US3785880A - Ni-fe-ta alloys for magnetic recording-reproducing heads - Google Patents

Ni-fe-ta alloys for magnetic recording-reproducing heads Download PDF

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US3785880A
US3785880A US00173964A US17397171A US3785880A US 3785880 A US3785880 A US 3785880A US 00173964 A US00173964 A US 00173964A US 17397171 A US17397171 A US 17397171A US 3785880 A US3785880 A US 3785880A
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alloy
percent
permeability
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cooled
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M Hinai
H Masumoto
Y Murakami
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FOUNDATION RES INST ELECTRIC A
FOUNDATION RES INST ELECTRIC AND MAGNETIC ALLOYS JA
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/147—Structure or manufacture of heads, e.g. inductive with cores being composed of metal sheets, i.e. laminated cores with cores composed of isolated magnetic layers, e.g. sheets

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  • HEATING TEMPERATURE v HEATING TIME HOUR n' -sa MAXIMUM PERMEABILITY VS.
  • HEATING TEMPERATURE AND TIME PA IIII I 51924 sum 07 0F 10 COOLING SPEED C /HOUR) FIQ'4A INITIAL PERMEABILITY v FROM 600C S COOLING SPEED PATENTEUJANISW 3.785.880
  • COOLING SPEED (C/HOUR MAXIMUM PERMEABILITY VS. COOLING SPEED FROM 600C PATENTED 1 sum user 10 0 mmw w N 0 mm. vfi qr? 5 Y m m -w v O f z 4 .3 2 .l Onw 8v Ewzwa xnd 2523:
  • the alloy of the present invention a high permeability, a high hardness, and a high electric resistivity can be obtained through simple heat treatment, and the alloy can easily be formed into magnetic recordingreproducing heads.
  • Permalloy nickel-iron alloy
  • the conventional Permalloy has a shortcoming in that its Vickers hardness l-Iv is in the order of about 130 and comparatively low, so that its abrasion resistivity is rather poor. Accordingly, there has been a pressing need for improving the hardness and abrasion resistivity of alloy materials for magnetic recording-reproducing heads.
  • an object of the present invention is to meet the aforesaid need by providing an alloy having excellent hardness and abrasion resistivity, along with a high permeability.
  • the applicants have carried out a series of tests on alloys, which have a permeability higher than that of binary Permalloy and high hardness and electric resistivity, while maintaining a high workability.
  • the applicants have found out that, with the addition of 3.1 to 23.0 Wt. percent of tantalum into nickel-iron alloys, magnetic and mechanical properties of the alloy can noticeably be improved.
  • an alloy consisting of 60.2 to 85.0 Wt. percent of nickel, 6.0 to 30.0 Wt. percent of iron, 3.1 to 23.0 Wt. percent of tantalum, and an inevitable amount of impurities, which alloy has a high initial permeability, e.g., 3,000 or higher, a high maximum permeability, e.g., 10,000 or higher, a Vickers hardness greater than 150, and a high electric resistivity.
  • the alloy of the invention can easily be heat treated and formed into the shape of magnetic heads, recording or reproducing.
  • the heat treatment for providing the desired high permeability'and high hardness, comprises steps of heating the alloy in vacuo or in a non-oxidizing atmosphere, for the purpose of thorough solution treatment and homogenization, at 800 C or higher, preferably 1,100 C or higher, for at least 1 minute, preferably longer than about 5 minutes, but not longer than about 100 hours depending on the alloy composition; cooling the alloy to a temperature above its order-disorder lattice transformation point, e.g., at about 600 C, so as to keep the alloy at the last mentioned temperature for a short while, e.g., 5 minutes to 1 hour, until uniform temperature is established throughout the alloy; and cooling the alloy from the temperature above the order-disorder lattice transformation point to room temperature at a rate faster than 1 C/hour but slower than 100 C/second, depending on the alloy composition.
  • the present invention it is also possible to produce the desired permeability and the high hardness by a process comprising steps of heating the alloy of the aforesaid composition in vacuo or in a non-oxidizing atmosphere, for the purpose of thorough solution treatment and homogenization, at 800 C or higher, preferably l,100 C or higher, for at least 1 minute, preferably longer than about 5 minutes, but not longer than about hours depending on the alloy composition; cooling the alloy to a temperature above its order-disorder lattice transformation point, e.g., at about 600 C.
  • the aforesaid solution treatment should preferably be effected at a temperature above 1,100 C, especially about 1,250 C, instead of at a temperature of 800 C to 1,100 C, for an extended period of time, so as to effect the solid solution treatment as thoroughly as possible.
  • the thorough solid solution treatment results in an outstanding improvement of the magnetic properties of the alloy.
  • the manner in which the alloy is cooled from the solution treatment temperature to a temperature above its order-disorder lattice transformation point, e.g., to about 600 C, does not affect its magnetic properties so seriously, regardless of whether it is cooled quickly or slowly.
  • the cooling speed when the alloy temperature crosses its order-disorder lattice transformation point has profound effects on the magnetic properties of the alloy, and hence, it is necessary to cool the alloy from its order-disorder lattice transformation point of about 600 C at a rate faster than 1 C/hour but slower than 100 C/second.
  • Such range of the-cooling speed is selected in order to cause the degree of order of the alloy to fall in a range of 0.1 to 0.6, preferably 0.2 to 0.5.
  • the alloy is comparatively quickly cooled at about 100 C/second, its degree of order becomes comparatively small, e.g., at about 0.1. Quick cooling faster than 100 C/second results in a degree of order smaller than 0.1 and does not provide the desired permeability.
  • the inventors have found-that the permeability of the alloy of the invention can be maximized when the degree of order of the alloy falls in a range of 0.1 to 0.6.
  • the aforesaid cooling from a temperature above the order-disorder lattice transformation point of the alloy at a rate faster than 1 C/hour but slower than 100 C/second will results in the desired degree of order in the range of 0.1 to 0.6.
  • the permeability of the alloy thus treated, especially when it is quickly cooled, may be further improved by tempering or reheating it to a temperature below its order-disorder lattice transformation point, e.g., in a range between 200C and 600C.
  • the permeability of the alloy of the aforesaid composition is maximized by making its degree of order be 0.1 to 0.6 by applying thorough solution treatment at 800 C or higher, preferably I,l C or higher, followed by cooling at a proper rate in the aforesaid range.
  • the additional tempering preferably in the range of 200 C to 600 C, will improve its degree of order for raising its permeability.
  • a higher treating temperature tends to allow a shorter treating time, while a lower treating temperature tends to require a longer treating time.
  • a greater mass tends to require a longer treating time, while a smaller mass tends to allow a shorter treating time.
  • the proper cooling speed for maximizing its permeability somewhat varies depending on its composition, but the cooling speed to be used in the method of the present invention is usually so slow that cooling in a furnace is preferred.
  • conventional nickel-iron alloys containing no tantalum e.g., Permalloy
  • high permeability cannot be obtained unless it is quickly cooled, for instance by forced-air-cooling.
  • the difference of the cooling speed between the conventional alloys a8d the alloy of the present invention is a very important factor in improving the properties of magnetic material.
  • such heads are usually heat treated for eliminating internal stress caused in the heads by the shaping process.
  • slow cooling in vacuo or in a non-oxidizing atmosphere is preferable.
  • the conventional alloys requiring quick cooling for producing a high permeability is not suitable for such slow cooling.
  • the alloy according to the present invention is particularly suitable for such post-shaping heat treatment.
  • FIG. 1A is a graph illustrating the relation between the composition of nickel-iron-tantalum alloys and their initial permeability
  • FIG. 1B is a graph illustrating the relation between the composition of nickel-iron-tantalum alloys and their maximum permeability
  • FIG. 2A is a graph representing sections along the lines 11-0 of FIGS. 1A and 1B (Fe:Ta 08:1 for n 1.2:1 for u
  • FIG. 2B is a graph representing sections along the lines b-b' of FIGS. 1A and 1B (NizTa 4.921 for n 5.6:1 for ;1.,,,);
  • FIG. 2C is a graph representing sections along the lines c-c' of FIGS. 1A and 1B (Ni:Fe 61:1 for p.,,, 6.9:] for ;1.,,,;);
  • FIG. 3A is a graph showing the relation between the initial permeability of Specimen No. 35 of the alloy according to the present invention and their heating temperature and heating time;
  • FIG. 3B is a graph showing the relation between the maximum permeability of Specimen No. 20 of the alloy according to the present invention and their heating temperature and heating time;
  • FIGS. 4A and 4B are graphs showing the effects of different cooling speeds on the initial permeability and the maximum permeability of the alloys of the present invention, respectively;
  • FIG. 5 is a graph showing magnetic hysteresis curves of Specimens No. 20 and No. 35 of the alloy according to the present invention.
  • FIG. 6 is a graph representing the effects of different tantalum contents in the alloy according to the present invention on their electric resistivity and Vickers hardness, assuming a constant nickel content of about 73 Wt. percent.
  • a suitable amount of a starting material consisting of 60.2 to 85.0 Wt. percent of nickel, 6.0 to 30.0 Wt. percent of iron, and 3.l to 23.0 Wt. percent of tantalum is melted by a melting furnace in air, preferably in vacuo or in a non-oxidizing atmosphere; a small amount (less than 1 Wt. percent) of a de-oxidizer and a de-sulfurizer, e.g., manganese, silicon, aluminum, titanium, calcium alloy, and the like, is added in the melt for removing impurities as far as possible; and the molten metal thus prepared is thoroughly agitated to homogenize its composition.
  • a de-oxidizer and a de-sulfurizer e.g., manganese, silicon, aluminum, titanium, calcium alloy, and the like
  • alloy specimens were prepared in the aforesaid manner. Each of the alloy specimens was poured into a mold for producing an ingot. The ingot was then shaped into sheets, each being 0.3 mm thick.
  • the alloys can be shaped into any other suitable form by forgiving or rolling at room temperature or at an elevated temperature.
  • Rings with an outer diameter of 44 mm and an inner diameter of 36 mm were punched out of the sheets thus prepared.
  • the rings were then heated at 800 or higher, preferably at l,l00 C or higher, for at least 1 minute, preferably longer than 5 minutes, but not longer than hours, in vacuo or in hydrogen or other nonoxidizing atmosphere, and then gradually cooled to a temperature close to their order-disorder transformation point of about 600 C (e.g., at a cooling speed of 1 C/second to 50 C/hour), so as to hold them at such temperature for a while (e.g., 5 minutes to 1 hour) until their composition become homogeneous, and finally they were further cooled at a suitable speed (e.g., l C/hour to 100 C/second, preferably 10 C/hour to 10 C/second, depending on the alloy composition).
  • a suitable speed e.g., l C/hour to 100 C/second, preferably 10 C/hour to 10 C/second, depending on the alloy composition.
  • the specimens were further heated at a temperature below their order-disorder lat-. tice transformation point, e.g., at about 600 C, for at least 1 minute, preferably longer than 5 minutes, but not longer than 100 hours, and then cooled.
  • a temperature below their order-disorder lat-. tice transformation point e.g., at about 600 C, for at least 1 minute, preferably longer than 5 minutes, but not longer than 100 hours, and then cooled.
  • the permeability of the ring specimens thus heat treated was measured by a conventional ballistic galvanometer method.
  • FIG. IA shows contours of the highest values of the initial permeability n of the nickel-iron-tantalum alloys of different compositions which were obtained by the aforesaid various heat treatments. Similar contours for the highest values of the maximum permeability of the nickel-iron-tantalum alloys of different compositions are shown in FIG. 1B after applying the aforesaid variety of heat treatments.
  • FIGS. 2A, 2B, and 2C are schematic sections of FIGS. 1A and 1B, taken along the lines a-a, b-b and c-c, respectively, illustrating the highest values of the initial permeability u, and the maximum permeability u along such sections.
  • Table I shows the physical properties of selected alloy specimens.
  • Another alloy, i.e., Specimen No. 20, consisting of 75.5 Wt. percent of nickel, nickeliron l3.5 Wt. percent ofiron, and l 1.0 Wt. percent of tantalum showed a maximum permeability of 256,000, when it was heated at 1,250 C for 3 hours and cooled in a furnace to 600 C for keeping it at 600 C for 10 minutes and then cooled to room temperature at a cooling rate of 240 C/hour.
  • Such values of permeability are considerably larger than those obtainable by using conventional binary alloys containing no tantalum; namely, a conventional nickel-iron alloy consisting of 78.5 Wt. percent of nickel and 21.5 Wt. percent of iron shows an initial permeability of 8,000 and a maximum permeability of 100,000, when it is heated at l,050 C and slowly cooled to 600 C followed by quick cooling from 600 C.
  • FIG. 3A shows the effects of different high heating temperatures and the heating time at such temperatures on the initial permeability of the ternary alloy, for the case of Specimen No. 35 of Table 1.
  • FIG. 3B shows similar effects on the maximum permeability of Specimen N0. 20.
  • the values of the permeability in FIGS. 3A and 3B were determined after cooling Specimens No. 35 and No. 20 from the illustrated high temperature in the range of 1,050 C to 1,350" in a special manner; namely, it was cooled to 600 C in a furnace for keeping it at 600 C for 10 minutes and then cooled to room temperature at a speed of 400 C/hour in the case of the initial permeability of Specimen No.
  • the permeability is materially influenced by the high heating temperature and the duration in which the alloy is heated at such high temperature.
  • a heat treatment at a temperature below l,l00 C results in comparatively low permeabilities; namely, an initial permeability not greater than 20,000 and a maximum permeability not greater than 150,000.
  • a high temperature heat treatment at l,100 C or higher results in comparatively high permeabilities; namely, an initial permeability greater than 20,000 and a maximum permeability greater than 150,000.
  • non-primed symbols in FIGS. 4A and 4B represent the permeability of the corresponding alloys, which were treated by heating at l,250 C for 3 hours, cooling to 600 C at 240 C/hour, and then further cooled from 600 C to room temperature at different speeds as specified by such non-primed symbols in the figures.
  • B C,, C C D,', and D represent the permeability of the corresponding alloy Specimens after further treating them from the corresponding non-primed conditions, respectively.
  • the heat treatments for the primed points were as follows.
  • FIG. 5 illustrates the hysteresis curves for the alloy Specimens having the highest permeability, i.e., Specimens No. 35 and No. 20. It is apparent from the figure that the hysteresis loss of Specimens No. 35 and 20 is extremely small.
  • EXAMPLE 11 Alloy Specimen No. 8 consisting of 76.0 Wt. percent of nickel, 16.0 Wt. percent of iron, and 8.0 Wt. percent of tantalum, as listed in Table 1., was made by using 99.8 percent pure electrolytic nickel, 99.97 percent pure electrolytic iron, and 99.9 percent pure tantalum. An ingot of the Specimen was formed by melting 800 grams of the starting pure metals in vacuo by using a crucible disposed in a high-frequency electric induction furnace, agitating the molten metal so as to produce a homogeneous melt of the alloy, and pouring the melt into a metallic mold having a cylindrical hole of 25 mm diameter and 170 mm height.
  • the ingot was hot forged at about 1,000 C into 7 mm thick sheets.
  • the sheets were hot rolled at about 600 to 900 C to a thickness of 1 mm, and then cold rolled at room temperature to make them into thin sheets of 0.3 mm thickness. Rings with an inner diameter of 36 mm and an outer diameter of 44 mm were punched out from the thin sheets.
  • the rings thus formed were subjected to different heat treatments, as shown in Table 3. Physical properties of the rings after the treatments are also shown in Table 3.
  • EXAMPLE 3 Alloy Specimen No. 35, consisting of 73.0 Wt. percent of nickel, 12.0 Wt. percent of iron, and 15.0 Wt. percent of tantalum, was made by using the same material in a similar manner as Example 1, so as to make similar rings. Different heat treatments were applied to the rings of Specimen No. 35, as shown in Table 5, together with the physical properties of the rings thus treated.
  • the heat treatment may be completed only by a primary treatment, which consists of heating a ternary alloy with a composition falling in the specific range of the invention, in a non-oxidizing atmosphere or in vacuo at 800 C or higher, preferably above l,l00 C, for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours, depending on the alloy composition, gradually cooling the alloy to about 600 C (e.g., at about 1 C/second to 50 C/hour), holding at this temperature for a short while (5 minutes to 1 hour), and then cooling the alloy from about 600C to room temperature at a cooling speed of 1 C/hour to 100 C/second, preferably 10 C/hour to 10 C/second.
  • a primary treatment which consists of heating a ternary alloy with a composition falling in the specific range of the invention, in a non-oxidizing atmosphere or in vacuo at 800 C or higher, preferably above l,l00 C, for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours,
  • a secondary heat treatment to the alloy treated by the aforesaid primary heat treatment, which secondary heat treatment comprises steps of heating the alloy in a non-oxidizing atmosphere or in vacuo at a temperature below the order-disorder lattice transformation point of the alloy, preferably at about 600 C, for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours, and then gradually cooling.
  • the optimal cooling speed to obtain excellent magnetic properties with conventional nickel-iron binary alloys is comparatively quick.
  • the optimal cooling speed for obtaining excellent magnetic properties decreases as the tantalum content in the alloy increases.
  • the tantalum content 15 Wt. percent and 1 l Wt. percent which gives the highest permeability among all the Specimens
  • the optimal cooling speed is so slow that it is preferable to cool it in a furnace. It is one of the important features of the present invention that the outstandingly high permeability of the alloy can be produced by a very simple heat treatment. 7
  • the alloy for magnetic heads should preferably have a high hardness and a high abrasion resistivity.
  • Conventional nickel-iron alloys for magnetic heads have a Vickers hardness in the order of about 130, which is not high enough for ensuring a high abrasion resistivity.
  • the Vickers hardness of the alloy according to the present invention increases with the tantalum content, as shown in FIG.
  • a Vickers hardness as high as 150 to 246 can be obtained by adding 3.1 to 23.0 Wt percent of tantalum.
  • the abrasion resistivity TABLE 3 Residual Hysteresis magnetic Coercive loss (erg per Saturated Initial Maximum flux denforce 0111. per flux density permepemiesity (G) (e) cycle) (G1 at mag- Electric ⁇ 'ickers Item ability abill netic field resistivity hardness No. Heat treatment (,u At maximum flux density of 5.000 G of 000 Oe.
  • tun-(111.1 (11v) I Heated at 1,150 C. in hydrogen for 3 11,600 112,800 4,410 0.0150 22.37 8, 910 45. 6 176 hours, cooled to 600 C. at 240 C./hour, and cooled to room temperature at 13,000 C./hour. 11 After I, reheated at 350 C. in vacuo for 1 0, 800 103,000
  • III Heated at 1,250 C. in hydrogen for 3 13, 020 120,600 4,370 0. 0127 20.15 8,920 4-1. T 174 hours, cooled to 600 C. at 240 CJhour, and cooled to room temperature at 2,800 C./hour. 1V After III, reheated at 350 C. in vacuo for 10,500 101,500 .1
  • the high hardness of the alloy according to the present invention makes the alloy particularly suitable for magnetic recording and reproducing heads, as pointed out in the foregoing. Furthermore, the outstandingly high permeability and the high electric resistivity of the alloy of the invention are also attractive in conventional electric and magnetic devices of various other types.
  • the contents of nickel, iron, and tantalum are restricted to 60.2 to 85.0 Wt. percent, 6.0 to 30.0 Wt. percent, and 3.1 to 23.0 Wt. percent, respectively, according to the present invention, because the alloy composition in the aforesaid range produces a high permeability and a high hardness suitable for magnetic TABLE Residual 11 ysteresls magnetic (loereive loss (erg per Saturated Initial Maximum flux den force em. per flux density permepermesity (G) (00.) cycle) (G) at mag- Electric Vickers 1m ability ability netie field resistivity hardness No. Heat treatment (#0) (I At maximum flux density of 5.000 G of 000 Oe.
  • u-cm.) (11v) 1 lieated at 1,150 C. in hydrogen for 3 30,100 110,200 2,550 0.0137 18,68 74 3 31g lmurs,-eoelcd to 000 C. at 240 (L/hour, and cooled to room temperature at 400 (L/hour. l l After I, rebooted at 400 C. in vacuo for 1 26, 000 87,500
  • V Heated at 1,250 O. in hydro en for 3 28,250 184,300 3,060 0.0142 24.05 6,960 73.5 208 hours, cooled to 600 C. at 240 C./hour, and cooled to room temperature at 240 C./hour.
  • ⁇ I Alter V reheated at 400 C. in vacuo for 24,800 150,500
  • alloy compositions outside the aforesaid range result in too low values of permeability and hardncss to use the alloy for magnetic heads.
  • the suitable contents of the ingredients in the alloy according-to the present invention will now be deinitial permeability n, of 34,800 and a maximum permeability u of 256,000.
  • nickel content less than 60.2 Wt. percent, the initial permeability u, is reduced to levels below 3,000, despite that a comparatively high maximum permeability u, can be achieved.
  • nickel content in excess of 85.0 Wt. percent the initial permeability u, and the maximum permeability a, become less than 3,000 and 10,000, respectively.
  • the nickel content is restricted to 60.2 to 85.0 Wt. percent.
  • An ingot of the alloy of the invention may be made by pouring a melt of the alloy into a suitable mold.
  • the ingot may be shaped into a desired form by working it at room temperature or at an elevated temperature, for instance by forging, rolling, drawing, swaging, or the like.
  • the alloy is heat treated by heating it at 800 C or higher (preferably higher than l,l00 C) in a non-oxidizing atmosphere, e.g., hydrogen, or in vacuo for at least I minute, preferably longer than 5 minutes, but not longer than about I00 hours, gradually cooling to a temperature above its order-disorder 0 transformation point, e.g., to about 600 C (for inccllent magnetic properties and high hardness can be 23.0 Wt. percent, the initial permeability n, and the maximum permeability u become smaller than 3,000 and 10,000, respectively.
  • the excessively high tantalum content also results in the deterioration of the workability of the alloy, especially its forgeability and rollability.
  • the tantalum content is restricted to 3.1 to 23.0 Wt. percent.
  • the alloy according to the present invention' consists of 60.2 to .0 Wt. percent of nickel, 6.0 to
  • the alloy may be reheated to a temperature below its order-disorder lattice transformation point, e.g., below about 600 C, for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours.
  • high permeability including an initial permeability u, of 34,800 and a maximum permeability of 256,000 can be obtained.
  • the alloy according to the present invention has a number of properties suitable for magnetic recording and reproducing heads; namely, a comparatively high electric resistivity, a high hardness, and a high workability at room temperature and at an elevated temperature in terms of forgeability, rollability, drawability, and swageability.
  • Wt. percent of tantalum, and an inevitable amount of impurities is heated at a temperature above 800 C, preferably above 1,100 C, in a non-oxidizing atmosphere or in vacuo for at least 1 minute but not longer than about 100 hours, gradually cooled to an intermediary temperature slightly above the order-disorder lattice transformation point of the alloy, for instance to about 600 C, and cooled to room temperature from the intermediary temperature at a cooling rate in a range of 1 C/hour to 100 C/second, preferably 10 C/hour to 10 C/second.
  • an initial permeability about 3,000 to 34,800 and a maximum permeability of about 10,000 to 256,000.
  • the alloy of the preceding item (a1) may be reheated at a temperature below its order-disorder lattice transformation point, e.g., below about 600 C, in a nonoxidizing atmosphere or in vacuo for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours, so as to generate the permeabilities of the item (a1).
  • the alloy of the preceding item (1) may be reheated at a temperature below its order-disorder lattice transformation point, e.g., below about 600 C, in a nonoxidizing atmosphere or in vacuo for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours, so as to generate the permeabilities of the item (b1):
  • An alloy consisting of 71.8 to 76.0 Wt. percent of nickel, 10.8 to 15.4 Wt. percent of iron, 9.0 to 16.5 Wt. percent of tantalum, and an inevitable amount of impurities is heated at a temperature above 800 C, preferably above l,100 C, in a non-oxidizing atmosphere or in vacuo for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours, gradually cooled to an intermediary temperature slightly above the order-disorder lattice transformation point of the alloy, for instance to about 600 C, and cooled to room temperature from the intermediary temperature at a cooling rate in a range of 1 C/hour to 100 C/second, preferably 10 C/hour to 10 C/ second.
  • the alloy of the preceding item (c1) may be reheated at a temperature below its order-disorder lattice transformation point, e.g., below about 600 C, in a nonoxidizing atmosphere or in vacuo for at least 1 minute, preferably longer than 5 minutes, but not longer than about hours, so as to generate the permeabilities of the item (c1).
  • An alloy consisting of 72.5 to 75.8 Wt. percent of nickel, 11.3 to 14.6 Wt. percent of iron, 9.8 to 15.6 Wt. percent of tantalum, and an inevitable amount of impurities is heated at a temperature above 800 C, preferably above 1,100 C, in a non-oxidizing atmosphere or in vacuo for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours, gradually cooled to an intermediary temperature slightly above the order-disorder lattice transformation point of the alloy, for instance to about 600 C, and cooled to room temperature from the intermediary temperature at a cooling rate in a range of 1 C/hour to 100 C/second, preferably 10 C/hour to 10 C/second.
  • an initial permeability about 10,000 to 34,800 and a maximum permeability of about 200,000 to 256,000.
  • the alloy fo the preceding item (d1) may be reheated at a temperature below its order-disorder lattice transformation point, e.g., below about 600 C, in a nonoxidizing atmosphere or in vacuo for at least 1 minute, preferably longer than 5 minutes, but not longer than about 100 hours, so as to generate the permeabilities of the item (d1).
  • a heat-treated alloy for magnetic recording and reproducing heads consisting essentially of 60.2 to 85.0 Wt. percent of nickel, 6.0 to 30.0 Wt. percent of iron, and 3.1 to 23.0 Wt. percent of tantalum, said alloy having a degree of order of 0.1 to 0.6, an electric resistivity of 23 to 94 all-cm and a Vickers hardness of greater than and having high initial permeability and maximum permeability of above 3,000 and 10,000, respectively.

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4608228A (en) * 1982-12-20 1986-08-26 Alps Electric Co., Ltd. Ni-Fe magnetic head including 1.5-2% Ta
US4710243A (en) * 1985-01-30 1987-12-01 The Foundation: The Research Institute Of Electric And Magnetic Alloys Wear-resistant alloy of high permeability and method of producing the same
CN110066953A (zh) * 2018-01-22 2019-07-30 屏东科技大学 薄膜电阻合金

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS50160831A (nl) * 1974-06-18 1975-12-26

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4608228A (en) * 1982-12-20 1986-08-26 Alps Electric Co., Ltd. Ni-Fe magnetic head including 1.5-2% Ta
US4710243A (en) * 1985-01-30 1987-12-01 The Foundation: The Research Institute Of Electric And Magnetic Alloys Wear-resistant alloy of high permeability and method of producing the same
US4830685A (en) * 1985-01-30 1989-05-16 The Foundation: The Research Institute Of Electric And Magnetic Alloys Wear-resistant alloy of high permeability and method of producing the same
CN110066953A (zh) * 2018-01-22 2019-07-30 屏东科技大学 薄膜电阻合金

Also Published As

Publication number Publication date
NL152298B (nl) 1977-02-15
NL7112665A (nl) 1972-03-21
JPS51536B1 (nl) 1976-01-08
NL152298C (nl) 1979-10-15

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