阅读说明：本技术 一种化学镍热处理工艺 (Chemical nickel heat treatment process ) 是由 朱万宇 游健 黄皓 李云仕 赵景勋 吴传伟 于 2020-06-02 设计创作，主要内容包括：本发明公开了一种化学镍热处理工艺,S3、将铝锂合金金属零件放入钝化液中,钝化液由浓度为110~130g/LK<Sub>2</Sub>Cr<Sub>2</Sub>O<Sub>7</Sub>和2～3g/LCrO<Sub>3</Sub>组成,控制钝化液温度为60~70℃,钝化时间为10~15min,钝化时间到达规定的时间后,即可完成对镀镍层的钝化处理；S4、利用清水清洗钝化后的铝锂合金金属零件,清洗后利用压缩空气吹干铝锂合金金属零件；S5、将吹干后的铝锂合金金属零件放入真空热处理炉中,对真空热处理炉抽真空,抽真空后将炉体内温度升温至250~450°C,保温时间控制在1~2h,保温达到规定时间后停止保温,铝锂合金金属零件随炉冷却到室,从而完成对镀镍层的热处理。本发明的有益效果是：工艺简单、有效改善铝锂合金表面镀镍层与基体之间的结合力、提高镀镍层耐腐蚀性能。(The invention discloses a chemical nickel heat treatment process, S3, placing an aluminum lithium alloy metal part into a passivation solution, wherein the concentration of the passivation solution is 110-130 g/LK 2 Cr 2 O 7 And 2 to 3g/LCrO 3 The method comprises the following steps of controlling the temperature of a passivation solution to be 60-70 ℃, passivating for 10-15 min, and completing passivation treatment of a nickel-plated layer after the passivation time reaches a specified time; s4, cleaning the passivated aluminum lithium alloy metal parts by clean water, and drying the aluminum lithium alloy metal parts by compressed air after cleaningA part; s5, placing the dried aluminum lithium alloy metal part into a vacuum heat treatment furnace, vacuumizing the vacuum heat treatment furnace, heating the temperature in the furnace body to 250-450 ℃ after vacuumizing, controlling the heat preservation time to be 1-2 h, stopping heat preservation after the heat preservation reaches the specified time, and cooling the aluminum lithium alloy metal part to a room along with the furnace, thereby completing the heat treatment of the nickel-plated layer. The invention has the beneficial effects that: the process is simple, the binding force between the nickel plating layer on the surface of the aluminum lithium alloy and the matrix is effectively improved, and the corrosion resistance of the nickel plating layer is improved.)

1. A chemical nickel heat treatment process is characterized in that: it comprises the following steps:

s1, sequentially carrying out cathode electrolytic degreasing, primary water washing, acid washing and secondary water washing treatment on the aluminum lithium alloy metal part;

s2, immersing the aluminum lithium alloy metal part into a nickel plating bath for chemical plating, wherein the plating solution in the nickel plating bath is prepared by the steps of respectively using 27-30 g/L nickel sulfate, 28-30 g/L sodium hypophosphite, 20g/L sodium acetate, 20g/L malic acid, 15g/L succinic acid and a small amount of brightener, controlling the pH value of the plating solution to be 4-5 and the temperature to be 85-90 ℃, and ensuring the thickness of a nickel plating layer on the aluminum lithium alloy metal part to be 10-15 microns after a period of chemical plating;

s3, putting the aluminum lithium alloy metal part into a passivation solution, wherein the concentration of the passivation solution is 110-130 g/LK₂Cr₂O₇And 2 to 3g/LCrO₃The method comprises the following steps of controlling the temperature of a passivation solution to be 60-70 ℃, passivating for 10-15 min, and completing passivation treatment of a nickel-plated layer after the passivation time reaches a specified time;

s4, cleaning the passivated aluminum lithium alloy metal part by using clear water, and drying the aluminum lithium alloy metal part by using compressed air after cleaning;

s5, placing the dried aluminum lithium alloy metal part into a vacuum heat treatment furnace, vacuumizing the vacuum heat treatment furnace, heating the temperature in the furnace body to 250-450 ℃ after vacuumizing, controlling the heat preservation time to be 1-2 h, stopping heat preservation after the heat preservation reaches the specified time, and cooling the aluminum lithium alloy metal part to a room along with the furnace, thereby completing the heat treatment of the nickel-plated layer;

s6, observing and analyzing the surface micro-morphology of the nickel-plated layer before and after heat treatment by adopting a scanning electron microscope and an INCA type energy spectrometer;

s7, analyzing the corrosion resistance of the nickel-plating layer before and after heat treatment by adopting a salt spray test.

2. The chemical nickel heat treatment process according to claim 1, characterized in that: and in the step S5, when the heat treatment is carried out, the temperature in the furnace body is raised to 250 ℃, the heat preservation time is controlled to be 1h, the heat preservation is stopped after the heat preservation reaches the specified time, and the aluminum-lithium alloy metal part is cooled to the room along with the furnace, thereby completing the heat treatment of the nickel-plated layer.

3. The chemical nickel heat treatment process according to claim 1, characterized in that: and in the step S5, when the heat treatment is carried out, the temperature in the furnace body is raised to 350 ℃, the heat preservation time is controlled to be 1.5h, the heat preservation is stopped after the heat preservation reaches the specified time, and the aluminum-lithium alloy metal part is cooled to the room along with the furnace, thereby completing the heat treatment of the nickel-plated layer.

4. The chemical nickel heat treatment process according to claim 1, characterized in that: and in the step S5, when the heat treatment is carried out, the temperature in the furnace body is raised to 450 ℃, the heat preservation time is controlled to be 2 hours, the heat preservation is stopped after the heat preservation reaches the specified time, and the aluminum-lithium alloy metal part is cooled to the room along with the furnace, thereby completing the heat treatment of the nickel-plated layer.

Technical Field

The invention relates to the technical field of improving the performance of a nickel plating layer, in particular to a chemical nickel heat treatment process.

Background

The process of plating metals or certain non-metals with a layer of nickel by electrolytic or chemical means is known as nickel plating. The nickel plating is divided into electro nickel plating and chemical nickel plating. The electroplating nickel is that in the electrolyte composed of nickel salt, conducting salt, pH buffering agent and wetting agent, the anode uses metallic nickel, the cathode is the plated part, and a layer of uniform and compact nickel plating layer is deposited on the cathode (aluminum lithium alloy metal part) by applying direct current. Bright nickel is obtained from the bath with brightener added, while dark nickel is obtained in the bath without brightener added. Electroless plating is also known as electroless plating and may also be referred to as autocatalytic plating. The specific process is as follows: under certain conditions, metal ions in the aqueous solution are reduced by the reducing agent and precipitate onto the surface of the solid substrate.

Researches show that the nickel plating layer can improve the corrosion resistance of the aluminum lithium alloy metal part, so that the service life of the aluminum lithium alloy metal part is obviously prolonged after the nickel plating layer is plated on the aluminum lithium alloy metal part. However, if the surface of the nickel layer of the aluminum-lithium alloy metal part is still corroded under the high-acid-base condition, the base material of the aluminum-lithium alloy metal part is corroded to a certain extent, and therefore, the use requirement cannot be met only by nickel plating. In addition, after the nickel layer is used for a period of time or impacted, the nickel layer is easy to fall off from the base material, and the main reason is that the bonding capability of the nickel layer and the base material is poor, so that the service life of the aluminum-lithium alloy metal part is shortened.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a chemical nickel heat treatment process which is simple in process, effectively improves the binding force between a nickel plating layer on the surface of an aluminum lithium alloy and a substrate and improves the corrosion resistance of the nickel plating layer.

The purpose of the invention is realized by the following technical scheme: a chemical nickel heat treatment process comprises the following steps:

s1, sequentially carrying out cathode electrolytic degreasing, primary water washing, acid washing and secondary water washing treatment on the aluminum lithium alloy metal part;

s2, immersing the aluminum lithium alloy metal part into a nickel plating bath for chemical plating, wherein the plating solution in the nickel plating bath is prepared by the steps of respectively using 27-30 g/L nickel sulfate, 28-30 g/L sodium hypophosphite, 20g/L sodium acetate, 20g/L malic acid, 15g/L succinic acid and a small amount of brightener, controlling the pH value of the plating solution to be 4-5 and the temperature to be 85-90 ℃, and ensuring the thickness of a nickel plating layer on the aluminum lithium alloy metal part to be 10-15 microns after a period of chemical plating;

s3, putting the aluminum lithium alloy metal part into a passivation solution, wherein the concentration of the passivation solution is 110-130 g/LK₂Cr₂O₇And 2 to 3g/LCrO₃The method comprises the following steps of controlling the temperature of a passivation solution to be 60-70 ℃, passivating for 10-15 min, and completing passivation treatment of a nickel-plated layer after the passivation time reaches a specified time;

s4, cleaning the passivated aluminum lithium alloy metal part by using clear water, and drying the aluminum lithium alloy metal part by using compressed air after cleaning;

s5, placing the dried aluminum lithium alloy metal part into a vacuum heat treatment furnace, vacuumizing the vacuum heat treatment furnace, heating the temperature in the furnace body to 250-450 ℃ after vacuumizing, controlling the heat preservation time to be 1-2 h, stopping heat preservation after the heat preservation reaches the specified time, and cooling the aluminum lithium alloy metal part to a room along with the furnace, thereby completing the heat treatment of the nickel-plated layer;

s6, observing and analyzing the surface micro-morphology of the nickel-plated layer before and after heat treatment by adopting a scanning electron microscope and an INCA type energy spectrometer;

s7, analyzing the corrosion resistance of the nickel-plating layer before and after heat treatment by adopting a salt spray test.

And in the step S5, when the heat treatment is carried out, the temperature in the furnace body is raised to 250 ℃, the heat preservation time is controlled to be 1h, the heat preservation is stopped after the heat preservation reaches the specified time, and the aluminum-lithium alloy metal part is cooled to the room along with the furnace, thereby completing the heat treatment of the nickel-plated layer.

And in the step S5, when the heat treatment is carried out, the temperature in the furnace body is raised to 350 ℃, the heat preservation time is controlled to be 1.5h, the heat preservation is stopped after the heat preservation reaches the specified time, and the aluminum-lithium alloy metal part is cooled to the room along with the furnace, thereby completing the heat treatment of the nickel-plated layer.

And in the step S5, when the heat treatment is carried out, the temperature in the furnace body is raised to 450 ℃, the heat preservation time is controlled to be 2 hours, the heat preservation is stopped after the heat preservation reaches the specified time, and the aluminum-lithium alloy metal part is cooled to the room along with the furnace, thereby completing the heat treatment of the nickel-plated layer.

The invention has the following advantages: the invention has simple process, effectively improves the binding force between the nickel plating layer on the surface of the aluminum lithium alloy and the matrix, and improves the corrosion resistance of the nickel plating layer.

Drawings

FIG. 1 is a cross-sectional SEM topography and EDS spectra of a nickel plating layer before heat treatment;

FIG. 2 is a cross-sectional SEM image and EDS spectrum of the nickel-plated layer after heat treatment;

FIG. 3 shows the corrosion of the nickel plating layer before and after the heat treatment by the salt spray test.

Detailed Description

The invention will be further described with reference to the accompanying drawings, without limiting the scope of the invention to the following: