DE1533378B1 - Alloy for permanent magnets with anisotropic columnar crystal structure - Google Patents

Description

Pour into exothermic molds or heated refractories 20 the atomic weights of selenium and sulfur. Shapes using shock plates, zones- The tellurium is preferably melted as

Melting process of a previously cast rod and pressed pieces made of tellurium powder or as fragments continuous pouring. a moderately brittle 50:50 copper-tellurium alloy

It has now been found that it is advantageous to add. The amount of tellurium added is approximately tellurium together with titanium. High energy densities 25 double the amount required in the alloy, and high coercive force can be achieved at the same time in order to compensate for the melting losses, which are due to the low melting point (454 ^cC ) and boiling point of a high energy density a content of cobalt (1390 ⁰ C) of tellurium occurs, which in the upper part of the usually niobium is another additive, which is to favor

area 30 of the columnar structure that is considered favorable for the cobalt content and / or improved or even above the usual upper limit of coercive force may be present. Niobium is more common of this Area. wisely available in conjunction with tantalum

Accordingly, a permanent magnet has the specified amounts of niobium somewhat larger with anisotropic columnar crystal structure after can be if these combined together Invention a composition in weight setting is used.

The cast or solidified magnet alloy is suitably subjected to the usual heat treatment subjected to the application of a magnetic field in the longitudinal direction of the columnar Includes crystal structure with subsequent tempering. Special examples of heat treatment and tempering are listed below.

In the following, examples are given for the application of the invention to magnets with a coercive force H _c of at least 1200 Oersted and an energy density (BH) _max of at least 6.0 · 10 ⁶ Gauss · Oersted by means of conventional technical processes to produce a columnar crystal structure from commercially available alloys containing titanium

The lowest content of tellurium is preferably 5 °, so far either for simultaneous high greater than 0.50%; Energy density and high coercive force have proven to be particularly advantageous, except through

Addition of sulfur and / or selenium were not suitable, or even have proven to be unsuitable even in the presence of sulfur and / or selenium. It seems that tellurium (as much as about 2000 oersted) facilitates in alloys with for the higher values of coercive force required large amounts of titanium to achieve very high energy densities (even above 8.0 x 10 ^θ Gauss · oersted), and that the simultaneous presence of sulfur and / or selenium with tellurium is conducive to achieving such a highly desirable combination of magnetic properties. Table 1 shows the composition (in weight

percent of 5 until 9% Aluminum, 11th until 22% Nickel, 33 until 50%. , preferably 34 until 50% Cobalt, 1 until 6% Copper, 1 until 9% Titanium, 0 until 4% Niobium, 0 until 1% Silicon, 0.10 until 4% Tellurium, Remainder iron and manufacturing-related Impurities.

a composition of the alloy in percent by weight is shown as follows:

6.5 to 8.5% aluminum,
12.0 to 16.0% nickel,
33.0 to 43.0% cobalt,
2.0 to 4.5% copper,
9.0% titanium,
3.0% niobium,
0.5% silicon,
3.0% tellurium,
Iron and manufacturing

6.0 to
0.8 to
0 to
0.5 to
rest

Impurities.

65 percent) of the alloys, all of which are exothermic, so sulfur and / or selenium can be used to reduce molds, are cast with shock plates.

Table 2 describes the different heat

tion of the brittleness must be present, but preferably in sufficient quantity to allow simultaneous treatments of the alloys, whereby all heat

treatments include isothermal treatment in a magnetic field, and

alloy Al Ni 1 7.08 May 15 Ί 7.65 14.96 3 7.07 14.96 4th 6.80 14.72 5 6.88 14.55 6th 7.04 13.46 7th 6.22 April 13

Table 3 shows
Properties.

the resulting magnetic

Tabel

Cu Ti Nb Si Se Te 4.42. 4.9 - 0.14 0.022 0.96 3.0 7.2 - X 0.032 1.02 2.84 7.4 - X - 0.7 2.93 8.25 - 0.19 0.288 0.77 3.06 8.0 - - 0.327 0.63 3.0 7.85 - 0.18 0.030 1.05 2.99 4.44 0.85 X - 1.00 Co 33.48 41.16 39.97 40.32 40.41 39.72 35.52

(X = not analyzed).

Table 2

Heat treatments A, B and C, including the

Application of a magnetic field and the

Starting

A, B, C Heating to the annealing temperature
(! 250 ° C) A.
B. Cooling in the air flow to room temperature
temperature in a magnetic field of 3400 Oer
sted
Cooling in the air flow up to ver
shrinkage of a glow color in 1.5 to
2 minutes (without magnetic field) A.
B.
C. Reheating in the magnetic field
from 7000 Oersted to 800 or 810 ⁰ C
and hold for 20 minutes (total
time in the oven 35 minutes)
Reheat in the salt bath to 820 ° C
in the magnetic field of 2800 Oersted and
hold for 13 minutes (total time
in the bathroom 15 minutes)
Quenching at 1250 ^° C. in a salt bath
to 820 ⁰ C in a magnetic
Field of 2800 Oersted and hold
for 15 minutes A, B, C Tempering: 59O ⁰ C for 48 hours,
plus 560 ^° C. for 48 hours

Table 3

alloy
and A. Remanence Coercive
force Energy density treatment A- S, (Gauss) H _c (Oersted) (Gauss Oersted) 1 A. 10,750 1215 6.25 · 10 ⁶ 2 B. 8.430 1655 6.22 · 10 ⁶ 3 B. 9.020 1722 7.5 -10 ⁶ 4th A. 8,950 2010 8.43 · 10 ⁶ 5 B. 8,350 1908 6.06 · 10 ^{6 6} I. C. 9.120 1628 7.69 · 10 ^{6 6th} C. 8.150 1980 7.0 -10 ⁶ 6) 8,700 1880 6.25 ■ 10 ⁶ 7th 11,700 1235 7.1 -10 ⁶

All of these magnets were then magnetized in a magnetic field of 7000 Oersted applied in the direction of the columnar crystal structure.
An alternative to cooling in an air stream is oil quenching. An alternative to the salt bath (KCL · NaNO ₃ ) is a bath of molten aluminum. Alternatives annealing is carried out at 68O ⁰ C for 4 hours and at 560 ⁰ C for 30 hours.

During the heat treatment field strengths in the range from 2500 to 3500 Oersted (like those mentioned above 2800 Oersted and 3400 Oersted) can be used, higher field strengths seem like the above-mentioned 7000 Oersted or even more, v / ie 10,000 Oersted or more, are very beneficial, around the bulge of the demagnetization curve, d. H. Energy density and coercive force, improve. It is believed that a silicon content of the alloy contributes to higher field strengths to make it more effective.

Claims (6)

Patent claims: 1. Alloy for the production of permanent magnets with anisotropic columnar crystal structure, consisting of (data in percent by weight): 5 until 9% Aluminum, 11th until 22% Nickel, 33 until 50%. , preferably 34 until 50% Cobalt, 1 until 6% Copper, 1 until 9% Titanium, 0 until 4% Niobium, 0 until 1% Silicon, Remainder iron and manufacturing-related Impurities, characterized in that the alloy tellurium in an amount of 0.10 to 4% contains. 2. Alloy according to claim 1, consisting of (data in percent by weight): 6.5 to 8.5% aluminum,
12 to 16% nickel,
33 to 43% cobalt, 2 to 4.5% copper, 6 to 9% titanium, 0.8 to 3% niobium, 0 to 0.5% silicon, Remainder iron and production-related impurities, characterized in that the alloy contains tellurium in the amount of 0.5 to 3%. 3. Alloy according to claim 1 or 2, characterized in that the amount of tellurium is 0.75 up to 1.5%. 4. Alloy according to claim 1 or 2, characterized in that the alloy contains sulfur an amount of 0.1 to 0.6% and tellurium in an amount of 0.3 to 1.8% and that the Tellurium to sulfur weight ratio is approximately 3: 1. 5. Alloy according to claim 1 or 2, characterized in that the alloy contains sulfur an amount of 0.15 to 0.3% and tellurium in an amount of 0.45 to 0.95% and that the Tellurium to sulfur weight ratio is about 3: 1. 6. Alloy according to claim 4 or 5, characterized in that sulfur is wholly or partially is replaced by selenium in an amount proportional to the atomic weights of both elements.