 950 to 1050 ^° C. 209813/0213 6. The method according to claim 1-5 »characterized in that the particle size of the reducible mixture below about 250 / rev. 79 The method according to claims 1-6, characterized in that the particle size of the iron compound below about 50 / U and that of the copper compound below about 20 / U lies. 8. The method according to claim 1-7 »characterized in that the bison compound consists of an iron oxide. 9 · The method according to claim 8, characterized in that the Iron compound from hematite, magnetite or reducible rolled sinter consists· 10. The method according to claim 1-9 »characterized in that the copper compound consists of copper oxide. 11. The method according to claim 10, characterized in that the copper compound consists of copper-I-oxide or of cement copper . 12. The method according to claim 10, characterized in that the copper compound consists of cement copper and that nitric acid is added to the mixture before the reduction. 13 · Method according to claims 1-9 »characterized in that the copper compound is water-soluble? and in the form of an aqueous Solution is supplied. 14 ·· The method according to claim 13, characterized in that the copper compound consists of copper (II) nitrate. 15 · Method according to claim 1 - 14 ·, characterized in that that the reducible mixture is mixed with an aqueous dispersion of an organic adhesive before the reduction 209813/0213 16. Procedure after. Claim. 1-15, characterized in that that one introduces finely divided carbon into the reducible "mixture to create the reduction conditions. 17 · Method according to claims 1 - 16, characterized in that the heating takes place in a reducing atmosphere. 18. The method according to claim 17, characterized in that this atmosphere contains hydrogen or carbon monoxide. 19. The method according to claim 17, characterized in that this atmosphere consists of dissociated ammonia. 20. The method according to claim 1-19, characterized in that the reduced mixture is comminuted by grinding. 21 · The method according to claim 1 to 20, characterized in that the alloy for the purpose of heat treatment is at least about 30 minutes at a temperature between the OL - ^ transition temperature the iron-rich alloy phase and a temperature about 150 ° -0 below this transition temperature holds and then cools it. 22. The method according to claim 21, characterized in that the heat treatment temperature is less than 50 ⁰ C below the transition temperature. 23 · The method according to claim 21 or 22, characterized in that that the heat treatment takes place at a temperature between about 825 and 845 ° C. 24. The method according to claim 21-23, characterized in that the heat-treated mixture is comminuted by grinding » For CHAS. PFIZER & CO., IUC. Brooklyn, ΙΓ.Υ., V.St.A. 209813/0213 Lawyer