Bright pickling additive for magnesium alloy containing heavy metal elements and preparation method of bright pickling additive

Abstract

The invention relates to the technical field of magnesium alloy surface treatment, in particular to a bright pickling additive for magnesium alloy containing heavy metal elements and a preparation method of the bright pickling additive. Comprising the following components: 5 g / L of potassium fluotitanate, 10 g / L of sodium metavanadate, 50-70 g / L of ammonium bifluoride, 30-50 g / L of sodium metasilicate nonahydrate, 100-200 mL / L of lactic acid and 50-70 mL / L of phytic acid, by adding the potassium fluotitanate, the potassium fluotitanate is reduced into TiO2 when making contact with a metal magnesium alloy matrix, so that the surface potential of a workpiece is balanced, the polishing effect is achieved, and by adding the ammonium bifluoride, the surface of the workpiece is not prone to being damaged. By adding sodium metasilicate nonahydrate, dirt formed on the surface of a magnesium alloy workpiece due to precipitates formed by metal ions such as Cu and Ag is reduced, and by adding sodium metasilicate nonahydrate, generation of heavy metal cation precipitates is reduced, so that dust on the working surface is reduced. The cleaning agent can be matched with low-concentration inorganic strong acid and organic acid to perform bright cleaning on magnesium alloy surfaces containing various heavy metals in different processing states under the environment operation from low temperature to medium temperature.

Description

Technical Field

[0001] The invention relates to the technical field of magnesium alloy surface treatment, in particular to a bright pickling additive for magnesium alloy containing heavy metal elements and a preparation method thereof. Background Art

[0002] Magnesium alloy is one of the lightest structural materials to date and is widely used in 3C electronics, aerospace, rail transportation and other fields. However, its active chemical properties and poor corrosion resistance are a major bottleneck in its promotion and application. Surface treatment is an effective method and way to solve this bottleneck. Among the many surface treatment methods, it is a necessary prerequisite to first obtain a bright and clean metal substrate appearance surface. However, some magnesium alloys containing Zr, Mn, Sn, Cu and heavy RE form black or dark thirsty or dark gray surfaces after encountering acid, which brings great trouble to subsequent processing and even makes conventional processing impossible.

[0003] In the prior art, a complex of concentrated acids with chelating properties such as HEDP and lactic acid can obtain a smooth surface on AZ series magnesium alloys and their castings and die castings, but it is difficult to meet the requirements in alloy systems containing heavy metals such as Zr, Mn, Sn, V, and W.

[0004] In order to obtain a smooth surface to be treated, the most commonly used method on the market is to etch with organic acid and then react and neutralize in a high-temperature alkaline liquid. However, this process is ineffective for surfaces etched with strong inorganic acids, while organic acids are expensive and waste liquid treatment is difficult. Summary of the invention

[0005] The purpose of the present invention is to provide a bright pickling additive for magnesium alloy containing heavy metal elements and a preparation method thereof, so as to solve the problem that the prior art is ineffective for treating the surface of magnesium alloy after being etched by strong inorganic acid, and the organic acid is expensive and the waste liquid treatment is difficult.

[0006] To achieve the above-mentioned purpose, the present invention provides a bright pickling additive for magnesium alloy containing heavy metal elements and a preparation method thereof. The bright pickling additive for magnesium alloy containing heavy metal elements comprises the following components: 5 g / L potassium fluorotitanate, 10 g / L sodium metavanadate, 50-70 g / L ammonium bifluoride, 30-50 g / L sodium metasilicate nonahydrate, 100-200 mL / L lactic acid and 50-70 mL / L phytic acid.

[0007] Among them, the preferred amount of ammonium bifluoride is 55 g / L, the preferred amount of sodium metasilicate nonahydrate is 50 g / L, the preferred amount of lactic acid is 150 mL / L, and the preferred amount of phytic acid is 50 mL / L.

[0008] The present invention also provides a method for preparing a bright pickling additive, which is applied to the bright pickling additive for magnesium alloy containing heavy metal elements as described above, and comprises the following steps:

[0009] S1: Take a 1L beaker, add 200mL pure water, add measured lactic acid and phytic acid to the pure water, stir evenly to obtain solution A;

[0010] S2: adding measured potassium fluorotitanate and sodium metavanadate to the above solution A and stirring to fully dissolve them to obtain solution B;

[0011] S3: adding measured amount of ammonium bifluoride to solution B and stirring until fully dissolved to obtain solution C;

[0012] S4: Take another 1L beaker, add pure water to 150mL, add the measured sodium metasilicate nonahydrate solution, and stir until fully dissolved to obtain solution D;

[0013] S5: Cool solutions C and D to room temperature, slowly add solution D to solution C while stirring, and continue stirring for 5-7 minutes after the addition is complete to obtain solution E;

[0014] S6: Add pure water to solution E to 1 L to obtain the bright pickling additive for magnesium alloy containing heavy metal elements.

[0015] The present invention also provides an application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements prepared by the preparation method of the bright pickling additive as described above is applied to the bright cleaning of ZK61 magnesium alloy forgings after machining, comprising the following steps:

[0016] Degrease the magnesium alloy forgings at 45-55°C for 1-3 minutes using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10;

[0017] After degreasing, the magnesium alloy forgings are cleaned with clean water at 50-70°C for 1-3 minutes, and then cleaned with clean water at 10-30°C for 1-3 minutes;

[0018] Using 10-30 mL / L nitric acid and 70-100 mL / L of the bright pickling additive for magnesium alloy containing heavy metal elements, pickling the cleaned magnesium alloy forgings at room temperature for 30-90 seconds;

[0019] The pickled magnesium alloy forgings are cleaned with clean water at 10-30°C for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

[0020] The present invention also provides an application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements prepared by the preparation method of the bright pickling additive as described above is applied to bright cleaning of MB26+Ce magnesium alloy sheet, comprising the following steps:

[0021] Degrease the magnesium alloy forgings at 45-55°C for 1-3 minutes using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10;

[0022] Using 20-30 mL / L nitric acid, 5-10 mL / L sulfuric acid and 100-150 mL / L of the bright pickling additive for magnesium alloy containing heavy metal elements, pickling the degreased magnesium alloy forging for 1-3 minutes at room temperature;

[0023] The pickled magnesium alloy forgings are cleaned with clean water at 10-30°C for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

[0024] The present invention also provides an application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements prepared by the preparation method of the bright pickling additive described above is applied to bright cleaning of the surface of AZ91D+0.1%Y die castings, comprising the following steps:

[0025] Degrease the magnesium alloy forgings at 45-55°C for 1-3 minutes using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10;

[0026] Pickling the degreased magnesium alloy forgings at 40-45° C. for 1-3 minutes using 30-70 mL / L of anhydrous acetic acid, 10-15 mL / L of phosphoric acid and 100-150 mL / L of the bright pickling additive for magnesium alloys containing heavy metal elements;

[0027] The pickled magnesium alloy forgings are cleaned with clean water at 10-30°C for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

[0028] The present invention also provides an application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements prepared by the preparation method of the bright pickling additive as described above is applied to bright cleaning of Mg-Gd-Y-Zn-Zr magnesium alloy extruded profiles, comprising the following steps:

[0029] Degrease the magnesium alloy forgings for 1-3 minutes at 45-55°C using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10;

[0030] The degreased magnesium alloy forgings are pickled for 1-3 minutes at room temperature using 30-50 mL / L nitric acid, 5-7 mL / L phosphoric acid, 10-15 g / L citric acid and 100-150 mL / L of the bright pickling additive for magnesium alloys containing heavy metal elements to complete the bright cleaning of the magnesium alloy forgings.

[0031] The invention discloses a bright pickling additive for magnesium alloy containing heavy metal elements and a preparation method thereof, wherein the addition of potassium fluorotitanate, a Ti ion providing agent, a Ti 4+ Complexed with phytic acid / lactic acid, it is reduced to TiO when in contact with the magnesium alloy matrix. 2 , TiO 2 It is a relatively positively charged particle, which accelerates galvanic corrosion and balances the potential on the workpiece surface, and has a polishing effect. Sodium metavanadate is used as a corrosion inhibitor. The addition of ammonium bifluoride has a strong complexing effect on cations, especially Cu, and reduces the formation of precipitation of metal ions such as Cu and Ag to form dirt on the surface of magnesium alloy workpieces. HF has the function of protecting the Mg matrix and corroding heavy metal ions at the same time. By adding sodium metasilicate nonahydrate, under strong stirring, Na 2 SiO 3 9H 2 O+H + →H 2 SiO 3 +Na + , forming nano-H 2 SiO 3 , nano H 2 SiO 3 The microscopic cage-like micelles are negatively charged and have an adsorption effect on heavy metal cations, which can significantly reduce the generation of heavy metal cation precipitation and reduce dust on the working surface. In summary, when the bright pickling additive provided by the technical solution is used to treat the surface of the magnesium alloy, it can be combined with low-concentration inorganic strong acid and organic acid in a low to medium temperature environment to perform bright cleaning on the surface of magnesium alloys containing various heavy metals in different processing states. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 The present invention is a flow chart of the steps of preparing the bright pickling additive.

[0034] Figure 2 The invention discloses a flow chart of the steps of applying the bright pickling additive for magnesium alloy containing heavy metal elements provided by the invention to the bright cleaning of ZK61 magnesium alloy forgings after machining.

[0035] Figure 3 The present invention is a flowchart of the steps of applying the bright pickling additive for magnesium alloy containing heavy metal elements provided by the present invention to bright cleaning of MB26+Ce magnesium alloy plate.

[0036] Figure 4 The present invention is a flowchart of the steps of applying the bright pickling additive for magnesium alloy containing heavy metal elements provided by the present invention to the bright cleaning of the surface of AZ91D+0.1%Y die castings.

[0037] Figure 5 The present invention is a flowchart of the steps of applying the bright pickling additive for magnesium alloy containing heavy metal elements provided by the present invention to bright cleaning of Mg-Gd-Y-Zn-Zr magnesium alloy extruded profiles.

[0038] Figure 6 It is a cleaning effect diagram of the present invention. DETAILED DESCRIPTION

[0039] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0040] The invention provides a bright pickling additive for magnesium alloy containing heavy metal elements. The bright pickling additive for magnesium alloy containing heavy metal elements comprises the following components: 5g / L potassium fluorotitanate, 10g / L sodium metavanadate, 50-70g / L ammonium hydrogen fluoride, 30-50g / L sodium metasilicate nonahydrate, 100-200mL / L lactic acid and 50-70mL / L phytic acid.

[0041] Among them, the preferred amount of ammonium bifluoride is 55 g / L, the preferred amount of sodium metasilicate nonahydrate is 50 g / L, the preferred amount of lactic acid is 150 mL / L, and the preferred amount of phytic acid is 50 mL / L.

[0042] In this embodiment, by adding potassium fluorotitanate, the Ti ion supplier, Ti 4+ Complexed with phytic acid / lactic acid, it is reduced to TiO when in contact with the magnesium alloy matrix. 2 , TiO 2It is a relatively positively charged particle, which accelerates galvanic corrosion and balances the potential on the workpiece surface, and has a polishing effect. Sodium metavanadate is used as a corrosion inhibitor. The addition of ammonium bifluoride has a strong complexing effect on cations, especially Cu, and reduces the formation of precipitation of metal ions such as Cu and Ag to form dirt on the surface of magnesium alloy workpieces. HF has the function of protecting the Mg matrix and corroding heavy metal ions at the same time. By adding sodium metasilicate nonahydrate, under strong stirring, Na 2 SiO 3 9H 2 O+H + →H 2 SiO 3 +Na + , forming nano-H 2 SiO 3 , nano H 2 SiO 3 The microscopic cage-like micelles are negatively charged and have an adsorption effect on heavy metal cations, which can significantly reduce the generation of heavy metal cation precipitation and reduce dust on the working surface. In summary, when the bright pickling additive provided by the technical solution is used to treat the surface of the magnesium alloy, it can be combined with low-concentration inorganic strong acid and organic acid in a low to medium temperature environment to perform bright cleaning on the surface of magnesium alloys containing various heavy metals in different processing states.

[0043] See also Figure 1 The present invention also provides a method for preparing a bright pickling additive, which is applied to the bright pickling additive for magnesium alloy containing heavy metal elements as described above, comprising the following steps:

[0044] S1: Take a 1L beaker, add 200mL pure water, add measured lactic acid and phytic acid to the pure water, stir evenly to obtain solution A;

[0045] S2: adding measured potassium fluorotitanate and sodium metavanadate to the above solution A and stirring to fully dissolve them to obtain solution B;

[0046] S3: adding measured amount of ammonium bifluoride to solution B and stirring until fully dissolved to obtain solution C;

[0047] S4: Take another 1L beaker, add pure water to 150mL, add the measured sodium metasilicate nonahydrate solution, and stir until fully dissolved to obtain solution D;

[0048] S5: Cool solutions C and D to room temperature, slowly add solution D to solution C while stirring, and continue stirring for 5-7 minutes after the addition is complete to obtain solution E;

[0049] S6: Add pure water to solution E to 1 L to obtain the bright pickling additive for magnesium alloy containing heavy metal elements.

[0050] In this embodiment, first, take a 1L beaker, add 200mL of pure water, add measured lactic acid and phytic acid to the pure water, stir evenly to obtain solution A, add measured potassium fluorotitanate and sodium metavanadate to solution A and stir to fully dissolve them to obtain solution B, add measured ammonium bifluoride to solution B, stir until fully dissolved to obtain solution C, then take another 1L beaker, add pure water to 150mL, add measured sodium metasilicate nonahydrate solution, stir until fully dissolved to obtain solution D, cool solutions C and D to room temperature, and slowly add solution D to solution C while stirring. After the addition is completed, continue stirring for 5-7 minutes to obtain solution E, and finally add pure water to solution E to 1L to obtain the bright pickling additive for magnesium alloys containing heavy metal elements.

[0051] Embodiment 1:

[0052] See also Figure 2 The present invention also provides an application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements prepared by the preparation method of the bright pickling additive as described above is applied to the bright cleaning of ZK61 magnesium alloy forgings after machining, comprising the following steps:

[0053] S101: Degrease the magnesium alloy forgings at 45-55°C for 1-3 minutes using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10;

[0054] S102: using clean water at 50-70° C. to clean the degreased magnesium alloy forging for 1-3 minutes, and then using clean water at 10-30° C. to clean the magnesium alloy forging for 1-3 minutes;

[0055] S103: using 10-30 mL / L nitric acid and 70-100 mL / L of the bright pickling additive for magnesium alloy containing heavy metal elements, pickling the cleaned magnesium alloy forging at room temperature for 30-90 seconds;

[0056] S104: Use clean water at 10-30°C to clean the pickled magnesium alloy forgings for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

[0057] Embodiment 2:

[0058] See also Figure 3 The present invention also provides an application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements prepared by the preparation method of the bright pickling additive as described above is applied to bright cleaning of MB26+Ce magnesium alloy sheet, comprising the following steps:

[0059] S201: Degrease the magnesium alloy forgings at 45-55°C for 1-3 minutes using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10;

[0060] S202: using 20-30 mL / L nitric acid, 5-10 mL / L sulfuric acid and 100-150 mL / L of the bright pickling additive for magnesium alloy containing heavy metal elements, pickling the degreased magnesium alloy forging at room temperature for 1-3 minutes;

[0061] S203: Use clean water at 10-30°C to clean the pickled magnesium alloy forgings for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

[0062] Embodiment 3:

[0063] See also Figure 4 The present invention also provides an application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements prepared by the preparation method of the bright pickling additive as described above is applied to the bright cleaning of the surface of AZ91D+0.1%Y die castings, comprising the following steps:

[0064] S301: Degrease the magnesium alloy forgings for 1-3 minutes at 45-55°C using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10;

[0065] S302: using 30-70 mL / L of anhydrous acetic acid, 10-15 mL / L of phosphoric acid and 100-150 mL / L of the bright pickling additive for magnesium alloy containing heavy metal elements, pickling the degreased magnesium alloy forging at 40-45° C. for 1-3 min;

[0066] S303: Use clean water at 10-30°C to clean the pickled magnesium alloy forgings for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

[0067] Embodiment 4:

[0068] See also Figure 5 The present invention also provides an application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements prepared by the preparation method of the bright pickling additive as described above is applied to bright cleaning of Mg-Gd-Y-Zn-Zr magnesium alloy extruded profiles, comprising the following steps:

[0069] S401: Degrease the magnesium alloy forgings at 45-55°C for 1-3 minutes using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10;

[0070] S402: using 30-50 mL / L nitric acid, 5-7 mL / L phosphoric acid, 10-15 g / L citric acid and 100-150 mL / L of the bright pickling additive for magnesium alloy containing heavy metal elements, pickling the degreased magnesium alloy forgings at room temperature for 1-3 minutes to complete the bright cleaning of the magnesium alloy forgings.

[0071] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A bright pickling additive for magnesium alloy containing heavy metal elements, characterized in that: The invention comprises the following components: 5 g / L potassium fluorotitanate, 10 g / L sodium metavanadate, 50-70 g / L ammonium hydrogen fluoride, 30-50 g / L sodium metasilicate nonahydrate, 100-200 mL / L lactic acid and 50-70 mL / L phytic acid.

2. The bright pickling additive for magnesium alloy containing heavy metal elements according to claim 1, characterized in that: The preferred amount of the ammonium bifluoride is 55 g / L, the preferred amount of the sodium metasilicate nonahydrate is 50 g / L, the preferred amount of the lactic acid is 150 mL / L, and the preferred amount of the phytic acid is 50 mL / L.

3. A method for preparing a bright pickling additive, applied to the bright pickling additive for magnesium alloy containing heavy metal elements as claimed in claim 2, characterized in that: The steps include: S1: Take a 1L beaker, add 200mL pure water, add measured lactic acid and phytic acid to the pure water, stir evenly to obtain solution A; S2: adding measured potassium fluorotitanate and sodium metavanadate to the above solution A and stirring to fully dissolve them to obtain solution B; S3: adding measured amount of ammonium bifluoride to solution B and stirring until fully dissolved to obtain solution C; S4: Take another 1L beaker, add pure water to 150mL, add the measured sodium metasilicate nonahydrate solution, and stir until fully dissolved to obtain solution D; S5: Cool solutions C and D to room temperature, slowly add solution D to solution C while stirring, and continue stirring for 5-7 minutes after the addition is complete to obtain solution E; S6: Add pure water to solution E to 1 L to obtain the bright pickling additive for magnesium alloy containing heavy metal elements.

4. An application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements is prepared by the preparation method of the bright pickling additive as claimed in claim 3, characterized in that: The steps include: Degrease the magnesium alloy forgings for 1-3 minutes at 45-55°C using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10; After degreasing, the magnesium alloy forgings are cleaned with clean water at 50-70°C for 1-3 minutes, and then cleaned with clean water at 10-30°C for 1-3 minutes; Using 10-30 mL / L nitric acid and 70-100 mL / L of the bright pickling additive for magnesium alloy containing heavy metal elements, pickling the cleaned magnesium alloy forgings at room temperature for 30-90 seconds; The pickled magnesium alloy forgings are cleaned with clean water at 10-30°C for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

5. An application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements is prepared by the preparation method of the bright pickling additive as claimed in claim 3, characterized in that: The steps include: Degrease the magnesium alloy forgings for 1-3 minutes at 45-55°C using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10; Using 20-30 mL / L nitric acid, 5-10 mL / L sulfuric acid and 100-150 mL / L of the bright pickling additive for magnesium alloy containing heavy metal elements, pickling the degreased magnesium alloy forging for 1-3 minutes at room temperature; The pickled magnesium alloy forgings are cleaned with clean water at 10-30°C for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

6. An application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements is prepared by the preparation method of the bright pickling additive as claimed in claim 3, characterized in that: The steps include: Degrease the magnesium alloy forgings at 45-55°C for 1-3 minutes using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10; Pickling the degreased magnesium alloy forgings at 40-45° C. for 1-3 minutes using 30-70 mL / L of anhydrous acetic acid, 10-15 mL / L of phosphoric acid and 100-150 mL / L of the bright pickling additive for magnesium alloys containing heavy metal elements; The pickled magnesium alloy forgings are cleaned with clean water at 10-30°C for 1-3 minutes to complete the smooth cleaning of the magnesium alloy forgings.

7. An application method of a bright pickling additive, wherein the bright pickling additive for magnesium alloy containing heavy metal elements is prepared by the preparation method of the bright pickling additive as claimed in claim 3, characterized in that: The steps include: Degrease the magnesium alloy forgings at 45-55°C for 1-3 minutes using 5g / L sodium hydroxide, 5g / L sodium carbonate, 5g / L sodium phosphate and OP-10; The degreased magnesium alloy forgings are pickled for 1-3 minutes at room temperature using 30-50 mL / L nitric acid, 5-7 mL / L phosphoric acid, 10-15 g / L citric acid and 100-150 mL / L of the bright pickling additive for magnesium alloys containing heavy metal elements to complete the bright cleaning of the magnesium alloy forgings.

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