Method for treating a metal surface

Abstract

A method for treating a surface of a metal material (110) is provided. The method includes a sealing step. The sealing step includes reacting the metal material (110) with a first nickel-free solution to form a sealing layer (140). The method includes a coating step. The coating step includes applying a second nickel-free solution to the sealing layer (140) to form a coating layer (150).

Description

[0001] This invention relates to a method for treating the surface of a metallic material. In particular, this invention relates to a method for treating the surface of a metallic material that includes a sealing step and a coating step.

[0002] It is known that surface treatments can be applied to metals to alter their surface properties. For example, surface treatments can be used to improve properties including surface hardness, corrosion resistance, or aesthetics. A common surface treatment is anodizing.

[0003] Anodizing improves the scratch and abrasion resistance of metal parts. This is attributed to its thick layer of metal oxide, which protects the metal from damage. Anodizing also improves the corrosion resistance of metal parts. Additionally, anodizing is known to be used to add color to the surface of metal parts. Anodizing is particularly suitable for processing parts made of aluminum. Due to this ability to customize color and improve product durability, anodizing is commonly used to process metal parts used in consumer products such as mobile phone cases.

[0004] Anodizing involves creating a thick metal oxide layer on a metal surface. This metal oxide layer can be formed by using the metal part to be treated as the anode in an electrolytic cell. An acid can be used as the electrolyte in the anodizing process. For example, at least one of chromic acid or sulfuric acid can be used as the electrolyte in the anodizing process.

[0005] Anodizing processes create porous metal oxide structures on the surface of metal parts. These pores can be elongated pores extending vertically from the surface of the metal part. These pores can then be used to adsorb dyes to color the surface of the metal part. However, these pores can also lead to corrosion. Therefore, after the anodizing process, the anodized surface of the metal part is typically sealed to close the pores in the metal oxide structure. This sealing is usually done by immersing the anodized metal part in a nickel acetate solution. The nickel acetate penetrates the pores and seals the metal oxide structure.

[0006] However, it has been found that using nickel acetate for sealing does not always provide the required surface durability. Additionally, some consumers are known to experience allergic reactions upon contact with nickel. Furthermore, in some cases, nickel mining can have negative environmental impacts.

[0007] Therefore, there is a need for a process to seal pores in anodized metal parts to provide more durable finished parts. Furthermore, this method needs to be cost-effective and compatible with existing anodizing processes.

[0008] According to this disclosure, a method for treating the surface of a metallic material is provided. The method may include a sealing step. The sealing step may include reacting the metallic material with a first nickel-free solution to form a sealing layer. The method may include a coating step. The coating step may include applying a second nickel-free solution to the sealing layer to form a coating layer.

[0009] According to the present invention, a method for treating the surface of a metallic material is provided. The method includes a sealing step. The sealing step includes reacting the metallic material with a first nickel-free solution to form a sealing layer. The method also includes a coating step. The coating step includes applying a second nickel-free solution to the sealing layer to form a coating layer.

[0010] The inventors have discovered that the multi-step process of the present invention offers several advantages compared to the single-step sealing process of the prior art. In particular, the inventors have found that the multi-step process of the present invention advantageously provides a more flexible and durable surface treatment compared to the single-step sealing process of the prior art. Furthermore, the multi-step process of the present invention eliminates the need for the use of nickel acetate in the sealing process. This advantageously reduces the likelihood of allergic reactions in users of the treated product. Additionally, reducing the use of nickel advantageously improves the sustainability of the sealing process.

[0011] The surface treatment method of the present invention includes at least a sealing step and a coating step. However, the surface treatment method of the present invention may include one or more additional steps. For example, the surface treatment method of the present invention may include one, two, three, four or more additional steps.

[0012] The coating step can be performed after the sealing step. Alternatively, the coating step can be performed immediately after the sealing step.

[0013] As used herein with reference to this invention, the term "nickel-free solution" refers to a solution that does not contain nickel metal or nickel-containing compounds.

[0014] The sealing step may include a hydration reaction in which a first nickel-free solution reacts with water to form a hydroxide.

[0015] Hydroxides can form a sealing layer that encloses the pores of the metal oxide structure. This can advantageously prevent corrosion of the metal within the pores of the metal oxide structure.

[0016] As used herein with reference to this invention, the term "hydration reaction" refers to a chemical reaction in which water reacts with an unsaturated matrix. Typically, hydration reactions involve reacting an alkene or alkyne with water to produce an alcohol.

[0017] At least one of the first and second nickel-free solutions may contain a compound containing a metallic element. At least one of the first and second nickel-free solutions may contain a light metal. At least one of the first and second nickel-free solutions may contain one or more of lithium, beryllium, sodium, magnesium, potassium, calcium, or combinations thereof or alloys thereof. At least one of the first and second nickel-free solutions may contain at least one of iron or an iron-containing compound.

[0018] The first nickel-free solution may contain light metals. The second nickel-free solution may contain light metals.

[0019] The first nickel-free solution may contain one or more of lithium, beryllium, sodium, magnesium, potassium, calcium, or combinations thereof or alloys thereof. The second nickel-free solution may contain one or more of lithium, beryllium, sodium, magnesium, potassium, calcium, or combinations thereof or alloys thereof.

[0020] The first nickel-free solution may contain at least one of iron or an iron-containing compound. The second nickel-free solution may contain at least one of iron or an iron-containing compound.

[0021] At least one of the first nickel-free solution and the second nickel-free solution may contain a semi-organic compound.

[0022] As used herein with reference to this invention, the term "semi-organic compound" refers to a hybrid material comprising both organic and inorganic compounds.

[0023] The first nickel-free solution may contain semi-organic compounds. The second nickel-free solution may contain semi-organic compounds.

[0024] The first nickel-free solution may contain polymer materials. The first nickel-free solution may contain hybrid polymer materials.

[0025] The second nickel-free solution may contain coatings.

[0026] The sealing step may include immersing the metal material in a first nickel-free solution.

[0027] The sealing step may include immersing the metal material in the first nickel-free solution for any duration. The sealing step may include immersing the metal material in the first nickel-free solution for at least 1 minute, at least 2 minutes, or at least 5 minutes.

[0028] The sealing step may include immersing the metal material in a first nickel-free solution for no more than 20 minutes, no more than 15 minutes, or no more than 10 minutes.

[0029] For example, the sealing step may include immersing the metal material in a first nickel-free solution for between about 1 minute and about 20 minutes, between about 2 minutes and about 15 minutes, or between about 5 minutes and about 10 minutes.

[0030] The sealing step may include applying the first nickel-free solution to the metallic material in any other manner. For example, the sealing step may include spraying the metallic material with the first nickel-free solution.

[0031] The sealing process can be performed at any temperature.

[0032] The sealing step may include reacting the metallic material with a first nickel-free solution at a temperature of at least 5 degrees Celsius, at least 10 degrees Celsius, or at least 20 degrees Celsius.

[0033] The sealing step may include reacting the metallic material with a first nickel-free solution at a temperature not exceeding 100 degrees Celsius, 85 degrees Celsius, or 70 degrees Celsius.

[0034] The sealing step may include reacting the metallic material with a first nickel-free solution at a temperature between about 5 degrees Celsius and about 100 degrees Celsius, between about 10 degrees Celsius and about 85 degrees Celsius, or between about 20 degrees Celsius and about 70 degrees Celsius.

[0035] The coating step may include immersing the metal material in a second nickel-free solution. The coating step may also include an electrophoresis step.

[0036] The coating step may include applying a second nickel-free solution to the metallic material for any duration.

[0037] The coating step may include applying a second nickel-free solution to the metallic material for at least 5 minutes, at least 10 minutes, or at least 15 minutes.

[0038] The coating process may include applying a second nickel-free solution to the metal material for no more than 50 minutes, no more than 30 minutes, or no more than 25 minutes.

[0039] For example, the coating step may include applying a second nickel-free solution to the metal material for about 5 minutes to about 50 minutes, about 10 minutes to about 30 minutes, or about 15 minutes to about 25 minutes.

[0040] The coating process can be performed at any temperature.

[0041] The coating step may include applying a second nickel-free solution to the metallic material at a temperature of at least 70 degrees Celsius, at least 75 degrees Celsius, or at least 80 degrees Celsius.

[0042] The coating step may include applying a second nickel-free solution to the metallic material at a temperature not exceeding 110 degrees Celsius, 100 degrees Celsius, or 95 degrees Celsius.

[0043] The coating step may include applying a second nickel-free solution to the metallic material at a temperature between about 70 degrees Celsius and about 110 degrees Celsius, between about 75 degrees Celsius and about 100 degrees Celsius, or between about 80 degrees Celsius and about 95 degrees Celsius.

[0044] The method may also include at least one additional step. This additional step may be performed before or after the sealing and coating steps.

[0045] The method may also include a pre-sealing cleaning step before the sealing step, in which debris and contaminants are removed from the metal material.

[0046] A pre-cleaning step can be performed after the anodizing step. The pre-cleaning step advantageously removes any debris and contaminants originating from the anodizing step. Providing a pre-cleaning step before the sealing step advantageously makes the sealing step more efficient. For example, the pre-cleaning step advantageously removes debris from the porous metal oxide structure to prevent debris from being sealed within the porous metal oxide structure.

[0047] The method may further include a post-coating cleaning step after the coating step, in which debris and contaminants are removed from the metal material.

[0048] The post-cleaning step can advantageously remove any debris and contaminants originating from the coating step.

[0049] At least one of the pre-sealing cleaning steps and the post-coating cleaning steps may include electrocleaning.

[0050] Pre-sealing cleaning steps may include electrolytic cleaning. Post-coating cleaning steps may include electrolytic cleaning.

[0051] As used herein with reference to this invention, the term "electrolytic cleaning" refers to a method for removing dirt, scale, or corrosion products from metal parts by using metal parts as electrodes in an electrolytic cell.

[0052] At least one of the pre-sealing cleaning step and the post-coating cleaning step may include cleaning in pure water.

[0053] Pre-sealing cleaning steps may include rinsing in pure water. Post-coating cleaning steps may include rinsing in pure water.

[0054] Pure water can be distilled water. Pure water can also be deionized water.

[0055] Cleaning metal materials with pure water is advantageous for removing debris and contaminants. Cleaning in pure water can be performed after electrolytic cleaning. This advantageously removes any debris and contaminants originating from the electrolytic cleaning process.

[0056] The method may further include a dyeing step, in which colored pigments are applied to the metal material, and the dyeing step is performed before the sealing step.

[0057] Providing a dyeing step prior to the sealing step advantageously allows the dye to penetrate into the porous metal oxide structure before the metal oxide passes through the sealing step.

[0058] The method may further include an anodizing step, in which a metal oxide layer is formed on the surface of the metal material, the anodizing step being performed prior to the sealing step. If a dyeing step is present, the anodizing step may be performed prior to the dyeing step.

[0059] Providing an anodizing step can advantageously improve the corrosion resistance and durability of metallic materials.

[0060] The metallic material can be any metallic material. Suitable metallic materials include, but are not limited to, titanium, aluminum, zinc, or their alloys.

[0061] Preferably, the metallic material comprises aluminum or an aluminum alloy.

[0062] Aluminum is particularly suitable for anodizing because it forms hard oxides, which improves the durability of the metal surface.

[0063] The metallic material may contain any suitable metallic component. For example, the metallic material may be a metallic component of an aerosol generating device. An aerosol generating device may be an electronic cigarette. The aerosol generating device may be designed for use with an aerosol generating article. For example, in cases where the aerosol generating article includes an aerosol generating matrix, the aerosol generating article may be designed to be heated by the aerosol generating device to generate an aerosol. In this case, the aerosol generating device may include a heater for heating the aerosol generating article. The heater may be a resistance heater. The heater may be an induction heater.

[0064] The metallic material can be any metal component of the aerosol generating device. It can also form part of the device's housing. This can be advantageous because anodizing processes can be used to customize the color of the housing to control the overall appearance of the device.

[0065] The invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0066] Example 1. A method for treating the surface of a metallic material, the method comprising: a sealing step, the sealing step comprising reacting the metallic material with a first nickel-free solution to form a sealing layer; and a coating step, the coating step comprising applying a second nickel-free solution to the sealing layer to form a coating layer.

[0067] Example 2. According to the method of Example 1, the sealing step includes a hydration reaction in which the first nickel-free solution reacts with water to form a hydroxide.

[0068] Example 3. According to the method of Example 1 or Example 2, at least one of the first nickel-free solution and the second nickel-free solution contains at least one of iron or an iron-containing compound.

[0069] Example 4. The method according to any of the preceding examples, wherein at least one of the first nickel-free solution and the second nickel-free solution comprises a semi-organic compound.

[0070] Example 5. According to the method of any of the preceding examples, wherein the sealing step includes immersing the metal material in the first nickel-free solution.

[0071] Example 6. According to the method of Example 5, wherein the sealing step includes immersing the metal material in the first nickel-free solution for at least 5 minutes.

[0072] Example 7. According to the method of Example 5 or Example 6, the sealing step includes immersing the metal material in the first nickel-free solution for no more than 10 minutes.

[0073] Example 8. The method according to any of the preceding examples, wherein the sealing step includes reacting the metal material with the first nickel-free solution at at least 20 degrees Celsius.

[0074] Example 9. The method according to any of the preceding examples, wherein the sealing step includes reacting the metal material with the first nickel-free solution at a temperature not exceeding 70 degrees Celsius.

[0075] Example 10. The method according to any of the preceding examples, wherein the coating step includes applying the second nickel-free solution to the metal material for at least 15 minutes.

[0076] Example 11. The method according to any of the preceding examples, wherein the coating step includes applying the second nickel-free solution to the metal material for no more than 25 minutes.

[0077] Example 12. According to the method of any of the preceding examples, the coating step includes applying the second nickel-free solution to the metal material at a temperature of at least 80 degrees Celsius.

[0078] Example 13. The method according to any of the preceding examples, wherein the coating step includes applying the second nickel-free solution to the metal material at a temperature not exceeding 95 degrees Celsius.

[0079] Example 14. The method according to any of the foregoing examples further includes a pre-sealing cleaning step before the sealing step, in which debris and contaminants are removed from the metal material.

[0080] Example 15. The method according to any of the foregoing examples further includes a post-coating cleaning step after the coating step, in which debris and contaminants are removed from the metal material.

[0081] Example 16. According to the method of Example 14 or Example 15, at least one of the pre-sealing cleaning step and the post-coating cleaning step includes electrolytic cleaning.

[0082] Example 17. The method according to any one of Examples 14 to 16, wherein at least one of the pre-sealing cleaning step and the post-coating cleaning step includes cleaning in pure water.

[0083] Example 18. The method according to any of the foregoing examples further includes a dyeing step in which a colored pigment is applied to the metal material, the dyeing step being performed prior to the sealing step.

[0084] Example 19. The method according to any of the foregoing examples further includes an anodizing step, in which a metal oxide layer is formed on the surface of the metal material, the anodizing step being performed prior to the sealing step.

[0085] Example 20. The method according to any of the preceding examples, wherein the metallic material comprises aluminum metal or an aluminum alloy.

[0086] Example 21. The method according to any of the preceding examples, wherein the metallic material constitutes part of the aerosol generating apparatus.

[0087] In the following non-limiting examples, the invention will be further described with reference to the accompanying drawings, wherein:

[0088] Figure 1 A schematic diagram showing the cross-sectional microstructure of a portion of an anodized material is provided.

[0089] Figure 2 A schematic diagram of the cross-sectional microstructure of a portion of anodized material that has undergone the dyeing process is shown.

[0090] Figure 3 A schematic diagram of the cross-sectional microstructure of a portion of anodized material that has undergone the dyeing step and the sealing step according to the invention is shown.

[0091] Figure 4A schematic diagram of the cross-sectional microstructure of a portion of an anodized material that has undergone the dyeing step, the sealing step according to the invention, and the coating step according to the invention is shown.

[0092] A multi-step process for treating the surface of a metallic material 110 is provided. In this example, the metallic material 110 is part of the housing of an electronic aerosol generating device formed of aluminum metal.

[0093] The metal material 110 first undergoes an anodizing process by using the metal material 110 as the anode in an electrolytic cell with a suitable electrolyte. This anodizing process produces a thick aluminum oxide layer 120 on the surface of the metal material 110. This thick aluminum oxide layer 120 includes a plurality of elongated pores extending from and perpendicular to the metal material 110. This is shown in... Figure 1 middle.

[0094] The anodized metal material 110 is then dyed in a dyeing step. This is achieved by applying a pigment 130 to the surface of the anodized metal material 110. The pigment 130 is immersed in the porous structure of the alumina layer 120. This is shown in... Figure 2 middle.

[0095] The anodized and dyed metal material 110 is then cleaned in a pre-sealing cleaning step. This pre-sealing cleaning step aims to remove any residue or debris from the anodizing and dyeing steps. The pre-sealing cleaning step includes electrolytic cleaning. The pre-sealing cleaning step also includes rinsing in pure water.

[0096] The anodized, dyed, and pre-cleaned metal material 110 is then subjected to a sealing step. In the sealing step, the metal material 110 is reacted with a first nickel-free solution to form a sealing layer 140. The sealing step is performed by immersing the metal material 110 in the first nickel-free solution at a temperature of approximately 25 degrees Celsius for between 5 and 10 minutes. The first nickel-free solution is a semi-organic compound. The first nickel-free solution contains a polymer material. The first nickel-free solution contains iron. The sealing step involves a hydration reaction. Figure 3 The image shows a sealed metal material 110.

[0097] The metal material 110, after anodizing, staining, pre-cleaning, and sealing, is then subjected to a coating step. In the coating step, a second nickel-free solution is applied to the sealing layer 140 to form a coating 150. The coating step is performed by immersing the metal material 110 in the second nickel-free solution at a temperature of approximately 85 degrees Celsius for between 15 and 25 minutes. The second nickel-free solution is a semi-organic compound. Figure 4 The coated metal material 110 is shown in the figure.

[0098] The metal material 110, which has undergone anodizing, staining, pre-cleaning, sealing, and coating, is then cleaned in a post-coating cleaning step. The post-coating cleaning step aims to remove any residue or debris from the sealing and coating steps. The post-coating cleaning step includes electrolytic cleaning. The post-coating cleaning step also includes rinsing in pure water.

[0099] For the purposes of this specification and the appended claims, unless otherwise stated, all figures representing quantities, quantities, percentages, etc., shall be understood to be modified by the term "about" in all cases. Furthermore, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed herein. Thus, in this document, the number A is understood to be A ± 10% of A. In this document, the number A may be considered to include a value within the general standard error of the measurement of the property modified by the number A. In some cases used in the appended claims, the number A may deviate from the percentage listed above, provided that the amount of deviation from A does not materially affect the essential and novel features of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed herein.

[0100] While many exemplary embodiments have been disclosed herein, it should be understood that other variations are possible. Such changes should not be considered as departing from the scope of this disclosure, and all such modifications that will be apparent to those skilled in the art are intended to be included within the scope of the appended claims. It should be understood that the features described above with respect to one aspect of the invention or this disclosure are equally applicable to other aspects of the invention or this disclosure.

Claims

1. A method for treating the surface of a metallic material, the method comprising: The sealing step includes reacting the metal material with a first nickel-free solution to form a sealing layer, and The coating step includes applying a second nickel-free solution to the sealing layer to form a coating.

2. The method according to claim 1, wherein the sealing step includes a hydration reaction, in which the first nickel-free solution reacts with water to form a hydroxide.

3. The method according to claim 1 or claim 2, wherein at least one of the first nickel-free solution and the second nickel-free solution comprises at least one of iron or an iron-containing compound.

4. The method according to any of the preceding claims, wherein at least one of the first nickel-free solution and the second nickel-free solution comprises a semi-organic compound.

5. The method according to any of the preceding claims, wherein the sealing step comprises immersing the metal material in the first nickel-free solution.

6. The method of claim 5, wherein the sealing step comprises immersing the metal material in the first nickel-free solution for at least 5 minutes.

7. The method according to claim 5 or claim 6, wherein the sealing step comprises immersing the metal material in the first nickel-free solution for no more than 10 minutes.

8. The method according to any of the preceding claims, wherein the sealing step comprises reacting the metal material with the first nickel-free solution at at least 20 degrees Celsius.

9. The method according to any of the preceding claims, wherein the sealing step comprises reacting the metal material with the first nickel-free solution at a temperature not exceeding 70 degrees Celsius.

10. The method according to any of the preceding claims, wherein the coating step comprises applying the second nickel-free solution to the metal material for at least 15 minutes.

11. The method according to any of the preceding claims, wherein the coating step comprises applying the second nickel-free solution to the metal material for no more than 25 minutes.

12. The method according to any of the preceding claims, wherein the coating step comprises applying the second nickel-free solution to the metal material at a temperature of at least 80 degrees Celsius.

13. The method according to any of the preceding claims, wherein the coating step comprises applying the second nickel-free solution to the metal material at a temperature not exceeding 95 degrees Celsius.

14. The method according to any of the preceding claims, further comprising an anodizing step, wherein a metal oxide layer is formed on the surface of the metal material in the anodizing step, the anodizing step being performed prior to the sealing step.

15. The method according to any of the preceding claims, wherein the metallic material constitutes part of the aerosol generating apparatus.

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