Magnesium alloy conversion film enhancement treatment agent and magnesium alloy surface treatment method
Technical Field
The invention relates to the field of metal surface treatment, in particular to a magnesium alloy conversion film enhancement treating agent and a magnesium alloy surface treatment method.
Background
Magnesium alloy, as an industrial material widely used, has received wide attention from various industries such as aerospace, automobiles, electronics, precision instruments and the like due to its advantages of small density, light weight, good shock absorption, strong impact resistance, good electromagnetic shielding, good wear resistance and the like. The magnesium alloy is mainly applied to the fields of aerospace, electronics, automobiles and the like, and in order to improve the requirement on the corrosion resistance of magnesium alloy devices, a protective layer needs to be formed on the surface of the magnesium alloy. For example, chinese patents CN101096761A and CN101418441A both adopt a phosphating process to form a phosphate conversion coating on the surface of the magnesium alloy, and although the formed phosphate conversion coating is a chromium-free conversion coating, the conversion coating is very thin and is easily scratched and damaged, so that the surface of the magnesium alloy is easily corroded and oxidized again in the air.
Therefore, there is a need for a treatment agent capable of enhancing the conversion coating of magnesium alloy.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention mainly aims to provide a magnesium alloy conversion coating reinforcing treatment agent which can improve the surface hardness of a magnesium alloy conversion coating, resist scratching and fingerprints and further improve the corrosion resistance of the magnesium alloy conversion coating.
The invention also aims to provide a magnesium alloy surface treatment method.
In order to achieve the purpose, the invention adopts the following technical scheme:
a magnesium alloy conversion coating reinforcing treatment agent comprises the following components: 3-15 g/L of lauric acid and/or myristic acid, 3-15 g/L of oleic acid, 3-15 g/L of TX-10 emulsifier, 3-15 g/L of ethanol, 1-5 g/L of sodium hydroxide or monoethanolamine, and the balance of water.
In one embodiment, the magnesium alloy conversion coating enhancement treatment agent comprises the following components: 5 g/L of lauric acid, 3 g/L of oleic acid, 3 g/L of TX-10 emulsifier, 15 g/L of ethanol, 5 g/L of sodium hydroxide and the balance of water.
In one embodiment, the magnesium alloy conversion coating enhancement treatment agent comprises the following components: 3 g/L of myristic acid, 5 g/L of oleic acid, 5 g/L of TX-10 emulsifier, 15 g/L of ethanol, 5 g/L of monoethanolamine and the balance of water.
In one embodiment, the magnesium alloy conversion coating enhancement treatment agent comprises the following components: 3 g/L of lauric acid, 3 g/L of myristic acid, 3 g/L of oleic acid, TX-105 g/L, 15 g/L of ethanol, 5 g/L of monoethanolamine and the balance of water.
In one embodiment, the ethanol is anhydrous ethanol.
The invention also provides a magnesium alloy surface treatment method using the magnesium alloy conversion film enhancement treating agent, which comprises the steps of sequentially carrying out degreasing and oil removing treatment, pickling and activating treatment, surface conditioning and ash removing treatment, chromium-free conversion treatment, conversion film enhancement treatment and drying treatment on the magnesium alloy;
and the conversion film enhancement treatment is to immerse the magnesium alloy subjected to chromium-free conversion treatment into the magnesium alloy conversion film enhancement treatment agent, treat the magnesium alloy at 50-60 ℃ for 20-30 s, wash the magnesium alloy with water and then perform drying treatment.
In one embodiment, the degreasing treatment is to immerse the magnesium alloy into a degreasing agent, treat the magnesium alloy at 60 ℃ for 6min, and perform acid washing and activating treatment after water washing.
The degreasing agent comprises the following components: 10 g/L of sodium hydroxide, 20 g/L of HEDP, 5 g/L of sodium pyrophosphate, 1.25 g/L of 1309 isomeric alcohol ether, 1 g/L of alkyl glycoside and the balance of water.
In one embodiment, the pickling activation treatment is to immerse the magnesium alloy subjected to degreasing and degreasing treatment into a pickling agent, treat the magnesium alloy for 1-2min at 50-60 ℃, and perform surface conditioning and ash removal after water washing.
Wherein the pickling agent is M330 pickling agent, which is produced by Tooming chemical industry in Boruo county, and the use amount of the pickling agent is 8-10% of grooving.
In one embodiment, the surface conditioning ash removal treatment is to immerse the magnesium alloy subjected to acid pickling activation treatment into a surface conditioning agent, treat the magnesium alloy for 1-2s at the temperature of 25-60 ℃, and perform a chromium-free conversion operation after water washing.
The surface conditioner is M440 surface conditioner, is produced in the east Ming chemical industry of Boruo county, and is grooved with the use amount of 20-25%.
In one embodiment, the chromium-free conversion treatment is to immerse the magnesium alloy subjected to surface conditioning and ash removal treatment into a coating agent, soak the magnesium alloy at normal temperature for 20-35 seconds, wash the magnesium alloy with water, and then perform conversion film strengthening treatment.
The coating agent is M531 coating agent, is produced in the Tooming chemical industry in Boruo county, and is grooved in an amount of 8-10%.
In one embodiment, the drying treatment is baking at 135 +/-5 ℃ for 10-25 min.
Compared with the prior art, the invention has the following advantages and technical effects:
(1) the magnesium alloy conversion film enhancement treating agent provided by the invention adopts 3-15 g/L of lauric acid and/or myristic acid, 3-15 g/L of oleic acid, 3-15 g/L of TX-10 emulsifier, 3-15 g/L of ethanol, 1-5 g/L of sodium hydroxide or monoethanolamine and the balance of water; a layer of protective film can be rapidly generated on the surface of the magnesium alloy conversion film, so that the hardness and the scratch-resistant effect of the magnesium alloy conversion film are obviously improved, and meanwhile, the magnesium alloy conversion film has a fingerprint-resistant function and the corrosion-resistant effect of the magnesium alloy conversion film is improved; after the magnesium alloy conversion film provided by the invention is used for enhancing treatment, the resistance and the coating adhesive force of the surface of the magnesium alloy conversion film are not influenced, and meanwhile, the magnesium alloy conversion film enhancing treatment agent is free of chromium and phosphorus, does not contain harmful substances to human bodies, and is beneficial to environmental protection.
(2) The magnesium alloy surface treatment method provided by the invention has the advantages of simple process and high efficiency, for example, in the conversion film enhancement treatment step, a layer of protective film can be formed on the magnesium alloy conversion film only by treating at 50-60 ℃ for 20-30 s, and various performances of the magnesium alloy conversion film can be enhanced.
Drawings
FIG. 1 is a process flow chart of a magnesium alloy surface treatment method according to embodiment 1 of the present invention;
FIG. 2 is a surface condition diagram of a magnesium alloy workpiece after fingerprint resistance, scratch resistance and salt spray tests according to example 1 of the present invention;
FIG. 3 is a surface condition diagram of a magnesium alloy workpiece after fingerprint resistance, scratch resistance and salt spray test in example 2 of the present invention;
FIG. 4 is a surface condition chart of a magnesium alloy workpiece after fingerprint resistance, scratch resistance and salt spray tests in example 3 of the present invention.
Detailed Description
The present invention will be described in further detail below with reference to specific examples and drawings, but the embodiments of the present invention are not limited thereto. All the raw materials and reagents used in the present invention are commercially available raw materials and reagents, unless otherwise specified. In the examples, the components are used in g and mL in parts by mass.
Example 1:
degreasing and deoiling: immersing a magnesium alloy workpiece into a degreasing agent, treating for 6min at 60 ℃, washing with water, and then performing acid pickling and activating treatment, wherein the degreasing agent comprises the following components: 10 g/L of sodium hydroxide, 20 g/L of HEDP, 5 g/L of sodium pyrophosphate, 1.25 g/L of 1309 isomeric alcohol ether, 1 g/L of alkyl glycoside and the balance of water.
Acid pickling and activating treatment: the magnesium alloy workpiece after degreasing and oil removing treatment is immersed into an M330 pickling agent (manufactured by Tooming chemical industry in Boruo county), grooving is carried out with the use amount of 8-10%, the magnesium alloy workpiece is treated for 1-2min at the temperature of 50-60 ℃, and the magnesium alloy workpiece is washed by water and then subjected to surface conditioning and ash removal operation.
Surface conditioning ash removal treatment: immersing the magnesium alloy workpiece subjected to acid pickling activation treatment into an M440 surface conditioner (manufactured by Toming chemical industry in Boruo county), grooving with the use amount of 20-25%, treating for 1-2s at 25-60 ℃, washing with water, and then performing chromium-free conversion operation.
And (3) chromium-free conversion treatment: and (2) immersing the magnesium alloy workpiece subjected to surface conditioning and ash removal treatment into an M531 coating agent (manufactured by Tomings chemical industry in Boruo county), slotting with the use amount of 8-10%, soaking for 20-35 s at normal temperature, washing with water, and then performing conversion film strengthening treatment operation.
And (3) conversion film enhancement treatment: immersing the magnesium alloy workpiece subjected to chromium-free conversion treatment into a magnesium alloy conversion film enhancing treatment agent, treating at 50-60 ℃ for 20-30 s, washing with water, and then performing drying treatment, wherein the magnesium alloy conversion film enhancing treatment agent comprises the following components: 5 g/L of lauric acid, 3 g/L of oleic acid, 3 g/L of TX-10 emulsifier, 15 g/L of absolute ethyl alcohol, 5 g/L of sodium hydroxide and the balance of water.
Drying treatment: and (3) placing the magnesium alloy workpiece subjected to the film enhancement treatment into a baking oven, and baking for 10-25 min at 135 +/-5 ℃.
Referring to fig. 1, a process flow chart of the magnesium alloy surface treatment in this example 1 is shown.
Example 2:
the difference from the embodiment 1 is that the magnesium alloy conversion coating enhancement treatment agent of the embodiment 2 comprises the following components: 3 g/L of myristic acid, 5 g/L of oleic acid, 5 g/L of TX-10 emulsifier, 15 g/L of absolute ethyl alcohol, 5 g/L of monoethanolamine and the balance of water.
Example 3:
the difference from the example 1 is that the magnesium alloy conversion coating enhancement treatment agent of the example 3 comprises the following components: 3 g/L of lauric acid, 3 g/L of myristic acid, 3 g/L of oleic acid, 5 g/L of TX-10 emulsifier, 15 g/L of absolute ethyl alcohol, 5 g/L of monoethanolamine and the balance of water.
Comparative example 1:
the difference from example 1 is that the magnesium alloy workpiece of comparative example 1 was not subjected to the conversion coating strengthening treatment operation.
Comparative example 2:
the difference from example 1 is that the magnesium alloy conversion coating enhancement treatment agent of comparative example 2 comprises the following components: 5 g/L of lauric acid, 3 g/L of TX-10 emulsifier, 15 g/L of absolute ethyl alcohol, 5 g/L of sodium hydroxide and the balance of water.
Comparative example 3:
the difference from example 1 is that the magnesium alloy conversion coating enhancement treatment agent of comparative example 3 comprises the following components: 5 g/L of oleic acid, 3 g/L of TX-10 emulsifier, 15 g/L of absolute ethyl alcohol, 5 g/L of sodium hydroxide and the balance of water.
Comparative example 4:
the difference from example 1 is that the magnesium alloy conversion coating reinforcing treatment agent of comparative example 4 comprises the following components: 5 g/L of lauric acid, 3 g/L of oleic acid, 15 g/L of absolute ethyl alcohol, 5 g/L of sodium hydroxide and the balance of water.
The magnesium alloy workpieces treated in the examples 1 to 3 and the comparative examples 1 to 4 are respectively subjected to salt spray tests for 48h, salt spray tests for 72h and salt spray tests for 96h, scratch resistance tests for 96h and fingerprint resistance tests, and the test results are shown in the table 1.
The fingerprint resistance test is to press the surface of the magnesium alloy with fingers and observe whether fingerprints remain;
in the scratch resistance test, a workpiece is scraped back and forth on the surface of the magnesium alloy, and whether scratches exist or not and the metal luster is exposed is observed;
and 5% sodium chloride neutral salt mist continuous spraying is adopted in the salt mist test, and whether white spots and corrosion spots exist on the surface of the magnesium alloy workpiece is observed.
TABLE 1 Effect of treatment methods on magnesium alloy conversion coating Performance
From the experimental results in table 1, it can be seen that the magnesium alloys in examples 1 to 3 all pass the salt spray test, the fingerprint resistance test and the scratch resistance test after surface treatment, that is, the magnesium alloy workpieces treated in examples 1 to 3 have no fingerprint residue after being pressed by fingers, and have no scratch even if being scraped back and forth by the workpieces, and have no white point and corrosive black point after 48h, 72h and 96h of salt spray test, and the corrosion resistance reaches 10 levels, and the surface conditions of the magnesium alloy workpieces after the test are shown in fig. 2, fig. 3 and fig. 4.
Compared with the example 1, the comparative example 1 is not subjected to the conversion coating strengthening treatment, namely the magnesium alloy conversion coating strengthening treatment agent is not used, and the experimental result shows that the comparative example 1 cannot pass the fingerprint resistance test, the scratch resistance test and the 72h and 96h salt spray test, so that the magnesium alloy conversion coating strengthening treatment agent can be used for really improving the hardness of the magnesium alloy conversion coating, strengthening the scratch resistance and corrosion resistance effects of the magnesium alloy conversion coating and endowing the magnesium alloy conversion coating with the fingerprint resistance function.
Compared with example 1, the components of the magnesium alloy conversion coating reinforcing treatment agent of comparative example 2 lack oleic acid and use lauric acid alone, comparative example 3 lacks lauric acid and use oleic acid alone, and both comparative example 2 and comparative example 3 fail the scratch resistance test, which shows that the effect of improving the hardness of the magnesium alloy conversion coating is limited and the scratch resistance cannot be prevented by using lauric acid or oleic acid alone.
Compared with the component of the example 1, the component of the magnesium alloy conversion coating enhancement treating agent of the comparative example 4 does not use the TX-10 emulsifier, and the component is represented by uneven surface color of the treated magnesium alloy, namely the component does not use the TX-10 emulsifier, the film forming uniformity of the conversion coating enhancement treating agent is influenced, and the enhancement effect of the conversion coating enhancement treating agent on the conversion coating is obviously influenced.
The above embodiments are the best mode for carrying out the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be regarded as equivalent substitutions and are included in the scope of the present invention.