A metal magnetic grating material, its preparation method and application

Abstract

The present invention discloses a metal magnetic grating material, a preparation method thereof and an application. The metal magnetic grating material comprises a stainless steel base layer, a buffer layer, a FeCoCr nano-film layer and a protective layer which are arranged in sequence. The buffer layer is composed of TiAl. The surface roughness Ra of the stainless steel base is 0.1 - 0.2; the thickness of the buffer layer is 100 - 500 nm; the thickness of the FeCoCr nano-film layer is 200 nm - 500 nm. The metal magnetic grating material provided by the present invention has good mechanical properties and magnetic properties, and the preparation process is simple, having broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic materials, and relates to a metal magnetic grating material, a preparation method thereof, and an application thereof. Background Art

[0002] An encoder is a device that converts angular displacement or linear displacement into an electrical signal, and is widely used in industries such as mechanical automation. Encoders are mainly divided into two categories: magnetic encoders and optical encoders. Compared with optical encoders, magnetic encoders have better anti-vibration, anti-corrosion, anti-pollution, anti-interference, and wide-temperature characteristics, and their stability is particularly prominent in harsh environments. A magnetic encoder mainly consists of a magnetoresistive sensor, a magnetic grating, a signal processing circuit, a main body structure, etc. Among them, the magnetic grating material is used for magnetic signal writing, and its magnetic properties are the key to determining the accuracy of the magnetic encoder. At present, improving the accuracy of the encoder undoubtedly puts forward higher requirements for the performance of the magnetic grating material. The magnetic properties of the magnetic grating material directly affect the storage density and stability of the magnetic encoder. Commonly used magnetic grating materials in the past were injection-molded ferrite or rubber ferrite. In order to improve the magnetic recording density, deformable iron-cobalt-chromium permanent magnet alloys, etc. were developed later. In order to further improve the magnetic recording density of the magnetic grating, some people have studied and developed making bulk materials into thin film materials. In the prior art, by using single-crystalline silicon as a substrate and depositing an iron-cobalt-chromium thin film on the single-crystalline silicon, the performance of the material is improved; however, in the application scenario of a high-precision magnetic encoder, usually the magnetic grating is directly installed on a high-speed rotating main shaft. If the thin film magnetic grating with single-crystalline silicon as the substrate is directly installed on the high-speed rotating main shaft, it may cause the single-crystalline silicon to break, which is not conducive to practical applications. Summary of the Invention

[0003] The technical problem solved by the present invention is that the thin film magnetic grating material with single-crystalline silicon as the substrate in the prior art has insufficient strength in practical applications, which in turn affects the magnetic properties of the material.

[0004] To solve the above technical problem, the present invention provides the following technical solutions:

[0005] The present invention provides a metal magnetic grating material, which includes a stainless steel base layer, a buffer layer, an FeCoCr nano-film layer (i.e., a magnetic layer), and a protective layer arranged in sequence. The buffer layer is composed of TiAl. The surface roughness Ra of the stainless steel substrate is 0.1 - 0.2; the thickness of the buffer layer is 100 - 500 nm; the thickness of the FeCoCr nano-film layer is 200 nm - 500 nm. Since the thickness of the magnetic layer (FeCoCr) is in the nanometer order, it has very high requirements for the flatness of the substrate. Therefore, it is necessary to make the surface of the stainless steel substrate as flat as possible. At the same time, the flatness of the substrate cannot fully meet the requirements of the material, and a buffer layer with a certain thickness is also required to ensure the flatness and uniformity of the magnetic layer. And if the thickness of the buffer layer is not enough, it cannot offset the influence of the substrate roughness. Therefore, choosing a buffer layer with an appropriate thickness is beneficial to the flatness of the material and also beneficial to the stability of the subsequent device made of the material.

[0006] The metal magnetic grating material provided by the present invention uses a TiAl layer as the buffer layer and adopts a structure of stainless steel substrate / TiAl / FeCoCr / Ta. In this type of structure, with stainless steel as the substrate, it can effectively improve the mechanical strength of the magnetic grating material and enhance the reliability and durability of the material. The use of the TiAl alloy nano-buffer layer can provide a better flatness for the FeCoCr nano-film. At the same time, its thermal expansion coefficient is quite similar to that of FeCoCr, which can reduce the stress that may be generated during annealing, thereby ensuring that the material has good magnetic properties. The selection of the buffer layer in the present invention is specifically chosen in combination with the characteristics of the FeCoCr material, and not any buffer layer can meet the usage requirements.

[0007] Optionally, the structure of the metal magnetic grating material is stainless steel base layer / TiAl buffer layer / FeCoCr magnetic layer / Ta protective layer; the stainless steel is selected from 314 stainless steel, and the thickness of the Ta protective layer is 10 nm.

[0008] Optionally, in the FeCoCr nano-film layer, the weight percentage of Fe:Co:Cr is 45:30:25.

[0009] Furthermore, the present invention also provides a preparation method of a metal magnetic grating material, including:

[0010] Step S1: Using a magnetron sputtering device, depositing a TiAl buffer layer on the stainless steel base layer by DC sputtering to obtain a first intermediate material;

[0011] Step S2: Depositing an FeCoCr nano-film layer on the first intermediate material by DC sputtering to obtain a second intermediate material;

[0012] Step S3: Depositing a protective layer on the second intermediate material by DC sputtering to obtain a third intermediate material;

[0013] Step S4: Perform vacuum annealing on the third intermediate material to obtain a metal magnetic grating material for a magnetic encoder.

[0014] The method for preparing the metal magnetic grating material provided by the present invention has the advantages of simple preparation process, simple control, high efficiency and low cost.

[0015] Optionally, the reaction conditions of the magnetron sputtering method in steps S1 - S3 include: the pressure is 0.2 Pa to 0.4 Pa, and the vacuum degree of the sputtering chamber is 1×10 -5 Pa to 3×10 -5 Pa.

[0016] Optionally, the deposition time in step S1 is 10 min to 70 min.

[0017] Optionally, the deposition time in step S2 is 30 min to 80 min.

[0018] Optionally, the deposition time in step S3 is 50 s to 90 s.

[0019] Optionally, the reaction conditions for vacuum annealing in step S4 include: the annealing temperature is 645 °C to 655 °C, preferably 650 °C; the annealing time is 30 min to 60 min, preferably 30 min; the vacuum degree is 4×10 -5 Pa to 5×10 -5 Pa.

[0020] Furthermore, the present invention also provides an application of a metal magnetic grating material and / or the metal magnetic grating prepared by the above method in the preparation of a magnetic encoder.

[0021] The above technical solutions provided by the embodiments of the present invention have at least the following beneficial effects:

[0022] For the metal magnetic grating material provided by the present invention, with the TiAl layer as the buffer layer and adopting the structure of 314 stainless steel substrate / TiAl / FeCoCr / Ta, by using 314 stainless steel as the substrate and TiAl as the buffer layer, a buffer layer and a Ta protective layer are respectively arranged on both sides of the FeCoCr magnetic layer, which can significantly improve the mechanical strength of the magnetic material, and can reduce the stress that may be generated during annealing, ensuring the magnetic properties of the metal magnetic grating material. The obtained material can fully meet the performance requirements of this type of magnetic material in the actual application process.

[0023] In the present invention, by successively adopting a preparation method of magnetron sputtering and vacuum annealing, and strictly controlling the process parameters of the magnetron sputtering and vacuum annealing processes, the prepared metal magnetic grating material has good performance. The coercivity of the metal magnetic grating material is above 500 Oe, and the remanence is above 0.3 T, which can meet the actual application requirements of the magnetic grating. Moreover, the preparation method of the metal magnetic grating provided by the present invention has the effects of simple preparation process, easy control, high efficiency and low cost. Detailed Embodiments

[0024] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to specific embodiments. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Example 1

[0026] In this example, the specific process of preparing the metal magnetic grating material includes:

[0027] S1. Prepare a 314 stainless steel substrate. In a magnetron sputtering device, using the DC sputtering method, deposit a TiAl buffer layer on the substrate under a vacuum degree of 3×10 -5 Pa for 10 minutes.

[0028] S2. Using the DC sputtering method, further deposit an FeCoCr nanometer thin film layer on the TiAl buffer layer under a vacuum degree of 3×10 -5 Pa for 30 minutes.

[0029] S3. Using the DC sputtering method, further deposit a Ta protective layer on the FeCoCr nanometer thin film layer under a vacuum degree of 3×10 -5 Pa for 50 seconds.

[0030] S4. After the deposition step is completed, perform vacuum annealing treatment on the material obtained in step S3 above. Among them, the annealing temperature is 650 °C, the annealing time is 30 minutes, and the vacuum degree of the annealing environment is 5×10 -5 Pa.

[0031] That is, a metal magnetic grating material with a structure of 314 stainless steel / TiAl(100 nm) / FeCoCr(200 nm) / Ta(10 nm) is obtained.

[0032] The coercivity of the metal magnetic grating material prepared in this example is 800 Oe, and the remanence is 0.3 T.

[0033] Due to the complex control of the phase composition of the FeCoCr material, it is usually difficult to simultaneously obtain an ideal structure with a very uniform distribution of soft magnetic and hard magnetic phases, resulting in the often difficult co - consideration of the coercivity and remanence of the FeCrCo alloy. When the coercivity is within 3000 Oe, the greater the coercivity, the better. And the remanence is the greater the better, which is beneficial to the subsequent signal reading.

[0034] Example 2

[0035] In this example, the specific process for preparing the metal magnetic grating material includes:

[0036] S1. Prepare a 314 stainless - steel substrate. In a magnetron sputtering device, using the DC sputtering method, deposit a TiAl buffer layer on the substrate at a vacuum degree of 3×10 -5 Pa for 10 min.

[0037] S2. Using the DC sputtering method, further deposit a FeCoCr nano - thin film layer on the TiAl buffer layer at a vacuum degree of 3×10 -5 Pa for 45 min.

[0038] S3. Using the DC sputtering method, further deposit a Ta protective layer on the FeCoCr nano - thin film layer at a vacuum degree of 3×10 -5 Pa for 50 s.

[0039] S4. After the deposition step is completed, perform vacuum annealing treatment on the material obtained in step S3 above. Among them, the annealing temperature is 650 °C, the annealing time is 30 min, and the vacuum degree of the annealing environment is 5×10 -5 Pa.

[0040] That is, a metal magnetic grating material with a structure of 314 stainless - steel / TiAl(100 nm) / FeCoCr(300 nm) / Ta(10 nm) is obtained.

[0041] The coercivity of the metal magnetic grating material prepared in this example is 940 Oe, and the remanence is 0.34 T.

[0042] Comparative Example 1

[0043] Other conditions are the same as those in Example 1, except that the buffer layer is not set. At this time, the coercivity of the obtained metal magnetic grating material is about 400 Oe, and the remanence is 0.17 T.

[0044] Comparative Example 2

[0045] Other conditions are the same as those in Example 1, except that the buffer layer is Cr. At this time, the coercivity of the obtained metal magnetic grating material is about 380 Oe, and the remanence is 0.16 T.

[0046] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A metal magnetic grating material, characterized in that, It includes a stainless steel base layer, a buffer layer, a FeCoCr nano-film layer, and a protective layer arranged in sequence. The buffer layer is composed of TiAl. The surface roughness Ra of the stainless steel base is 0.1 - 0.2; the thickness of the buffer layer is 100 - 500 nm; the thickness of the FeCoCr nano-film layer is 200 nm - 500 nm; The structure of the metal magnetic grating material is stainless steel base layer / TiAl buffer layer / FeCoCr magnetic layer / Ta protective layer; the stainless steel is selected from 314 stainless steel, and the thickness of the Ta protective layer is 10 nm; In the FeCoCr nano-film layer, the weight percentage of Fe:Co:Cr is 45:30:

25.

2. The preparation method of the metal magnetic grating material according to claim 1, characterized in that It includes: Step S1: Using a magnetron sputtering device, depositing a TiAl buffer layer on the stainless steel base layer by DC sputtering to obtain a first intermediate material; Step S2: Depositing a FeCoCr nano-film layer on the first intermediate material by DC sputtering to obtain a second intermediate material; Step S3: Depositing a protective layer on the second intermediate material by DC sputtering to obtain a third intermediate material; Step S4: Performing vacuum annealing treatment on the third intermediate material to obtain the metal magnetic grating material for a magnetic encoder; The reaction conditions of the magnetron sputtering method in steps S1 - S3 include: the pressure is 0.2 Pa to 0.4 Pa, and the vacuum degree of the sputtering chamber is 1×10 -5 Pa to 3×10 -5 Pa; The deposition time in Step S1 is 10 min - 70 min; the deposition time in Step S2 is 30 min - 80 min; the deposition time in Step S3 is 50 s - 90 s; The reaction conditions for vacuum annealing in step S4 include: the annealing temperature is 645°C to 655°C, the annealing time is 30 min to 60 min; the vacuum degree is 4×10 -5 Pa to 5×10 -5 Pa.

3. Application of the metal magnetic grating material according to Claim 1 or the metal magnetic grating material prepared by the method according to Claim 2 in the preparation of a magnetic encoder.