WO2011109923A1

WO2011109923A1 - Processing procedure and corrosion protection method for magnetic refrigeration material

Info

Publication number: WO2011109923A1
Application number: PCT/CN2010/000619
Authority: WO
Inventors: 杨晓峰
Original assignee: 杨晓冰
Priority date: 2010-03-08
Filing date: 2010-05-04
Publication date: 2011-09-15
Also published as: CN102189406A

Abstract

Provided are a processing procedure and a corrosion protection method for a magnetic refrigeration material, Gd or Gd-based alloy being used as raw material of the magnetic refrigeration material, which include the following steps: making Gd metal or Gd-based alloy ingot; subjecting the Gd metal or Gd-based alloy ingot to cold rolling and heat treatment in a vacuum, thereby forming a rolled sheet; subjecting the rolled sheet to surface treatment; cutting precisely the rolled sheet; and coating the surface of the rolled sheet.

Description

Magnetic refrigeration material processing method and anticorrosion method thereof

The invention relates to a magnetic refrigeration material processing method and an anticorrosion method thereof, in particular to a magnetic refrigeration material processing method using the rare earth metal cerium and its multi-component alloy as raw materials and an anti-corrosion method thereof. Background technique

At present, people use a lot of refrigeration materials, such as liquid ammonia, liquid helium, freon, lithium bromide and other chemical materials, these refrigeration materials are cooled by the principle of gasification endothermic and liquefaction heat dissipation, they are not only expensive, but also their production and use. It will bring pollution and damage to the environment.

At the end of the 1920s, scientists discovered the principle of magnetocaloric effect, that is, the magnetic refrigeration material emits heat to the outside during isothermal magnetization, and absorbs heat from the outside when adiabatic demagnetization, thereby achieving the purpose of refrigeration. Subsequently, many scientists and engineers have a magnetocaloric effect. Materials, magnetic refrigeration technology and equipment have been extensively researched and developed. So far, low-temperature magnetic refrigeration devices below 20K have been put into practical use in some fields, but their production must be carried out at low temperatures, and the cost is too high.

Room temperature magnetic refrigeration refers to a new type of refrigeration technology using magnetic materials as the working medium. The principle is to utilize the magnetocaloric effect (MCE) of magnetic refrigeration materials, that is, magnetic system. When the cold material is isothermally magnetized, heat is released to the outside, and the principle of absorbing heat from the outside when the adiabatic demagnetization is achieved, thereby achieving the purpose of refrigeration. Magnetic refrigeration is a green and environmentally friendly refrigeration technology. Compared with traditional refrigeration, it has no destructive effect on the atmospheric ozone layer, no room temperature effect, high unit refrigeration rate, low energy consumption and few moving parts, so the mechanical vibration and noise are small, the working frequency is low, and the reliability is high. In terms of thermal efficiency, magnetic refrigeration can reach 30% - 60% of the Carnot cycle, while refrigeration cycles relying on gas compression-expansion can only reach 5% to 10%. Magnetic refrigeration applications range from μ Κ, mK and above to room temperature. In the low temperature field, magnetic refrigeration technology has a good application prospect in the preparation of liquid nitrogen, liquid helium, especially green energy liquid hydrogen; in high temperature, especially near room temperature, magnetic refrigeration in refrigerators, air conditioners and supermarket food refrigeration systems There is a broad application prospect, so the improvement of the production method of magnetic refrigeration materials is very urgent.

At present, the main materials of magnetic refrigeration materials are: pure bismuth (Gd), pure granules, rolled ruthenium, ruthenium-based alloy, ritual alloy rolled sheet.

The results of many years of experiments by professionals show that compared with other traits, the rolling sheet of rare earth metal bismuth or bismuth based alloy is a more advantageous development direction. The rolled sheet is dense and the corrosion resistance is relatively high. Therefore, in order to ensure the quality and reduce the low cost, in order to facilitate the industrialization of magnetic refrigeration technology, it is a technical research project in front of the global people. The invention provides a relatively economical production process of magnetic refrigeration materials.

Ordinary methods of smelting metal or ceremonial alloys are often unable to achieve large technological improvements due to their density limitations. Therefore, in order to achieve higher unit magnetic refrigeration capacity, in the past, the surface area was increased in the direction of cold rolling. Due to the denser material of the metal sheet or the Zaki alloy sheet, there are more magnetic refrigerants in the unit volume, which can directly improve the magnetic refrigeration capacity. . Therefore, it is necessary to provide a method for producing a magnetic refrigerating material using rare earth metal cerium and its multi-alloy as a raw material in a more efficient and cost-effective manner and preserving the material. Summary of the invention

In order to achieve the above object, the present invention provides a method for processing a magnetic refrigeration material and a method for preventing the same, comprising the steps of: processing a base metal or a ruthenium-based alloy ingot; cold rolling the above-mentioned base metal or ruthenium-based alloy ingot; Vacuum-heat-treating to form a rolled sheet; surface-treating the rolled sheet; precisely dividing the rolled sheet; and plating the surface of the rolled sheet. .

The present invention has the advantages of being able to produce a magnetic refrigerating material using rare earth metal cerium and its multi-alloy as raw materials more efficiently and at a lower cost and to preserve the material.

The invention will be described in detail below by way of preferred embodiments in conjunction with the accompanying drawings. DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of the process flow of the present invention. detailed description

Referring to Figure 1, the method of the present invention includes the steps of:

Processing of base metal or bismuth based alloy ingots;

Performing cold rolling and vacuum heat treatment on the above-mentioned metal or bismuth-based alloy ingot to form a rolled sheet; Surface treatment of the above rolled sheet;

Finely dividing the rolled piece; and

The surface of the rolled sheet is subjected to a plating treatment.

The steps shown in Figure 1 are described in detail below. Note: In the description process, the process principle is mainly described by the preparation method of base metal or bismuth based alloy ingot. The processing technology of bismuth-based binary or multi-alloy is the same.

Processing of base metal or bismuth based alloy ingots:

The metal ingot is smelted by a vacuum intermediate frequency furnace according to a reduction reaction method to produce an industrial grade metal ingot (relative purity greater than 99.9%, total amount greater than 99.5%). At the same time, in order to remove light impurities, it is stipulated that the frequency must be remelted in a vacuum.

Specific process description:

The wet fluorinated barium fluoride and the metal calcium are pressed into a tablet by a hydraulic press; then the two are loaded into the tungsten crucible;

Vacuuming the vacuum intermediate frequency furnace such that the vacuum in the vacuum intermediate frequency furnace is higher than 1 * 10 - ¹ Pa;

Heating the tungsten crucible to 1400-1600 degrees Celsius, thereby causing the cesium fluoride and the metal calcium to melt and undergo a reduction reaction;

The melt melted and subjected to the reduction reaction is cast to form a cast body;

Cooling the cast body by a water-cooled copper mold to form a gift ingot;

After the temperature of the antimony ingot is close to room temperature, the antimony ingot is taken out from the tungsten crucible; the ingot is crushed and then placed in a vacuum intermediate furnace to be remelted and cast. If it is necessary to prepare a Zaki-based alloy ingot, the metal does not need to be remelted. The metal and the other metals required can be directly weighed according to the ratio and then directly smelted into a ingot by a vacuum intermediate frequency furnace. This process can be directly realized. Alloying and removal of light calcium impurities. Alloy ratio is

GdxByMz, where X = (0. 6- 0. 85) , Y = (0. 4-0. 15) , ∑ = margin), about other alloys Β, Μ can be any of other metals of rare earths.

The surface impurities of the ingot may be removed by polishing and polishing the surface of the cooled ingot or the base alloy ingot (referred to as the ingot).

The ingot can then be divided into pre-set gauge blanks using lathes, milling machines and wire-cutting equipment to meet roughing requirements.

The cut blank is cleaned and polished to remove the oxide layer and surface impurities left by the processing.

5-1. 2毫米为, and according to the rolling process in cold rolling, the thickness of the rolled sheet is 0. 5-1. 2 mm, and the rolling process is performed according to the final thickness of the rolled sheet. The process is supplemented by vacuum heat treatment to eliminate rolling stress and reduce the hardening of the material after rolling (the empirical formula for vacuum heat treatment temperature is: (metal melting point + 273) / 2-273.

After processing into a suitable size of rolled sheet, after vacuum heat treatment, it is selected according to the customer's requirements for surface grinding (for example, double-side grinding machine can be used for finishing).

There are several techniques for precise segmentation of rolled sheets, which are selected or combined according to customer requirements accuracy and number of processing. The details are as follows:

Die stamping and splitting: If the customer requires relatively low dimensional accuracy, the stamping die can be made for segmentation processing. The above method is suitable for larger batch processing, and the cost is lower and the speed is faster. However, the tolerance is large.

In order to meet the requirements of high precision and small batch size, it is possible to make suitable tooling and fixtures, and use laser cutting, high-pressure waterjet cutting or wire cutting to carry out coarse division, and reserve appropriate machining allowance for fine grinding or CNC milling machine processing. To meet the tolerances required by the customer.

In the actual production process, the above-mentioned types of processing methods can be combined and used according to the customer's precision requirements. .

Rolling surface coating treatment:

Metal or 4L-based binary or multi-alloys are more active and more susceptible to oxidation, requiring plating on their surfaces.

It must be considered that the thermal conductivity of the coating and the thickness of the coating can be in accordance with the material conditions, so the following two requirements must be met:

The coating thickness is controlled as much as possible at 6-10 μm.

And use a coating or coating with a thermal conductivity close to or equal to the thermal conductivity of the substrate. For example: The thermal conductivity of the metal iridium is: W / (m. k) = 10. 6. The thermal conductivity of binary and multi-alloys can be professional. Thermal conductivity tester.

For example: Polytetrafluoroethylene coatings, Parylene conformal coatings, or other methods can be used as coating choices.

In the ordinary electroplating process, there are pickling processes. The pickling process leads to oxidation and blackening of the surface of the material, and the dense oxide layer formed simultaneously is not easy to remove. Pickling, electric degreasing, electrodeposition, etc. are required in the electroplating process. The process will lead to hydrogen embrittlement of the workpiece, so in principle, the ordinary water-plating anti-corrosion method is excluded.

Example of coating: After many tests, it can be determined that zinc-chromium coating is a suitable choice! The corrosion protection mechanism is now described as follows:

Barrier effect: Due to the laminar overlap of flaky zinc and aluminum, it hinders the progress of corrosive media such as water and oxygen reaching the matrix, which can provide an isolated shielding effect.

Passivation: During the treatment of zinc-chromium coating, chromic acid reacts chemically with zinc, aluminum powder and matrix metal to form a dense passivation film. This passivation film has good corrosion resistance.

Cathodic protection: The main protective effect of the zinc-aluminum-chromium coating is the same as that of the galvanized layer.

The construction process of zinc-chromium coating is as follows:

Organic solvent degreasing;

Mechanical shot blasting (blasting);

Spraying

Bake

Secondary spraying

Bake

dry.

The choice of anti-corrosion method is not limited to the zinc-chromium coating. Any coating or coating that meets the thermal conductivity requirements and meets the thickness requirements, which does not cause hydrogen embrittlement and surface oxidation, can be used as a surface anti-corrosion method for materials.

After many years of experiments, it is shown that the magnetic refrigeration rolled sheet with rare earth metal lanthanum or bismuth based alloy is a more advantageous development direction, because the rolled rare earth lanthanum or ritual alloy sheet, It has high density and good corrosion resistance. Rolling magnetic refrigeration material The method of manufacturing, improving the production process, reducing the production conditions, saving the production cost, and enhancing the anti-corrosion performance of the product, is recognized as a promising new magnetic refrigeration material preparation technology.

Rare-earth magnetic refrigeration materials are non-polluting refrigerant materials. The use of magnetic refrigeration materials to replace the current refrigerators, electric water tanks, water rejection and air conditioners using Freon refrigerant can eliminate the environment caused by the production and use of Freon refrigeration. Pollution and damage to the atmospheric ozone layer. Magnetic refrigeration is based on the principle of magnetocaloric effect, which uses an external magnetic field to cause an orderly and disorderly change (phase change) of the magnetic moment of the magnetic working fluid to cause the heat absorption and heat release of the magnet to perform the refrigeration cycle, compared with the gas compression refrigeration. Magnetic refrigeration has the characteristics of high entropy density, small volume, simple structure, low noise, high efficiency and low power consumption. Currently, magnetic refrigeration has been widely used in low temperature areas. At present, due to the ban of Freon gas, research on room temperature magnetic refrigeration has become an international research topic. In 2010, China will completely ban the production and use of refrigerants such as CFCs and hydrochlorofluorocarbons such as Freon. Therefore, it is necessary to accelerate the research and development of magnetic refrigeration technology and applications.

The invention adopts the metal as the raw material and the rolled base multi-alloy as raw materials, and produces the ingot by two smelting in a vacuum intermediate frequency furnace, and then forms a rolled sheet by cold rolling and vacuum heat treatment, and the rolled sheet is subjected to surface treatment and After precise division, a cold-rolled magnetic refrigeration material can be obtained by surface plating or coating.

Claims

Claim

A method for processing a magnetic refrigerating material and a method for preserving the same, the magnetic refrigerating material comprising a crucible or a base alloy as a raw material, comprising the steps of:

Processing of base metal or bismuth based alloy ingots;

The above-mentioned base metal or 4L-based alloy ingot is pre-segmented into a preform, cold-rolled and vacuum-heat treated to form a rolled sheet;

Surface treatment of the above rolled sheet;

Finely dividing the rolled piece; and

The surface of the rolled sheet is subjected to a plating treatment.

The method for processing a magnetic refrigeration material according to claim 1, and the method for preventing corrosion thereof, wherein: the step of processing the base metal or the base alloy ingot comprises:

The wet fluorinated barium fluoride and the metal calcium are pressed into a tablet by a hydraulic press; then the two are loaded into the tungsten crucible of the vacuum intermediate frequency furnace;

Vacuuming the vacuum intermediate frequency furnace so that the degree of vacuum is higher than 1 * 10 - ^ 0 ;

Cooling the cast body by a water-cooled copper mold to form a gift ingot;

After the temperature of the antimony ingot is close to room temperature, the antimony ingot is taken out from the vacuum intermediate frequency furnace; the ingot is crushed and then placed in a vacuum intermediate frequency furnace to be remelted and cast.

The method of processing a magnetic refrigerating material according to claim 2, and the method for preserving the same, characterized in that the step of surface-treating the rolled sheet comprises ingot forming a crucible or a base alloy ingot for cooling the furnace. The surface is subjected to a polishing method to remove surface impurities of the ingot.

The method of processing a magnetic refrigerating material according to claim 3, and the method of preserving the same, characterized in that the step of precisely dividing the rolled piece comprises the step of dividing the ingot into a preform of a predetermined specification .

The method for processing a magnetic refrigeration material according to claim 4, wherein the step of plating the surface of the rolled sheet comprises washing and polishing the blank to remove the remaining The step of oxidizing the layer and surface impurities.

The magnetic refrigeration 'material processing method according to claim 4 and the anti-corrosion method thereof, characterized in that the step of dividing the ingot into a pre-set specification blank is by die stamping, laser cutting, high pressure Waterjet cutting or wire cutting is carried out.

The method of processing a magnetic refrigeration material according to claim 5, wherein the step of plating the surface of the rolled sheet comprises forming a polytetrafluoroethylene coating on the surface of the rolled sheet. Or Parylene conformal coating.

The method of processing a magnetic refrigeration material according to claim 5, wherein the step of plating the surface of the rolled sheet comprises forming a zinc chromium coating on the surface of the rolled sheet.

The method of processing a magnetic refrigeration material according to claim 8, wherein the thickness of the chromium-plated coating layer is 6-10 μm.

10. The method of processing a magnetic refrigeration material according to claim 1 and an anticorrosive side thereof The method is characterized in that: the step of processing the base metal or the bismuth based alloy ingot comprises: pressing the wet fluorinated barium fluoride and the metal calcium into an ingot by a hydraulic press; and then charging the two into the vacuum Tungsten bismuth of medium frequency furnace;

Vacuuming the vacuum intermediate frequency furnace such that the vacuum of the vacuum intermediate frequency furnace is higher than 1 * 10 - ¹ Pa;

Cooling the cast body by a water-cooled copper mold to form a gift ingot;

When the temperature of the antimony ingot is close to room temperature, the antimony ingot is taken out from the tungsten crucible; the base metal and other metals required are weighed according to the ratio, and then directly smelted into a ingot by a vacuum intermediate frequency furnace, wherein the alloy ratio is GdxByMz, Where X=(0.6-0.85),

Y = (0.4 - 0.15), Ζ = balance, and other alloys Β, Μ may be any of other metals of the rare earth.