CN113652904A

CN113652904A - Elastic strip and preparation method thereof

Info

Publication number: CN113652904A
Application number: CN202111009328.6A
Authority: CN
Inventors: 乐林江; 沈伟; 乐政
Original assignee: Yancheng Keao Mechanical Co ltd
Current assignee: Yancheng Keao Mechanical Co ltd
Priority date: 2021-08-31
Filing date: 2021-08-31
Publication date: 2021-11-16
Anticipated expiration: 2041-08-31
Also published as: CN113652904B

Abstract

The application provides a spring strip and a preparation method thereof, the spring strip comprises a substrate and an alloy layer, wherein the alloy layer is formed by infiltrating a powder infiltration agent into the surface of the substrate; the components in the alloy layer and the contents of various components are as follows: 1 to 22 weight percent of aluminum, 0.1 to 7 weight percent of magnesium, 20 to 80 weight percent of zinc, 0.01 to 1.25 weight percent of manganese and the balance of components in the base material. For the elastic strip protected in the application, when zinc, aluminum, magnesium and manganese in the alloy layer are in the proportion stated in claim 1 and the alloy layer is larger than 20 micrometers, the hardness, the salt spray resistance, the instant bearing capacity and the like of the elastic strip are all optimal, the comprehensive performance is high, and the service life of the elastic strip is greatly prolonged. And the preparation method is simple, the cost is low, and the method has great application and popularization.

Description

Elastic strip and preparation method thereof

Technical Field

The application relates to the field of chemistry, in particular to the technical field of surface treatment of elastic strips and the like, and particularly relates to an elastic strip and a preparation method thereof.

Background

The fastener is an important component in a railway system, and the railway steel rail is fixed on the sleeper through the elastic fastener, so that the train can safely and quickly pass through the rail. The most important of the elastic fasteners is the elastic strip, which is usually a spatial three-dimensional twisted beam structure. The buckling pressure is generated through the bending and twisting deformation of the elastic strips to act on the rail, so that the reliable connection between the steel rails is effectively ensured for a long time, the integrity of the rail is kept as much as possible, the longitudinal and transverse movement of the steel rails relative to the sleeper is prevented, the gauge is ensured to be normal, and the running safety of rail vehicles is ensured. In addition, the contact between the train wheels and the steel rails is rigid, so that vibration cannot be avoided, and the special elastic structure of the elastic strips enables the elastic strips to absorb impact energy generated when the train runs, so that the shock absorption effect is achieved. The elastic strip works under repeated alternating stress, bears various effects of bending, torsion, fatigue, corrosion and the like, and also bears extremely high instantaneous impact load when a vehicle passes through, so that the requirement on the performance of the elastic strip is very strict.

At present, the method for the anticorrosion treatment of the elastic strip mainly comprises powder zinc impregnation and closed passivation treatment, and the closed passivation layer is easy to fall off under the comprehensive factors of alternating load, sand wind, acid rain, ultraviolet light and the like, so that the actual service life of the elastic strip is difficult to reach the design service life. Therefore, it is necessary to develop a high corrosion-resistant and high wear-resistant elastic strip product, which better satisfies the use of railway systems.

In the field, the related researches are mature, and the purpose of overcoming various obstacles in the prior art is more challenging.

Disclosure of Invention

In view of this, the embodiment of the present application provides an elastic strip and a preparation method thereof, so as to solve technical defects in the prior art.

The invention of the application provides an elastic strip, which comprises a substrate and an alloy layer, wherein the alloy layer is formed by infiltrating a powder infiltration agent into the surface of the substrate to form an alloy layer containing multiple elements;

the components in the alloy layer and the contents of various components are as follows: 1 to 22 wt% of aluminum, 0.1 to 7 wt% of magnesium, 20 to 80 wt% of zinc, 0.01 to 1.25 wt% of manganese, and the balance of the components in the base material, the balance being typically 8 to 32 wt%, such as 8%, 10%, 12%, 14%, 15%, 18%, 22%, 25%, 28%, 30%, 31%, 32%, and the like.

Further, the thickness of the alloy layer is greater than 20 μm, such as 20 μm to 100 μm.

Further, the balance contains iron, and the content of the iron is not less than 8%.

Further, in the alloy layer, the content of manganese is 1% to 15%, preferably 5% to 12% of the content of magnesium.

Further, the powder penetrant is a multi-element powder penetrant, and comprises the following components in parts by weight: 60-80 parts of zinc powder, 5-20 parts of zinc-aluminum alloy powder, 1-20 parts of aluminum-magnesium alloy powder and 0.1-5 parts of an activating agent, wherein the activating agent contains Mn. Preferably 65-75 parts of zinc powder, 10-18 parts of zinc-aluminum alloy powder, 8-18 parts of aluminum-magnesium alloy powder and 2-4 parts of an activating agent, wherein the activating agent contains Mn.

Further, the activating agent is ammonium chloride and potassium permanganate, wherein in the activating agent, the ratio of potassium permanganate is 2 wt% -20 wt%, and the balance is ammonium chloride.

Further, the powder penetrating agent also comprises rare earth oxide and/or dispersant, wherein, in the powder penetrating agent,

further, the weight portion of the rare earth oxide is 0.1-1, preferably 0.3-0.6.

Furthermore, the weight portion of the dispersing agent is 10-100 parts, and preferably 20-30 parts.

Further, the dispersant is at least one of alumina, silica, magnesia, aluminum nitride, silicon nitride and silicon carbide.

Further, the rare earth oxide includes cerium oxide and/or lanthanum oxide.

Furthermore, in the zinc-aluminum alloy powder, the aluminum content is 5 wt% -15 wt%, and the balance is zinc.

Furthermore, in the aluminum-magnesium alloy powder, the aluminum content is 40 wt% -60 wt%, and the balance is magnesium.

Another aspect of the present invention is to provide a method for preparing the elastic strip according to any one of the above paragraphs, the method comprising:

step 1: adopting a co-infiltration process, rotating the powder infiltration agent and the matrix together in a co-infiltration device so as to uniformly mix the infiltration agent;

step 2: heating the co-cementation device to a preset temperature, and then preserving heat for 1-10 hours to finish the zinc cementation;

preferably, the co-permeation device is vacuumized to enable the vacuum degree to be less than 100Pa, and then temperature rise treatment is carried out; more preferably, the reaction temperature in Step2 is between 400 ℃ and 450 ℃, and the reaction time is more than 1 hour.

Further, at Step2,

firstly, vacuumizing a co-permeation device to enable the vacuum degree of the co-permeation device to be less than 100 Pa;

secondly, the temperature in the co-permeation device is raised to be within the range of 100 ℃ to 200 ℃, and the retention time is longer than 1 hour, such as 1 hour to 3 hours. Ensure that the ammonium chloride can be fully decomposed under the temperature condition and the potassium permanganate is not decomposed. The following reaction then takes place: 2KMnO₄+16HCl＝2KCl+2MnCl₂+5Cl₂↑+8H₂O；

Thirdly, raising the temperature to 400-450 ℃ and reacting for 1-9 hours to finish the zinc impregnation.

The invention has the beneficial effects that:

the application breaks through the obstacles in the prior art, and suitability improvement is made from the elastic strip, the powder penetrating agent, the preparation method and the like, so that the obtained elastic strip has excellent performance, can work under repeated alternating stress, can bear various complex environments such as bending, torsion, fatigue, corrosion and the like for a long time, and can bear extremely high instantaneous impact load when a vehicle passes through the elastic strip. Has great application and popularization prospect. Specifically, the method comprises the following steps:

for the elastic strip protected in the application, when zinc, aluminum, magnesium and manganese in the alloy layer are in the proportion stated in claim 1 and the alloy layer is larger than 20 micrometers, the hardness, brittleness, plasticity, salt mist resistance, instant bearing capacity and the like of the elastic strip are all optimal, namely the comprehensive performance is high, and the service life of the elastic strip is greatly prolonged.

For the multi-element permeating agent for preparing the elastic strip alloy layer in the application, the components of the multi-element permeating agent and the content of each component are selected, so that the elastic strip can be obtained by co-permeating with the elastic strip substrate, the content of each metal element in the elastic strip is gradually reduced from the surface layer to the deep layer, no deposition phenomenon exists, the permeating depth is deep, the falling phenomenon cannot occur, the hardness can reach about HV430-440, and the elastic strip can resist a neutral salt spray test for 3500 hours after sand blowing. And the proportions of the components in the penetrating agent can not only prepare the elastic strip, but also have no waste phenomenon, and can realize synchronous penetration, so the penetrating agent has good effect and low comprehensive cost.

The preparation method is designed aiming at the type of the penetrating agent and the action of each component in the penetrating agent, and can assist the penetrating agent to enter the elastic strip matrix efficiently and orderly to obtain the alloy layer. The preparation method is low in temperature and can be completed only by 400-450 ℃, the defect that the mechanical property of the elastic strip is easy to deteriorate due to too high temperature is avoided, and the method is simple to operate, low in cost and high in economic benefit.

In conclusion, the elastic strip can be applied to complex or harsh environments, such as tracks needing to be subjected to high pressure of wind, sunlight and the like for a long time, and has the advantages of long service life, low cost, easiness in popularization and use and excellent application prospect.

Drawings

FIG. 1 is a schematic illustration of the appearance of a slug treated with and without an osmotic agent according to an embodiment of the present application;

fig. 2 is an appearance diagram of the elastic strip according to the embodiment of the present application after being used for 2 years.

Fig. 3 is a schematic cross-sectional view of an example of the present application after the completion of the penetration of the elastic strip.

Fig. 4 is a schematic surface electron microscope after the penetration of the elastic strip according to the embodiment of the present application.

Fig. 5 is a photograph of a cross-section of a bullet strip of the present application after 3000 hours of salt spray.

FIG. 6 is a schematic surface electron microscope illustrating a comparative elastic strip after the penetration in the embodiment of the present application.

Detailed Description

The following description of specific embodiments of the present application refers to the accompanying drawings.

In the present invention, unless otherwise specified, scientific and technical terms used herein have the meanings that are commonly understood by those skilled in the art. Also, the reagents, materials and procedures used herein are those that are widely used in the corresponding fields.

Example 1

The embodiment provides an elastic strip which comprises a substrate and an alloy layer, wherein the alloy layer is formed by infiltrating a powder infiltration agent into the surface of the substrate to form the alloy layer containing multiple elements.

The components in the alloy layer and the contents of various components are as follows: 1 to 22 weight percent of aluminum, 0.1 to 7 weight percent of magnesium, 20 to 80 weight percent of zinc, 0.01 to 1.25 weight percent of manganese, and the balance of 5 to 20 weight percent, and the balance being components of the substrate, such as iron, nickel, and other alloy elements if the substrate is composed of iron, nickel, and other alloy elements, iron, nickel, and other alloy elements if the substrate is composed of only iron and nickel, and iron, nickel, and the balance being iron if the substrate is composed of only iron, and the balance being iron, and the like.

Preferably, the contents of the components and the various components in the alloy layer are: 5 wt% -15 wt% of aluminum, 3 wt% -5 wt% of magnesium, 60 wt% -75 wt% of zinc, 0.04 wt% -0.6 wt% of manganese, and the balance of components in the base material, wherein the balance is generally 8 wt% -32 wt%, wherein the components infiltrated into the alloy layer are aluminum, magnesium, zinc and manganese, for example, the content of the infiltrated components in the alloy layer can be any one of the following groups: 5 wt% of aluminum, 5 wt% of magnesium, 60 wt% of zinc and 0.6 wt% of manganese; 15 wt% of aluminum, 3 wt% of magnesium, 75 wt% of zinc and 0.04 wt% of manganese; ③ 12 percent of aluminum, 4 percent of magnesium, 65 percent of zinc and 0.3 percent of manganese; 9 wt% of aluminum, 4.5 wt% of magnesium, 70 wt% of zinc and 0.5 wt% of manganese.

The alloy layer has a thickness of more than 20 μm, such as 20 μm to 100 μm, specifically, such as 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc. In the system of the present application, the thickness of the alloy layer is generally between 50 and 75 μm, such as 53 μm, 58 μm, 62 μm, 67 μm, etc., which is far beyond the level of the prior art. The powder is uniformly immersed and the immersion depth is deeper, so that the overall performances of the elastic strip, such as corrosion resistance, wear resistance, plasticity, rigidity, instant pressure-bearing capacity and the like, are more excellent, and the elastic strip can be used in the environment with higher requirements on the elastic strip, such as a track and the like.

Preferably, the balance contains iron, and the content of iron is not less than 8%. In practice, the spring strips are generally of steel structure, iron being the main component, and therefore, the iron content will generally be above 10%. In the system of the application, manganese in the alloy layer can form a composite system with iron, so that the harmful effect of the iron can be reduced, and the wear resistance and the corrosion resistance of the iron are improved.

In a further preferred embodiment, the manganese content in the alloy layer is 1% to 15%, preferably 5% to 12%, such as 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12% of the magnesium content. During the infiltration of the powder into the surface of the strip, the infiltrated layer or strip will contain a certain amount of iron, which, as mentioned above, is an important factor in the corrosion resistance of the high magnesium content structure of the surface layer. The addition of manganese can greatly reduce the deleterious effects of iron in the infiltrated layer. Manganese is added into the infiltrated layer, mainly for improving the corrosion resistance and the wear resistance of the infiltrated layer surface layer. When the magnesium contains 1-15% of manganese, the corrosion resistance of the surface layer can be greatly improved, the defects caused by high local magnesium content are avoided, and a complex with better performance can be generated with the magnesium. In particular, because excessive magnesium is easily enriched in the outermost layer of the zinc-magnesium-aluminum infiltrated layer, the excessive magnesium causes the surface layer of the infiltrated layer tissue to be rapidly corroded in the corrosion process. Manganese is added into the infiltrated layer structure, and the purpose is mainly to improve the corrosion resistance of the infiltrated layer surface layer. If the content of manganese is too high, the plasticity of the alloy layer can be reduced, so that the content is proper in the system, other metal components can be balanced, and the comprehensive effect of the elastic strip is increased.

In the present embodiment, it is shown through a large number of experimental data that when the alloy layer contains the above-described specific amounts of the alloy components and the alloy layer is larger than 20 μm, the hardness, brittleness, plasticity, salt spray resistance, and the like are optimized. Namely, when the metal alloy layer on the surface of the elastic strip contains zinc, aluminum, magnesium and manganese with specific contents, the corrosion resistance and the wear resistance of the elastic strip are greatly improved, and the service life is greatly prolonged.

Example 2

Based on example 1, it is known that the alloy layer of the spring bar of the present invention contains zinc, aluminum, magnesium, and manganese in specific amounts, and therefore, the alloy layer has excellent corrosion resistance and wear resistance. However, the spring strips of the embodiments can be obtained by adding these components in the alloy layer, mainly by using the following multi-component powder impregnation agent.

The multi-element powder penetrant comprises the following components in parts by weight: 60-80 parts of zinc powder, 5-20 parts of zinc-aluminum alloy powder, 1-20 parts of aluminum-magnesium alloy powder and 0.1-5 parts of an activating agent, wherein the activating agent contains Mn. Preferably, 65-75 parts of zinc powder, 10-18 parts of zinc-aluminum alloy powder, 8-18 parts of aluminum-magnesium alloy powder and 2-4 parts of an activating agent. For example, the components of the multi-element powder penetration agent can be any one of the following groups: 65 parts of zinc powder, 18 parts of zinc-aluminum alloy powder, 8 parts of aluminum-magnesium alloy powder and 4 parts of an activating agent; 75 parts of zinc powder, 10 parts of zinc-aluminum alloy powder, 18 parts of aluminum-magnesium alloy powder and 2 parts of an activating agent; 70 parts of zinc powder, 13 parts of zinc-aluminum alloy powder, 11 parts of aluminum-magnesium alloy powder and 3 parts of an activating agent; 72 parts of zinc powder, 16 parts of zinc-aluminum alloy powder, 16 parts of aluminum-magnesium alloy powder and 4 parts of activating agent.

The activating agent is ammonium chloride and potassium permanganate, and in the activating agent, the proportion of the potassium permanganate is 2 wt% -20 wt%, preferably 6-15 wt%, such as 6 wt%, such as 7 wt%, such as 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, and the like, and the balance is ammonium chloride. The potassium permanganate starts to decompose at about 220 ℃ to 350 ℃, the decomposition starting temperature of the ammonium chloride is 100 ℃, and the ammonium chloride can react with the potassium permanganate at 100-200 ℃ to generate substances capable of permeating manganese and catalyzing other components to permeate or react. While other ammonium halides are not preferred because the hydrogen fluoride from the decomposition of ammonium fluoride does not react with potassium permanganate, ammonium bromide, ammonium iodide, ammonium fluoride are not used because the decomposition temperature is higher than that of potassium permanganate.

In a further preferred embodiment, the powder penetrant further comprises a rare earth oxide and/or a dispersant, wherein the weight part of the rare earth oxide in the powder penetrant is 0.1-1 part; preferably 0.3-0.6 parts of rare earth oxide, such as 0.3 part, 0.4 part, 0.5 part and 0.6 part. The rare earth oxide has the function of promoting infiltration.

Preferably, the rare earth oxide is a nano rare earth oxide comprising cerium oxide and/or lanthanum oxide.

In a more preferred embodiment, the dispersant is present in an amount of 10 to 100 parts by weight. The dispersant is preferably 20-30 parts, such as 20 parts, 22 parts, 26 parts, 28 parts and 30 parts.

Preferably, the dispersant is preferably at least one of alumina, silica, magnesia, aluminum nitride, silicon nitride, and silicon carbide. These dispersants are effective in preventing the metal powder from binding in the system of the present invention.

As a further preferred embodiment, in the zinc-aluminum alloy powder, the aluminum content is 5 wt% to 15 wt%, and the balance is zinc, for example, the aluminum content may be 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, or the like. The use of the zinc-aluminum alloy powder promotes a certain amount of aluminum to be synchronously infiltrated in the process of zinc infiltration; if the aluminum content in the zinc-aluminum alloy powder is too high, the aluminum co-penetration effect is poor, and therefore, the ratio is optimal. Moreover, if a certain amount of aluminum is simultaneously infiltrated into the infiltrated layer, the aluminum and the iron in the matrix can form an iron-aluminum intermetallic compound phase, which has a significant effect on improving the wear resistance of the infiltrated layer as a whole.

In the aluminum-magnesium alloy powder, the aluminum content is 40 wt% -60 wt%, and the balance is magnesium, for example, the aluminum content can be 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, and the like. The two are eutectic alloys, and the mass ratio of the two is in the above proportion, the melting point of the alloy is just about 450 ℃, which is far lower than the melting points of simple substance magnesium and aluminum, and the simple substance magnesium and aluminum are both higher than 650 ℃, therefore, the powder zinc impregnation process is more beneficial to promoting the synchronous infiltration of magnesium and aluminum, and compared with other proportions, the infiltration uniformity and amount are better, and therefore, the comprehensive effect is better. In addition, the magnesium and the aluminum form alloy powder, so that the defects that the magnesium powder is easy to explode and oxidize and is low in content, and the magnesium powder is difficult to continuously permeate to form local parts and even cause the reduction of metal performance are avoided. Moreover, in the system of the present application, the magnesium content in the aluminum magnesium alloy powder is generally not more than 70 wt%, and since excess magnesium is easily concentrated in the outermost layer of the carburized layer in the zinc-magnesium carburized layer, the excess magnesium causes relatively poor corrosion resistance and wear resistance of the carburized layer surface layer.

In the embodiment, the multi-element powder infiltration agent contains pure zinc powder, which can be normally infiltrated in the process of the application; the aluminum-magnesium alloy powder simultaneously contains two alloy powders of zinc-aluminum alloy powder and aluminum-magnesium alloy powder, wherein the zinc-aluminum alloy powder enables a certain amount of aluminum to be synchronously infiltrated when the infiltrated zinc passes through. The aluminum-magnesium alloy powder is eutectic alloy, and the melting point of the aluminum-magnesium alloy powder are low in the proportion given by the application, so that the system and the infiltration method are more favorable for promoting the simultaneous infiltration of magnesium and aluminum while zinc infiltration is carried out. The multielement powder penetrating agent also contains an activating agent, wherein the activating agent contains more ammonium chloride, can decompose and provide ammonia and hydrogen halide gas, can play a role in cleaning the surface of the metal piece once, and can also play a role in activating other components so as to promote the zinc penetration. Meanwhile, the hydrogen halide can react with potassium permanganate, the generated manganese chloride can be used as a manganese source to enable manganese to enter a permeable layer, the manganese chloride also has a certain effect of promoting metal permeation, and more importantly, chloride ions in the active manganese chloride also contribute to promoting manganese permeation into permeable layer tissues. The reaction of potassium permanganate and hydrogen chloride can provide manganese chloride as manganese permeating agent and produce potassium chloride as excellent catalyst for permeating various metals. Pure manganese metal cannot permeate, manganese chloride is basically hydrated manganese chloride and cannot be used, and potassium chloride is not preferable because the manganese chloride is also hydrated potassium chloride. In addition, the effect of rare earth oxide, dispersing agent and the like in the application is matched, so that aluminum, magnesium and manganese are synchronously infiltrated in the process of zinc infiltration. The system can be permeated synchronously as far as possible, so that a certain metal element is not easy to enrich on the surface layer to influence the performance, and the system can ensure that the thickness of a permeated layer reaches the thickness of the permeated layer while the system is permeated synchronously20 to 100 μm, so that the metal can realize excellent corrosion resistance and wear resistance. More importantly, the system of the present application also enables the zinc and magnesium to act in the percolated layer, thereby increasing its corrosion resistance. Specifically, the atomic radius of zinc is 0.1332 nanometers, the atomic radius of magnesium is 0.1598 nanometers, the difference between the atomic radii of the zinc and the magnesium is less than 15%, and meanwhile, the magnesium and the zinc are in a close-packed hexagonal structure, so that the magnesium and the zinc can jointly act to form a permeation layer. Although magnesium is not corrosion resistant by itself, it can occupy some of the zinc atom sites in the zinc crystal structure, particularly at the grain boundaries, and some amount of magnesium can accumulate at the zinc weak grain boundaries and form MgZn by high temperature reaction₂、Mg₂Zn₁₁Equal zinc-magnesium alloy phase, MgZn₂、Mg₂Zn₁₁The alloy phase itself is a high corrosion resistant phase, and the original weak grain boundary structure can be promoted to be changed into a strong grain boundary structure formed at the grain boundary, particularly, the strong grain boundary structure is opaque to corrosive substances such as chloride ions, and the corrosive substances can be blocked outside. At the same time, MgZn₂、Mg₂Zn₁₁In the corrosion process of the zinc-magnesium alloy phase, a corrosion product is changed from a loose structure of common powder zinc impregnation into a compact structure, so that the corrosion resistance of the metal piece is greatly improved, and the service life of the metal piece is greatly prolonged.

In summary, the top of the figure of the elastic strip provided in this embodiment is a schematic surface view of the elastic strip treated with the permeability agent of the present application, and the bottom of the figure is a schematic surface view of the elastic strip without any treatment, as shown in fig. 1. The treated elastic strip has good comprehensive performance, and the multielement powder penetrating agent can realize that the alloy layer of the elastic strip product contains aluminum, magnesium, zinc and manganese with specific content, so that the penetrating agent is complementary with the elastic strip product to comprehensively realize excellent corrosion resistance and wear resistance.

Example 3

On the basis of the embodiment 1 and/or the embodiment 2, the embodiment discloses a preparation method of the elastic strip, which comprises the following steps:

step 1: a rotary furnace body co-infiltration process is adopted, the powder infiltration agent and the matrix rotate together in the multi-element alloy co-infiltration furnace, so that the uniform mixing of the infiltration agent is ensured, and the uniform reaction can be ensured; the mixing uniformity and the reaction uniformity can be realized by the conventional technology in the field at present, and the method is very basic condition guarantee.

Step 2: heating the co-cementation device to a preset temperature, and then preserving heat for 1-10 hours (usually 4-7 hours) to finish the zinc cementation;

preferably, the co-infiltration furnace is evacuated to a vacuum degree of less than 100Pa, and then subjected to a temperature raising treatment, wherein the vacuum degree is maintained throughout the reaction. The reaction temperature in Step2 is 400-450 ℃, and the reaction time is more than 1 hour.

In a further preferred embodiment, in Step2,

firstly, vacuumizing the co-permeation furnace to enable the vacuum degree of the co-permeation furnace to be less than 100Pa, then heating, and maintaining the vacuum degree of the co-permeation furnace to be less than 100Pa through vacuumizing so as to quickly pump away the generated chlorine and water vapor. Prevent the steam from influencing the powder infiltration and prevent the chlorine from causing potential safety hazard.

Secondly, the temperature in the co-cementation furnace is raised to be within the range of 100 ℃ to 200 ℃, the retention time is longer than 1 hour, usually 1 to 3 hours, such as 1 hour, 2 hours and 3 hours. The ammonium chloride can be fully decomposed at the temperature (the decomposition starting temperature of the ammonium chloride is 100 ℃, the ammonium chloride is decomposed into HCl), and the potassium permanganate is not decomposed, and the following reaction formula is generated: 2KMnO₄+16HCl＝2KCl+2MnCl₂+5Cl₂↑+8H2O；

And thirdly, raising the temperature to 400-450 ℃, reacting for 1-9 hours, usually reacting for 2-5 hours, such as 2 hours, 3 hours, 4 hours and 5 hours, and completing zinc impregnation.

In the method and the impregnation agent system of the embodiment, the temperature is low, and the impregnation can be completed only by 400-450 ℃, so that the defect that the mechanical property of the elastic strip is easy to deteriorate due to too high temperature is avoided.

In this embodiment, the specific reaction can improve the reaction effect of the present application, and the penetrating agent can be effectively utilized and effectively penetrate into the elastic strip, so as to obtain the elastic strip as described in example 1.

Example 4

The preparation method comprises the following steps: the multi-element powder penetrant and the elastic strip are put into a multi-element alloy co-infiltration furnace by adopting a rotary furnace body co-infiltration process, and the multi-element powder penetrant and the elastic strip rotate together to ensure that the penetrant is uniformly mixed and reacts uniformly. After the two are mixed, the co-permeation furnace is vacuumized to make the vacuum degree less than 100Pa, then the temperature in the co-permeation device is raised to about 120 ℃, and the reaction lasts for 2 hours. Then the temperature is raised to about 420 ℃ again, and the reaction time is 6 hours.

Experimental example 1: multi-element powder penetrating agent: 70 parts of zinc powder, 15 parts of zinc-aluminum alloy powder, 13 parts of aluminum-magnesium alloy powder, 3 parts of an activating agent, 0.4 part of lanthanum oxide and 25 parts of a dispersing agent.

Wherein, the activating agent is ammonium chloride and potassium permanganate, and in the activating agent, the ratio of the potassium permanganate is 13wt percent, and the ammonium chloride is 87 percent.

The dispersant is alumina and magnesia in a weight ratio of 3: 1.

In the zinc-aluminum alloy powder, the aluminum content is 12 wt%, and the balance is zinc;

in the aluminum-magnesium alloy powder, the aluminum content is 50 wt%, and the balance is magnesium.

The multi-element powder penetrating agent and the elastic strip in the experimental example are prepared by the method to obtain the processed elastic strip with the alloy layer on the surface.

Experimental example 2: multi-element powder penetrating agent: 65 parts of zinc powder, 18 parts of zinc-aluminum alloy powder, 8 parts of aluminum-magnesium alloy powder, 4 parts of an activating agent, 0.3 part of lanthanum oxide and 30 parts of a dispersing agent.

Wherein, the activating agent is ammonium chloride and potassium permanganate, and in the activating agent, the ratio of the potassium permanganate is 8 wt%, and the ammonium chloride is 92%.

The dispersant is aluminum nitride and magnesium oxide, and the weight ratio of the aluminum nitride to the magnesium oxide is 1: 2.

In the zinc-aluminum alloy powder, the aluminum content is 15 wt%, and the balance is zinc;

in the aluminum-magnesium alloy powder, the aluminum content is 40 wt%, and the balance is magnesium.

Experimental example 3: multi-element powder penetrating agent: 75 parts of zinc powder, 10 parts of zinc-aluminum alloy powder, 18 parts of aluminum-magnesium alloy powder, 2 parts of an activating agent, 0.6 part of cerium oxide and 20 parts of a dispersing agent.

Wherein, the activating agent is ammonium chloride and potassium permanganate, and in the activating agent, the ratio of potassium permanganate is 15 wt%, and the ammonium chloride is 85%.

The dispersant is alumina and silicon oxide, and the weight ratio of the alumina to the silicon oxide is 1: 1.

In the zinc-aluminum alloy powder, the aluminum content is 5 wt%, and the balance is zinc;

in the aluminum-magnesium alloy powder, the aluminum content is 60 wt%, and the balance is magnesium.

Blank control: the elastic strip is not subjected to any treatment.

Adding no manganese: the potassium permanganate in the experimental example 1 is removed, and the product performance is greatly influenced by simple removal, so that the magnesium content is doubled, and the active reagent magnesium chloride is added, so that the comprehensive performance of the product is high.

The untreated bars used in the above examples, blank control, and manganese free method were the same. The main component of the elastic strip is iron.

The results of the neutral salt spray test after sand blasting were obtained for each of the test strips obtained in test example 1, test example 2, test example 3, blank control and manganese-free test, and are shown in the following table.

Use performance	Experimental example 1	Experimental example 2	Experimental example 3	Blank control	Without addition of manganese
						Hardness (HV)	440	432	433	350	395
Salt spray resistance test	＞3500h	＞3500h	＞3500h	＜100h	＜2000h
						Sulfur dioxide resistance	High strength	High strength	High strength	Weak (weak)	Is preferably used

As is clear from the above table, the overall effect of the experimental examples is very excellent. And as can be seen from the above table, the microhardness HV350 of the original surface of the matrix is HV395 which does not contain manganese after infiltration, but the hardness of the matrix can reach HV 430-HV 440, so that the hardness of the matrix is greatly improved, the wear resistance of the matrix is greatly improved, and the effect is excellent. And the salt spray resistance in the experimental example is excellent, the salt spray resistance test shows that the salt spray resistance is more than 3500h, compared with the manganese-free and blank control, the effect is very surprising, and the service life of the elastic strip can reach 100 years or more by reasonable conjecture and comprehensive practical application. Fig. 2 is a photograph of a railway test section using the bullet strip of the present patent after two years of use, showing that the surface is free from any rust and corrosion. Fig. 5 is a microscopic cross-sectional photograph of the salt spray of the experimental example after 3000 hours, and it is understood that the thickness of the alloy layer can reach about 21 μm after the salt spray test of 3000 hours, and the effect is obvious. In the test without manganese, the salt spray test was only 2000 hours.

Fig. 3 is a schematic sectional electron microscope view of the elastic strip in experimental example 1 after the permeation agent is permeated, and fig. 4 is a schematic surface electron microscope view after the permeation agent is permeated. As can be seen, the thickness of the alloy layer is relatively uniform and relatively thick, and the average thickness is about 60-70 μm. The alloy content infiltrated in the entire alloy layer of experimental example 1 was 70 wt% of zinc, 8.7 wt% of aluminum, 4.0 wt% of magnesium, 0.46 wt% of manganese, 12% of iron, and the balance was nickel contained in the matrix. In the surface layer shown in the figure, the contents of the metals are 78% of zinc, 10.5% of aluminum, 5.1% of magnesium, 0.7% of manganese, 5% of iron and the balance of nickel. The metal content in the alloy layer is basically uniform and less from top to bottom, and no phenomenon of deposition exists somewhere. According to the direction from the surface to the inside, at the depth of about 20 μm, the contents of each element are 74% of zinc, 9.8% of aluminum, 4.7% of magnesium and 0.44% of manganese; at a depth of about 40 μm, the contents of the elements are 63% zinc, 8.1% aluminum, 3.4% magnesium and 0.29% manganese, and at a depth of about 55 μm, the contents of the elements are 27% zinc, 2.5% aluminum, 1.4% magnesium and 0.1% manganese. And the surface of this application experimental example is smooth, level.

Through the experiments, the metal infiltration amount of the multi-element metal infiltration agent can be obtained as described in example 1, the salt spray resistance and the wear resistance of the multi-element metal infiltration agent are obviously improved, the sulfur dioxide resistance effect is good, and the multi-element metal infiltration agent can be suitable for being used in severe environments such as rails and the like.

Example 5

In order to further study the treated spring strips, the applicant also performed several tests on the treated spring strips, such as the thickness of the alloy layer, and the distribution of the metal elements in different thicknesses.

Comparative example 1: the contents of the respective metal powders of the multi-element powder impregnation agent are the same as those of experimental example 1 in example 4, and the preparation method is the same, and the differences are only that: with the metal Mn, the Mn added is the same as the potassium permanganate in mole number, the activator is only ammonium chloride, and the amount is the same as that of the ammonium chloride in experimental example 1.

Comparative example 2: the contents of the respective metal powders of the multi-element powder impregnation agent are the same as those of experimental example 1 in example 4, and the preparation method is the same, and the differences are only that: ammonium chloride was not added.

Comparative example 3: the contents of the respective metal powders of the multi-element powder impregnation agent are the same as those of experimental example 1 in example 4, and the preparation method is the same, and the differences are only that: potassium permanganate is not added.

Comparative example 4: the contents of the respective metal powders of the multi-element powder impregnation agent are the same as those of experimental example 1 in example 4, and the preparation method is the same, and the differences are only that: ammonium chloride was replaced by ammonium fluoride.

Comparative example 5: the contents of the respective metal powders of the multi-element powder impregnation agent are the same as those of experimental example 1 in example 4, and the preparation method is the same, and the differences are only that: ammonium chloride was replaced with ammonium bromide.

Comparative example 6: the contents of the respective metal powders of the multi-element powder impregnation agent are the same as those of experimental example 1 in example 4, except that: the preparation method directly heats the mixture to about 420 ℃.

The wear resistance and corrosion resistance of the above examples were tested and the content of metal infiltrated in the alloy layer was tested.

As is clear from the above table, the overall effect of experimental example 1 is very excellent, and it is described in example 4. Comparative example 1 has a certain manganese content, but the content is extremely low, and the content of other aluminum, magnesium and the like in the alloy layer is also greatly reduced, and magnesium is mainly concentrated in a shallow layer and is hardly detected after 20 μm; and the overall thickness of the alloy layer is significantly different from that of experimental example 1. For comparative examples 2 to 5, the resistance model was also significantly smaller than that of the experimental example, and the thickness of the infiltrated layer was also significantly smaller than that of the experimental example, and in addition, the infiltrated layer contained almost no manganese element, and had poor salt spray resistance and significantly inferior corrosion resistance to the experimental example. For comparative example 6, although the contents of the respective elements in the alloy layer were substantially within the protection range of the present application due to the change of conditions in the preparation method, the overall properties were less than those of the experimental examples.

In addition, the uniformity of appearance was better in the experimental example as shown in fig. 4, while the uniformity of appearance was generally worse in the comparative example, and fig. 6 is an appearance electron microscope image of comparative example 1, from which it was seen that the flatness of appearance was worse.

The salt spray tests are shown in the following table:

as can be seen from the table, in the experimental example 1, after 3500h, no red rust still appears, and the salt spray resistance is more than 3500 h; comparative example 6 shows red rust at 3500 hours, the salt spray resistance of which is > 3000 hours and less than 3500 hours; comparative examples 1, 3 and 5, which all showed a large amount of white rust at around 2000h and an obvious red rust at 3000h, had salt spray resistance < 3000 h; the red rust appeared at 2000h in comparative examples 2 and 4, and the salt spray resistance was < 2000 h.

It should be noted that the content of each component in the penetrant of the present application is set according to the characteristics of interaction or mutual restriction among various components, and the effect of the penetrant of the present application is achieved by the combined action of the components, so that the manganese element is an important component in the present application, and if the manganese element cannot normally permeate or the permeation amount is small, the performance of the elastic strip is greatly affected. In fact, if the alloy layer does not contain manganese originally, the better performance can be realized by adjusting the proportion of other components, the addition amount of the type of the auxiliary agent and the like. However, according to the action of the elastic strip and the like, the applicant finds that the comprehensive performance of the added manganese is better through tests and research. Therefore, on the premise of adding manganese, the research and test adopts the form of adding manganese and the proportion of other components, and if the proportion or other components are not proper, the performance difference is very large. Therefore, under the conditions of the present application, for example, the amount of a certain component is greatly adjusted or a certain component or a plurality of components are slightly added and replaced, the performance of the elastic strip is probably greatly influenced.

Example 6

Experimental example: as in experimental example 1 of example 4.

Comparative group 1: multi-element powder penetrating agent: 50 parts of zinc powder, 45 parts of zinc-aluminum alloy powder, 23 parts of aluminum-magnesium alloy powder, 3 parts of an activating agent, 0.4 part of lanthanum oxide and 25 parts of a dispersing agent. The others were in accordance with experimental example 1.

Comparative group 2: multi-element powder penetrating agent: 50 parts of zinc powder, 5 parts of zinc-aluminum alloy powder, 5 parts of aluminum-magnesium alloy powder, 3 parts of an activating agent, 0.4 part of cerium oxide and 25 parts of a dispersing agent.

Comparative group 3: multi-element powder penetrating agent: 35 parts of zinc powder, 5 parts of zinc-aluminum alloy powder, 5 parts of aluminum-magnesium alloy powder, 3 parts of an activating agent, 0.4 part of lanthanum oxide and 25 parts of a dispersing agent.

Comparative group 4: multi-element powder penetrating agent: 50 parts of zinc powder, 45 parts of zinc-aluminum alloy powder, 13 parts of aluminum-magnesium alloy powder, 3 parts of an activating agent, 0.4 part of lanthanum oxide and 25 parts of a dispersing agent. The activating agent is ammonium chloride and potassium permanganate, in the activating agent, the ratio of potassium permanganate is 58 wt%, and the ammonium chloride is 42%

The other parts of the above comparative group (including the preparation method) were identical to those of the experimental group 1, and the hardness and neutral salt spray resistance were measured as follows.

Use performance	Examples of the experiments	Comparative group 1	Comparative group 2	Comparative group 3	Comparative group 4
						Hardness (HV)	440	377	368	360	356

The metal contents of the alloy layers in the above comparative groups are all inconsistent with the scope of protection of the present application, i.e. are not within the scope of example 1 or claim 1 of the present application. The corrosion resistance of the comparative group as a whole was weak. The contents of magnesium and aluminum in comparative example 1 were greatly increased and mainly concentrated in the surface layer and the depth range of 10 μm, and a local excess of magnesium occurred, affecting the performance, and the waste was severe and the cost was high.

The magnesium and aluminum contents in comparative example 2 are greatly reduced, and the comprehensive performance is reduced.

In comparative example 3, zinc powder is greatly reduced, metal components infiltrated into the alloy layer are mainly concentrated within 20 μm, the thickness of the whole alloy is small and is basically between 10 and 30, the hardness is greatly reduced, and the corrosion resistance is weak.

The comparative example 4 has a reduced hardness and a significantly reduced plasticity, and is easily damaged due to a reduced instantaneous impact resistance when the vehicle passes. And the endurance of the instantaneous impact of comparative examples 3 and 2 is also significantly reduced.

Thus, in the present application, the various components and amounts of the various components are complementary and the reduction, addition or replacement of one component can have a greater effect on the performance of the elastic strip.

In the present invention, it should be noted that there are many factors that can affect the performance of the spring strip after the metal element is infiltrated, and these factors are not only related to the ratio of the metal element in the alloy layer, but also have a great relationship with diffusion or infiltration, such as the same metal content as in this embodiment, but if the infiltration is not uniform, there are situations where some portions are deposited more and other portions are too little, and the improvement performance on the metal may be very weak, and sometimes not only the performance of the metal surface layer is not improved, but also the performance of the metal surface layer is reduced. Moreover, the same metal content, if the depth of penetration is too shallow, will also greatly affect the properties of the metal. And the bullet strip type in this application, cooperation the penetrant in this application, can realize the infiltration in step, degree of depth infiltration, and from the top layer to between the inlayer of alloy-layer, the comparatively even reduction of each metal, certain local metal condition too much can not appear, and through the mode of adding ammonium chloride and potassium permanganate under the specific condition, make manganese get the infiltration again very big compound with iron and magnesium, formed the alloy-layer that increases metallic property, very big less or avoided the harm of the side effect that magnesium probably brought and iron in the bullet strip. And the effect is better by matching with the method of the application.

In the invention, all the raw material powder is a market product and can be normally purchased, and the alloy powder comprises zinc-aluminum alloy powder, aluminum-magnesium alloy powder and other alloy powder which can be purchased.

Unless otherwise indicated, numerical ranges herein include not only the entire range within its two endpoints, but also several sub-ranges subsumed therein.

The preferred embodiments and examples of the present application have been described in detail with reference to the accompanying drawings, but the present application is not limited to the embodiments and examples described above, and various changes can be made within the knowledge of those skilled in the art without departing from the concept of the present application.

Claims

1. The elastic strip comprises a substrate and an alloy layer, wherein the alloy layer is formed by infiltrating a powder infiltration agent into the surface of the substrate and contains a plurality of metal elements; the method is characterized in that:

the components in the alloy layer and the contents of various components are as follows: 1 to 22 weight percent of aluminum, 0.1 to 7 weight percent of magnesium, 20 to 80 weight percent of zinc, 0.01 to 1.25 weight percent of manganese and the balance of components in the base material.

2. The spring bar according to claim 1, wherein the thickness of the alloy layer is 20 μm to 100 μm;

preferably, the balance contains iron, and the content of iron is not less than 8%.

3. The spring bar according to claim 1, wherein the manganese content in the alloy layer is 1% to 15% of the magnesium content.

4. The bullet strip of claim 1 wherein said powder penetrant is a multi-element powder penetrant comprising, in parts by weight: 60-80 parts of zinc powder, 5-20 parts of zinc-aluminum alloy powder, 1-20 parts of aluminum-magnesium alloy powder and 0.1-5 parts of an activating agent, wherein the activating agent contains Mn.

5. The bullet strip of claim 4 wherein said activator is ammonium chloride and potassium permanganate, wherein the potassium permanganate is present in a ratio of 2 wt% to 20 wt%, and the balance is ammonium chloride.

6. The strip magnet as claimed in claim 4, further comprising a rare earth oxide and/or a dispersant, wherein, in said powder impregnation agent,

the weight part of the rare earth oxide is 0.1-1 part;

the weight part of the dispersing agent is 10-100 parts.

7. The spring bar according to claim 6, wherein the dispersant is at least one of alumina, silica, magnesia, aluminum nitride, silicon nitride, and silicon carbide;

the rare earth oxide includes cerium oxide and/or lanthanum oxide.

8. The elastic strip according to claim 5, wherein in the zinc-aluminum alloy powder, the aluminum content is 5 to 15 wt%, and the balance is zinc;

in the aluminum-magnesium alloy powder, the aluminum content is 40-60 wt%, and the balance is magnesium.

9. A method of making a bullet strip according to any one of claims 1 to 8, wherein said method comprises:

10. The method for preparing the elastic strip according to claim 1, wherein Step2 comprises the steps of:

firstly, vacuumizing a co-permeation device to enable the vacuum degree of the co-permeation device to be less than 100Pa, and maintaining the vacuum degree in the reaction process;

secondly, raising the temperature in the co-permeation device to be within the range of 100-200 ℃, and staying for 1-3 hours;