Patent Description:
The assembly of polymer and magnesium has been used in various ways for lithium-ion batteries for automotive, smartphones, or electronic devices, requiring waterproof characteristics. The bonding strength of polymer and magnesium, however, has been pointed out as a potential issue due to its low reliability. <CIT> discloses an etching agent: an aqueous solution including acid, and an organic nitrogen compound having a molecular structure containing N-OH or N-O- for a magnesium component and a replenishing solution therefor used for roughening the surface of a magnesium component. <CIT> provides a method for producing a metal-resin complex capable of improving bonding strength by producing a metal alloy having a more uniform etching surface using an alkaline aqueous solution to which a chelating agent is added and an acid aqueous solution to which the chelating agent and an amic acid are added, and injection-molding the resin composition by using the produced metal alloy. <CIT> discloses the manufacturing method of a lightweight and strong composite of a magnesium alloy and a carbon fiber reinforced plastic (CFRP), by strongly bonding the magnesium alloy and the CFRP using an epoxy adhesive. The magnesium alloy having specific ultra-fine irregularities is compatible with an epoxy resin adhesive and exhibits thus strong adhesion.

Thus, by anodizing the magnesium and raising the activity and frictional force of the surface of magnesium, an even stronger bonding between magnesium and polymer has been used for manufacturing thereof. However, even with the etching treatment and ultrasonic waves treatment, it's impossible to acquire sufficient adhesion and shielding with polymer.

This invention is a method to treat the surface of magnesium to solve the above issue. The purpose of this invention is to provide a method to treat the surface of magnesium to manufacture metallic assembly of polymer and magnesium with excellent bonding strength and shielding.

The purpose of the invention is a method to treat the magnesium surface for the bonded coupling of the mixture of the polymer and magnesium, this is a method comprising,.

The step (a), proceeds with an acidic solution mixing sulfuric acid, phosphoric acid and trace amounts of nitric acid, at <NUM>~<NUM> for <NUM>∼<NUM> seconds.

The step (b), proceeds by ultrasonic treatment with the alkali cleaning agent, at <NUM>~<NUM> at <NUM>~<NUM> and <NUM> W for <NUM>~<NUM> seconds.

The step (c), proceeds a second etching with an acidic solution mixing sulfuric acid, phosphoric acid and trace amounts of nitric acid, at <NUM>~<NUM> for <NUM>~<NUM> seconds.

The step (d), proceeds with a mixed solution of <NUM>∼20wt. % C<NUM>K<NUM>O<NUM>, <NUM>~10wt. % Na<NUM>O<NUM>Si, <NUM>~1wt. % C<NUM>H<NUM>O<NUM> and <NUM>-<NUM>. % C<NUM>H<NUM>Na<NUM>O<NUM>S<NUM> (sodium lignin sulphonate) adding <NUM>~lwt. % Silane Coupling agent, at <NUM>∼<NUM>, with <NUM>~<NUM> and 400W for <NUM>∼<NUM> seconds.

The step (e), proceeds with a mixed acidic solution of sulfuric acid and hydrochloric acid at a <NUM>~<NUM> for <NUM>~<NUM> seconds.

The step (f), proceeds with a mixed solution of <NUM>∼20wt. % C<NUM>K<NUM>O<NUM>, <NUM>~10wt. % Na<NUM>O<NUM>Si, <NUM>~1wt. % C<NUM>H<NUM>O<NUM> and <NUM>-<NUM>. % C<NUM>H<NUM>Na<NUM>O<NUM>S<NUM> (sodium lignin sulphonate) adding <NUM>~lwt. % Silane Coupling agent, at <NUM>∼<NUM>, with <NUM>~<NUM> and 400W for <NUM>∼<NUM> seconds.

In the steps of (d) and (f), the Silane coupling additive as the additive is used one of (RO)<NUM>Si-(CH<NUM>)<NUM>-NH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-Si(OC<NUM>H<NUM>)<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-SH, (RO)<NUM>Si-CH=CH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-OOC(CH<NUM>)C=CH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-O-CHCH<NUM>O and (RO)<NUM>Si-(CH<NUM>)<NUM>CH<NUM>.

According to the present invention, the magnesium surface is roughened by an etching process utilizing an acidic solution to the magnesium surface, a first surface treatment with ultrasonic waves to generate cracks in the surface with mite, and through a second etching process utilizing an acidic solution, to form micro-cracks. The surface is further roughened with micro-cracks through second etching using acidic solution. After this, through the first and second silane coupling treatment using ultrasonic waves, a large amount of microcracks are generated on the surface, and then silane penetrates into the generated cracks to maximize the bonding strength between the polymer and magnesium through the bonding action of the polymer and silane. The effect is to maximize the bonding strength between the polymer and magnesium by the bonding action of the polymer and silane.

Referring the below schematics, this explains how to manufacture the bonding of the polymer and magnesium with this invention.

This invention is a method to treat the surface of magnesium in order to maximize the bonded coupling of the polymer mixture with magnesium, the method comprising:.

The etching step (a), proceeds with an acidic solution mixing sulfuric acid, phosphoric acid and trace amounts of nitric acid, at <NUM>~<NUM> for <NUM>~<NUM> seconds.

The etching creates irregular etching patterns on the surface of the magnesium and roughens the surface of the magnesium.

The step (b), proceeds by ultrasonic treatment with the alkali cleaning agent, at <NUM>~<NUM> at <NUM>~<NUM> and <NUM> W for <NUM>∼<NUM> seconds,.

The ultrasonic treatment produces microcracks on the etched magnesium surface. the step (c), proceeds a secondary etching with an acidic solution mixing sulfuric acid, phosphoric acid and trace amounts of nitric acid, at <NUM>~<NUM> for <NUM>~<NUM> seconds.

Secondary etching forms irregular etch marks on the magnesium surface, further roughening the surface.

The step (d), proceeds with a mixed solution of <NUM>∼20wt. % C<NUM>K<NUM>O<NUM>, <NUM>~10wt. % Na<NUM>O<NUM>Si, <NUM>~1wt. % C<NUM>H<NUM>O<NUM> and <NUM>∼<NUM>. % C<NUM>H<NUM>Na<NUM>O<NUM>S<NUM> (sodium lignin sulphonate) adding <NUM>~lwt. % Silane Coupling agent, at <NUM>∼<NUM>, with <NUM>~<NUM> and <NUM> W for <NUM>∼<NUM> seconds.

Microcracks are additionally formed on the etched magnesium surface, and a silane coupling agent is penetrated into the formed microcrack region.

In the (d) step, the electrolyte to be used may be one of C<NUM>K<NUM>O<NUM>, NaHCO<NUM>, NaOH, Na<NUM>CO<NUM>, Na<NUM>SO<NUM>, K<NUM>SO<NUM>, Na<NUM>SO<NUM>, NaNO<NUM>, KNO<NUM>, NaNO<NUM>, NaClO<NUM>, CH<NUM>COONa, Na<NUM>B<NUM>O<NUM>, NaH<NUM>PO<NUM>, (NaPO<NUM>)<NUM>, Na<NUM>MoO<NUM>, Na<NUM>SiO<NUM>, and Na<NUM>HPO<NUM>.

In the (d) step, the Silane coupling additive as the additive may be one of (RO)<NUM>Si-(CH<NUM>)<NUM>-NH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-Si(OC<NUM>H<NUM>)<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-SH, (RO)<NUM>Si-CH=CH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-OOC(CH<NUM>)C=CH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-O-CHCH<NUM>O and (RO)<NUM>Si-(CH<NUM>)<NUM>CH<NUM>.

The surface is etched to make it rougher, and at the same time, about <NUM>% of the magnesium surface containing a silane coupling agent penetrating into the microcrack is removed with etching.

The step (f), proceeds with a mixed solution of <NUM>∼20wt. % C<NUM>K<NUM>O<NUM>, <NUM>~10wt. % Na<NUM>O<NUM>Si, <NUM>~1wt. % C<NUM>H<NUM>O<NUM> and <NUM>∼<NUM>. % C<NUM>H<NUM>Na<NUM>O<NUM>S<NUM> (sodium lignin sulphonate) adding <NUM>~lwt. % Silane Coupling agent, at <NUM>∼<NUM>, with <NUM>~<NUM> and <NUM> W for <NUM>∼<NUM> seconds.

In the (f) step, the Silane coupling additive as the additive may be one of (RO)<NUM>Si-(CH<NUM>)<NUM>-NH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-Si(OC<NUM>H<NUM>)<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-SH, (RO)<NUM>Si-CH=CH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-OOC(CH<NUM>)C=CH<NUM>, (RO)<NUM>Si-(CH<NUM>)<NUM>-O-CHCH<NUM>O and (RO)<NUM>Si-(CH<NUM>)<NUM>CH<NUM>.

After the step (c), upon the magnesium with the second anodizing treatment, the ultrasonic treatment shall proceed with a solvent of H<NUM>SO<NUM> of <NUM>∼<NUM>. % after adding an additive, C<NUM>H<NUM>(OH)<NUM> of <NUM>~<NUM>. %, for <NUM> to <NUM> minutes at 400W, <NUM>~<NUM>, at the temperature of <NUM> to <NUM>.

By the first and second silane coupling treatment using ultrasonic waves, surface roughness is increased on the surface of magnesium, a large amount of fine micro-cracks are formed, such that the silane coupling agent penetrates into the formed micro-cracks, and is coupled to the polymer through a chemical reaction. There is an effect of maximizing the bonding force between the polymer and magnesium by such surface roughness and microcracks and silane coupling agents.

<FIG> represents the changes in the oxide film from each process after treating the surface of magnesium.

<FIG> represents the specific shapes of the oxide film, generated from each process.

After this, specific examples and figures will be explained.

The step (a), proceeds with an acidic solution mixing sulfuric acid, phosphoric acid and trace amounts of nitric acid, at <NUM>~<NUM> for <NUM>~<NUM> seconds.

The step (b), proceeds by ultrasonic treatment with the alkali cleaning agent, at <NUM>~<NUM> at <NUM>~<NUM> and <NUM> W for <NUM>∼<NUM> seconds.

The step (c), proceeds a secondary etching with an acidic solution mixing sulfuric acid, phosphoric acid and trace amounts of nitric acid, at <NUM>~<NUM> for <NUM>~<NUM> seconds.

The specimens were made by conventional methods.

After step (a) , the step (b) and the step (c),.

The step (d), proceeds with a mixed solution of <NUM>∼20wt. % C<NUM>K<NUM>O<NUM>, <NUM>~10wt. % Na<NUM>O<NUM>Si, <NUM>~1wt. % C<NUM>H<NUM>O<NUM> and <NUM>-<NUM>. % C<NUM>H<NUM>Na<NUM>O<NUM>S<NUM> (sodium lignin sulphonate) adding <NUM>~lwt. % Silane Coupling agent, at <NUM>∼<NUM>, with <NUM>~<NUM> and <NUM> W for <NUM>∼<NUM> seconds.

The specimens were made by above methods.

The step (f), proceeds with a mixed solution of <NUM>∼20wt. % C<NUM>K<NUM>O<NUM>, <NUM>~10wt. % Na<NUM>O<NUM>Si, <NUM>~1wt. % C<NUM>H<NUM>O<NUM> and <NUM>-<NUM>. % C<NUM>H<NUM>Na<NUM>O<NUM>S<NUM> (sodium lignin sulphonate) adding <NUM>~lwt. % Silane Coupling agent, at <NUM>∼<NUM>, with <NUM>~<NUM> and <NUM> W for <NUM>∼<NUM> seconds.

With the specimens from embodiments <NUM> to <NUM>, tests were conducted to measure the bonding strength and sealing quality by the resistance test, T-Bend test, tensile strength test, and rest time test. The followings are the results thereof.

By using the specimens from embodiment <NUM> to <NUM>, to measure the bonding strength, after <NUM>,<NUM> hours of the temperature and humidity test, the T-bend test was conducted and the results thereof are marked in Table <NUM>.

As shown in Table <NUM>, it may be seen that only the samples of embodiment <NUM> is additionally performed, have best bonding strength between polymer and magnesium rather than the samples of comparative embodiments <NUM>, <NUM>, and <NUM>.

<FIG> is a specimen produced for the T-Bend test, and show a test method.

<FIG> is a picture of the test results showing "No Good" quality from the test results of the T-Bend test and how to conduct such a test.

<FIG> is a picture of the test results showing "Good" quality from the test results of the T-Bend test and how to conduct such a test.

By using the specimens from embodiments <NUM> to <NUM>, to measure the bonding strength, after <NUM>,<NUM> hours of the temperature and humidity test, the tensile strength test was conducted and the results show in <FIG>.

<FIG> is a specimen produced for a tensile strength test, and it has the polymer overlaid on the magnesium specimen from each embodiment.

<FIG> is a picture of the experimental method of the tensile strength test.

Just as a graph in <FIG>, rather than the specimen from embodiment <NUM>, the specimen from embodiment <NUM> shows excellent tensile strength before and after the temperature and humidity test.

Also, rather than the specimen from embodiment <NUM>, the specimen from embodiment <NUM> shows excellent tensile strength before and after the temperature and humidity test.

Finally, rather than the specimen from embodiment <NUM>, the specimen from embodiment <NUM> shows excellent tensile strength before and after the temperature and humidity test.

<FIG> is a picture of the amount of the polymer remaining on the magnesium surface, separated from the specimens of embodiments <NUM> to <NUM> after conducting the experiments on the tensile strength after the temperature and humidity test.

<FIG> is a picture of the separated side of the specimen from embodiment <NUM>, showing that <NUM>% of the polymer remains on the magnesium surface due to the separation.

The graph in <FIG> is the test results of the tensile strength for each embodiment after overlaying of <NUM> to <NUM> months.

Likewise, the decrease in tensile force over pass time is greater the specimen of embodiment <NUM> than in the specimen of embodiment <NUM>.

Also, the decrease in tensile force over pass time is superior the specimen of embodiment <NUM> than in the specimen of embodiment <NUM>.

Finally, the decrease in tensile force over pass time is better the specimen of embodiment <NUM> than in the specimen of embodiment <NUM>.

By using the specimens from embodiments <NUM> to <NUM>, to measure the sealing condition between the magnesium and polymer, the temperature and humidity test was conducted and the results thereof are shown in <FIG>.

Just as a graph in <FIG>, rather than the specimen from embodiment <NUM>, the specimen from embodiment <NUM> shows better sealing quality.

Also, rather than the specimen from embodiment <NUM>, the specimen from embodiment <NUM> shows better sealing quality.

Finally, rather than the specimen from embodiment <NUM>, the specimen from embodiment <NUM> shows the best sealing quality.

<FIG> is a picture of a specimen for a temperature and humidity test.

<FIG> is a picture of a device to experiment with the temperature and humidity test.

Claim 1:
As a method to treat the magnesium surface for the bonded coupling of the mixture of the polymer and magnesium, this is a method comprising,
(a) an etching step wherein the magnesium surface is treated by an acidic solution,
(b) a first surface treatment step wherein the magnesium surface is treated by ultrasonic waves.
(c) a second surface treatment step wherein the magnesium surface is treated by an acidic solution;
(d) a first silane coupling processing step wherein the magnesium surface is treated by ultrasonic waves
(e) a surface activation treatment step wherein the magnesium surface is treated by acidic solution
(f) a second silane coupling processing step wherein the magnesium surface is treated by ultrasonic waves; and
the step (a), is performed in an acidic solution mixing sulfuric acid, phosphoric acid and trace amounts of nitric acid, at <NUM>~<NUM> for <NUM>∼<NUM> seconds.
the step (b), proceeds by ultrasonic treatment with the alkali cleaning agent, at <NUM>~<NUM> at <NUM>~<NUM> and <NUM> W for <NUM>~<NUM> seconds.
the step (c), proceeds a secondary etching with an acidic solution mixing sulfuric acid, phosphoric acid and trace amounts of nitric acid, at <NUM>~<NUM> for <NUM>~<NUM> seconds.
the step (d), proceeds with a mixed solution of <NUM>∼20wt.% C<NUM>K<NUM>O<NUM>, <NUM>~10wt.% Na<NUM>O<NUM>Si, <NUM>~1wt.% C<NUM>H<NUM>O<NUM> and <NUM>-<NUM>.01wt.% C<NUM>H<NUM>Na<NUM>O<NUM>S<NUM> (sodium lignin sulphonate) adding <NUM>~lwt.% Silane Coupling agent, at <NUM>∼<NUM>, with <NUM>~<NUM> and <NUM> W for <NUM>∼<NUM> seconds.
the step (e), proceeds with a mixed acidic solution of sulfuric acid and hydrochloric acid at a <NUM>~<NUM> for <NUM>∼<NUM> seconds.
the step (f), proceeds with a mixed solution of <NUM>∼20wt.% C<NUM>K<NUM>O<NUM>, <NUM>~10wt.% Na<NUM>O<NUM>Si, <NUM>~1wt.% C<NUM>H<NUM>O<NUM> and <NUM>-<NUM>.01wt.% C<NUM>H<NUM>Na<NUM>O<NUM>S<NUM> (sodium lignin sulphonate) adding <NUM>~lwt.% Silane Coupling agent, at <NUM>∼<NUM>, with <NUM>~<NUM> and <NUM> W for <NUM>∼<NUM> seconds.