WO2019209266A1

WO2019209266A1 - Metal and polymer coating of metal substrates

Info

Publication number: WO2019209266A1
Application number: PCT/US2018/029092
Authority: WO
Inventors: Kuan-Ting Wu; Chi-Hao Chang; Chien-Ting Lin
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2018-04-24
Filing date: 2018-04-24
Publication date: 2019-10-31

Abstract

Examples of coating of metal and polymer on a metal substrate are described. In an example, the metal substrate has a layer of ionic polymers, where the ionic polymers encapsulate a metal oxide. The metal oxide in the ionic polymers is reduced to a metal using a laser.

Description

METAL AND POLYMER COATING OF METAL SUBSTRATES

BACKGROUND

[0001 ] Metal substrates are used for fabrication of various components of devices. The components may include body parts of devices, such as mobile phones, tablets, laptops, styluses, keyboards, and the like. The metal substrate may be made of magnesium, aluminum, copper, titanium, or an alloy of similar light weight metals.

BRIEF DESCRIPTION OF DRAWINGS

[0002] The following detailed description references the drawings, wherein:

[0003] Fig. 1 illustrates a sectional view of a polymer coated metal substrate, according to an example of the present subject matter;

[0004] Fig. 2 illustrates an apparatus for e!ectroiytica!!y coating an ionic polymer layer on a metal substrate in the presence of ultrasonic vibrations followed by application of a laser beam to obtain a metal region, according to an exa ple of the present subject matter;

[0005] Fig. 3 illustrates an apparatus for electrolytically coating an ionic polymer layer on a metal substrate in the presence of ultrasonic vibrations followed by application of a laser beam to obtain a metal region, according to another example of the present subject matter;

[0008] Fig. 4 illustrates a method of coating a layer of ionic polymers on a metal substrate and obtaining a region of metal by laser treatment, according to an example of the present subject matter; and

[0007] Fig. 5 illustrates a method of fabricating a polymer coated metal substrate, according to an example of the present subject matter.

DETAILED DESCRIPTION

[0008] Metal substrates made of magnesium, aluminum, copper, titanium, or a combination thereof, are strong, and are light in weight. Such metal substrates are used for manufacturing body parts, housings, and enclosures of portable or handheld devices, such as mobile phones, tablets, laptops, styluses, keyboards, and the like.

[0009] Metallic impressions may be formed on components made of metal substrates to provide desirable surface finishes or decorations, or to show brand logos on such components. The metallic impressions may be formed using lithographic or other complex and tedious fabrication techniques, which may significantly increase the production time and cost. Further, the metallic impressions formed using such techniques may not be precise or structurally stable.

[0010] The present subject matter describes approaches for forming metallic impressions on metal substrates. Such approaches include coating metal and polymer on the metal substrates to achieve such metallic impressions. The approaches for coating metal and polymer on metal substrates, according to examples of the present subject matter, are easy and fast, and involve less handling of the metal substrates during the coating procedure. Also, the metallic impressions formed on the metal substrates are structurally stable and precise.

[001 1 ] in an example implementation of the present subject matter, a metal substrate is immersed in a solution including ionic polymers. The solution may be referred to as an electrolytic solution. The ionic polymers encapsulate a metal oxide. For coating a layer of ionic polymers on the metal substrate, a voltage is provided to the metal substrate, which electrolyzes the electrolytic solution. The voltage may be in a range of 30 V to 150 V. As a result of electrolysis, ionic polymers in the electrolytic solution are released and are deposited on the metal substrate to form a layer of the ionic polymers on the metal substrate. Upon depositing the layer of ionic polymers on the metal substrate, a region of the layer, at which a metallic impression is to be formed, is treated with a laser. The laser treatment reduces the metal oxide, encapsulated by the ionic polymers in the treated region of the layer, to a metal.

[0012] The laser treatment may be done selectively in a region of the layer of ionic polymers to obtain a metallic impression. The metal converted from the metal oxide in the laser treated region results in a lustrous metallic impression. While the methodology of coating metal and polymer on a metal substrate, according to the present subject matter, is simple and easy, the metallic impression formed on the metal substrates by laser treatment are structurally stable and precise.

[0013] Further, in an example implementation, the electrolytic solution and the metal substrate immersed in the electrolytic solution may be subjected to ultrasonic vibrations during the electrolysis. The ultrasonic vibrations facilitate strong binding of ionic polymers with the metal substrate. Further, the ionic polymers may fill up micro-pores that may be present on the surface of the metal substrate. Thus, the ionic polymer layer on the metal substrate may have improved surface uniformity.

[0014] The following detailed description refers to the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar parts. While several examples are described in the description, modifications, adaptations, and other implementations are possible. Accordingly, the following detailed description does not limit the disclosed examples. Instead, the proper scope of the disclosed examples may be defined by the appended claims.

[0015] Fig. 1 illustrates a sectional view of a polymer coated metal substrate 100, according to an example of the present subject matter. The polymer coated metal substrate 100 includes a metal substrate 102. The metal substrate 102 may be made of magnesium, aluminum, zinc, titanium, lithium, niobium, steel, copper, other metals, or a combination thereof.

[0018] The polymer coated metal substrate 100, as shown in Fig. 1 , also includes a layer 104 of ionic polymers on the metal substrate 102. The ionic polymers encapsulate a metal oxide 106. For this, the ionic polymers are embedded with metal oxide capsules. The metal oxide may include an oxide of a metal selected from boron, copper, nickel, zinc, aluminum, zirconium, silicon, tin, bismuth, tungsten, molybdenum, chromium, magnesium, manganese, cerium, titanium, barium, or a combination thereof. In an example, the metal oxide in the ionic polymers may have a concentration in a range of 0.1 % by weight to 3.0% by weight. The encapsulated metal oxide in the ionic polymers may be selected depending on the type of color, luster, and surface finish to be provided on the metal substrate. The layer 104 of ionic polymers may completely cover the metal substrate 102, as depicted in the sectional view in Fig. 1 , or may only cover a portion of the metal substrate 102 in other examples. The layer 104 may have a thickness in a range of 5 micrometers (pm) to 25 pm.

[0017] in an example implementation, the layer 104 is coated or deposited on the metal substrate 102 through electrolysis of an electrolytic solution having the ionic polymers. In an example, the ionic polymers in the electrolytic solution may have a concentration in a range of 5% by weight to 20% by weight. The metai substrate 102 is immersed in the electrolytic solution and a voltage, in a range of 30 V to 150 V, is provided to the metai substrate 102 for coating the layer 104. The layer 104 may thus be referred to as the eiectrolytical!y coated layer 104 of ionic polymers.

[0018] in an example implementation, the layer 104 of ionic polymers may be coated in the presence of ultrasonic vibrations. For this, the electrolytic solution and the metal substrate 102 immersed in the electrolytic solution are subjected to ultrasonic vibrations while the voltage is being provided to the metai substrate 102. The ultrasonic vibrations may be provided at a frequency in a range of about 15 kHz to about 400 kHz.

[0019] Further, as shown in Fig 1 , the polymer coated metai substrate 100 also includes a metal region 108 that is obtained by providing a laser beam on the layer 104. In an example implementation, the laser beam may be from a COz laser, an Nd-YAG laser, an excimer laser, a fiber-coupled laser, an infrared laser, an ultraviolet laser, or a multi-beam laser. The laser beam reduces the encapsulated metal oxide in the region of the layer 104 to form the metal region 108. Although depicted as a block, the metai region 108, in an example, may be of any pattern, shape, and structure, depending on the metallic impression to be provided on the metal substrate 102. The metal region 108 may include a metallic surface finish, a metallic decoration, or a logo.

[0020] in an example implementation, components, such as body parts, housings, and enclosures of portable or handheld devices, may be made, at least partially, of polymer coated metal substrate 100. For this, the metal substrate 102 may be forged, die-casted, computer-numeric control (CNC) machined, or molded, in the shape of the component, prior to coating the layer 104 of ionic polymers.

[0021 ] Further, in an example implementation, the metal substrate 102, prior to coating the layer 104 of ionic polymers, may be cleaned, washed, polished, degreased, and/or activated. The metal substrate 102 may be chemically cleaned using an alkaline agent, for example, sodium hydroxide. The metal substrate 102 may be washed in a buffer solution. The cleaning and washing of the metal substrate may help In removing foreign particles, if any, present on the surface of the metal substrate. Further, the metal substrate may be chemically polished using abrasives to remove irregularities that may be present on the surface of the metal substrate. The metal substrate may also be degreased through ultrasonic degreasing to remove impurities, such as fat, grease, or oil from the surface of the metal substrate. Further, the metal substrate may also be activated through acid treatment for removing the natural oxide layer, if any, present on the surface of the metal substrate.

[0022] Further, in an example implementation, prior to providing the laser beam, the metal substrate 102, coated with the layer 104, is heated at a temperature in a range of 1 10 degrees Celsius (°C) to 170 °C for a time duration in a range of 20 minutes to 40 minutes. This heating of the metal substrate cures the layer 104 of ionic polymers.

[0023] in an example implementation, ionic polymers may be cationic polymers or anionic polymers, depending on the setup used for coating the layer 104 of ionic polymers. Examples of setup and procedure used for coating the layer 104 of ionic polymers on the metal substrate 102 is described in detail with reference to Figs. 2 and 3.

[0024] Fig. 2 illustrates an apparatus for electroiytically coating an ionic polymer layer on a metal substrate in the presence of ultrasonic vibrations, followed by applying a laser beam to obtain a metal region, according to an example of the present subject matter. Fig. 2 shows a setup 200 of the apparatus having an ultrasonic cleaner 202 that can operate at ultrasonic frequencies in a range of 15 kHz to 400 kHz. The ultrasonic cleaner 202 has a container that can hold liquids in which a substrate may be immersed for providing ultrasonic vibrations through the liquid to the substrate

[0025] For the purpose of coating a layer of ionic polymers on the metal substrate 102, a solution 204 comprising ionic polymers is poured into the container of the ultrasonic cleaner 202 For the setup 200, shown in Fig. 2, the ionic polymers are cationic polymers. The cationic polymers include polymers selected from a group comprising polyethyieneimine (PEI) polymer, polydiailyldimethyiammonium chloride (polyDADMAC) polymer, poiydimetby!diai!yiammonium chloride (polyDIMDAC) polymer, and silicone epoxy copolymer. The cationic polymers in the solution 204 may have a concentration in a range of about 5% by weight to about 20% by weight of the solution 204. The cationic polymers encapsulate a metal oxide. The metal oxide may include an oxide of a metal selected from boron, copper, nickel, zinc, aluminum, zirconium, silicon, tin, bismuth, tungsten, molybdenum, chromium, magnesium, manganese, cerium, titanium, barium, or a combination thereof in an example, the metal oxide in the cationic polymers may have a concentration in a range of 0.1 % by weight to 3.0% by weight of the cationic polymers. Further, the solution 204 may be at a temperature in range of 25 °C to 40 °C.

[0028] After pouring the solution 204 in the container of the ultrasonic cleaner 202, the metal substrate 102 is immersed as a cathode terminal in the solution 204. Also, an element, such as a block 206, is immersed as an anode terminal in the solution 204. The metal substrate 102 and the block 208 are electrically connected to a negative terminal 210 and a positive terminal 212 of a voltage source 208, respectively, and immersed in the solution 204. The block 208 may be made of stainless steel, brass, copper, galvanized iron, mild steel, lead, nickel, nickel-chromium, tungsten, tin plate, zinc, phosphor bronze, aluminum, or graphite. The voltage source 208 may be a constant voltage source or a variable voltage source that can provide a voltage in a range of 30 V to 150 V.

[0027] In an example implementation, the metal substrate 102 may be formed in a shape of a component that is to include or be coated, at least partially, with the polymer coated metal substrate and a metallic impression. Also, the metal substrate 102 may be cleaned, washed, polished, degreased, and/or activated, in a manner as described above, before coating a layer of cationic polymers on the metal substrate 102.

[0028] After immersing the metal substrate 102 and the block 208 In the solution 204, the voltage source 208 may be switched ON to provide a voltage across the metal substrate 102 and the block 206. The voltage electrolyzes the solution 204, which causes positively charged particles 214 of the cationic polymers, present in the solution 204, to move towards the cathode terminal, i.e. , the metal substrate 102. As a result, the positively charged particles 214 of the cationic polymers form a layer of cationic polymers on the metal substrate 102. It may be noted that the positively charged particles 214 of the cationic polymers encapsulate a metal oxide (not shown in Fig. 2).

[0029] Further, in an example implementation, the ultrasonic cleaner 202 may be switched ON, while the voltage source 208 is switched ON, to provide ultrasonic vibrations to the solution 204 and the metal substrate 102 during the electrolysis of the solution 204. The ultrasonic cleaner 202 may be operated at an ultrasonic frequency in a range of 15 kHz to 400 kHz.

[0030] in an example implementation, the voltage for electrolysis of the solution 204 may be provided for a time duration in a range of 20 seconds to 60 seconds. After this time duration, the voltage source 208 and the ultrasonic cleaner 202 are switched OFF, and the metal substrate 102, coated with the layer of cationic polymers, is removed from the solution 204. it may be noted that the voltage from the voltage source 208, the ultrasonic frequency from the ultrasonic cleaner 202, and the time duration for which the voltage source 208 is switched ON, may vary depending on the type of metal substrate 102, the type of cationic polymers in the solution 204, and the type of metal oxide encapsulated in the cationic polymers.

[0031 ] in an example implementation, the metal substrate 102, coated with the layer of cationic polymers, is heated at a temperature in a range of 1 10 °C to 170 °C for a time duration in a range of 20 minutes to 40 minutes. This heating of the metal substrate cures the layer of cationic polymers. In an example implementation, the layer of cationic polymers coated on the metal substrate 102 may have a thickness in a range of 5 pm to 25 pm

[0032] After heating, the metal substrate 102, coated with the layer of cationic polymers, is treated with a laser 216 to form a metallic impression as described earlier. In an example, a region of the layer of cationic polymers is treated with the laser 216. The laser 216 may be a CO2 laser, an Nd-YAG laser, an excimer laser, a fiber-coupled laser, an infrared laser, an ultraviolet laser, or a multi-beam laser. It may be noted that the type of laser used may depend on the type of metal substrate 102, the type of cationic polymers coated on the metal substrate, and the type of metal oxide encapsulated in the cationic polymers. The treatment by laser 218 over a region of the layer of cationic polymers reduces the encapsulated metal oxide in the region to obtain a metal region 218. The metal region 218, in an example, may be of any pattern, shape, and structure, depending on the metallic impression to be provided on the metal substrate 102.

[0033] Fig 3 illustrates an apparatus for electrolytlcaliy coating an ionic polymer layer on a metal substrate in the presence of ultrasonic vibrations, followed by applying a laser beam to obtain a metal region, according to another example of the present subject matter. Fig. 3 shows a setup 300 of the apparatus having an ultrasonic cleaner 302 which is similar to the ultrasonic cleaner 202. A solution 304 comprising ionic polymers is poured into the container of the ultrasonic cleaner 302. For the setup 300, shown in Fig. 3, the ionic polymers are anionic polymers. The anionic polymers include polymers selected from a group comprising polyarylphosphate polymer, po!yacy!ic polymer, and polyacrylamide- acrylic copolymer. The anionic polymers in the solution 304 may have a concentration in a range of about 5% by weight to about 20% by weight of the solution 304. The anionic polymers encapsulate a metal oxide. The metal oxide may include an oxide of a metal selected from boron, copper, nickel, zinc, aluminum, zirconium, silicon, tin, bismuth, tungsten, molybdenum, chromium, magnesium, manganese, cerium, titanium, barium, or a combination thereof in an example, the metal oxide in the anionic polymers may have a concentration in a range of 0.1 % by weight to 3.0% by weight of the anionic polymers. Further, the solution 304 may be at a temperature in range of 25 °C to 40 °C. [0034] After pouring the solution 304 in the container of the ultrasonic cleaner 302, the metal substrate 102 is immersed as an anode terminal in the solution 304. Also, an element, such as a block 306, is immersed as a cathode terminal in the solution 304. The metal substrate 102 and the block 306 are electrically connected to a positive terminal 310 and a negative terminal 312 of a voltage source 308, respectively, and immersed in the solution 304. The block 306 may be made of stainless steel, brass, copper, galvanized iron, mild steel, lead, nickel, nickel-chromium, tungsten, tin plate, zinc, phosphor bronze, aluminum, or graphite. The voltage source 308 may be a constant voltage source or a variable voltage source that can provide a voltage in a range of 30 V to 150 V.

[0035] In an example implementation, the metal substrate 102 may be formed in a shape of a component that is to include or be coated, at least partially, with the polymer coated metal substrate and a metallic impression. Also, the metal substrate 102 may be cleaned, washed, polished, degreased, and/or activated, in a manner as described above, before coating a layer of anionic polymers on the metal substrate 102.

[0036] After immersing the metal substrate 102 and the block 306 in the solution 304, the voltage source 308 may be switched ON to provide a voltage across the metal substrate 102 and the block 306. The voltage electrolyzes the solution 304, which causes negatively charged particles 314 of the anionic polymers, present in the solution 304, to move towards the anode terminal, i.e., the metal substrate 102 As a result, the negatively charged particles 314 of the anionic polymers form a layer of anionic polymers on the metal substrate 102. It may be noted that the negatively charged particles 314 of the anionic polymers encapsulate a metal oxide (not shown in Fig 3).

[0037] Further, in an example implementation, the ultrasonic cleaner 302 may be switched ON, while the voltage source 308 is switched ON, to provide ultrasonic vibrations to the solution 304 and the metal substrate 102 during the electrolysis of the solution 304. The ultrasonic cleaner 302 may be operated at an ultrasonic frequency in a range of 15 kHz to 400 kHz. [0038] In an example implementation, the voltage for electrolysis of the solution 304 may be provided for a time duration in a range of 20 seconds to 60 seconds. After this time duration, the voltage source 308 and the ultrasonic cleaner 302 are switched OFF, and the metal substrate 102, coated with the layer of anionic polymers, is removed from the solution 304. it may be noted that the voltage from the voltage source 308, the ultrasonic frequency from the ultrasonic cleaner 302, and the time duration for which the voltage source 308 is switched ON, may vary depending on the type of metal substrate 102, the type of anionic polymers in the solution 304, and the type of metal oxide encapsulated in the anionic polymers.

[0039] in an example implementation, the metal substrate 102, coated with the layer of anionic polymers, is heated at a temperature in a range of 1 10 °C to 170 °C for a time duration in a range of 20 minutes to 40 minutes. This heating of the metal substrate cures the layer of anionic polymers. In an example implementation, the layer of anionic polymers coated on the metal substrate 102 may have a thickness in a range of 5 pm to 25 pm.

[0040] After heating, the metal substrate 102, coated with the layer of anionic polymers, is treated with a laser 316 to form a metallic impression as described earlier in an example, a region of the layer of anionic polymers is treated with the laser 316. The laser 316 may be a CO2 laser, an Nd-YAG laser, an excimer laser, a fiber-coupled laser, an infrared laser, an ultraviolet laser, or a multi-beam laser it may be noted that the type of laser used may depend on the type of metal substrate 102, the type of anionic polymers coated on the metal substrate, and the type of metal oxide encapsulated in the anionic polymers. The treatment by laser 316 over a region of the layer of anionic polymers reduces the encapsulated metal oxide in the region to obtain a metal region 318. The metal region 318, in an example, may be of any pattern, shape, and structure, depending on the metallic impression to be provided on the metal substrate 102.

[0041 ] in an example implementation, a top layer may be coated on the polymer coated metal substrate 100. The top layer may be spray coated on the polymer coated metal substrate 100. The top layer may be of a material selected from fluorinated olefin-based polymers, specialty fluoroacrylates, fiuorosilicone acrylates, fluorourethanes, perfluoropolyethers/perfluoropolyoxetanes, f!uorote!omers (C-6 or lower products), polytetrafluoroethylene (PTFE), polyvinylidenefluouride (PVDF), fluorosiloxane, and fluoro UV polymers. After spray coating the top layer, the polymer coated metal substrate 100 is heated at a temperature in a range of 80 °C to 80 °C for a time duration in a range of 5 minutes to 15 minutes. This heating of the metal substrate cures the top layer. The top layer may have a thickness in a range of 1 pm to 10 pm. The fop layer may be optically dear or transparent. The top layer may be a functional layer, such as a UV coating, an anti-finger print coating, a soft touch coating, an anti- bacterial coating, an anti-smudge coating, a silky coating, and the like. In an example, the top layer may be a protective coating to protect the polymer coating and the metallic impression formed on the metal substrate.

[0042] Fig. 4 illustrates a method 400 of coating a layer of ionic polymers on a metal substrate and obtaining a region of metal by laser treatment, according to an example of the present subject matter. The metal substrate may be made of magnesium, aluminum, zinc, titanium, lithium, niobium, steel, copper, or a combination thereof. The metal substrate may be formed in a shape of a component, such as a body part of a device. As described earlier, the metal substrate may be cleaned, washed, polished, degreased, and/or activated, prior to coating a layer of ionic polymers on the metal substrate.

[0043] At block 402 of the method 400, the metal substrate is immersed in a solution including ionic polymers, where the ionic polymers encapsulate a metal oxide. In an example implementation, the ionic polymers are cationic polymers, and the metal substrate is immersed as a cathode terminal. In an example implementation, the ionic polymers are anionic polymers, and the metal substrate is immersed as an anode terminal in addition, a block made of stainless steel, brass, copper, galvanized iron, mild steel, lead, nickel, nickel-chromium, tungsten, tin plate, zinc, phosphor bronze, aluminum, or graphite, may be immersed in the electrolytic solution as a terminal of a polarity opposite to that of the metal substrate. The type of ionic polymers, the type of metal oxide, the concentration of the ionic polymers in the solution, the concentration of metal oxide in the ionic polymers, and the temperature of the solution, may be as described earlier.

[0044] At block 404, a voltage is provided to the metal substrate, immersed in the solution, to deposit a layer of the ionic polymers on the metal substrate. The voltage may be in a range of 30 V to 150 V. In an example implementation, the layer of ionic polymers coated on the metal substrate may have a thickness in a range of 5 pm to 25 pm. The voltage may be provided to the metal substrate for a time duration in a range of 20 seconds to 60 seconds, after which the metal substrate, coated with the layer of ionic polymers, is removed from the solution. The metal substrate, coated with the layer of ionic polymers, may then be heated at a temperature in a range of 1 10 °C to 170 °C for a time duration in a range of 20 minutes to 40 minutes.

[0045] At block 406, a region of the layer of the ionic polymers is treated with a laser to reduce the metal oxide of the ionic polymers in the region to a metal. The laser may be a CC½ laser, an Nd-YAG laser, an excimer laser, a fiber-coupled laser, an infrared laser, an ultraviolet laser, or a multi-beam laser.

[0046] in an example implementation, the solution of ionic polymers may be held in a container of an ultrasonic cleaner, and the solution and the metal substrate immersed in the solution are treated at an ultrasonic frequency while the voltage is being provided to the metal substrate. The ultrasonic frequency may be in a range of 15 kHz to 400 kHz.

[0047] Fig. 5 illustrates a method 500 of fabricating a polymer coated metal substrate, according to an example of the present subject matter. The method 500 may be used to fabricate the polymer coated metal substrate 100, as described above. The metal substrate may be made of one of magnesium, aluminum, zinc, titanium, lithium, niobium, steel, copper, and a combination thereof. The metal substrate may be formed in a shape of a component, such as a body part of a device. As described earlier, the metal substrate may be cleaned, washed, polished, degreased, and/or activated, prior to coating a layer of ionic polymers on the metal substrate.

[0048] At block 502 of the method 500, the metal substrate is immersed as an electrode in a solution having ionic polymers of concentration in a range of 5% to 20% by weight of the solution. The ionic polymers encapsulate a metal oxide of concentration in a range of 0.1 % to 3% by weight of the ionic polymers. The metal oxide may include an oxide of a metal selected from boron, copper, nickel, zinc, aluminum, zirconium, silicon, tin, bismuth, tungsten, molybdenum, chromium, magnesium, manganese, cerium, titanium, barium, or a combination thereof. Further, a block made of stainless steel, brass, copper, galvanized iron, mild steel, lead, nickel, nickel-chromium, tungsten, tin plate, zinc, phosphor bronze, aluminum, or graphite, may be immersed in the solution as an electrode of polarity opposite to that of the metal substrate.

[0049] in an example implementation, the metal substrate is immersed as a cathode in the solution, and the ionic polymers in the solution are cationic polymers selected from a group comprising polyethyleneimine (PEI) polymer, poiydiailyldimethylammonium chloride (polyDADMAC) polymer, poiydimethyldiailyiammonium chloride (polyDIMDAC) polymer, and silicone epoxy copolymer in another example implementation, the metal substrate is immersed as an anode in the solution, and the ionic polymers in the solution are anionic polymers selected from a group comprising po!yary!phosphate polymer, po!yacylic polymer, and polyacrylamide-acrylic copolymer.

[0050] At block 504, the solution and the metal substrate are treated at an ultrasonic frequency. The ultrasonic frequency may be in a range as described above. At block 506, a voltage is provided to the metal substrate while treating at the ultrasonic frequency, to deposit a layer of ionic polymers on the metal substrate. The voltage may be in a range as described earlier.

[0051 ] The voltage may be provided for a time duration in a range of 20 seconds to 60 seconds. After this, the metal substrate, coated with the layer of ionic polymers, Is removed from the solution, and heated at a temperature in a range of 1 10 °C to 170 °C for a time duration in a range of 20 minutes to 40 minutes.

[0052] After heating the metal substrate, a laser beam is provided on a region of the layer of the ionic polymers, at block 508. The laser beam reduces the metal oxide of the ionic polymers in the region to a metal, thereby resulting in a lustrous metallic impression. In an example implementation, the laser beam is from a CO2 laser, an Nd-YAG laser, an excimer laser, a fiber-coupled laser, an infrared laser, an ultraviolet laser, or a multi-beam laser.

[0053] in an example implementation, after providing the laser beam, a fop layer may be spray coated on the layer of ionic polymers and the region of metal. In an example, the top layer may be a protective coating to protect the polymer coating and the region of metal formed on the metal substrate. The top layer may be of a material selected from fluorinated olefin-based polymers, specialty f!uoroacry!ates, f!uorosi!icone acrylates, fluorourethanes, perfluoropolyethers/perfiuoropolyoxetanes, fluorotelomers (C-6 or lower products), poiytetrafluoroethyiene (PTFE), poiyvinylidenefiuouride (PVDF), fluorosiloxane, and fluoro UV polymers. The metal substrate, coated with the top layer, may then be heated at a temperature in a range of 60 °C to 80 °C for a time duration in a range of 5 minutes to 15 minutes.

[0054] Although examples for the present disclosure have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not limited to the specific features or methods described herein. Rather, the specific features and methods are disclosed and explained as exa ples of the present disclosure.

Claims

We claim:

1. A method comprising:

immersing a metal substrate in a solution including ionic polymers, wherein the ionic polymers encapsulate a metal oxide;

providing a voltage to the metal substrate, immersed in the solution, to deposit a layer of the ionic polymers on the metal substrate; and

treating a region of the layer of the ionic polymers with a laser to reduce the metal oxide of the ionic polymers in the region to a metal.

2. The method as claimed in claim 1 , wherein the ionic polymers are cationic polymers, and wherein the metal substrate is immersed as a cathode terminal.

3. The method as claimed in claim 1 , wherein the ionic polymers are anionic polymers, and wherein the metal substrate is immersed as an anode terminal.

4. The method as claimed in claim 1 , wherein the ionic polymers in the solution has a concentration in a range of about 5% by weight to about 20% by weight of the solution.

5. The method as claimed in claim 1 , wherein the metal oxide includes an oxide of a metal selected from boron, copper, nickel, zinc, aluminum, zirconium, silicon, tin, bismuth, tungsten, molybdenum, chromium, magnesium, manganese, cerium, titanium, barium, or a combination thereof.

8. The method as claimed in claim 1 , wherein the laser is a C0₂ laser, an Nd- YAG laser, an excimer laser, a fiber-coupled laser, an infrared laser, an ultraviolet laser, or a multi-beam laser.

7. The method as claimed in claim 1 , wherein the solution is in a container of an ultrasonic cleaner, wherein the method comprises: treating the solution and the metal substrate at a frequency in a range of about 15 kHz to about 400 kHz while the voltage is being provided to the metai substrate.

8. The method as claimed in claim 1 , wherein the voltage is in a range of 30 V to 150 V.

9. A method comprising:

immersing a metai substrate as an electrode in a solution including ionic polymers, wherein the ionic polymers encapsulate a metai oxide;

treating the solution and the metal substrate at an ultrasonic frequency; providing a voltage to the metal substrate, immersed in the solution while treating at the ultrasonic frequency, to deposit a layer of the ionic polymers on the metai substrate; and

providing a laser beam on a region of the layer of the ionic polymers to reduce the metal oxide of the ionic polymers in the region to a metai.

10. The method as claimed in claim 9, wherein the ionic polymers are cationic polymers selected from a group comprising poiyefhy!eneimine (PE!) polymer, poiydiailyidimethy!ammonium chloride (po!yDADMAC) polymer, poiydimethyldiailyiammonium chloride (polyDIMDAC) polymer and silicone epoxy copolymer.

1 1. The method as claimed in claim 9, wherein the ionic polymers are anionic polymers selected from a group comprising poiyary!pbosphate polymer, poiyacylic polymer and polyacrylamide-acrylic copolymer

12. The method as claimed in claim 9, wherein the metai oxide includes an oxide of a metai selected from boron, copper, nickel, zinc, aluminum, zirconium, silicon, tin, bismuth, tungsten, molybdenum, chromium, magnesium, manganese, cerium, titanium, barium, or a combination thereof.

13. The method as claimed in claim 9, wherein the laser beam is selected from a CO2 laser, an Nd-YAG laser, an excimer laser, a fiber-coupled laser, an infrared laser, an ultraviolet laser, or a multi-beam laser.

14. A polymer coated metal substrate comprising:

a metal substrate;

an eiectrolyticaliy coated layer of ionic polymers, deposited in the presence of ultrasonic vibrations, on the metal substrate, the Ionic polymers encapsulating a metal oxide; and

a metal region obtained by providing a laser beam on the eiectrolyticaliy coated layer to reduce the metal oxide in the ionic polymers to a metal.

15. The polymer coated metal substrate as claimed in claim 14, wherein the metal oxide includes an oxide of a metal selected from boron, copper, nickel, zinc, aluminum, zirconium, silicon, tin, bismuth, tungsten, molybdenum, chromium, magnesium, manganese, cerium, titanium, barium, or a combination thereof, and wherein the laser beam is from a CO2 laser, an Nd-YAG laser, an excimer laser, a fiber-coupled laser, an infrared laser, an ultraviolet laser, or a multi-beam laser.