METHOD FOR PRODUCING A COMPONENT FROM AN AMORPHOUS-PHASE METAL ALLOY

Abstract

The invention relates to a method for producing a component from an at least partially amorphous metal alloy, having the steps of: preparing a powder of an at least partially amorphous metal alloy, wherein the powder consists of spherical powder particles and the powder particles have a diameter of less than 125 m; pressing the powder into the desired shape of the component to be generated; compressing and sintering the powder by means of a heat treatment of the powder during pressing or after pressing at a temperature between the transformation temperature and the crystallisation temperature of the amorphous phase of the metal alloy, wherein the duration of the heat treatment is chosen such that the component is sintered after heat treatment and has an amorphous fraction of at least 85 percent. The invention also relates to a component made of a pressed, sintered, spherical, amorphous metal alloy powder, wherein the component has an amorphous fraction of at least 85 percent, and to the use of such a component as gear wheel, abrasive wheel, wear-resistant component, housing, watch casing, part of a gearing or semi-finished product.

Claims

1-15. (canceled)

16. A process for producing a component of an at least partly amorphous metal alloy comprising the following steps: providing a powder of an at least partly amorphous metal alloy, the powder consisting of spherical particles having a diameter of less than 125 m; pressing the powder into the desired shape of the component to be produced; compressing and sintering the powder by a heat treatment, during or after the pressing, at a temperature between the transformation temperature and the crystallization temperature of the amorphous phase of the metal alloy, the duration of the heat treatment being selected so that after the heat treatment the component is sintered and has an amorphous proportion of at least 85 percent.

17. The process according to claim 16, wherein the heat treatment is done under vacuum, the powder being compressed by heat treatment under a vacuum of at least 10.sup.3 mbar.

18. The process according to claim 16, wherein the powder is compressed by hot isostatic pressing or hot pressing.

19. The process according to claim 16, wherein the duration of heat treatment is selected so that the component's amorphous proportion is at least 90 percent.

20. The process according to claim 16, wherein a powder is used that is made of an amorphous metal alloy comprising at least 50 weight percent zirconium.

21. The process according to claim 16, wherein a powder of an amorphous metal alloy of a) 58 to 77 weight percent zirconium; b) 0 to 3 weight percent hafnium; c) 20 to 30 weight percent copper; d) 2 to 6 weight percent aluminum; and e) 1 to 3 weight percent niobium is provided.

22. The process according to claim 16, wherein the spherical amorphous metal alloy powder is produced by atomization.

23. The process according to claim 16, wherein the powder has less than 1 weight percent of particles with a diameter smaller than 5 m, or the powder is screened or treated by air classification, so that it has less than 1 weight percent of particles with a diameter smaller than 5 m.

24. The process according to claim 16, wherein the heat treatment of the powder takes place at a temperature (T) between the transformation temperature and a maximum temperature that exceeds the transformation temperature (T.sub.T) by 30% of the temperature difference between the transformation temperature (T.sub.T) and the crystallization temperature (T.sub.C) of the amorphous phase of the metal alloy, exceeding it by 20% or 10% of this temperature difference.

25. The process according to claim 16, wherein the duration of the heat treatment is selected as a function of the geometric shape of the component to be produced or as a function of the largest relevant diameter of the component to be produced.

26. The process according to claim 16, wherein the duration of heat treatment is in the time range from 3 to 900 seconds per millimeter thickness, or in the time range from 5 to 600 seconds with respect to the greatest relevant diameter of the component to be produced.

27. The process according to claim 16, wherein the powder particles are plastically deformed by the heat treatment.

28. A component made of a pressed, sintered, spherical, amorphous metal alloy powder, the component having an amorphous proportion of at least 85 percent.

29. The component according to claim 28, which is produced by a process comprising: providing a powder of an at least partly amorphous metal alloy, the powder consisting of spherical particles having a diameter of less than 125 m; pressing the powder into the desired shape of the component to be produced; compressing and sintering the powder by a heat treatment, during or after the pressing, at a temperature between the transformation temperature and the crystallization temperature of the amorphous phase of the metal alloy, the duration of the heat treatment being selected so that after the heat treatment the component is sintered and has an amorphous proportion of at least 85 percent.

Description

EXAMPLE 1

[0068] An alloy made of 70.5 weight percent zirconium (Haines & Maassen Metallhandelsgesellschaft mbH Bonn, Zr-201-Zirkon Crystalbar), 0.2 weight percent hafnium (Alpha Aesar GmbH & Co KG Karlsruhe, Hafnium Crystal Bar milled chips 99.7% article number 10204), 23.9 weight percent copper (Alpha Aesar GmbH & Co KG Karlsruhe, Copper plate, Oxygen free, High Conductivity (OFCH) article number 45210), 3.6 weight percent aluminum (Alpha Aesar GmbH & Co KG Karlsruhe, Aluminium Ingot 99.999% article number 10571), and 1.8 weight percent niobium (Alpha Aesar GmbH & Co KG Karlsruhe, niobium foil 99.97% article number 00238) was melted in an induction melting system (VSG, inductively heated vacuum, melting, and casting system, Nrmont, Freiberg) under 800 mbar of argon (Argon 6.0, Linde AG, Pullach) and poured into a water-cooled copper mold. A fine powder was produced from the alloy produced in this way by spraying the melt with argon in a Nanoval atomization apparatus (Nanoval GmbH & Co. KG, Berlin) using a process such as is disclosed in WO 99/30858 A1, for example.

[0069] Separation by means of air classification with a Condux fine classifier CFS (Netzsch-Feinmahltechnik GmbH Selb Deutschland) removes the fines, so that less than 0.1% of the particles are smaller than 5 m in size, i.e., at least 99.9% of the particles have a diameter or dimensions of 5 m or greater, and screening through a test sieve with a mesh size of 125 m (Retsch GmbH, Haan-Deutschland, article number 60.131.000125) removes all powder particles that are larger than 125 m. The powder produced in this way is investigated by means of X-ray diffractometry, and the proportion that is amorphous is greater than 95%.

[0070] 5.0 grams of the powder fraction obtained in this way are compressed in a laboratory press 54MP250D (mssiencetific Chromatographie-Handel GmbH, Berlin) with a compression mold (32 mm, P0764, mssiencetific Chromatographie-Handel GmbH, Berlin) and a 15 ton force of pressure. The pressed parts are then compressed in vacuum sintering (Gero high-temperature vacuum tempering furnace LHTW 100-200/22, Neuhausen) at 410 C. and a pressure of about 10.sup.5 mbar for 120 seconds. The pressed parts are then finally compressed by hot isostatic pressing under a pressure of 200 megapascal (200 MPa) in highly purified argon (Argon 6.0, Linde AG, Pullach) at a temperature of 400 C. for 90 seconds.

[0071] Fifteen components produced in this way are investigated by means of metallographic micrographs to determine the amorphous proportion of the surface in the texture. This investigation showed that an average of 92% of the surfaces are amorphous.

EXAMPLE 2

[0072] An alloy made of 70.5 weight percent zirconium (Haines & Maassen Metallhandelsgesellschaft mbH Bonn, Zr-201-Zirkon Crystalbar), 0.2 weight percent hafnium (Alpha Aesar GmbH & Co KG Karlsruhe, Hafnium Crystal Bar milled chips 99.7% article number 10204), 23.9 weight percent copper (Alpha Aesar GmbH & Co KG Karlsruhe, Copper plate, Oxygen free, High Conductivity (OFCH) article number 45210), 3.6 weight percent aluminum (Alpha Aesar GmbH & Co KG Karlsruhe, Aluminium Ingot 99.999% article number 10571) and 1.8 weight percent niobium (Alpha Aesar GmbH & Co KG Karlsruhe, niobium foil 99.97% article number 00238) was melted in an induction melting system (VSG, inductively heated vacuum, melting, and casting system, Nrmont, Freiberg) under 800 mbar of argon (Argon 6.0, Linde AG, Pullach) and poured into a water-cooled copper mold. A fine powder was produced from the alloy produced in this way by spraying the melt with argon in a Nanoval atomization apparatus (Nanoval GmbH & Co. KG, Berlin) using a process such as is disclosed in WO 99/30858 A1, for example. Separation by means of air classification with a Condux fine classifier CFS (Netzsch-Feinmahltechnik GmbH Selb Deutschland) removed the fines, so that less than 0.1% of the particles are smaller than 5 m in size, and screening through a test sieve with a mesh size of 125 m (Retsch GmbH, Haan-Deutschland, article number 60.131.000125) removed all powder particles that are larger than 125 m. The powder produced in this way was investigated by means of X-ray diffractometry, and the proportion that is amorphous is greater than 95%.

[0073] In every case, 15.0 grams of this powder fraction obtained in this way were sintered by hot pressing with a pressure of 200 megapascal (200 MPa) at a temperature of 400 C. for 3 minutes.

[0074] Fifteen components produced in this way were investigated by means of metallographic micrographs to determine the amorphous proportion of the surface in the texture. This investigation showed that an average of 85% of the surfaces are amorphous.

EXAMPLE 3

[0075] An alloy made of 70.6 weight percent zirconium (Haines & Maassen Metallhandelsgesellschaft mbH Bonn, Zr-201-Zirkon Crystalbar), 23.9 weight percent copper (Alpha Aesar GmbH & Co KG Karlsruhe, Copper plate, Oxygen free, High Conductivity (OFCH) article number 45210), 3.7 weight percent aluminum (Alpha Aesar GmbH & Co KG Karlsruhe, Aluminium Ingot 99.999% article number 10571) and 1.8 weight percent niobium (Alpha Aesar GmbH & Co KG Karlsruhe, niobium foil 99.97% article number 00238) was melted in an induction melting system (VSG, inductively heated vacuum, melting, and casting system, Nrmont, Freiberg) under 800 mbar of argon (Argon 6.0, Linde AG, Pullach) and poured into a water-cooled copper mold. A fine powder was produced from the alloy produced in this way by spraying the melt with argon in a Nanoval atomization apparatus (Nanoval GmbH & Co. KG, Berlin) using a process such as is disclosed in WO 99/30858 A1, for example.

[0076] Separation by means of air classification with a Condux fine classifier CFS (Netzsch-Feinmahltechnik GmbH Selb Deutschland) removed the fines, so that less than 0.1% of the particles are smaller than 5 m in size, and screening through a test sieve with a mesh size of 125 m (Retsch GmbH, Haan-Deutschland, article number 60.131.000125) removed all powder particles that are larger than 125 m. The powder produced in this way was investigated by means of X-ray diffractometry, and its amorphous proportion is greater than 95%.

[0077] In every case, 15.0 grams of this powder fraction obtained in this way were sintered by pressing with a pressure of 200 megapascal (200 MPa) at a temperature of 400 C. for 3 minutes.

[0078] Fifteen components produced in this way are investigated by means of metallographic micrographs to determine the amorphous proportion of the surface in the texture. This investigation showed that an average of 87% of the surfaces are amorphous.

EXAMPLE 4

[0079] An alloy made of 70.6 weight percent zirconium (Haines & Maassen Metallhandelsgesellschaft mbH Bonn, Zr-201-Zirkon Crystalbar), 23.9 weight percent copper (Alpha Aesar GmbH & Co KG Karlsruhe, Copper plate, Oxygen free, High Conductivity (OFCH) article number 45210), 3.7 weight percent aluminum (Alpha Aesar GmbH & Co KG Karlsruhe, Aluminium Ingot 99.999% article number 10571) and 1.8 weight percent niobium (Alpha Aesar GmbH & Co KG Karlsruhe, niobium foil 99.97% article number 00238) was melted in an induction melting system (VSG, inductively heated vacuum, melting, and casting system, Nrmont, Freiberg) under 800 mbar of argon (Argon 6.0, Linde AG, Pullach) and poured into a water-cooled copper mold. A fine powder was produced from the alloy produced in this way by spraying the melt with argon in a Nanoval atomization apparatus (Nanoval GmbH & Co. KG, Berlin) using a process such as is disclosed in WO 99/30858 A1, for example.

[0080] Separation by means of air classification with a Condux fine classifier CFS (Netzsch-Feinmahltechnik GmbH Selb Deutschland) removed the fines, so that less than 0.1% of the particles are smaller than 5 m in size, and screening through a test sieve with a mesh size of 125 m (Retsch GmbH, Haan-Deutschland, article number 60.131.000125) removed all powder particles that are larger than 125 m. The powder produced in this way was investigated by means of X-ray diffractometry, and the proportion that is amorphous is greater than 95%.

[0081] 50 grams of the powder fraction obtained in this way were compressed in a laboratory press 54MP250D (mssiencetific Chromatographie-Handel GmbH, Berlin) with a compression mold (32 mm, P0764, mssiencetific Chromatographie-Handel GmbH, Berlin) and a maximum force of pressure of 25 tons, and were sintered under highly purified argon (Argon 6.0, Linde AG, Pullach) at a temperature of 410 C. for 5 minutes.

[0082] The component produced in this way was investigated by means of several metallographic micrographs [to determine] the amorphous proportion of the surface in the texture. This investigation showed that an average of 90% of the surfaces are amorphous.

[0083] The following table presents the measured results for examples 1 through 4 in connection with a reference measurement:

TABLE-US-00001 Crystallization enthalpy Crystallinity J/g % Amorphicity % Reference 47.0 0 100 range Example 1 34.0 8 92 Example 2 31.5 15 85 Example 3 32.2 13 87 Example 4 33.3 10 90

[0084] Testing and Checking Methods

[0085] 1) Method for Determining Particle Size of Metal Alloy Powders:

[0086] The particle size of inorganic powders was determined by laser light scattering using a Sympatec Helos BR/R3 (Sympatec GmbH), equipped with a RODOS/M dry disperser with a VIBRI vibratory feeder (Sympatec GmbH). Sample quantities of at least 10 g were fed in dry, dispersed at a primary pressure of 1 bar, and the measurement was started. The starting criterion was an optical concentration of 1.9% to 2.1%. The measurement time was 10 seconds. The results were evaluated by MIE theory, and d50 was used as the measure of particle size.

[0087] 2) Test Method for Determining Density:

[0088] For determining density, a geometrically exact rectangular parallelepiped can be produced by grinding the surfaces, so that they can be exactly measured with a digital micrometer (PR1367, Mitutoyo Messgerte Leonberg GmbH, Leonberg). The volume is now determined mathematically. Then, the exact weight is determined on an analytical balance (XPE analytical balances of Mettler-Toledo GmbH). Dividing the measured weight by the calculated volume gives the density.

[0089] The theoretical density of an amorphous alloy corresponds to the density at the melting point.

[0090] 3) Test Method for Determining the Proportion of Amorphous Surface in the Component:

[0091] To do this, in every case fifteen metallographic sections are prepared as described in DIN EN ISO 1463, each of which is polished with SiC paper 1200 (Struers GmbH, Willich), and then in the following polishing steps with 6 m, 3 m, and 1 m diamond products (Struers GmbH, Willich), and finally with OP-S chemical-mechanical oxide polishing suspensions (Struers GmbH, Willich). The ground surfaces produced in this way are examined under an optical microscope (Leica DM 4000 M, Leica DM 6000 M) with a magnification of 1,000 to determine the crystalline proportion of the surface in the micrograph. This involves using the software Leica Phase Expert to evaluate the proportion of the surface that is crystalline as a percentage of the total area of the section, the dark areas being evaluated as crystalline and the light areas being evaluated as amorphous. To do this, the amorphous matrix is defined as a reference phase and expressed as a percentage of the total measured area. In every case, 10 different sample surfaces were measured and averaged.

[0092] 4) Test Method for Determining Transformation Temperatures:

[0093] This was done using a Netzsch 404 F1 Pegasus differential scanning calorimeter (Erich NETZSCH GmbH & Co. Holding KG) equipped with a high temperature tube furnace with a resistance meander heater, an integrated control thermocouple type S, DSC404F1A72 sample carrier system, Al.sub.2O.sub.3 crucible with cover, an OTS system to remove residual oxygen during measurement, including three getter rings, and an evacuation system for automatic operation with a two-stage rotary pump. All measurements were carried out under a shielding gas (Argon 6.0, Linde AG) with a flow rate of 50 mL/min. The results were evaluated using the software Proteus 6.1. The transformation temperature was determined using the tangent method (glass transition) in the range between 380 C. and 420 C. (onset, mid, inflection, end). The crystallization temperature was determined using complex peak evaluation in the temperature range 450-500 C. (area, peak, onset, end, width, height), and the Tm was determined using complex peak evaluation in the temperature range 875-930 C. (area, peak, onset, end, width, height). To carry out the measurement, a 25 mg0.5 mg sample was weighed in the crucible, and the measurement was carried out at the following heating rates and temperature ranges.

[0094] 20-375 C.: heating rate 20 K/min

[0095] 375-500 C.: heating rate 1 K/min

[0096] 500-850 C.: heating rate 20 K/min

[0097] above 850 C.: heating rate 10 K/min

[0098] The amorphous proportion of the component was determined by determining the crystallization enthalpy by the complex peak method using a 100% amorphous sample (obtained by melt spinning) with a crystallization enthalpy of 47.0 J/g as a reference.

[0099] The quotient of the crystallization enthalpy of the component to that of the reference gives the proportion of the amorphous phase.

[0100] 5) Determining Elemental Composition by Means of Emission Spectrometry Analysis (Inductively Coupled Plasma):

[0101] This was done using a Varian Vista-MPX emission spectrometer (Varian Inc.). For each metal, two calibration samples were prepared from standard solutions with known metal content (e.g., 1,000 mg/L) in an aqua regia matrix (concentrated hydrochloric acid and concentrated nitric acid, in the ratio 3:1), and the measurements were carried out.

[0102] The parameters of the ICP instrument were:

[0103] Power: 1.25 kW

[0104] Plasma gas: 15.0 L/min (argon)

[0105] Carrier gas: 1.50 L/min (argon)

[0106] Atomization gas pressure: 220 kPa (argon)

[0107] Repetition: 20 s

[0108] Stabilization time: 45 s

[0109] Observation height: 10 mm

[0110] Draw in sample: 45 s

[0111] Rinsing time: 10 s

[0112] Pump speed: 20 rpm

[0113] Repetitions: 3

[0114] To measure a sample: 0.10 g0.02 g of the sample is put in a container, to which 3 mL of nitric acid and 9 mL of hydrochloric acid are added, as indicated above, and allowed to dissolve for 60 minutes in a microwave oven (company: Anton Paar, device: Multiwave 3000) at 800-1,200 W. The dissolved sample is transferred into a 100 mL flask with 50 volume percent hydrochloric acid and measured.

[0115] The inventive features disclosed in the preceding description, as well as in the claims, the flowchart, and the sample embodiments can be essential for implementing the invention in its various embodiments; this is true both for each individual feature and also for any combination of features.