RU2280910C1 - Magnetic material and its product - Google Patents

Abstract

FIELD: powder metallurgy; navigation equipment and aircraft automation systems.

SUBSTANCE: proposed magnetic material designed for producing permanent magnets based on rare-earth element with metals of iron group has in its composition iron, cobalt, boron, and at least one element of terbium, dysprosium, holmium, erbium, thulium group, as well as cerium and gadolinium, and at least one element of samarium, lanthanum, neodymium, yttrium, and praseodymium group, formula of this chemical composition being as follow, atom percent: (Ce_{1 - x1 - x2- x3}R¹ _{x1 x3}R² _x2GD_x3)_14-20(Fe_{1 - y}Co_y1)_rB_{4 - 10}, where R¹ is at least one element of Tb, Dy, Ho, Er, Tm group; R² is at least one element of Sm, La, Nd, Y, Pr group, where x1 = 0.2 - 0.5; y1 = 0.2 - 0.3, x2 and x3 are chosen considering following conditions: x1 + x2 + x3 = 0.75 - 0.99; x3/x1 ≥ 0.01.

EFFECT: enhanced residual magnetic flux density and temperature stability of material, extended range of magnet sizes.

3 cl, 1 tbl, 5 ex

Description

The invention relates to the field of powder metallurgy, in particular, to magnetic materials for permanent magnets based on rare-earth elements with metals of the iron group.

Known magnetic material based on neodymium, cerium, lanthanum, iron, aluminum, boron of the following chemical composition, atomic%: (Nd _0.6 Ce _0.27 La _0.13 ) _15.5 Fe _73.9 Al _3.1 V _7.5 (Tang W. and other. Preparation and microstructure of La-containing R-Fe-B permanent magnets. J. Appl. Phys., 1989, V. 65, No. 8, p. 3142-3145).

The disadvantages of the known magnetic material are:

insufficiently high magnetic properties: the value of the coercive force (N _Ci ) is 8.1 kOe, while the magnitude of the temperature coefficient of induction (TCI) is not more than -0.1% / ° C (in the range of 20 ÷ 100 ° C).

Products of known magnetic material are, for example, prisms, cylinders, ring magnets with a radial or axial texture, etc.

The disadvantages of the products are:

- insufficiently high value of H _Ci , which imposes restrictions on the geometric dimensions of products, especially ring magnets with a radial texture;

- insufficiently high temperature stability of the material (high value of TCI, in absolute value), which limits the scope of application of products from it in technology.

Known magnetic material based on neodymium, iron, cobalt, boron of the following chemical composition, at.%: Nd ₁₅ (Fe _1-x Co _x ) ₇₇ В ₈ , where x = 0 ÷ 0.2 (Sagawa M. and other. Permanent magnet materials based on the rare earth-iron-boron tetragonal compounds. IEEE Trans. on Magnet. 1984, V.MAG-20, No. 5, p. 1584-1589).

The disadvantages of the known magnetic material are:

insufficiently high magnetic properties: the value of H _Ci does not exceed 10.3 kOe, and the value of the TCI ≤ -0.074% / ° C.

Products of known magnetic material are, for example, prisms, cylinders, ring magnets with a radial or axial texture, etc.

The disadvantages of the products are:

- insufficiently high value of H _Ci , which imposes restrictions on the geometric dimensions of products, especially ring magnets with a radial texture;

- insufficiently high temperature stability of the material (high value of TCI, in absolute value), which limits the scope of application of products from it in technology.

The closest analogue taken as a prototype is a magnetic material having a chemical composition corresponding to the formula, at.%:

(Nd _1-x1-x2 Tb _x1 R _x2 ) _14-17 (Fe _1-y1 Co _y1 ) _75-80 T _y2 B _6-8 ,

where R is at least one element selected from the group of dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), and T is at least one element selected from the group of aluminum (Al), gallium (Ga), titanium (Ti), niobium (Nb), molybdenum (Mo), moreover

x1 + x2 = 0.1-0.99

x1 / x2≥0.10

y1 = 0.2-0.55

y2 = 0.01-10 (RF Patent No. 2136069)

The disadvantages of the magnetic material of the prototype are not high magnetic properties. For example, when the value of TCI = -0.05% / ° С (20 ÷ 100 ° С), the value of the residual induction (V _R ) does not exceed 8.5 kG.

Products from the magnetic material of the prototype are any sizes of magnets (for example, prisms, cylinders, rings with axial and radial texture (CMRT).

The disadvantage of the products are:

the impossibility of manufacturing magnets with a TCI value of more than -0.05% / ° C, with a residual induction B _{R of} more than 8.5 kG.

An object of the invention is to increase the residual induction of the material while increasing temperature stability.

The stated technical problem is achieved in that a magnetic material is developed containing iron, cobalt, boron and at least one element selected from the group of terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm ), which additionally contains cerium (Ce) and gadolinium (Gd), and at least one element selected from the group of samarium (Sm), lanthanum (La), neodymium (Nd), yttrium (Y), praseodymium (Pr), while the chemical composition corresponds to the formula, at.%:

(Ce _1-x1-x2-x3 R ¹ _x1 R ² _x2 Gd _x3 ) _14-20 (Fe _1-y1 Co _y1 ) _stop At _4-10 ,

where R ¹ is at least one element selected from the group Tb, Dy, But, Er, Tm, R ² is at least one element selected from the group Sm, La, Nd, Y, Pr, where

x1 = 0.2-0.5,

y1 = 0.2-0.3,

and the values x2 and x3 are selected from the following conditions:

x1 + x2 + x3 = 0.75-0.99,

x3 / x1≥0.01.

The magnetic material further comprises at least one element selected from the group aluminum (Al), gallium (Ga), titanium (Ti), niobium (Nb), molybdenum (Mo), copper (Cu), and the chemical composition corresponds to the formula at.%:

(Ce _1-x1-x2-x3 R ¹ _x1 R ² _x2 Gd _x3 ) _14-20 (Fe _1-y1 Co _у1 ) _stop T _y2 V _4-10 ,

where T is at least one element selected from the group Al, Ga, Ti, Nb, Mo, Cu;

y2 = 0.01-4.

Also proposed is a product made of the above magnetic material.

The authors found that in the Ce-LR-HR-Fe-Co-B system, where LR is light and HR is heavy rare earth metals, respectively, the HR / (Ce + LR + HR) ratio in the main magnetic phase (Ce, LR, HR) ₂ (Fe, Co) ₁₄ V is always higher than in the Nd-HR-Fe-Co-B system (with the same content of other alloying elements), which leads to an increase in the TCI of the material. It was established that doping with gadolinium makes the coercive force less sensitive to temperature changes, which also leads to an increase in the TCI value of the material. It has been established that the positive influence of Sm, La, Nd, Y, Pr, as well as Al, Ga, Ti, Nb, Mo, Cu within the stated limits is associated with a change in the chemical composition of the phases, as well as the phase composition of the material.

Examples of implementation

An alloy of a given composition was smelted in a vacuum induction furnace. The magnets were made using powder technology, including: crushing the ingot to a size of less than 600 microns, fine grinding in a protective medium to a single crystal particle size, pressing witness samples in a magnetic field of 10 kOe, sintering in a vacuum furnace at a temperature of 1080-1140 ° С. The obtained blanks of witness specimens were ground to a size of 10 × 10 × 10 mm. The value of TCI was measured in the range of 20-100 ° C.

The compositions and properties of the proposed magnetic material and the material of the prototype are shown in the table.

The proposed magnetic material with a TCI value of more than -0.05% / ° C makes it possible to increase the value of B _R by 4-25% and H _Ci by 5-8% compared with the magnetic prototype material, which makes it possible to expand the range of products.

The application of the proposed magnetic material will improve the accuracy and stability of the navigation equipment and aircraft automation systems, as well as produce magnets of any standard size.

Table
The compositions and properties of the proposed magnetic material and the material of the prototype Suggested material No. The composition of the magnetic material, at.% Magnetic properties B _R , kgf N _Ci , kE TCI,% / ° C one (Ce _0.25 Dy _0.05 Tb _0.40 Er _0.05 Nd _0.01 Pr _0.17 Sm _0.02 Gd _0.05 ) _14.5 (Fe _0.7 Co _0.3 ) _ost. B ₈ 8.9 19.0 -0.03 2 (Ce _0.01 Dy _0.18 Ho _0.01 Er _0.01 Nd _0.03 Pr _0.75 Gd _0.01 ) _15.5 (Fe _0.8 Co _0.2 ) _rest B _7.1 8.8 18.1 -0.042 3 (Ce _0.25 Dy _0.1 Tb _0.4 Nd _0.01 Pr _0.18 Sm _0.01 Gd _0.05 ) _15.3 (Fe _0.7 Co _0.3 ) _rest Cu _0.005 Ti _0.005 V ₆ 8.8 17.6 -0.025 four (Ce _0.01 Dy _0.01 Tb _0.18 Er _0.01 Nd _0.3 Pr _0.35 Y _0.05 Gd _0.09 ) _15.2 (Fe _0.8 Co _0.2 ) _rest Cu _2.8 Ti ₁ Al _0.2 B ₇ 8.9 17.7 -0.042 5 (Ce _0.01 Dy _0.41 Tb _0.01 Nd _0.01 Pr _0.56 Gd _0.01 ) _14.1 (Fe _0.76 Co _0.24 ) _rest At _7.3 9.5 17.7 -0.022 6 (Ce _0.05 Dy _0.2 Tb _0.05 Tm _0.05 Ho _0.01 Pr _0.57 Y _0.02 Gd _0.05 ) ₁₅ (Fe _0.75 Co _0.25 ) _rest Al _0.1 Ti _0.1 B _6.7 10.0 18.0 -0.025 7 (Ce _0.06 Dy _0.15 Tb _0.14 Nd _0.58 Sm _0.03 Gd _0.04 ) _14.4 (Fe _0.8 Co _0.2 ) _ost. Al _0.1 Ti _0.04 Nb _0.02 V ₆ 10.6 17.7 -0.043 8 (Ce _0.04 Dy _0.3 Tb _0.07 Ho _0.01 Nd _0.47 La _0.01 Sm _0.05 Gd _0.05 ) _14.9 (Fe _0.75 Co _0.25 ) _rest Cu _1.6 Ti _0.45 V _6.2 9.0 18.1 -0.02 Prototype (Nd _0.69 Dy _0.25 Tb _0.06 ) _16.0 (Fe _0.77 Co _0.23 ) _rest Al _{0.9V 7.29} 8.5 16.8 -0.05

Claims (3)

1. A magnetic material containing iron, cobalt, boron, and at least one element selected from the group of terbium, dysprosium, holmium, erbium, thulium, characterized in that it additionally contains cerium and gadolinium, and at least one element, selected from the group of samarium, lanthanum, neodymium, yttrium, praseodymium, while the chemical composition corresponds to the formula, at.%: (Ce _1-x1-x2-x3 R ¹ _x1 R ² _x2 Gd _x3 ) _14-20 (Fe _1-y1 Co _y1 ) _stop B _4-10 where R ¹ is at least one element selected from the group Tb, Dy, But, Er, Tm, R ² is at least one element selected from the group Sm, La, Nd, Y, Pr, where x1 = 0.2-0.5, y1 = 0.2-0.3, and the values x2 and x3 are selected from the following conditions: x1 + x2 + x3 = 0.75-0.99 x3 / x1≥0.01. 2. The magnetic material according to claim 1, characterized in that it further comprises at least one element selected from the group aluminum, gallium, titanium, niobium, molybdenum, copper, while the chemical composition corresponds to the formula, at.%: (Ce _1-x1-x2-x3 R ¹ _x1 R ² _x2 Gd _x3 ) _14-20 (Fe _1-y1 Co _y1 ) _stop T _y2 B _4-10 , where T is at least one element selected from the group Al, Ga, Ti, Nb, Mo, Cu, where y2 = 0.01-4. 3. A product of magnetic material, characterized in that it is made of magnetic material according to any one of paragraphs. 1 or 2.