Method for preparing nano-porous alloy by femtosecond laser

Abstract

The invention discloses a method for preparing a nano-porous alloy by femtosecond laser. The method comprises the following steps: proportioning and weighing high-purity raw materials according to alloy components; the preparation method comprises the following steps: preparing a precursor master alloy ingot by using a vacuum arc melting or induction melting technology, and then cutting / cold-rolling the master alloy ingot or preparing the master alloy ingot into an alloy strip as a precursor alloy by using a melt rapid quenching technology; and carrying out irradiation treatment on the precursor alloy by adopting a femtosecond laser, and meanwhile, carrying out purging protection in a flow velocity range of 0-20 m / s under the assistance of 0.1-0.15 MPa high-purity Ar or N2 gas, so as to obtain the nano-porous alloy material. According to the method, the composition and morphology of the nano material can be effectively regulated and controlled, and the requirements of traditional nano porous metal preparation processes such as a dealloying method and a deposition method on the chemical stability of the precursor can be met; the prepared nano-porous alloy materials such as Cu, Ti, Zr, Mn and Al with active chemical activity are expected to be applied to the fields of adsorption, filtration, catalysis, engineering processing and the like.

Description

Technical Field

[0001] The invention relates to the technical field of new materials, and in particular to a method for preparing nano porous alloy using femtosecond laser. Background Art

[0002] Nanoporous metal is a new type of functional material composed of nanopores and metal ligaments. It has the characteristics of porous materials, metal materials and nanomaterials, and has application prospects in medicine, catalysis, separation, sensors, electronics, optics, microfluidics and micromechanics. At present, the main ways to prepare nanoporous metal materials are: metal powder sintering method, template method, Layer-by-Layer self-assembly technology, deposition method and dealloying method.

[0003] Femtosecond laser is a pulse laser with a duration of femtosecond (fs) level. It has the characteristics of short pulse, high energy and high peak power. It has broad application prospects in various fields such as environment, information, medical treatment, national defense and industry. In terms of material processing, the high frequency and high resolution characteristics of femtosecond laser make it have little impact on the surrounding materials. It can safely realize micro-area cladding, cutting, drilling, engraving and heat treatment processes, making it widely used in material additive manufacturing, surface modification, nanomaterial processing and integrated circuit etching, etc. However, there are no reports on the preparation of nanoporous metals.

[0004] The present invention combines the high energy density, high processing precision and cladding and etching processing characteristics of femtosecond lasers for alloy materials, and proposes the idea of ​​processing nanoporous metals using Si-based alloys as precursors and femtosecond lasers. The design concept of the present invention is similar to the demolding process of preparing nanoporous materials by the template method. The principle is to use the radiation difference between Si single substance and its oxide and metal materials to rapidly volatilize Si-based materials under the action of laser, and the remaining metal alloy is rapidly cooled under the condition of high-speed purge of inert gas to form metal ligaments. At the same time, as the processing depth increases, the internal volatile gas continues to overflow and prevents the closure of metal pores, thereby activating the process of nanoporous materials with connectivity characteristics. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing nanoporous alloy by femtosecond laser to solve the above technical problems.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: A method for preparing nanoporous alloy by femtosecond laser comprises the following steps: Step 1, weighing the high-purity raw materials according to the alloy composition; Step 2: Prepare a precursor master alloy ingot by vacuum arc melting or induction melting technology, and then cut / cold-roll the master alloy ingot to less than 0.5 mm or use melt rapid quenching technology to make an alloy strip with a thickness of 10-20 μm as a precursor alloy; Step 3: The precursor alloy is irradiated with a femtosecond laser, and purged with 0.1-0.15 MPa high-purity Ar or N2 gas at a flow rate of 0-20 m / s to obtain a nanoporous alloy material.

[0007] As a further embodiment of the present invention, the step 1 uses high-purity raw materials such as Si, Fe, Co, Y, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Hf, Ta, W, Al, B and C with a purity greater than 99 wt.% according to M a Si b O c X d , where M = Fe, Co, Y, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Hf, Ta, W, Al; X = B, C, O, P; a, b, c and d represent the atomic percentage of the corresponding elements, respectively, satisfying 10 ≤ a ≤ 50, 20≤ b ≤ 80, 0≤ c ≤ 35, 0≤ d ≤ 35, and a + b + c +d = 100 nominal composition for proportioning, where O and P elements are respectively made using metal oxides with fixed ratios and Fe-P / Ni-P binary alloys.

[0008] As a further embodiment of the present invention, the size of the precursor flake is less than 1 mm; and the irradiation power of the femtosecond laser is 40-80 .

[0009] As a further solution of the present invention, in an atmospheric environment and at a low flow rate, with a purge flow rate of ≤3 m / s, nanowires composed of SiO2 and metal materials are obtained on the surface of the precursor alloy; when the purge flow rate is around 3-9 m / s, Si nanowires and nanoporous materials with different morphological characteristics are obtained; when the purge speed is above 10 m / s, a nanoporous material composed of an alloy is obtained.

[0010] Compared with the prior art, the present invention has the following advantages: the method of the present invention can effectively control the composition and morphology of nanomaterials, and can overcome the requirements of traditional nanoporous metal preparation processes such as dealloying and deposition methods on the chemical stability of precursors, and effectively prepare chemically active nanoporous Cu, Ti, Zr, Mn and Al alloy materials, which are expected to be applied in the fields of adsorption, filtration, catalysis and engineering processing. The present invention expands the research scope of nanoporous metal materials and opens up a new direction for the practical application of femtosecond lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Cu 60 Si 40 X-ray diffraction pattern of the alloy quenched ribbon.

[0012] Figure 2 Cu 60 Si 40 SEM images of the alloy strip after femtosecond laser irradiation.

[0013] Figure 3 Cu 60 Si 40 SEM image of the alloy strip after femtosecond laser irradiation under 2 m / s Ar gas purge.

[0014] Figure 4 Cu 60 Si 40 SEM image of the alloy strip after femtosecond laser irradiation under 8 m / s Ar gas purge.

[0015] Figure 5 Cu 60 Si 40 SEM images of the alloy strip after femtosecond laser irradiation under 15 m / s Ar gas purge conditions. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] Example 1

[0018] Now with the composition of Cu 60 Si 40 Taking the rapidly cooled alloy strip as an example, the implementation method of this patent is described in detail with reference to the accompanying drawings.

[0019] Preparation of precursor alloy: weigh the mixture and select high purity Cu (99.9 wt. %) and Si (99.999 wt. %) raw materials according to Cu 60 Si 40 Nominal ingredients are weighed.

[0020] Alloy ingot smelting: weighed metal raw materials are mixed and placed in a water-cooled copper crucible in an arc melting furnace and vacuumed to 2×10 -3 Pa, then fill in a proper amount of argon gas and start melting the alloy. After melting, turn the alloy ingot upside down and melt it repeatedly for several times to obtain an alloy ingot with uniform composition.

[0021] The alloy ingot was crushed and placed in a quartz tube with a nozzle. Using the single-roller belt-spinning technology, the alloy sample was melted and sprayed onto a high-speed rotating copper roller under argon protection to prepare Cu 60 Si 40 Alloy strip samples.

[0022] The microstructure analysis of the precursor alloy strips; using X-ray diffraction (XRD) ( Cu - Kα radiation, λ =0.15406 nm) to analyze the microstructure of the alloy strip. Figure 1 As shown, the XRD spectrum shows that the quenched Cu 60 Si 40 Fcc-Si and Cu3Si phases are precipitated in the alloy strips. Femtosecond laser irradiation processing: Precursor surface treatment, use sandpaper to polish the surface of the strip sample, then fix it on the femtosecond laser sample stage for irradiation treatment, and purge it with Ar gas of different flow rates. The sandpaper is above 1500 mesh, the irradiation power is in the range of 50-80 W, and the purge rate is 0-20 m / s.

[0023] The microstructure, morphology and composition analysis of nanoporous materials; the microstructure of the alloy strip after dealloying was observed by scanning electron microscopy (SEM), and the phase structure and composition of the nanomaterials were determined by combining XRD and energy dispersive analysis (EDX). Figure 2 The surface pore structure shown in the figure is mainly composed of Cu-Si compounds, with pore sizes ranging from 0.2 to 15 μm and ligament thickness of about 4 μm. When the purge speed is 2 m / s, the morphology of the sample is as follows: Figure 3 As shown in Figure 2, the material is mainly composed of SiO2 nanowires with an average diameter of about 120 nm. When the purge speed is further increased to 8 m / s, the irradiated sample forms a nanoporous structure composed of single-crystalline Si (such as Figure 4 The surface pores are uniform and show an obvious sponge-like structure, with average pore and ligament thicknesses of about 40 and 15 nm, respectively. Figure 5 The surface morphology of the sample was shown when the purge speed was increased to 15 m / s. At this time, the surface flatness of the sample was significantly reduced, but a nanoporous structure mainly composed of single-element Cu was formed in the sample, with an average pore size of about 50 nm and a ligament thickness of about 80 nm.

[0024] Example 2

[0025] The precursor alloy is Cu 70 Si 30 Cold rolled sheets; The specific implementation steps are the same as those in Example 1. The first step 1.3 is to prepare the precursor alloy using cutting and cold rolling processes. The thickness of the precursor alloy after cold rolling is less than 0.5 mm. The pore size is 1-12 μm and the ligament thickness is about 5 μm when the purge speed is 0; the nanowire diameter is about 100 nm when the purge speed is 3 m / s; the nanoporous pore size is 50 nm and the ligament thickness is about 12 nm when the purge speed is 8 m / s; the average pore size and ligament thickness of the nanoporous are 50 nm and 100 nm respectively when the purge speed is 15 m / s.

[0026] Example 3

[0027] The precursor alloy is Cu 20 Si 80 Alloy flakes; The specific implementation steps are the same as those in Example 2. The first step 1.3 is to prepare the precursor alloy by using wire cutting to make a thin slice of about 2 mm, and then polishing its surface by metallographic polishing. The pore size at the purge speed of 0 is 5-20 μm, and the ligament thickness is about 3 μm; the nanowire diameter at the purge speed of 2 m / s is about 140 nm; the nanoporous pore size at the purge speed of 8 m / s is 50 nm, and the ligament thickness is about 12 nm; the average pore size and ligament thickness of the nanoporous at the purge speed of 15 m / s are 60 nm and 70 nm, respectively.

[0028] Example 4

[0029] The precursor alloy is Ti 20 Cr 10 Si 70 quenching strip; The specific implementation steps are the same as those in Example 1. At a strong purge speed of 20 m / s, a nano-alloy consisting of a Ti2Cr phase was obtained, and the average pore diameter and ligament thickness thereof were approximately 50 nm and 80 nm, respectively.

[0030] Example 5

[0031] The precursor alloy is Ni 20 Al 20 Si 55 Quench strip of P5; The specific implementation steps are the same as those in Example 1. The first step 1.1 is to use NiP master alloy in the batching and prepare a master alloy ingot by induction melting. At a strong purge speed of 20 m / s, a nano alloy composed of NiAl phase is obtained, and its average pore diameter and ligament thickness are approximately 30 nm and 50 nm, respectively.

[0032] Example 6

[0033] The precursor alloy is Fe30 Si 50 B 20 quenching strip; The specific implementation steps are the same as those in Example 1. In the first step 1.1, FeB master alloy is used for mixing. At a strong purge speed of 20 m / s, a nano alloy composed of α-Fe and FeB phases is obtained, and its average pore diameter and ligament thickness are both about 40 nm.

[0034] The above is a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, changes, modifications, substitutions and variations made to the implementation methods are still within the scope of protection of the present invention.

Claims

1. A method for preparing nanoporous alloy based on femtosecond laser technology, characterized in that The process is completed by femtosecond laser irradiation etching, and the gas purge conditions during the irradiation process determine the composition, morphology and size of the nanomaterial; the size of the obtained nanomaterial is in the range of 0.02-20 μm.

2. According to claim 1, the precursor alloy is Si-based a Si b O c X d (M = Fe, Co, Y, Ti, V, Cr, Mn, Ni, Cu, Zn, Zr, Nb, Hf, Ta, W, Al; X = B, C, O, P; a, b, c and d represent the atomic percentage of the corresponding elements, respectively, satisfying 10 ≤ a ≤ 50, 20 ≤ b ≤ 80, 0 ≤ c ≤ 35, 0 ≤ d ≤ 35, and a + b + c + d = 100) alloy, which is characterized in that: firstly, a precursor alloy master alloy ingot with uniform composition is obtained by arc melting or induction melting, and then the precursor alloy strips or sheets are formed by liquid rapid cooling or cutting cold rolling; finally, irradiation treatment is carried out under inert gas purge conditions to obtain a nanomaterial with adjustable composition and morphology.

3. According to claim 2, the size of the precursor sheet is less than 1 mm; the irradiation power of the femtosecond laser is 40-80; the inert protective gas is Ar gas or N2 gas, and the purge speed during the irradiation process is in the range of 0-20 m / s.

4. According to claim 3, under the conditions of no inert gas protection and low flow rate (≤3 m / s), nanowires composed of SiO2 and metal materials can be obtained on the surface of the precursor alloy after femtosecond laser irradiation; Si nanowires and nanoporous materials with different morphological characteristics can be obtained at a purge flow rate of about 3-9 m / s; and nanoporous materials composed of alloys can be obtained when the purge speed is above 10 m / s.

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