A method for preparing porous iron by rapid solidification of iron-zinc alloy and continuous annealing and dezincification

Abstract

The present application belongs to the technical field of continuous preparation of porous metal materials, and relates to a method for preparing porous iron by rapid solidification of iron-zinc alloy + continuous annealing and dezincification, wherein iron and zinc are smelted under a protective atmosphere to obtain Fe-Zn alloy melt; the obtained Fe-Zn alloy melt is rapidly solidified by single-roller spin-chilling to form Fe-Zn alloy ribbons; the Fe-Zn alloy ribbons are subjected to continuous annealing treatment under a protective atmosphere, so that zinc is removed in the form of gas phase, and porous iron ribbons are obtained; and the porous iron ribbons are cooled and wound to obtain continuous porous iron ribbons. The present application realizes the continuous and large-scale production of porous iron ribbons, and the dezincification process is a pure physical gas phase removal process, without generation of acid and alkali waste liquid, and is green and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of continuous preparation technology of porous metal materials, and relates to a method for preparing porous iron by rapid solidification of iron-zinc alloy followed by continuous annealing and dezincification. Background Technology

[0002] Porous iron is a strip-shaped functional material with pure iron or low-carbon iron as its matrix, featuring a uniformly distributed, interconnected, or semi-connected microporous structure. Porous iron strips combine the mechanical stability of iron-based metals, the uniform thickness and pore distribution, and the functional properties of porous media. Due to its low cost, good conductivity, and large specific surface area, porous iron is in high demand in fields such as energy catalysis, water treatment, flexible electronics, and shielding and absorption. However, existing preparation processes are mostly powder metallurgy, foaming molding, and electrochemical deposition. These methods suffer from technical bottlenecks in the preparation of porous iron strips, such as poor pore connectivity, low strength; low efficiency and instability of intermittent annealing; coarse and severely segregated microstructure in ordinary cast state; and severe environmental pollution and sample corrosion caused by liquid-phase dezincification. Currently, no mature integrated process for preparing porous iron strips using rapid solidification of iron-zinc alloys and annealing dezincification has been publicly disclosed.

[0003] In the prior art, patent publication number CN119566306A discloses a porous iron and its preparation method, which involves mixing iron powder with PMMA, carbon powder, solid wax, etc., granulating, pressing, and sintering, leaving pores through the decomposition of a pore-forming agent. This method cannot achieve continuous production. Patent publication number CN121592929A discloses a three-dimensional nano-iron-carbon foam alloy material and its preparation method and application, which uses a ternary alloy (Fe-MC) dealloying method, employing Fe, M (Mn / Al), and C, selectively removing M through chemical corrosion (acid or alkali), and then stabilizing the structure through heat treatment. This method requires the use of strong acids or strong alkalis for wet corrosion, generating a large amount of waste liquid, posing a high risk of environmental pollution, and incurring high post-treatment costs. The alloy system is complex, and carbon elements need to be introduced as stabilizers, increasing the difficulty and cost of material design and smelting; the process route is an intermittent operation, making it difficult to achieve continuous, large-scale production. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a method for preparing porous iron by rapidly solidifying iron-zinc alloy and continuously annealing and dezincifying, which solves the problems of difficult continuous production of porous iron, uneven pore size, low efficiency, and high pollution, and obtains porous iron materials with uniform pore distribution, stable structure, and rollability.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing porous iron by rapid solidification of iron-zinc alloy followed by continuous annealing and dezincification includes the following steps: 1) Iron and zinc are smelted under a protective atmosphere to obtain an Fe-Zn alloy melt; 2) The Fe-Zn alloy melt obtained in step 1 is rapidly solidified by single-roll spin quenching to produce Fe-Zn alloy strips; 3) The Fe-Zn alloy ribbon obtained in step 2 is subjected to continuous annealing under a protective atmosphere to remove zinc in the gas phase, thereby obtaining a porous iron ribbon. 4) Cool and rewind the porous iron strip obtained in step 3 to obtain a continuous porous iron strip.

[0006] In step 1), the chemical composition of the Fe-Zn alloy melt is composed of Fe: 45%~70%, Zn: 29.8%~54.8%, and Mo: 0.1%~0.2% by mass percentage, which improves the high-temperature strength of ferrite and prevents the collapse of pores. The melting is carried out under argon protection at a temperature of 1400~1500℃, and the melt is held at the temperature for 10 minutes after melting to make the melt fully homogenized.

[0007] The process parameters for rapid solidification by single-roll quenching mentioned in step 2) are as follows: Roller speed: 18~40m / s; Cooling rate: 104~106K / s; Obtain Fe-Zn ribbons with a thickness of 30~2000μm; The Fe-Zn ribbons are ultrafine-grained, free of segregation, and have a highly dispersed zinc phase.

[0008] In step 3), the Fe-Zn alloy strip is continuously dezincified online in a continuous annealing furnace under vacuum or nitrogen protection. The strip speed is 0.5~5m / s, the preheating zone is 220~280℃, the main dezincification temperature zone is 390~500℃, the stabilization zone is 490~580℃, and the total online processing time is 30~180s. Zinc continuously volatilizes and is removed in gaseous form at high temperature, achieving continuous, uniform, and deep dezincification. In step 4), after the porous iron strip exits the furnace, it is cooled with nitrogen and manually rolled to obtain a continuous porous iron strip.

[0009] In step 1), the raw materials for preparing the Fe-Zn alloy melt are pure iron powder and pure zinc powder.

[0010] The porous iron strip has a pore size of 0.1~100μm, a porosity of 42%~72%, and a thickness of 30~200μm.

[0011] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes a rapid solidification iron-zinc alloy combined with a continuous annealing dezincification process to prepare porous iron. By designing an Fe-Zn binary alloy system, single-roll spin quenching is employed for rapid solidification to obtain thin strips with uniform composition and fine microstructure. Taking advantage of zinc's low boiling point, continuous online annealing is performed under a protective atmosphere, allowing zinc to be physically removed in the gaseous phase, resulting in directly wound porous iron strips. This enables continuous, online, green, large-scale, and efficient industrial production of porous iron strips, yielding porous iron materials with uniform pore distribution, stable structure, and rollability to meet application requirements in fields such as battery electrodes and catalyst supports.

[0012] The porous iron rapid solidification structure prepared by this invention is ultra-fine and uniform, with high pore size consistency after zinc removal. The entire preparation process involves gas-phase physical zinc removal, is acid- and alkali-free, and produces zero waste liquid, making it environmentally friendly. Segmented temperature control prevents collapse and ensures a stable framework. The porous iron strips can be directly applied to electrodes and catalytic meshes, possessing extremely high industrial value. Detailed Implementation

[0013] The present invention will now be described in detail, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0014] The alloy composition and rapid solidification parameters of the examples are shown in Table 1, the continuous annealing process parameters are shown in Table 2, and the post-treatment process and product performance are shown in Table 3. Table 1: Alloy composition and rapid solidification parameters Table 2: Continuous Annealing Process Parameters Table 3: Post-processing techniques and product performance of the examples This invention utilizes a rapid solidification iron-zinc alloy combined with a continuous annealing dezincification process to prepare porous iron. By designing an Fe-Zn binary alloy system, single-roll spin quenching is employed for rapid solidification to obtain thin strips with uniform composition and fine microstructure. Taking advantage of zinc's low boiling point, continuous online annealing is performed under a protective atmosphere, allowing zinc to be physically removed in the gaseous phase, resulting in directly wound porous iron strips. This enables continuous, online, green, large-scale, and efficient industrial production of porous iron strips, yielding porous iron materials with uniform pore distribution, stable structure, and rollability to meet application requirements in fields such as battery electrodes and catalyst supports.

Claims

1. A method for preparing porous iron by rapid solidification of an iron-zinc alloy followed by continuous annealing and dezincification, characterized in that, Includes the following steps: 1) Iron and zinc are smelted under a protective atmosphere to obtain an Fe-Zn alloy melt; 2) The Fe-Zn alloy melt obtained in step 1 is rapidly solidified by single-roll spin quenching to produce Fe-Zn alloy strips; 3) The Fe-Zn alloy ribbon obtained in step 2 is subjected to continuous annealing under a protective atmosphere to remove zinc in the gas phase, thereby obtaining a porous iron ribbon. 4) Cool and rewind the porous iron strip obtained in step 3 to obtain a continuous porous iron strip.

2. The method for preparing porous iron by rapid solidification of iron-zinc alloy followed by continuous annealing and dezincification according to claim 1, characterized in that, In step 1), the chemical composition of the Fe-Zn alloy melt is composed of Fe: 45%~70%, Zn: 29.8%~54.8%, and Mo: 0.1%~0.2% by mass percentage. The melt is smelted under argon protection at a temperature of 1400~1500℃, and then held at that temperature for 10 minutes to ensure that the melt is fully homogenized.

3. The method for preparing porous iron by rapid solidification of iron-zinc alloy followed by continuous annealing and dezincification according to claim 1, characterized in that, The process parameters for rapid solidification by single-roll quenching mentioned in step 2) are as follows: Roll speed: 18~40m / s; cooling rate: 104~106K / s; resulting in Fe-Zn thin strips with a thickness of 30~2000μm.

4. The method for preparing porous iron by rapid solidification of iron-zinc alloy followed by continuous annealing and dezincification according to claim 1, characterized in that, In step 3), the Fe-Zn alloy strip is continuously dezincified online in a continuous annealing furnace under vacuum or nitrogen protection. The strip speed is 0.5~5m / s, the preheating zone is 220~280℃, the main dezincification temperature zone is 390~500℃, the pore stabilization zone is 490~580℃, and the total online processing time is 30~180s.

5. The method for preparing porous iron by rapid solidification of iron-zinc alloy followed by continuous annealing and dezincification according to claim 1, characterized in that, In step 4), the porous iron strip is cooled with nitrogen after exiting the furnace to obtain a continuous porous iron strip.

6. The method for preparing porous iron by rapid solidification of iron-zinc alloy followed by continuous annealing and dezincification according to claim 1, characterized in that, In step 1), the raw materials for preparing the Fe-Zn alloy melt are pure iron powder and pure zinc powder.

7. The method for preparing porous iron by rapid solidification of iron-zinc alloy followed by continuous annealing and dezincification according to claim 1, characterized in that, The porous iron strip has a pore size of 0.1~100μm, a porosity of 42%~72%, and a thickness of 30~200μm.

Images