US3770492A - Method of manufacture of materials from polycrystalline filaments - Google Patents
Method of manufacture of materials from polycrystalline filaments Download PDFInfo
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- US3770492A US3770492A US00258298A US3770492DA US3770492A US 3770492 A US3770492 A US 3770492A US 00258298 A US00258298 A US 00258298A US 3770492D A US3770492D A US 3770492DA US 3770492 A US3770492 A US 3770492A
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- metal
- filaments
- mass
- iron
- polycrystalline
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- 238000000034 method Methods 0.000 title claims abstract description 27
- 239000000463 material Substances 0.000 title claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 11
- 229910052751 metal Inorganic materials 0.000 claims abstract description 82
- 239000002184 metal Substances 0.000 claims abstract description 82
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 57
- 229910052742 iron Inorganic materials 0.000 claims abstract description 25
- 230000008569 process Effects 0.000 claims abstract description 21
- 238000000151 deposition Methods 0.000 claims abstract description 20
- 230000008021 deposition Effects 0.000 claims abstract description 12
- 238000009792 diffusion process Methods 0.000 claims abstract description 8
- 230000008018 melting Effects 0.000 claims abstract description 7
- 238000002844 melting Methods 0.000 claims abstract description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 22
- 238000005470 impregnation Methods 0.000 claims description 19
- 238000010438 heat treatment Methods 0.000 claims description 15
- 229910052759 nickel Inorganic materials 0.000 claims description 11
- 238000000576 coating method Methods 0.000 claims description 8
- 239000011248 coating agent Substances 0.000 claims description 7
- 229910001092 metal group alloy Inorganic materials 0.000 claims description 5
- 238000004220 aggregation Methods 0.000 claims description 4
- 230000002776 aggregation Effects 0.000 claims description 4
- 238000000354 decomposition reaction Methods 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 abstract description 7
- 239000000956 alloy Substances 0.000 abstract description 7
- 230000003647 oxidation Effects 0.000 abstract description 7
- 238000007254 oxidation reaction Methods 0.000 abstract description 7
- 239000000126 substance Substances 0.000 abstract description 6
- 238000004381 surface treatment Methods 0.000 abstract description 4
- 238000009736 wetting Methods 0.000 abstract description 4
- 238000005275 alloying Methods 0.000 abstract description 3
- 239000007792 gaseous phase Substances 0.000 abstract description 3
- 238000005245 sintering Methods 0.000 description 10
- 150000002739 metals Chemical group 0.000 description 8
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- 125000004429 atom Chemical group 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 4
- 150000002736 metal compounds Chemical class 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000001465 metallisation Methods 0.000 description 3
- 238000005272 metallurgy Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 229910052755 nonmetal Inorganic materials 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000002269 spontaneous effect Effects 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 241000234282 Allium Species 0.000 description 1
- 235000002732 Allium cepa var. cepa Nutrition 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 229910052728 basic metal Inorganic materials 0.000 description 1
- 150000003818 basic metals Chemical class 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- FQNHWXHRAUXLFU-UHFFFAOYSA-N carbon monoxide;tungsten Chemical group [W].[O+]#[C-].[O+]#[C-].[O+]#[C-].[O+]#[C-].[O+]#[C-].[O+]#[C-] FQNHWXHRAUXLFU-UHFFFAOYSA-N 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000007596 consolidation process Methods 0.000 description 1
- 238000009770 conventional sintering Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- ZFAKTZXUUNBLEB-UHFFFAOYSA-N dicyclohexylazanium;nitrite Chemical compound [O-]N=O.C1CCCCC1[NH2+]C1CCCCC1 ZFAKTZXUUNBLEB-UHFFFAOYSA-N 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 238000000454 electroless metal deposition Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000003595 mist Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 239000012254 powdered material Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- 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
- B22F3/002—Manufacture of articles essentially made from metallic fibres
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C47/00—Making alloys containing metallic or non-metallic fibres or filaments
- C22C47/02—Pretreatment of the fibres or filaments
- C22C47/06—Pretreatment of the fibres or filaments by forming the fibres or filaments into a preformed structure, e.g. using a temporary binder to form a mat-like element
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/06—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of metallic material
- C23C16/08—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of metallic material from metal halides
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49801—Shaping fiber or fibered material
Definitions
- ABSTRACT A process for the manufacture of high-strength materials from metallic polycrystalline filamentary material, e.g. iron, which has been deposited from the gaseous phase, wherein a mass of the filaments is consolidated by deposition of a metal thereon to join and bond the filaments at their points of intersection, whereafter the mass is briefly heated under pressure to produce a diffusion bond between the metal of the filaments and the metal deposited thereon and to compact the mass.
- metallic polycrystalline filamentary material e.g. iron
- the mass may be impregnated with a metal of lower melting point.
- Loose unb onded masses of filaments may be similarly impregnated, particularly if the filaments are given a prior surface treatment to reduce oxidation and so ensure wetting of the filaments by the impregnating metal.
- the impregnating metal forms an alloy with the metal of the filaments, the latter may be provided with one or more intermediate layers of a non-alloying substance.
- the invention is concerned with the .combinationof 5 polycrystalline metal filaments, which are also known as polycrystalline whiskers, by metallurgical measures.
- polycrystalline metal filaments isintendedto mean such metal filaments as originate fromthegaseous phase and which, in the original state, are composed of extremely small a and in most cases submicroscopically fine crystals (see German Patent No. 1,224,934).
- Examples of such polycrystalline metal filaments are iron filaments with a granular size of between 70 and 90 A and a carbon content of between 0.8 and 1.6 percent. These iron filaments are of extraordinary hardness, of between 1,300 kp/sq.mm.
- the present invention uses for the manufacture of high-strength materials polycrystalline fila ments which are produced from the gaseous phase, in other words not-produced from originally compact material. These filaments grow by aggregation of originally free metal atoms into their filament form and, by reason of unusual structure and an extremely high number of dislocations, they have outstandingstrength which exceeds that of conventional metal filaments by more than a power of ten.
- the present invention arises from the relisation that the described polycrystalline filaments of high strength cannot be readily sintered by conventional processes and yield optimum results.
- the strength of sintered products from conventional powders and metal filaments generally depends on the degree of residual porosity and since the inherent strength of the starting material is not greatly affected by the sintering process, the results of the sintered powder metallurgical processing of polycrystalline filaments and the mechanical properties of the materials thereby obtaineddepends to a greatextent upon the duration of the sintering process, in fact to'the opposite extent than with the sinteringof conventional basic materials.
- the object of the invention is therefore to retain the valuable strength properties of the polycrystalline filaments during processing to form porous or compact materials.
- the filaments are firstshaken, riddled or compressed to the desired pore volume,'then aremetallically bonded to one another at their points of intersection or contact and finally the thus consolidated porous mass is briefly heated to such a temperature that a diffusion exhange of atoms occurs between the metallic bonding substance and the fila ments.
- the consolidation porous mass is compressed ruring the brief period of heating.
- the metallicbonding may be effected by passing a stream of carrier gas, charged with a thermally decomposable metal compound in vapour, mist or aerosol-like form, through the porous mass of filaments, the porous mass .beingmaintained at the decomposition temperature of 'the relevant metal compound.
- decomposition temperature is in this case not the temperature of complete thermal decomposition but a temperature at which preferably a maximum of only some threequarters of the weight of metal compound is decomposed.
- the deposition of metals on the fibres gives rise to a metallic bonding or joining of the points of intersection of the filaments.
- the mass of filaments already has aconsiderable mechanical strength.
- the subsequent exposure of the 'metallised porous skeleton to an elevated temperature causes at least one type of atom, either that of the filaments or of the metallic deposition product, to penetrate the boundary layer between thefilament surface and the metal deposit by the onset ofdiffusion.
- EXAMPLE by passing a stream of argon through the gas permeable carbon electrodes, an electric current is fed to it through the electrodes which brings the porous mass of filaments to a temperature of for example 140C by resistance heating, whereupon iron pentacarbonyl vapour is added to the stream of argon. This results in iron being deposited on the polycrystalline iron fialments, bonding the iron filaments into a mechanically rigid skeleton in the manner described.
- this solidified filament skeleton is for a period of a few seconds brought to a temperature of 650C by resistance heating in the same manner as previously but at increased current intensity, and at the same time a strong pressure is exerted from both sides on the heated filament skeleton by the two electrodes, the pressure being between 0.3 and 14 kg/sq.mm. according to the degree of residual porosity required.
- the bonding of the iron filaments using the procedure outlined in the present example can be achieved in the same way by thermal decomposition of nickel tetracarbonyl, molybdenum hexacarbonyl, tungsten carbonyl, dicomenchromium, dibenzolchromium, etc.
- the metallic bonding of the metal filaments is achieved by electro-less deposition of metals, in that one of the known reaction solutions for electro-less deposition, for example a solution for the electro-less deposition of nickel, is passed through the porous mass of filaments at the prescribed working temperature of for example 96C until such time as a sufficient quantity of metal is deposited on the filaments, which is necessary for bonding at their points of intersection. Subsequently, the procedure is as previously described.
- one of the known reaction solutions for electro-less deposition for example a solution for the electro-less deposition of nickel
- the advantage of using electro-less metal deposition for bonding the points of intersection of the filaments resides on the one hand in that metals can be used, the thermally decomposable metal compunds of which are too expensive and therefore uneconomical, and on the other in that the amorphous form in which metals are deposited by the electro-less process permits of a particularly marked approximation of the metal precipitate to the natural surface texture of the metal filaments to that the rapid onset of sintering or fusion of both types of metals at their boundary interface is encouraged. Furthermore, this process is additionally assisted by the known presence of phosphorus as a consequence of the deposition reaction. Finally, the onset of the diffusion bonding is also promoted in that the phosphorus present reduces the melting temperature of the metal deposit, which is directly connected with a more rapid diffusion.
- a porous body made from iron filaments, produced and solidified in this way, can in known manner be impregnated with metals and metal alloys which have a lower melting point than the polycrystalline metal filaments and the metallic bonding substance, an essential condition being that the iron filaments are wetted by the impregnation metal. For this reason, it is advantageous to avoid oxidation on the overall surface of the already solidified metal filament skeleton, for which purpose this latter, after removal of the electrodes, is brought into contact under protective gas, with the appropriate metal melt, which by capillary action fills in the pores in the system.
- synthetic plastics material can be used as the impregnation material by proceeding accordingly.
- the invention resolves the problem of a direct impregnation of loose polycrystalline metal filaments in that these metal filaments already undergo a surface treatment while they are being manufactured, this surface treatment largely preventing a subsequent harmful oxidation, in any event sufficiently not to interfere adversely with the wetting stage of the impregnation process.
- the polycrystalline whiskers are, according to one embodiment of the invention, coated during their manufacture with a thin and only slowly oxidising metal coating to a thickness of 0.3 to 1 m. for example with a coating of nickel, after which they never lose their wettability, even when stored.
- the polycrystalline filaments which, when they are manufactured, initially have a metallically clean surface are wetted with a liquid film, to the exclusion of air, safeguarding them against spontaneous oxidation until the impregnation process takes place, although the liquid used must be one which can be removed immediately prior to or during the impregnation process by complete evaporation.
- a liquid film to the exclusion of air, safeguarding them against spontaneous oxidation until the impregnation process takes place, although the liquid used must be one which can be removed immediately prior to or during the impregnation process by complete evaporation.
- paraffins or so-called vapour phase inhibitors such as dicyclohexyl-aminonitrite or l-nitronaphthalene have proved successful.
- the invention resolves this industrially very important problem by manufacturing the polycrystalline metal filaments so that in the course of their thickness growth, one or more intermediate layers are incorporated which are not capable of alloying with aluminium and its alloys, or at least are only so capable with more difficulty than the basic metal of the polycrystalline metal filament.
- polycrystalline iron filaments are produced so that their natural growth is interrupted on one or more occasions by an oxidation process or by the deposition of another metal such as tungsten or molybdenum or by the deposition of some other metal and subsequent oxidation of this metal.
- Metal filaments produced from iron in this way have in cross-section, where a plurality of the described intermediate layers are present, a structure similar to an onion skin, the surface of the filaments consisting of iron.
- the object of avoiding the consumption of the polycrystalline fibres which come in contact with a molten batch of aluminum and its alloys during the impregnation process is thus achieved because although the outermost surface of the filaments can be consumed as an alloy is formed, the underlying coating of oxide or foreign metal represents an alloy-retarding barrier and all subsequent intermediate coatings of a foreign substance take on this same task one after another.
- the advantages of this embodiment of the invention include the fact that polycrystalline metal filaments with such a structure are suitable both for impregnation of a loose filament association as well as for the impregnation of a metal filament skeleton, in which filaments have been primarily metallically bonded at the points of intersection. in the latter case, it is expedient to establish the bonding of the points of intersection of the metal filaments by metal deposition, incorporatingintermediate layers of foreign substances, as has just been described in the case of the manufacture of polycrystalline metal filaments.
- the metallic impregnation of a mechanically rigid skeleton of bonded non-metal fibers according to the invention has as far as procedural technique is concemed, the decisive advantage that metallisation renders the non-metal filaments wettable while on the other hand the metallic bonding of the non-metallic fil aments at the points of intersection, in the same way as with the pure metal filaments, enables the filament association to withstand the intense mechanical loading forces due to capillary forces without destruction. Even an intentionally intimate packing of the filaments in such a skeleton can therefore be maintained during the impregnation process, while is is known to be extremely difficult to achieve a high proportion of fibers solely by stirring loose fibers or filaments into a metal melt.
- A1 filaments high-rigidity carbon filaments, boron filaments, silicon whiskers and the like into a copper matrix.
- a process for the manufacture of high-strength materials from polycrystalline iron metal whiskers and filaments comprising:
- said aforementioned metal depositing step being carried out by thermally decomposing iron pentacarbonyl metal compound in the vapor state to form decomposed iron metal which adheres mechanically to the skeleton of iron filaments and is next to the same type of atoms for diffusing;
- a process for the manufacture of high-strength materials from polycrystalline iron metal whiskers and filaments comprising:
- said aforementioned metal depositing step being carried out by depositing nickel to a coating thickness of from 0.3 to l millimicrons from a solution used for the electroless deposition of nickel under conditions of elevated temperature of about 96C for a time which is sufficient in order to provide said metal thickness;
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
- Powder Metallurgy (AREA)
- Laminated Bodies (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
A process for the manufacture of high-strength materials from metallic polycrystalline filamentary material, e.g. iron, which has been deposited from the gaseous phase, wherein a mass of the filaments is consolidated by deposition of a metal thereon to join and bond the filaments at their points of intersection, whereafter the mass is briefly heated under pressure to produce a diffusion bond between the metal of the filaments and the metal deposited thereon and to compact the mass. Thereafter the mass may be impregnated with a metal of lower melting point. Loose unbonded masses of filaments may be similarly impregnated, particularly if the filaments are given a prior surface treatment to reduce oxidation and so ensure wetting of the filaments by the impregnating metal. Where the impregnating metal forms an alloy with the metal of the filaments, the latter may be provided with one or more intermediate layers of a non-alloying substance.
Description
United States Patent 1 Schladitz 1 Nov. 6, 1973 METHOD OF MANUFACTURE OF MATERIALS FROM POLYCRYSTALLINE FILAMENTS [76] Inventor: Hermann J. Schladitz, Bodenseestr.
3a, Munich, Germany [22] Filed: May 31, 1972 21 Appl. No.: 258,298
Related 0.8. Application Data [63] Continuation of Ser. No. 31,022, Aug. 22, 1970,
abandoned.
[30] Foreign Application Priority Data Apr. 25, 1969 Germany P 19 21 211.4
[56] References Cited UNITED STATES PATENTS 10/1970 Glass 117/107.2 R ll/l969 Milewski.... l17/107 2 R 4/1969 Schladitz l17/107.2 R
3,359,098 12/1967 Teaford 75/208 Primary Examiner-Alfred L. Leavitt Assistant Examiner-J. Massie Att0rney-Kane, Dalsimer, Kane, Sullivan & Kurucz [57] ABSTRACT A process for the manufacture of high-strength materials from metallic polycrystalline filamentary material, e.g. iron, which has been deposited from the gaseous phase, wherein a mass of the filaments is consolidated by deposition of a metal thereon to join and bond the filaments at their points of intersection, whereafter the mass is briefly heated under pressure to produce a diffusion bond between the metal of the filaments and the metal deposited thereon and to compact the mass. Thereafter the mass may be impregnated with a metal of lower melting point. Loose unb onded masses of filaments may be similarly impregnated, particularly if the filaments are given a prior surface treatment to reduce oxidation and so ensure wetting of the filaments by the impregnating metal. Where the impregnating metal forms an alloy with the metal of the filaments, the latter may be provided with one or more intermediate layers of a non-alloying substance.
2 Claims, N0 Drawings METHOD OF MANUFACTUREOF MATERIALS FROM POLYCRYSTALLINE FILAMENTS This'is a continuation of application Ser. No. 31,022,
filed Apr. 22, 1970, now abandoned.
The invention is concerned with the .combinationof 5 polycrystalline metal filaments, which are also known as polycrystalline whiskers, by metallurgical measures. The term polycrystalline metal filamentsisintendedto mean such metal filaments as originate fromthegaseous phase and which, in the original state, are composed of extremely small a and in most cases submicroscopically fine crystals (see German Patent No. 1,224,934). Examples of such polycrystalline metal filaments are iron filaments with a granular size of between 70 and 90 A and a carbon content of between 0.8 and 1.6 percent. These iron filaments are of extraordinary hardness, of between 1,300 kp/sq.mm.
.Ml-lV and 2,400 kp/sq.mm. MHV and have tensile strengths of up to 850 kp/sq.mm.
It is well known that in sintered-powder metallurgy, in addition to more or less spherical powderparticles, it is also advantageous to sinter elongated powder particles, e.g. dendritic material, and it islikewise known to sinter that metallic filaments,"preferably into porous bodies. For the sintering of metallicfilaments, the tiesignation filament metallurgy was even introduced, although the sintering of fibrous materialszhas hitherto, inprocedure, hardly differed from the sintering of powdered material.
These conventional metallic filaments (see Friedrich Eisenkolb, Fortschritte der Pulver-Metallurgie, 1963, Vol. 2, p. 904) do not howeverform part of the objectof the invention, since in their strength properties and structure they do not differ from the conventinal basic materials of sinteredpowder metallurgy. The filaments obtained by drawing, spinning or cutting, as used in the so-called filament metallurgy, offer no substantial advantages over powders in terms of mechanical strength.
They are significant rathermore from the point ofview of their applications.
In contrast, the present invention uses for the manufacture of high-strength materials polycrystalline fila ments which are produced from the gaseous phase, in other words not-produced from originally compact material. These filaments grow by aggregation of originally free metal atoms into their filament form and, by reason of unusual structure and an extremely high number of dislocations, they have outstandingstrength which exceeds that of conventional metal filaments by more than a power of ten. It is true that, in addition 'to the polycrystalline filaments of the afore-described type, other high-strength filaments are also known, namely the so-called single crystal whiskers, appositely also referred to as hair crystals, but his a known fact that these cannot be sintered because such a process destroys the cause of high strength, namely a virtually fault-free lattice structure.
The present invention arises from the relisation that the described polycrystalline filaments of high strength cannot be readily sintered by conventional processes and yield optimum results. Whereas the strength of sintered products from conventional powders and metal filaments generally depends on the degree of residual porosity and since the inherent strength of the starting material is not greatly affected by the sintering process, the results of the sintered powder metallurgical processing of polycrystalline filaments and the mechanical properties of the materials thereby obtaineddepends to a greatextent upon the duration of the sintering process, in fact to'the opposite extent than with the sinteringof conventional basic materials. It is well known that the strength of a sintered product generally increases with the duration of the sintering process, inter alia, whilethe sintering of polycrystalline filaments can, for equally long sintering times result in a diminution in the strength of the startingimaterial and hence also of the sintered product.
The object of the invention is therefore to retain the valuable strength properties of the polycrystalline filaments during processing to form porous or compact materials. According tothe invention, the filaments are firstshaken, riddled or compressed to the desired pore volume,'then aremetallically bonded to one another at their points of intersection or contact and finally the thus consolidated porous mass is briefly heated to such a temperature that a diffusion exhange of atoms occurs between the metallic bonding substance and the fila ments. Preferably the consolidation porous mass is compressed ruring the brief period of heating. The metallicbondingmay be effected by passing a stream of carrier gas, charged with a thermally decomposable metal compound in vapour, mist or aerosol-like form, through the porous mass of filaments, the porous mass .beingmaintained at the decomposition temperature of 'the relevant metal compound. The term decomposition temperature is in this case not the temperature of complete thermal decomposition but a temperature at which preferably a maximum of only some threequarters of the weight of metal compound is decomposed.
The deposition of metals on the fibres gives rise to a metallic bonding or joining of the points of intersection of the filaments. In this state,the mass of filaments already has aconsiderable mechanical strength. The subsequent exposure of the 'metallised porous skeleton to an elevated temperature causes at least one type of atom, either that of the filaments or of the metallic deposition product, to penetrate the boundary layer between thefilament surface and the metal deposit by the onset ofdiffusion. By virtue of the extremely finely crystalline metal deposition which is obtained from thermally decomposablemetal compounds, which results in a maximum possible approximation of the metal deposit to the natural surface structure of the metal filaments, a spontaneous sintering or fusion on the aforesaid boundary interface occurs. The importance of the process described arises from the fact that with the unusually high hardness of the polycrystalline metal filaments, an approximation to this result is not possible by pressing and moulding of the filaments. The brief heating of the filaments which have been metallically prebonded, according to the invention, can be effected in a few seconds by per se known means, e.g. by induction heating, direct resistance heating, hot compression,
etc.
EXAMPLE by passing a stream of argon through the gas permeable carbon electrodes, an electric current is fed to it through the electrodes which brings the porous mass of filaments to a temperature of for example 140C by resistance heating, whereupon iron pentacarbonyl vapour is added to the stream of argon. This results in iron being deposited on the polycrystalline iron fialments, bonding the iron filaments into a mechanically rigid skeleton in the manner described. Thereafter, while pure argon is passed through it, this solidified filament skeleton is for a period of a few seconds brought to a temperature of 650C by resistance heating in the same manner as previously but at increased current intensity, and at the same time a strong pressure is exerted from both sides on the heated filament skeleton by the two electrodes, the pressure being between 0.3 and 14 kg/sq.mm. according to the degree of residual porosity required. The bonding of the iron filaments using the procedure outlined in the present example can be achieved in the same way by thermal decomposition of nickel tetracarbonyl, molybdenum hexacarbonyl, tungsten carbonyl, dicomenchromium, dibenzolchromium, etc.
In an alternative method of carrying out the invention, the metallic bonding of the metal filaments is achieved by electro-less deposition of metals, in that one of the known reaction solutions for electro-less deposition, for example a solution for the electro-less deposition of nickel, is passed through the porous mass of filaments at the prescribed working temperature of for example 96C until such time as a sufficient quantity of metal is deposited on the filaments, which is necessary for bonding at their points of intersection. Subsequently, the procedure is as previously described.
The advantage of using electro-less metal deposition for bonding the points of intersection of the filaments resides on the one hand in that metals can be used, the thermally decomposable metal compunds of which are too expensive and therefore uneconomical, and on the other in that the amorphous form in which metals are deposited by the electro-less process permits of a particularly marked approximation of the metal precipitate to the natural surface texture of the metal filaments to that the rapid onset of sintering or fusion of both types of metals at their boundary interface is encouraged. Furthermore, this process is additionally assisted by the known presence of phosphorus as a consequence of the deposition reaction. Finally, the onset of the diffusion bonding is also promoted in that the phosphorus present reduces the melting temperature of the metal deposit, which is directly connected with a more rapid diffusion.
A porous body made from iron filaments, produced and solidified in this way, can in known manner be impregnated with metals and metal alloys which have a lower melting point than the polycrystalline metal filaments and the metallic bonding substance, an essential condition being that the iron filaments are wetted by the impregnation metal. For this reason, it is advantageous to avoid oxidation on the overall surface of the already solidified metal filament skeleton, for which purpose this latter, after removal of the electrodes, is brought into contact under protective gas, with the appropriate metal melt, which by capillary action fills in the pores in the system. Naturally, synthetic plastics material can be used as the impregnation material by proceeding accordingly.
Although in theory and in practice, impregnation of a filament skeleton solidified in the manner described results in maximum possible solidification under the conditions indicated, it is of course also possible advantageously to apply the known impregnation process for porous sintered bodies to filament skeletons made from non-solidified polycrystalline metal filaments. The object of the invention, to manufacture high-rigidity materials from polycrystalline filaments, cannot however be readily achieved without using the above-described process for the primary metallic bonding of the point of intersection of the filaments, i.e. when utilising loosely shaken or riddled or pressed filaments, since the polycrystalline filaments have naturally a coating of oxide, however thin, without which, by virtue of their extremely large surface area, they would spontaneously oxidise, developing a considerable heat. Certainly it is obvious to remove the existing oxide coating by reductive measures prior to impregnation with metals, but the relatively high reduction temperature, for example in the case of reduction with carbon monoxide or hydrogen, will reduce the strength of the metal filaments in an undesirable degree.
Therefore, the invention resolves the problem of a direct impregnation of loose polycrystalline metal filaments in that these metal filaments already undergo a surface treatment while they are being manufactured, this surface treatment largely preventing a subsequent harmful oxidation, in any event sufficiently not to interfere adversely with the wetting stage of the impregnation process. The polycrystalline whiskers are, according to one embodiment of the invention, coated during their manufacture with a thin and only slowly oxidising metal coating to a thickness of 0.3 to 1 m. for example with a coating of nickel, after which they never lose their wettability, even when stored. According to a further embodiment of the invention, the polycrystalline filaments which, when they are manufactured, initially have a metallically clean surface, are wetted with a liquid film, to the exclusion of air, safeguarding them against spontaneous oxidation until the impregnation process takes place, although the liquid used must be one which can be removed immediately prior to or during the impregnation process by complete evaporation. As examples of such liquids, paraffins or so-called vapour phase inhibitors such as dicyclohexyl-aminonitrite or l-nitronaphthalene have proved successful.
These measures achieve the object of the invention, to combine polycrystalline filaments metallically into a compact material of high strength, avoiding a conventional sintering process and without having to allow for the strength of the filaments diminishing by excessively long processing temperatures, because the capillary wetting of the filaments with liquid metals occurs so rapidly that physical reactions which cause the loss of strength at elevated temperatures or when the filaments dwell for long periods in these temperatures, cannot arise to a dangerous extent.
The measures described, which are suitable for producing high strength bodies by metallic combination of polycrystalline filaments, do not however produce a complete success if these filaments are solidified by impregnation with metals which have a readiness to alloy with the material of these filaments. Such a case occurs for example if it is intended to combine iron filaments with light metal or light metal alloys. In this case, there is a danger that the iron filaments, while forming an alloy, may become more or less rapidly consumed by the impregnation metal. The invention resolves this industrially very important problem by manufacturing the polycrystalline metal filaments so that in the course of their thickness growth, one or more intermediate layers are incorporated which are not capable of alloying with aluminium and its alloys, or at least are only so capable with more difficulty than the basic metal of the polycrystalline metal filament. For example, according to one embodiment of the invention, polycrystalline iron filaments are produced so that their natural growth is interrupted on one or more occasions by an oxidation process or by the deposition of another metal such as tungsten or molybdenum or by the deposition of some other metal and subsequent oxidation of this metal. Metal filaments produced from iron in this way have in cross-section, where a plurality of the described intermediate layers are present, a structure similar to an onion skin, the surface of the filaments consisting of iron.
The object of avoiding the consumption of the polycrystalline fibres which come in contact with a molten batch of aluminum and its alloys during the impregnation process is thus achieved because although the outermost surface of the filaments can be consumed as an alloy is formed, the underlying coating of oxide or foreign metal represents an alloy-retarding barrier and all subsequent intermediate coatings of a foreign substance take on this same task one after another. The advantages of this embodiment of the invention include the fact that polycrystalline metal filaments with such a structure are suitable both for impregnation of a loose filament association as well as for the impregnation of a metal filament skeleton, in which filaments have been primarily metallically bonded at the points of intersection. in the latter case, it is expedient to establish the bonding of the points of intersection of the metal filaments by metal deposition, incorporatingintermediate layers of foreign substances, as has just been described in the case of the manufacture of polycrystalline metal filaments.
The metallic impregnation of a mechanically rigid skeleton of bonded non-metal fibers according to the invention has as far as procedural technique is concemed, the decisive advantage that metallisation renders the non-metal filaments wettable while on the other hand the metallic bonding of the non-metallic fil aments at the points of intersection, in the same way as with the pure metal filaments, enables the filament association to withstand the intense mechanical loading forces due to capillary forces without destruction. Even an intentionally intimate packing of the filaments in such a skeleton can therefore be maintained during the impregnation process, while is is known to be extremely difficult to achieve a high proportion of fibers solely by stirring loose fibers or filaments into a metal melt.
An example of this is the incorporation of A1 filaments, high-rigidity carbon filaments, boron filaments, silicon whiskers and the like into a copper matrix.
I claim:
1. A process for the manufacture of high-strength materials from polycrystalline iron metal whiskers and filaments comprising:
providing a mass of iron whiskers which are grown by aggregation of the iron atoms into filament form;
pressing said whiskers into a compressed mass of the form or shape in order to provide a formed filament skeleton mass for later metal impregnation;
mechanically bonding iron metal to filaments in said skeleton filament mass to thereby connect filaments to each other at contact points by a step of depositing metal thereon;
said aforementioned metal depositing step being carried out by thermally decomposing iron pentacarbonyl metal compound in the vapor state to form decomposed iron metal which adheres mechanically to the skeleton of iron filaments and is next to the same type of atoms for diffusing;
thereafter heating and compressing said mass under a pressure between about 0.3 and 14 kg/sq mm, said heating being to a temperature of about 650C by means of resistance heating for a period of about a few seconds which causes a diffusion exhange of atoms between the deposited metal and the filaments;
and impregnating the aforesaid heated product with a metal or metal alloy of lower melting point to thereby provide an impregnated mass of highstrength. 2. A process for the manufacture of high-strength materials from polycrystalline iron metal whiskers and filaments comprising:
providing a mass of iron whiskers which are grown by aggregation of the iron atoms into filament form resulting from iron pentacarbonyl decomposition;
pressing the mass of whiskers into a compressed skel etal mass of the form or shape in order to provide a formed filament skeleton mass for subsequent metal impregnation;
mechanically bonding nickel metal to said filaments in the compressed mass to connect to each other at contact points by a step of depositing metal thereon;
said aforementioned metal depositing step being carried out by depositing nickel to a coating thickness of from 0.3 to l millimicrons from a solution used for the electroless deposition of nickel under conditions of elevated temperature of about 96C for a time which is sufficient in order to provide said metal thickness;
thereafter compressing said mass under a pressure between about 0.3 and 14 kg sq/mm while heating to a temperature of about 650C by resistance heating for a period of about a few seconds and thereby causing a diffusion exchange of atoms between the deposited nickel metal and the iron fila-- ments;
and impregnating the aforesaid heating product with a metal or metal alloy of lower melting point to provide an impregnated mass of high strength.
Claims (1)
- 2. A process for the manufacture of high-strength materials from polycrystalline iron metal whiskers and filaments comprising: providing a mass of iron whiskers which are grown by aggregation of the iron atoms into filament form resulting from iron pentacarbonyl decomposition; pressing the mass of whiskers into a compressed skeletal mass of the form or shape in order to provide a formed filament skeleton mass for subsequent metal impregnation; mechanically bonding nickel metal to said filaments in the compressed mass to connect to each other at contact points by a step of depositing metal thereon; said aforementioned metal depositing step being carried out by depositing nickel to a coating thickness of from 0.3 to 1 millimicrons from a solution used for the electroless deposition of nickel under conditions of elevated temperature of about 96*C for a time which is sufficient in order to provide said metal thickness; thereafter compressing said mass under a pressure between about 0.3 and 14 kg sq/mm while heating to a temperature of about 650*C by resistance heating for a period of about a few seconds and thereby causing a diffusion exchange of atoms between the deposited nickel metal and the iron filaments; and impregnating the aforesaid heating product with a metal or metal alloy of lower melting point to provide an impregnated mass of high strength.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19691921211 DE1921211B2 (en) | 1969-04-25 | 1969-04-25 | PROCESS FOR MANUFACTURING HIGH STRENGTH MATERIALS FROM POLYCRYSTALLINE METAL WHISPER |
Publications (1)
Publication Number | Publication Date |
---|---|
US3770492A true US3770492A (en) | 1973-11-06 |
Family
ID=5732397
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00258298A Expired - Lifetime US3770492A (en) | 1969-04-25 | 1972-05-31 | Method of manufacture of materials from polycrystalline filaments |
Country Status (8)
Country | Link |
---|---|
US (1) | US3770492A (en) |
AT (1) | AT304889B (en) |
CA (1) | CA926600A (en) |
CH (1) | CH516960A (en) |
DE (1) | DE1921211B2 (en) |
FR (1) | FR2043296A5 (en) |
GB (1) | GB1309648A (en) |
SE (1) | SE371212B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4046302A (en) * | 1975-05-26 | 1977-09-06 | Schladitz Hermann J | Methods of manufacturing bodies of conglomerated particles |
US4066450A (en) * | 1974-11-26 | 1978-01-03 | Kabushiki Kaisha Toyota Cho Kenkyusho | Metal body having large surface area and process for producing same |
US4940596A (en) * | 1987-06-12 | 1990-07-10 | Minnesota Mining And Manufacturing Company | Process for metal fibers |
US5240768A (en) * | 1987-06-12 | 1993-08-31 | Minnesota Mining And Manufacturing Company | Articles containing metal fibers |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8328576D0 (en) * | 1983-10-26 | 1983-11-30 | Ae Plc | Reinforcement of pistons for ic engines |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3359098A (en) * | 1965-02-17 | 1967-12-19 | Allied Chem | Consolidation by chemical sintering |
US3441408A (en) * | 1964-11-10 | 1969-04-29 | Hermann J Schladitz | High strength metal filaments and the process and apparatus for forming the same |
US3476641A (en) * | 1965-06-01 | 1969-11-04 | Gen Technologies Corp | High-strength single crystal whisker paper composites and laminates |
US3536519A (en) * | 1967-08-31 | 1970-10-27 | Cava Ind | Whiskers |
-
1969
- 1969-04-25 DE DE19691921211 patent/DE1921211B2/en not_active Withdrawn
-
1970
- 1970-03-24 AT AT273670A patent/AT304889B/en not_active IP Right Cessation
- 1970-04-08 CH CH518370A patent/CH516960A/en not_active IP Right Cessation
- 1970-04-13 SE SE7004959A patent/SE371212B/xx unknown
- 1970-04-13 GB GB1741270A patent/GB1309648A/en not_active Expired
- 1970-04-14 FR FR7013379A patent/FR2043296A5/fr not_active Expired
- 1970-04-24 CA CA081073A patent/CA926600A/en not_active Expired
-
1972
- 1972-05-31 US US00258298A patent/US3770492A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3441408A (en) * | 1964-11-10 | 1969-04-29 | Hermann J Schladitz | High strength metal filaments and the process and apparatus for forming the same |
US3359098A (en) * | 1965-02-17 | 1967-12-19 | Allied Chem | Consolidation by chemical sintering |
US3476641A (en) * | 1965-06-01 | 1969-11-04 | Gen Technologies Corp | High-strength single crystal whisker paper composites and laminates |
US3536519A (en) * | 1967-08-31 | 1970-10-27 | Cava Ind | Whiskers |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4066450A (en) * | 1974-11-26 | 1978-01-03 | Kabushiki Kaisha Toyota Cho Kenkyusho | Metal body having large surface area and process for producing same |
US4046302A (en) * | 1975-05-26 | 1977-09-06 | Schladitz Hermann J | Methods of manufacturing bodies of conglomerated particles |
US4940596A (en) * | 1987-06-12 | 1990-07-10 | Minnesota Mining And Manufacturing Company | Process for metal fibers |
US5240768A (en) * | 1987-06-12 | 1993-08-31 | Minnesota Mining And Manufacturing Company | Articles containing metal fibers |
Also Published As
Publication number | Publication date |
---|---|
CA926600A (en) | 1973-05-22 |
CH516960A (en) | 1971-12-31 |
AT304889B (en) | 1973-01-25 |
SE371212B (en) | 1974-11-11 |
FR2043296A5 (en) | 1971-02-12 |
DE1921211A1 (en) | 1971-02-11 |
GB1309648A (en) | 1973-03-14 |
DE1921211B2 (en) | 1972-05-18 |
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