CN103996477A - Corrosion-resistant sintered NdFeB magnet modified through copper-tin crystal boundary and preparing process thereof - Google Patents
Corrosion-resistant sintered NdFeB magnet modified through copper-tin crystal boundary and preparing process thereof Download PDFInfo
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Abstract
The invention discloses a corrosion-resistant sintered NdFeB magnet modified through the copper-tin crystal boundary and a preparing process thereof. A general formula of the corrosion-resistant sintered NdFeB magnet modified through the copper-tin crystal boundary is (RExFe100-x-y-zCoyBz)100-v(Cu100-uSnu)v. The corrosion-resistant sintered NdFeB magnet has the advantages that compared with a magnet not modified through the copper-tin crystal boundary, the prepared magnet has the higher corrosion-resistant capacity; compared with an existing magnet preparing method, a high-potential low-melting-point copper-tin alloy is utilized for carrying out crystal boundary modification, the sintering temperature and heat treatment temperature are lowered, a large number of energy sources can be saved, and the production cost of materials is reduced.
Description
Technical field
The present invention relates to permanent magnetic material technical field, be specifically related to the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin and the preparation technology thereof of low weightless resistance to acid attack.
Background technology
Sintered NdFeB (NdFeB) is the Permanent magnet metallics that China gives priority to during " 12 ", there is high remanent magnetism, high energy product, high-coercive force and low-expansion advantage, can make the electromagnetic energy of various ways and the function element that mechanical energy is changed mutually, be widely used in the fields such as energy traffic, electrical engineering, communication, medical engineering, office automation.The remanent magnetism of NdFeB
b r, maximum magnetic energy product
(BH) maxand HCJ
i h ctheoretical value is respectively up to 1.6 T, 63 MGOe, 75 kOe, and the ferromagnetism of material comes from Nd
2fe
14the intrinsic hard magnetic of B compound, closely related with the institutional framework of magnet.Sintered NdFeB is by Nd
2fe
14b principal phase with taking rich Nd mutually as main Grain-Boundary Phase forms, rich Nd plays degaussing coupling mutually, is the essential condition that magnet has excellent permanent magnetism.But rich Nd is but very active mutually, and its corrosion potential is much smaller than the potential value of principal phase, and this makes Sintered NdFeB be easy to occur grain boundary corrosion, make the magnetic property of material reduce and even disappear.Therefore, low corrosion stability has restricted the application of NdFeB, has hindered further developing of sintered NdFeB industry.
For the problems referred to above, people often adopt the mode of adding the elements such as Co, Cu, Mo, Nb or the mixed powder interpolation of employing compound (AlN, MgO, ZnO) micro-nano ground rice in melting forward direction magnet, improve the corrosion resistance of NdFeB.Facts have proved, preceding method can improve the character of NdFeB Grain-Boundary Phase to a certain extent, adjusts the distribution along crystal boundary situation of rich Nd phase, improves the resistance to corrosion of magnet; But the increase rate of magnet corrosion stability is but limited, is difficult to meet the instructions for use of high-end field, people have to adopt the modes such as plating, electrophoresis or chemical plating to carry out surface treatment or protection to magnet.The surfacecti proteon that it is pointed out that NdFeB not only can increase production process and cost, and pollutes the environment, and causes environmental issue.Therefore, be necessary to develop a kind of energy assertive evidence (self) novel sintered neodymium iron boron against corrosion.
Summary of the invention
For the problem existing in the above-mentioned state of the art, the invention provides a kind of highly and can work in coordination with the feature of enhancing Nd-Fe-B crystal boundary structure chemical stability based on copper (Cu) and tin (Sn) electrode potential, be of value to the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin and the preparation technology thereof of magnet densification in conjunction with copper tin (Cu-Sn) alloy low melting point.
Technical solution of the present invention is: the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin,
General formula is (RE
xfe
100-x-y-zco
yb
z)
100-v(Cu
100-usn
u)
v; Wherein:
RE rare earth element comprises one or both elements in neodymium Nd and praseodymium Pr, dysprosium Dy, holmium Ho, cerium Ce, lanthanum La, terbium Tb, gadolinium Gd, and x is that RE rare earth element is at RE
xfe
100-x-y-zco
yatomic percent in B alloy, 12.7 at.%≤x≤15.5 at.%;
Y is that cobalt Co element is at RE
xfe
100-x-y-zco
yb
zatomic percent in alloy, 0.5 at.%≤y≤2.2 at.%;
Z is that boron element is at RE
xfe
100-x-y-zco
yb
zatomic percent in alloy, 5.5 at.%≤z≤6.5 at.%;
U is that Sn is at Cu
100-usn
uatomic percent in alloy, 14.9 at.%≤u≤45.5 at.%;
V is Cu
100-usn
uthe mass ratio of alloy in the whole material composition system of the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin, 0.1 wt.%≤v≤1.1 wt.%.
The crystal boundary modified Sintered NdFeB magnet against corrosion of foregoing copper tin, the atomic percent that Nd in described RE rare earth element accounts for RE total amount is that 60-90%(is preferred, the atomic percent that Nd accounts for RE total amount is 73%-85%, is more preferably, and the atomic percent that Nd accounts for RE total amount is 78%).
The crystal boundary modified Sintered NdFeB magnet against corrosion of foregoing copper tin, preferred, 13.0 at.%≤x≤14.2 at.%, is more preferably, x=13.4 at.%.
The crystal boundary modified Sintered NdFeB magnet against corrosion of foregoing copper tin, preferred, 1.0 at.%≤y≤1.8 at.%, is more preferably, y=1.6 at.%.
The crystal boundary modified Sintered NdFeB magnet against corrosion of foregoing copper tin, preferred, 5.7 at.%≤z≤6.1 at.%, is more preferably, z=5.9 at.%.
The crystal boundary modified Sintered NdFeB magnet against corrosion of foregoing copper tin, preferred, 15.2 at.%≤u≤23.5 at.%, is more preferably, u=20.0 at.%.
The crystal boundary modified Sintered NdFeB magnet against corrosion of foregoing copper tin, preferred, 0.4 wt.%≤v≤0.7 wt.%, is more preferably, v=0.5 wt.%.
Another object of the present invention provides above-mentioned (RE
xfe
100-x-y-zco
yb
z)
100-v(Cu
100-usn
u)
vthe preparation method of permanent magnetic material, concrete steps are as follows:
Step 1: according to master alloying RE
xfe
100-x-y-zco
yb
zin composition proportion, weigh RE, Fe, Co and ferro-boron raw material, in vacuum smelting fast solidification stove, prepare afterwards the rapid hardening strip of master alloying, and strip carried out to hydrogen quick-fried (HD) and process and obtain RE
xfe
100-x-y-zco
yb
zalloy bits, further adopt the method for airflow milling to make the master alloying powder that average particle size particle size is 1-5 μ m;
Step 2: according to auxiliary alloy Cu
100-usn
uin composition proportion, weigh Cu and Sn raw material, carry out vacuum melting at vacuum arc furnace ignition afterwards, first the raw material that weigh up are put into stove, be evacuated to 10
-3pa, and pour high-purity argon, melt back 7 times, prepares the uniform Cu of composition
100-usn
ualloy pig, and after coarse crushing, carry out ball milling, making average particle size particle size is the auxiliary alloy powder of 1-3 μ m;
Step 3: step 1 and step 2 are prepared to RE
xfe
100-x-y-zco
yb
zmaster alloying and Cu
100-usn
uauxiliary alloyed powder takes according to the mass ratio of design, under the condition of argon shield, add batch mixer to enter middle row batch mixing, when batch mixing, adding alloy powder total weight percent is the gasoline of 0.5%-2.5 wt.%, and master alloying and auxiliary alloy mix 2.5 h, make uniform mixed powder;
Step 4: the mixed powder that step 3 is prepared is orientated die mould in the magnetic field of 1.0-2.2 T, molding pressure is 150-210 MPa, obtain briquetting and on hydraulic press, carry out 190-230 MPa etc. static pressure, prepare closely knit pressed compact;
Step 5: it is 10 that the pressed compact that step 4 is prepared is put into vacuum degree
-4in pa high vacuum sintering furnace, carry out sintering, sintering temperature is 1040-1100 DEG C, and insulation 3.0-4.5h, passes into afterwards argon gas and carry out rapid cooling, and cooling rate is 200 DEG C/min, is cooled to room temperature and obtains neodymium iron boron magnetic body.
Step 6: the neodymium iron boron magnetic body that step 5 is prepared carries out second annealing heat treatment, first tempering 1.5-3.5 h in the temperature range of 830-920 DEG C, in backward tempering furnace, pass into argon gas magnet fast cooling to room temperature; And then be warming up to 420-630 DEG C of second annealing that carries out 2.0-3.5 h, (mass loss of corroding 200 h in 120 DEG C, 2 atm, 100% relative humidity environment is lower than 1.5 mg/cm to prepare low weightlessness
2) resistance to acid attack is (at the 0.1 M HNO of 25 DEG C
3corrosion electric current density in solution is lower than 0.5 mA/cm
2) the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin.
In the present invention in the pulverizing process of master alloying, the particular content of smelting technology, rapid hardening belt-rejecting technology, the quick-fried crushing process of hydrogen and air-flow grinding process is shown in respectively " superpower permanet magnetic body---the rare-earth system permanent magnetic material " that Zhou Shouzeng, Dong Qingfei write, Beijing: metallurgical industry publishing house, 2004.2 the second edition, p158-159, p498-504, p326-332, p508-511, p170-172.
The invention has the beneficial effects as follows: the magnet making, with compared with the crystal boundary modified magnet of signal bronze, has higher resistance to corrosion; Simultaneously compared with existing magnet preparation method, utilize the signal bronze of high potential low melting point to carry out crystal boundary modified, reduce sintering and heat treatment temperature, can save a large amount of energy, reduce the production cost of material.
Brief description of the drawings
Fig. 1 is the Cu of the embodiment of the present invention 1
80.0sn
20.0addition be 0.5 wt.% sintered NdFeB in 120 DEG C, 2 atm, 100% relative humidity environment, corrode the surface topography after 200 h.
Fig. 2 is the Cu of the embodiment of the present invention 1
80.0sn
20.0addition be 0.5 wt.% sintered NdFeB at the 0.1 M HNO of 25 DEG C
3corrosion polarization curve in solution.
Embodiment
Below with reference to embodiment, the present invention will be further described, and embodiments of the invention are only for technical scheme of the present invention is described, and non-limiting the present invention.
embodiment 1:
(1) melting: master alloying and auxiliary alloy are prepared respectively, master alloying Nd
10.45pr
1.95dy
1.0fe
79.1co
1.6b
5.9after chemical ratios batching, pack into after vacuum melting furnace, furnace air is evacuated to 10
-3after Pa, start the melting of heating, and carry out rapid hardening rejection tablet through copper roller (linear resonance surface velocity 1.6m/s), obtain the thick rejection tablet of 0.2-0.30mm; Auxiliary alloy Cu
80.0sn
20.0after batching, pack in vaccum sensitive stove in proportion, furnace air is evacuated to 10
-3after Pa, start the melting of heating, when batching is rubescent in stove, close vacuum valve, applying argon gas, waits that raw material is molten to be poured into a mould after clear, prepares auxiliary alloy cast ingot.
(2) powder process: the powder process respectively of master alloying and auxiliary alloy, master alloying Nd
10.45pr
1.95dy
1.0fe
79.1co
1.6b
5.9rapid hardening rejection tablet, carry out coarse crushing, the Nd of coarse crushing by hydrogen quick-fried (HD) process
10.45pr
1.95dy
1.0fe
79.1co
1.6b
5.9alloy is considered to be worth doing through airflow milling operation, and making average particle size particle size is the master alloying powder of 3.0 μ m; Cu
80.0sn
20.0auxiliary alloy pig carries out ball milling powder process after the fragmentation of Hubei Province at disintegrating machine, ball powder ratio 10:1, and rotating speed 300r/min, ball milling 48 h, making average particle size particle size is the auxiliary alloyed powder of 2.0 μ m.
(3) mixed powder: after powder process completes, join in master alloying together with the gasoline of the auxiliary alloy of 0.5 wt% and 1.0 wt.%, mix 2.0 h on batch mixer, obtain the finely dispersed mixed powder of auxiliary alloyed powder.
(4) moulding: the powder mixing is placed on the press with magnetic field, be orientated compacting, alignment magnetic field 2.0 T, pressing pressure 200MPa, obtains closely knit pressed compact, said process completes in the glove box that seals and be filled with nitrogen completely, afterwards pressed compact is carried out to Vacuum Package, put into band and be full of the magazine of machine oil, and on press, wait static pressure compacting, pressure used is 195 MPa, obtains closely knit briquetting.
(5) sintering: it is 10 that briquetting is put into vacuum degree
-4in pa high vacuum sintering furnace, carry out sintering, 1070 DEG C of sintering temperatures, temperature retention time 3.0h, passes into afterwards argon gas and carries out rapid cooling, and initial cooling rate is 200 DEG C/min, obtains neodymium iron boron magnetic body.
(6) heat treatment: sintered magnet is placed in vacuum annealing furnace, is heated to 880 DEG C of insulation 2.0 h, pass into argon gas in backward tempering furnace magnet fast cooling is caused to room temperature; And then be warming up to 460 DEG C of second annealings that carry out 2.0 h, finally prepare the crystal boundary modified Sintered NdFeB magnet of magnesium copper alloy.
comparative example 1:
Adopt traditional preparation method to prepare component prescription identical with embodiment 1 without the crystal boundary modified sintered magnet of signal bronze, in comparative example 1, copper, tin element add in melting link, its melting rejection tablet, hydrogen be quick-fried-airflow milling, magnetic field orientating moulding, sintering and heat treated preparation technology parameter and example 1 in master alloying Nd
10.45pr
1.95dy
1.0fe
79.1co
1.6b
5.9preparation process in parameter identical.
Adopt PCT-30-2 high pressure accelerated life test machine to measure the weightlessness that magnet (1 × 1 × 0.5cm) is placed 200 h in 120 DEG C, 2 atm, 100% relative humidity environment, adopt CHI660D electrochemical workstation to measure magnet at the 0.1 M HNO of 25 DEG C
3corrosion electric current density in solution, result is as shown in table 1.
Weightlessness and the acid etching test data of table 1. example 1 and comparative example
| ? | Quality (mg) before test | Quality (mg) after test | Mass loss (mg/cm 2) | Corrosion electric current density (mA/cm 2) |
| Embodiment 1 | 3778 | 3775 | 0.75 | 0.2 |
| Comparative example 1 | 3770 | 3752 | 4.5 | 2.3 |
The data of contrast table 1 are known, and the mass loss of the crystal boundary modified sintered magnet of signal bronze and corrosion electric current density are lower than the respective value of magnet in comparative example, and the mass loss of embodiment 1 is lower than 1.0 mg/cm
2, corrosion electric current density is less than 0.5mA/cm
2, all reduced an order of magnitude than the respective value of comparative example 1.
Fig. 1 is the Cu of the embodiment of the present invention 1
80.0sn
20.0addition be 0.5 wt.% sintered NdFeB in 120 DEG C, 2 atm, 100% relative humidity environment, corrode the surface topography after 200 h.As seen from Figure 1: the magnet of example 1 is in hygrothermal environment after long-time accelerated corrosion, and obvious corrosion pit does not appear in material surface, show to adopt the crystal boundary modified sintered NdFeB of signal bronze to have good antioxidant anticorrosive ability.
Fig. 2 is the Cu of the embodiment of the present invention 1
80.0sn
20.0addition be 0.5 wt.% sintered NdFeB at the 0.1 M HNO of 25 DEG C
3corrosion polarization curve in solution.As seen from Figure 2: the magnet of example 1 is little at strong acid electrolyte environment corrosion electric current density, show to adopt the crystal boundary modified sintered NdFeB of signal bronze to have good antiacid electrochemical corrosion ability.
embodiment 2:
(1) melting: master alloying and auxiliary alloy are prepared respectively, master alloying Nd
11.2pr
2.5dy
1.0fe
78.3co
1.0b
6.0after chemical ratios batching, pack into after vacuum melting furnace, furnace air is evacuated to 10
-3after Pa, start the melting of heating, and carry out rapid hardening rejection tablet through copper roller (linear resonance surface velocity 1.8m/s), obtain the thick rejection tablet of 0.2-0.3mm; Auxiliary alloy Cu
54.5sn
45.5after batching, pack in vaccum sensitive stove in proportion, furnace air is evacuated to 10
-3after Pa, start the melting of heating, when batching is rubescent in stove, close vacuum valve, applying argon gas, waits that material is molten to be poured into a mould after clear, prepares auxiliary alloy cast ingot.
(2) powder process: the powder process respectively of master alloying and auxiliary alloy, master alloying Nd
11.2pr
2.5dy
1.0fe
78.3co
1.0b
6.0rapid hardening rejection tablet, carry out coarse crushing, the Nd of coarse crushing by hydrogen quick-fried (HD) process
11.2pr
2.5dy
1.0fe
78.3co
1.0b
6.0alloy is considered to be worth doing through airflow milling operation, and making average particle size particle size is the master alloying powder of 3.0 μ m; Cu
54.5sn
45.5auxiliary alloy pig carries out ball milling powder process after the fragmentation of Hubei Province at disintegrating machine, ball powder ratio 10:1, and rotating speed 280 r/min, ball milling 36 h, making average particle size particle size is the auxiliary alloyed powder of 2.0 μ m.
(3) mixed powder: after powder process completes, join in master alloying together with the gasoline of the auxiliary alloy of 1.0 wt% and 1.0 wt.%, mix 2.0 h on batch mixer, obtain the finely dispersed mixed powder of auxiliary alloyed powder.
(4) moulding: the powder mixing is placed on the press with magnetic field, be orientated compacting, alignment magnetic field 2.0 T, pressing pressure 200MPa, obtains closely knit pressed compact, said process completes in the glove box that seals and be filled with nitrogen completely, afterwards pressed compact is carried out to Vacuum Package, put into band and be full of the magazine of machine oil, and on press, wait static pressure compacting, pressure used is 210 MPa, obtains closely knit briquetting.
(5) sintering: it is 10 that briquetting is put into vacuum degree
-4in pa high vacuum sintering furnace, carry out sintering, 1090 DEG C of sintering temperatures, temperature retention time 3.0h, passes into afterwards argon gas and carries out rapid cooling, and initial cooling rate is 200 DEG C/min, obtains neodymium iron boron magnetic body.
(6) heat treatment: sintered magnet is placed in vacuum annealing furnace, is heated to 900 DEG C of insulation 2.0 h, pass into argon gas in backward tempering furnace magnet fast cooling is caused to room temperature; And then be warming up to 500 DEG C of second annealings that carry out 2.0 h, finally prepare the crystal boundary modified Sintered NdFeB magnet of magnesium copper alloy.
comparative example 2:
Adopt traditional preparation method to prepare component prescription identical with embodiment 2 without the crystal boundary modified sintered magnet of signal bronze, in comparative example 2, copper, tin element add in melting link, its melting rejection tablet, hydrogen be quick-fried-airflow milling, magnetic field orientating moulding, sintering and heat treated preparation technology parameter and example 2 in master alloying Nd
11.2pr
2.5dy
1.0fe
78.3co
1.0b
6.0preparation process in parameter identical.
Adopt PCT-30-2 high pressure accelerated life test machine to measure the weightlessness that magnet (1 × 1 × 0.5 cm) is placed 200h in 120 DEG C, 2 atm, 100% relative humidity environment, adopt CHI660D electrochemical workstation to measure magnet at the 0.1 M HNO of 25 DEG C
3corrosion electric current density in solution, result is as shown in table 2.
Weightlessness and the acid etching test data of table 2. example 2 and comparative example
| ? | Quality (mg) before test | Quality (mg) after test | Mass loss (mg/cm 2) | Corrosion electric current density (mA/cm 2) |
| Embodiment 2 | 3775 | 3770 | 1.25 | 0.4 |
| Comparative example 2 | 3764 | 3680 | 21 | 4.5 |
The data of contrast table 2 are known, and the mass loss of the crystal boundary modified sintered magnet of signal bronze is lower than the respective value of magnet in comparative example, and the mass loss of embodiment 2 is lower than 1.5 mg/cm
2, corrosion electric current density is less than 0.5 mA/cm
2, all reduced an order of magnitude than the analog value of comparative example 2.
embodiment 3:
(1) melting: master alloying and auxiliary alloy are prepared respectively, master alloying Nd
9.5pr
2.8ho
2.5fe
77.1co
2.0b
6.1after chemical ratios batching, pack into after vacuum melting furnace, furnace air is evacuated to 10
-3after Pa, start the melting of heating, and carry out rapid hardening rejection tablet through copper roller (linear resonance surface velocity 2.0 m/s), obtain the thick rejection tablet of 0.2-0.35mm; Auxiliary alloy Cu
85.0sn
15.0after batching, pack in vaccum sensitive stove in proportion, furnace air is evacuated to 10
-3after Pa, start the melting of heating, when batching is rubescent in stove, close vacuum valve, applying argon gas, waits that material is molten to be poured into a mould after clear, prepares auxiliary alloy cast ingot.
(2) powder process: the powder process respectively of master alloying and auxiliary alloy, master alloying Nd
9.5pr
2.8ho
2.5fe
77.1co
2.0b
6.1rapid hardening rejection tablet, carry out coarse crushing, the Nd of coarse crushing by hydrogen quick-fried (HD) process
9.5pr
2.8ho
2.5fe
77.1co
2.0b
6.1alloy is considered to be worth doing through airflow milling operation, and making average particle size particle size is the master alloying powder of 3.0 μ m; Cu
54.5sn
45.5auxiliary alloy pig carries out ball milling powder process after the fragmentation of Hubei Province at disintegrating machine, ball powder ratio 10:1, and rotating speed 300r/min, ball milling 48 h, making average particle size particle size is the auxiliary alloyed powder of 2.0 μ m.
(3) mixed powder: after powder process completes, join in master alloying together with the gasoline of the auxiliary alloy of 0.9 wt% and 1.5 wt.%, mix 2.0 h on batch mixer, obtain the finely dispersed mixed powder of auxiliary alloyed powder.
(4) moulding: the powder mixing is placed on the press with magnetic field, be orientated compacting, alignment magnetic field 1.8 T, pressing pressure 210MPa, obtains closely knit pressed compact, said process completes in the glove box that seals and be filled with nitrogen completely, afterwards pressed compact is carried out to Vacuum Package, put into band and be full of the magazine of machine oil, and on press, wait static pressure compacting, pressure used is 220 MPa, obtains closely knit briquetting.
(5) sintering: it is 10 that briquetting is put into vacuum degree
-4in pa high vacuum sintering furnace, carry out sintering, 1100 DEG C of sintering temperatures, temperature retention time 2.5h, passes into afterwards argon gas and carries out rapid cooling, and initial cooling rate is 200 DEG C/min, obtains neodymium iron boron magnetic body.
(6) heat treatment: sintered magnet is placed in vacuum annealing furnace, is heated to 890 DEG C of insulation 2.0 h, pass into argon gas in backward tempering furnace magnet fast cooling is caused to room temperature; And then be warming up to 580 DEG C of second annealings that carry out 2.0 h, finally prepare the crystal boundary modified Sintered NdFeB magnet of magnesium copper alloy.
comparative example 3:
Adopt traditional preparation method to prepare component prescription identical with embodiment 3 without the crystal boundary modified sintered magnet of signal bronze, in comparative example 3, copper, tin element add in melting link, its melting rejection tablet, hydrogen be quick-fried-airflow milling, magnetic field orientating moulding, sintering and heat treated preparation technology parameter and example 3 in master alloying Nd
9.5pr
2.8ho
2.5fe
77.1co
2.0b
6.1preparation process in parameter identical.
Adopt PCT-30-2 high pressure accelerated life test machine to measure the weightlessness that magnet (1 × 1 × 0.5 cm) is placed 200h in 120 DEG C, 2 atm, 100% relative humidity environment, adopt CHI660D electrochemical workstation to measure magnet at the 0.1 M HNO of 25 DEG C
3corrosion electric current density in solution, result is as shown in table 3.
Weightlessness and the acid etching test data of table 3. example 3 and comparative example
| ? | Quality (mg) before test | Quality (mg) after test | Mass loss (mg/cm 2) | Corrosion electric current density (mA/cm 2) |
| Embodiment 3 | 3776 | 3772 | 1.0 | 0.3 |
| Comparative example 3 | 3764 | 3618 | 11.5 | 3.7 |
The data of contrast table 3 are known, and the mass loss of the crystal boundary modified sintered magnet of signal bronze is lower than the respective value of magnet in comparative example, and the mass loss of embodiment 3 is lower than 1.5 mg/cm
2, corrosion electric current density is less than 0.5 mA/cm
2, all reduced an order of magnitude than the analog value of comparative example 3.
The application obtains the subsidy of Shandong Province's Natural Science Fund In The Light (ZR2013EMM010) and China's post-doctors science fund (2014M551899).
Finally it should be noted that, embodiment is the embodiment of optimum of the present invention, be not limited to the present invention, although the present invention is had been described in detail with reference to previous embodiment, for a person skilled in the art, its technical scheme that still can record aforementioned each embodiment is modified, or part technical characterictic is wherein equal to replacement.Within the spirit and principles in the present invention all, any amendment of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.
Claims (8)
1. the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin, is characterized in that,
General formula is (RE
xfe
100-x-y-zco
yb
z)
100-v(Cu
100-usn
u)
v; Wherein:
RE rare earth element comprises one or both elements in neodymium Nd and praseodymium Pr, dysprosium Dy, holmium Ho, cerium Ce, lanthanum La, terbium Tb, gadolinium Gd, and x is that RE rare earth element is at RE
xfe
100-x-y-zco
yatomic percent in B alloy, 12.7 at.%≤x≤15.5 at.%;
Y is that cobalt Co element is at RE
xfe
100-x-y-zco
yb
zatomic percent in alloy, 0.5 at.%≤y≤2.2 at.%;
Z is that boron element is at RE
xfe
100-x-y-zco
yb
zatomic percent in alloy, 5.5 at.%≤z≤6.5 at.%;
U is that Sn is at Cu
100-usn
uatomic percent in alloy, 14.9 at.%≤u≤45.5 at.%;
V is Cu
100-usn
uthe mass ratio of alloy in the whole material composition system of the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin, 0.1 wt.%≤v≤1.1wt.%.
2. the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin according to claim 1, it is characterized in that, the atomic percent that Nd in described RE rare earth element accounts for RE total amount is that 60-90%(is preferred, the atomic percent that Nd accounts for RE total amount is 73%-85%, be more preferably, the atomic percent that Nd accounts for RE total amount is 78%).
3. the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin according to claim 1, is characterized in that, preferred, 13.0 at.%≤x≤14.2 at.%, is more preferably, x=13.4 at.%.
4. the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin according to claim 1, is characterized in that, preferred, 1.0 at.%≤y≤1.8 at.%, is more preferably, y=1.6 at.%.
5. the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin according to claim 1, is characterized in that, preferred, 5.7 at.%≤z≤6.1 at.%, is more preferably, z=5.9 at.%.
6. the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin according to claim 1, is characterized in that, preferred, 15.2 at.%≤u≤23.5 at.%, is more preferably, u=20.0 at.%.
7. the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin according to claim 1, is characterized in that, preferred, 0.4 wt.%≤v≤0.7 wt.%, is more preferably, v=0.5 wt.%.
8. according to the preparation method of the arbitrary described crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin of claim 1-7, it is characterized in that, step is as follows:
Step 1: according to master alloying RE
xfe
100-x-y-zco
yb
zin composition proportion, weigh RE, Fe, Co and ferro-boron raw material, (in vacuum smelting fast solidification stove) prepares the rapid hardening strip of master alloying afterwards, and to strip carry out hydrogen quick-fried (HD) process obtain RE
xfe
100-x-y-zco
yb
zalloy bits, further adopt the method for airflow milling to make the master alloying powder that average particle size particle size is 1-5 μ m;
Step 2: according to auxiliary alloy Cu
100-usn
uin composition proportion, weigh Cu and Sn raw material, carry out vacuum melting at vacuum arc furnace ignition afterwards, first the raw material that weigh up are put into stove, vacuumize (to 10
-3pa), and pour high-purity argon, melt back 7 times, prepares the uniform Cu of composition
100-usn
ualloy pig, and carry out ball milling after coarse crushing, make auxiliary alloy powder (average particle size particle size be 1-3 μ m);
Step 3: step 1 and step 2 are prepared to RE
xfe
100-x-y-zco
yb
zmaster alloying and Cu
100-usn
uauxiliary alloyed powder takes according to the mass ratio of design, under the condition of argon shield, add batch mixer to enter middle row batch mixing, when batch mixing, add gasoline (gasoline consumption is the 0.5%-2.5 wt.% of alloy powder total weight percent), master alloying and auxiliary alloy mix that (time is 2.5 h), makes uniform mixed powder;
Step 4: the mixed powder that step 3 is prepared is orientated die mould in the magnetic field of 1.0-2.2 T, molding pressure is 150-210 MPa, obtain briquetting and on hydraulic press, carry out 190-230 MPa etc. static pressure, prepare closely knit pressed compact;
Step 5: it is 10 that the pressed compact that step 4 is prepared is put into vacuum degree
-4in pa high vacuum sintering furnace, carry out sintering, sintering temperature is 1040-1100 DEG C, and insulation 3.0-4.5h, passes into afterwards argon gas and carry out rapid cooling, and cooling rate is 200 DEG C/min, is cooled to room temperature and obtains neodymium iron boron magnetic body;
Step 6: the neodymium iron boron magnetic body that step 5 is prepared carries out second annealing heat treatment, first tempering 1.5-3.5 h in the temperature range of 830-920 DEG C, in backward tempering furnace, pass into argon gas magnet fast cooling to room temperature; And then be warming up to 420-630 DEG C of second annealing that carries out 2.0-3.5 h, prepare the crystal boundary modified Sintered NdFeB magnet against corrosion of copper tin of low weightlessness, resistance to acid attack.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104821218A (en) * | 2015-05-07 | 2015-08-05 | 安徽万磁电子有限公司 | Sintered Nd-Fe-B magnet with zinc-aluminum-titanium-cobalt composite additive and preparation method thereof |
| CN104952607A (en) * | 2015-06-16 | 2015-09-30 | 北京科技大学 | Manufacturing method of light rare earth-copper alloy NdFeB magnet with grain boundary being low melting point |
| CN106601401A (en) * | 2016-12-14 | 2017-04-26 | 中国工程物理研究院材料研究所 | Preparation method of high-abundance rare earth sintered neodymium-iron-boron magnet capable of regulating and controlling grain boundary multi-layer structure and product prepared by preparation method |
| CN106782974A (en) * | 2016-12-26 | 2017-05-31 | 浙江中科磁业有限公司 | A kind of preparation method of neodymium iron boron magnetic body |
| CN108281272A (en) * | 2018-01-16 | 2018-07-13 | 宁波招宝磁业有限公司 | A kind of preparation method of low-cost and high-performance Sintered NdFeB magnet |
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| CN109585113A (en) * | 2018-11-30 | 2019-04-05 | 宁波韵升股份有限公司 | A kind of preparation method of Sintered NdFeB magnet |
| CN110257724A (en) * | 2019-07-16 | 2019-09-20 | 宁德市星宇科技有限公司 | A kind of preparation method of the neodymium iron boron magnetic body containing lanthanum and cerium |
| CN110335733A (en) * | 2019-06-05 | 2019-10-15 | 宁波合力磁材技术有限公司 | A kind of neodymium iron boron magnetic body resistant to high temperature and preparation method thereof |
| CN111180190A (en) * | 2020-01-14 | 2020-05-19 | 江西理工大学 | Method for improving magnetic property of sintered neodymium-iron-boron magnet |
| CN114446628A (en) * | 2022-01-28 | 2022-05-06 | 中国第一汽车股份有限公司 | Soft magnetic composite material and preparation method and application thereof |
| CN114639540A (en) * | 2020-12-15 | 2022-06-17 | 太原理工大学 | Neodymium iron boron permanent magnet surface copper-infiltrated layer and preparation method thereof |
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| CN104952607A (en) * | 2015-06-16 | 2015-09-30 | 北京科技大学 | Manufacturing method of light rare earth-copper alloy NdFeB magnet with grain boundary being low melting point |
| CN106601401A (en) * | 2016-12-14 | 2017-04-26 | 中国工程物理研究院材料研究所 | Preparation method of high-abundance rare earth sintered neodymium-iron-boron magnet capable of regulating and controlling grain boundary multi-layer structure and product prepared by preparation method |
| CN106601401B (en) * | 2016-12-14 | 2018-04-03 | 中国工程物理研究院材料研究所 | Preparation method of high abundance rare earth Sintered NdFeB magnet of crystal boundary sandwich construction regulation and control and products thereof |
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| CN110335733A (en) * | 2019-06-05 | 2019-10-15 | 宁波合力磁材技术有限公司 | A kind of neodymium iron boron magnetic body resistant to high temperature and preparation method thereof |
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