Method for improving corrosion resistance of iron-based nanocrystalline alloy strip
阅读说明：本技术 一种提高铁基纳米晶合金带材耐蚀性的方法 (Method for improving corrosion resistance of iron-based nanocrystalline alloy strip ) 是由 邓毕力 王波 张朋 罗顶飞 潘振海 晋立从 徐敏义 王玉川 于 2020-07-17 设计创作，主要内容包括：本发明公开了一种提高铁基纳米晶合金带材耐蚀性的方法,属于软磁性材料技术领域。本发明方法首先利用快淬急冷技术将高温母合金熔体喷射到高速旋转的冷却铜辊上,然后将得到的软磁合金带材卷绕于导辊上并牵引带材一端使带材依次穿过盐浴池和加热装置分别进行盐浴加热处理和恒温加热处理,然后自然冷却收卷得到纳米晶合金带材。本发明方法中所采用的母合金原料的配方为：B:5～11％；Si:5.8～9.2％；Cu:0.6～1.4％；Nb:1.2～2.8％；Cr:1.2～2.0％；Mo:0.5～1.2％；Mn:0.8～2.0％；余量为Fe,其中,B和Si的质量百分比之和为14.2～16.8％；Cr和Mo的质量比为2:1。本发明方法通过优化合金元素成分、配比及热处理方式,可以在保持纳米晶合金带材优异的软磁性能的基础上大大提高纳米晶合金带材的耐蚀性。(The invention discloses a method for improving corrosion resistance of an iron-based nanocrystalline alloy strip, and belongs to the technical field of soft magnetic materials. The method comprises the steps of firstly spraying high-temperature master alloy melt onto a cooling copper roller rotating at a high speed by using a rapid quenching and quenching technology, then winding the obtained soft magnetic alloy strip on a guide roller, drawing one end of the strip to enable the strip to sequentially pass through a salt bath and a heating device to respectively carry out salt bath heating treatment and constant temperature heating treatment, and then naturally cooling and winding to obtain the nanocrystalline alloy strip. The formula of the master alloy raw material adopted in the method of the invention is as follows: 5-11% of B; 5.8 to 9.2 percent of Si; 0.6 to 1.4 percent of Cu; 1.2 to 2.8 percent of Nb; 1.2 to 2.0 percent of Cr; 0.5 to 1.2 percent of Mo; 0.8 to 2.0 percent of Mn; the balance of Fe, wherein the sum of the mass percentages of B and Si is 14.2-16.8%; the mass ratio of Cr to Mo is 2: 1. The method can greatly improve the corrosion resistance of the nanocrystalline alloy strip on the basis of keeping the excellent soft magnetic performance of the nanocrystalline alloy strip by optimizing the components, the proportion and the heat treatment mode of the alloy elements.)
1. A method for improving the corrosion resistance of an iron-based nanocrystalline alloy strip is characterized by comprising the following steps:
(1) adding alloy raw materials in a formula amount into a smelting furnace, preserving heat for 10-30 min at 1520-1560 ℃ after melting, adding a purifying agent, standing for many times, and slagging to finally enable all components in the alloy mother liquor to be uniformly distributed, wherein the respective contents of Al, O and N are below 10 ppm; the formula of the alloy raw materials is as follows: 5-11% of B; 5.8 to 9.2 percent of Si; 0.6 to 1.4 percent of Cu; 1.2 to 2.8 percent of Nb; 1.2 to 2.0 percent of Cr; 0.5 to 1.2 percent of Mo; 0.8 to 2.0 percent of Mn; the balance of Fe, wherein the percentages are calculated by the mass percent of the elements, and the sum of the mass percent of B and Si is 14.2-16.8%; the mass ratio of Cr to Mo is 2: 1;
(2) introducing alloy mother liquor in a smelting furnace into a tundish, sealing a water gap by using a stopper rod, and standing for 30-40 min to ensure that the temperature of the mother liquor is uniform;
(3) then the plug rod is lifted, the mother liquor enters a nozzle bag and is sprayed onto a cooling roller rotating at high speed through a nozzle, so that the alloy mother liquor is 10 degrees6～107Cooling and forming at the speed of 1350-1400 ℃ per sec to obtain a soft magnetic alloy strip;
(4) winding the alloy strip obtained in the step (3) on a guide roller, and then drawing one end of the alloy strip to enable the alloy strip to pass through a salt bath to be subjected to salt bath heating treatment, wherein the salt bath heating temperature is 450-550 ℃, and the salt bath heating time is 3-5 s;
(5) the alloy strip subjected to salt bath heating treatment passes through a heating device to be heated at a constant temperature of 400-450 ℃ for 5-15 s;
(6) and naturally cooling the alloy strip heated at the constant temperature, and rolling to obtain the nanocrystalline alloy strip.
2. The method according to claim 1, wherein the scavenger in the step (1) is composed of 50-55% of silica, 35-40% of calcium oxide, and 10-15% of mill scale.
3. The method of claim 1, wherein the nozzle slot width of step (3) is 80 to 200 μm; the distance between the nozzle and the cooling roller is 50-200 microns.
4. The method of claim 1, wherein the alloy strip in step (4) and step (5) moves at a speed of 0.2 to 0.5 m/s.
5. The method of claim 1, wherein the salt bath of step (4) is a mixture of NaNO3 and KNO3, wherein the mass ratio of NaNO3 to KNO3 is 0.8: 1.
Technical Field
The invention relates to a method for improving the corrosion resistance of an iron-based nanocrystalline alloy strip, belonging to the technical field of soft magnetic materials.
Background
The nano-crystalline soft magnetic material is a novel soft magnetic material developed on an amorphous soft magnetic matrix and consists of an amorphous matrix and ferromagnetic nano-crystalline grains. The iron-based nanocrystalline alloy is a novel soft magnetic alloy material with a nanocrystalline structure, which is obtained by firstly utilizing a rapid quenching technology to spray high-temperature master alloy melt onto a cooling copper roller rotating at a high speed, rapidly cooling and solidifying at a speed of up to a million degrees per second to form an amorphous alloy strip with a long-range disordered structure, and then precipitating a nanoscale magnetic alpha-iron phase through crystallization heat treatment.
The iron-based nanocrystalline material has excellent comprehensive magnetic properties of high saturation induction (1.6T) and high initial permeability (8 × 10)4) Low Hc (0.32A/M), low high frequency loss at high magnetic induction (P0.5T/20 kHz: 30W/kg), a resistivity of 80 μ Ω/cm, higher than permalloy (50-60 μ Ω/cm), and high Br (0.9) or low Br value (1000Gs) after longitudinal or transverse magnetic field treatment. The material with the best comprehensive performance in the current market has the following optimal frequency range: 20kHz-50 kHz. The high-frequency inductor core is widely applied to high-power switching power supplies, inverter power supplies, magnetic amplifiers, high-frequency transformers, high-frequency converters, high-frequency choke coil cores, current transformer cores, leakage protection switches and common-mode inductor cores.
The nanocrystalline alloy strip is often required to be rolled and stacked into a plurality of layers and then used for magnetic heads, transformers, choke coils, high-efficiency motors, reactors and the like, and thus higher requirements are put forward on the corrosion resistance of the nanocrystalline alloy strip. The conventional corrosion resisting method such as coating the corrosion resisting paint can not only influence the soft magnetic performance of the nanocrystalline alloy strip material, but also the thickness of the nanocrystalline alloy strip material is increased due to the existence of the coating, and the total thickness after the nanocrystalline alloy strip material is coiled into multiple layers is far larger than the thickness without the coating. Therefore, how to make the nanocrystalline alloy strip have excellent corrosion resistance on the basis of maintaining the excellent soft magnetic performance of the nanocrystalline alloy strip is a problem to be solved urgently at present.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a method for improving the corrosion resistance of an iron-based nanocrystalline alloy strip.
In order to achieve the technical purpose, the technical scheme of the invention is as follows:
a method for improving the corrosion resistance of an iron-based nanocrystalline alloy strip comprises the following steps:
(1) adding alloy raw materials in a formula amount into a smelting furnace, preserving heat for 10-30 min at 1520-1560 ℃ after melting, adding a purifying agent, standing for many times, and slagging to finally enable all components in the alloy mother liquor to be uniformly distributed, wherein the respective contents of Al, O and N are below 10 ppm; the formula of the alloy raw materials is as follows: 5-11% of B; 5.8 to 9.2 percent of Si; 0.6 to 1.4 percent of Cu; 1.2 to 2.8 percent of Nb; 1.2 to 2.0 percent of Cr; 0.5 to 1.2 percent of Mo; 0.8 to 2.0 percent of Mn; the balance of Fe, wherein the percentages are calculated by the mass percent of the elements, and the sum of the mass percent of B and Si is 14.2-16.8%; the mass ratio of Cr to Mo is 2: 1;
(2) introducing alloy mother liquor in a smelting furnace into a tundish, sealing a water gap by using a stopper rod, and standing for 30-40 min to ensure that the temperature of the mother liquor is uniform;
(3) then the plug rod is lifted, the mother liquor enters a nozzle bag and is sprayed onto a cooling roller rotating at high speed through a nozzle, so that the alloy mother liquor is 10 degrees6～107Cooling and forming at the speed of 1350-1400 ℃ per sec to obtain a soft magnetic alloy strip;
(4) winding the alloy strip obtained in the step (3) on a guide roller, and then drawing one end of the alloy strip to enable the alloy strip to pass through a salt bath to be subjected to salt bath heating treatment, wherein the salt bath heating temperature is 450-550 ℃, and the salt bath heating time is 3-5 s;
(5) the alloy strip subjected to salt bath heating treatment passes through a heating device to be heated at a constant temperature of 400-450 ℃ for 5-15 s;
(6) and naturally cooling the alloy strip heated at the constant temperature, and rolling to obtain the nanocrystalline alloy strip.
Preferably, the purifying agent in the step (1) consists of 50-55% of silicon dioxide, 35-40% of calcium oxide and 10-15% of iron scale.
Preferably, the width of the nozzle seam in the step (3) is 80-200 microns; the distance between the nozzle and the cooling roller is 50-200 microns.
Preferably, the moving speed of the alloy strip in the step (4) and the step (5) is 0.2-0.5 m/s.
Preferably, the salt bath in the step (4) adopts NaNO3And KNO3In which NaNO is present3And KNO3The mass ratio of (A) to (B) is 0.8: 1.
From the above description, it can be seen that the present invention has the following advantages:
(1) by designing the components of the nanocrystalline alloy elements and optimizing the proportion of the components, the method can greatly improve the corrosion resistance of the nanocrystalline alloy strip on the basis of keeping the excellent soft magnetic performance of the nanocrystalline alloy strip.
(2) According to the invention, through improving the heat treatment mode, the salt bath is adopted to carry out heat treatment on the amorphous alloy base material in the nanocrystalline alloy before constant-temperature heating, so that not only can double-sided rapid heating of the amorphous alloy base material be realized, the heat treatment time be greatly reduced, but also the surface passivation of the amorphous alloy base material can be realized, the alloy surface oxidation in the subsequent constant-temperature heating process can be effectively prevented, the corrosion resistance of the nanocrystalline alloy strip is greatly improved, and meanwhile, the protective gas is not required to be introduced or only a small amount of protective gas is required to be introduced in the subsequent constant-temperature heating process.
Detailed Description
The present invention will be described in detail with reference to the following examples and test examples, but the present invention is not limited to the claims.