Method and device for dry treatment of metal surfaces by means of electroactive solid particles

Abstract

The invention relates to a method and a device for the dry treatment of a metal surface (1) by means of electroactive solid particles (9), comprising a step of bringing the particles (9) into contact with an electrode (3) of a power source (2), a step of projecting the particles (9) onto the metal surface to be treated, and a step of transporting an electrical charge from the particles to the metal surface to be treated. During the projection step, the electrical transmission between the power source (2) and the metal surface (1) is preferably carried out by means of the net charge of the particles (9), or by means of electrical conductivity by means of contact or by means of an electric arc. The current applied to the electrode is preferably a direct current or a current comprising a positive portion and a negative portion. Preferably, an electrically conductive element is present in the medium between the particles (9), which electrically conductive element increases the electrical conductivity between the particles by means of the arc. Preferably, the method involves the step of using abrasive particles simultaneously or continuously with the electroactive particles.

Description

[0001] This application is a divisional application of application number 202080055237.3, application date July 31, 2020, and invention name “Method and device for dry treatment of metal surfaces with the aid of electroactive solid particles”.

[0002] Purpose of the Invention

[0003] The present invention relates to a method for treating or polishing metal surfaces, characterized in that electroactive solid particles are sprayed onto the part to be polished from an electrode connected to a power supply. This method allows dry polishing of metal surfaces without having to introduce the surface to be treated into a water tank, which allows the treatment of surfaces that were previously difficult to treat due to their size, position, etc. (e.g., large components, immovable components, etc.). The advantages and features of this method represent a significant novelty compared to the prior art.

[0004] The present invention also provides a device for treating metal surfaces by spraying electroactive solid particles from the electrodes of a power supply onto the metal surface to be treated. These devices allow the metal surface to be treated from a given distance without having to introduce the surface into a water tank. This allows the surface of large components, immovable components, etc. to be treated. These devices can be designed to treat large components with the help of a robotic arm so that they can be used in a cabin, so that they can be used on a line in a production line, so that they can be used in a portable or stand-alone device. These devices have advantages and represent a significant improvement over the prior art described in detail below. Technical Field

[0005] The field of the invention is the industrial field engaged in metal surface treatment, that is, the industrial field engaged in polishing metal surfaces, which is used in fields such as aviation, construction, automation, medicine, sintering lasers and many other application fields. Background Art

[0006] Currently, there are polishing systems on the market that use abrasive particles to spray onto the surface to be treated. The particles are forcefully pushed against the surface, producing a polishing effect proportional to the driving force. This type of polishing system that uses abrasive particles to spray has a number of disadvantages. Polishing systems that use abrasive particles to spray lead to a lack of uniformity on the surface to be treated, as grinding is related to the pressure between the surface and the particles. Parts with larger exposures are subjected to more grinding action, which results in a loss of sharpness in vertices and edges. This limits applications where accuracy or maintaining sharp edges is required. Furthermore, polishing systems that use abrasive particles to spray lead to the inclusion of identical abrasive particles on the metal surface, which reduces the surface's properties with respect to durability, chemical resistance, and traction. There are also significant risks to respiratory health associated with polishing systems that use abrasive particles, as well as with the abrasive particles and the suspended dust and particulates generated during the process.

[0007] On the other hand, there is a dry electrolytic polishing system, which is disclosed in ES2604830 (A1) as a "Method for smoothing and polishing metals by ion transport with the aid of free solids." This method is based on the introduction and friction of the part to be treated in a medium composed of solid particles capable of ion transport, while applying an electric potential between the part and a counter electrode. This dry electrolytic polishing system allows the production of surfaces with low roughness and good finish. In addition, the system does not significantly modify vertices or corner edges in the object to be polished. This dry electrolytic polishing system has several disadvantages, among which it should be noted that it is not feasible for treating large-sized parts (such as aircraft wings) and cannot be applied to the treatment of immovable elements (such as architectural elements).

[0008] The method for dry polishing of metal surfaces by spraying electroactive particles, the object of the present invention, represents a significant advance, as it allows combining the good finish of dry electrolytic polishing systems with the advantages of polishing by spraying abrasive particles, thus expanding the application areas of the former and reducing the disadvantages of the latter. However, in order to achieve this objective, several obstacles must be overcome in a unique manner (for example, the nature of the solid particles to be used, their degree of compaction, or the type of electric current). Summary of the Invention

[0009] The method and apparatus for dry polishing of metal surfaces by spraying electroactive particles have a number of identified advantages and features as detailed below.

[0010] The term "electroactive solid particles" as used herein refers to particles that can be charged, can conduct electricity, or have both properties to some extent.

[0011] The term "spray of particles" is understood herein in the broadest sense of any method or system in which the particles reach the surface to be treated, regardless of whether the driving force is gravity, fluid flow, compressed gas, electrostatic forces, centrifugal forces, etc.

[0012] The term "power source" is understood herein to mean any element capable of supplying electrical energy to the electroactive solid particles. The power source provides electrical energy to the solid particles. The current applied by the power source may be AC ​​(alternating current), DC (direct current), or pulsed current. Preferably, the power source includes a system that allows control of the applied voltage and intensity.

[0013] The basic steps defining the method and apparatus of the present invention are:

[0014] - bringing the electroactive solid particles into contact with electrodes of a power supply;

[0015] - spraying the electroactive solid particles of the device onto the metal surface; and

[0016] - Bringing electroactive solid particles into contact with a metal surface.

[0017] The minimum elements defining the apparatus of the present invention are:

[0018] - a group of electroactive solid particles;

[0019] - a power source having electrodes that transfer electrical charge to the electroactive solid particles;

[0020] - means for spraying electroactive solid particles onto the metal surface to be treated; and

[0021] - A nozzle through which the electroactive solid particles leave the device.

[0022] The interaction that exists between these smallest elements is as follows. The electroactive particles contact the electrode of the power source, and this electrode transfers the charge to the electroactive particles. From the electrode, the particles move towards the metal surface to be treated, where they come into contact and transfer part of the electrical energy. This contact generates redox processes on the metal surface, producing a polishing effect. Figure 1 , a diagram of a prototype is shown as an example.

[0023] Due to the electrical nature of the process, the surface to be treated should be electrically conductive, preferably metallic. This includes surfaces of non-conductive materials such as plastics undergoing the metallization process.

[0024] As far as we know, the charge transport from the electrode to the surface to be treated by means of a particle flow has not been described in the literature to date. Three possible charge transport mechanisms have been conceptualized simultaneously, and these and various intermediate or derived scenarios occur according to the following mechanisms:

[0025] 1) Net charge of the particle;

[0026] 2) by virtue of electrical conductivity through contact; and

[0027] 3) By means of electric arc or ionized gas through electrical conductivity.

[0028] A schematic diagram of these mechanisms can be seen in Figure 2.

[0029] Depending on the controllable parameters of the system, one mechanism can be promoted over the other. These parameters are mainly electrical parameters, particle type, injection type and environment.

[0030] Under low compaction conditions, the mechanism of charge transport through particles with a net charge is enhanced. In an ideal situation, the particles are isolated from each other, which means that there is no direct contact between them. The energy density U that a particle can carry can be determined by the dielectric particle constant ε r and the applied electric field E.

[0031] For example, experiments have shown that microporous gel particles of sulfonated polystyrene-divinylbenzene with a diameter of 600 μm containing 4% sulfuric acid exhibit ε r =1.10.10 8 (measured at 100 Hz), which for an applied electric field of 30 kV means 437 kJ m -1 These same particles, when sprayed onto a metal surface, create an electrical discharge that processes the surface. For example, when the particles are sprayed onto a 316 stainless steel surface, they create a detectable current path and a perceptible surface modification.

[0032] This mechanism is facilitated by particles with high dielectric constants and applied voltages that allow for greater stored electrical energy density and a high separation of the particles that prevents voltage discharge between the particles.

[0033] This mechanism promotes the transfer of charge through electrical conductivity, which is achieved through contact, when continuous contact between the particles and the surface being treated is established. In this case, the current flows directly through the particles, which is why this mechanism is favored by particles with high electrical conductivity and high flow compactness. This mechanism generates relatively high current densities, allowing parts to be processed at higher speeds.

[0034] The mechanism of charge transfer via discharge and arcing implies that the charge is transferred from the power source to the component through the medium between the particles. This means that the charge transfer occurs at least partially through an ionized gas. A range of possibilities exist, including avalanche and crown discharges.

[0035] Although these discharges can generate charge particles and particle surfaces, they primarily occur between particles, which means that the medium between particles and the distance between particles are parameters that have a strong influence on triggering the mechanism.

[0036] For various particle types and sizes, there is a range of distances between particles that trigger this mechanism. Increasing the conductivity of the space between particles increases the range of functional distances and allows for greater operating margins. In a preferred embodiment, elements are added that facilitate the conductivity between particles achieved by the arc. These elements can be solid, liquid, ionic, etc., as well as using electromagnetic radiation.

[0037] In the case of liquid elements that promote electrical conductivity between particles by means of an electric arc (which has the ability to generate droplets or aerosols), the liquid element increases the conductivity of the medium between the particles. There are also solid elements that promote electrical conductivity between particles by means of an electric arc. Due to the transmission of electricity, these arcs produce micron- or nanometer-sized particles in suspension (for example, derivatives of carbon, carbon fiber types, graphite, or micronized carbon). Due to the passage of electricity, these carbon compounds increase their temperature and produce volatile elements or suspended elements that promote electrical transmission. It is also possible to add elements that have the ability to trap electrolyte and promote electrical conductivity between particles by means of an electric arc (for example, gel-type materials), some of which are significantly larger than the average diameter of the particles (for example, rods or cylinders that form an electrical bridge).

[0038] Generating ions in the spaces between the particles significantly increases the conductivity between the particles achieved by the arc. Ions can be generated using ionizable or volatile substances (e.g., iodine) or by using electromagnetic radiation (ionizing or non-ionizing). These different elements that increase the conductivity of the spaces between the particles can be used in combination with one another. They can be mixed with the electroactive particles, added at another point to adjust the medium, or they can be incorporated into the electroactive particles. Preferably, the particles can retain a predetermined amount of liquid, in which case the vibration and friction of the process create droplets and aerosols between the particles that change the conductivity of the system. Ultrasound can also be used to generate droplets or atomize the system. The use of electromagnetic radiation can increase the conductivity of the medium. The use of ionizing electromagnetic radiation (i.e., ultraviolet, X-rays, and gamma rays) directly generates ions in the medium, which increases the conductivity of the group of particles and gas to each other. Electromagnetic non-ionizing radiation can also be used to increase conductivity. For example, by using microwave radiation, plasma can be generated from the particles, which increases the conductivity of the medium.

[0039] Discharge is more likely to occur with AC (alternating current) than with DC (direct current). For example, experimentally, a visible arc was observed starting at 25 kV using DC. Under the same conditions, arcing was observed at voltages of orders of magnitude lower than 2 kV using 50 Hz AC.

[0040] In order to maintain a stable current with a coronal arc, the frequency of the AC can be increased (even by several orders of magnitude), operated at a voltage in the order of kilovolts, and the pressure of the medium reduced.

[0041] The power supply provides electrical energy to the solid particles. The electric current applied by the power supply can be AC, DC or pulsed current. Preferably, the power supply includes a system that allows control of the applied voltage and intensity. DC is the electric current that produces the fastest effect on the surface, so it is a preferred choice in particle / surface systems that do not accumulate residues during the process. If a system utilizing DC produces surface accumulation, an electric current that includes polarity reversal can be used to improve the result. The most suitable way to obtain an electric current with polarity reversal is to use AC. It can be used directly or rectified by means of a diode or other electroactive element. A preferred alternative is a power supply using a pulsed current, which allows control of the parameters of the applied pulse (such as positive or negative voltage, positive or negative pulse duration, pause duration, etc.).

[0042] The electrical parameters applied by the power supply determine the effect of the particles on the surface. The potential difference applied for producing a polishing effect is in the large range of 1V to 50kV, which is a feature of the electrical transport mechanism. The current applied to the electrode can be DC, AC or pulsed current. For example, a 30kV DC source at a distance of 18cm between the electrode and the surface to be processed, where particles are ejected by gravity pulses and are not compacted, produces a polishing effect on the metal surface. Moreover, for example, a 30V DC source at a distance of 2cm between the electrode and the surface to be processed, where particles are compacted and continuously ejected by gravity, produces a polishing effect on the metal surface. Moreover, for example, a 50Hz to 2kV AC source at a distance of 18cm between the electrode and the surface to be processed, where particles are ejected by gravity pulses and are not compacted and are pushed by 5 bar air, produces visible arcs and a polishing effect on the metal surface. A larger proportion relative to the individual charge transport mechanisms explained previously can be assigned to each of these examples in a qualitative manner.

[0043] The electrode is a conductive element electrically connected to a power source, and the particles contact this element before leaving and spraying towards the surface to be treated. The shape of the electrode depends on the application or surface to be treated. Usually, the contact area of ​​the particles and the electrode at the moment before spraying them is maximized. For example, the pipe through which the particles are circulated is connected to a straight cylindrical shape and leaves the metal electrode (for example copper). And, for example, in order to process a relatively flat plate or surface, the electrode can be a "curtain-type" system for applying particles, that is, linearly leaving the groove. In a preferred embodiment, the electrode is made of a nozzle.

[0044] Electroactive solid particles can transfer electrical charge from a power source to the metal surface to be treated.

[0045] Preferably, the solid particles can retain a liquid. The retained liquid can partially dissolve rust and salts formed by the passage of electric current, which improves surface cleanliness. Preferably, the electroactive solid particles are manufactured in a polymer gel because they provide a compromise between physical integrity and the ability to retain liquid in their structure. Preferably, the electroactive particles are made of sulfonated polystyrene-divinylbenzene gels because they facilitate this process due to their reversible ability to retain dissolved metal ions. Preferably, the liquid retained in the electroactive particles is an acidic aqueous solution because most rust, hydroxides and metal salts are more soluble in acidic media. Preferably, the acidic aqueous solution includes one or more strong acids (pK a <2), due to their greater dissociation, strong acids increase electrical transport, while they improve the solubility of rust, hydroxides and metal salts, which leads to optimal surface cleaning.

[0046] The charge transfer process can generate redox reactions on the metal surface, which can form metal rust on the surface. For a good surface finish, controlled removal of the formed rust is necessary. This surface rust can be removed, for example, by abrasion or dissolution.

[0047] The removal of metallic rust from a surface by means of a grinding action can occur through the action of the same electroactive particles used as abrasive particles. Rust can also be removed by the action of non-electroactive abrasive particles. The action of the abrasive particles can occur simultaneously with the action of the electroactive particles (abrasive and non-abrasive particles are ejected simultaneously) or continuously. With this configuration, a novel dry electrolytic polishing process is provided that is combined with a sanding-type grinding process.

[0048] Alternatively or additionally, surface rust removal can be performed by dissolution. Dissolution can be performed by particles that do not contain liquid or by liquid retained in the particles. Preferably, dissolution is performed by liquid retained in the electroactive particles to cause dissolution of rust at the same stage as rust formation.

[0049] The ejection of particles from a metal surface requires a driving force. In its simplest form, this driving force is gravity.

[0050] Preferably, the driving force is provided by a controllable element. The controllable element is preferably a driving force of a compressed gas. The use of a pressurized gas allows for control of the speed and pressure of the particle-surface contact, and for control of particle flow and compaction.

[0051] In an alternative embodiment, the particles are ejected onto the metal surface by the driving force of a turbine which drives the particles by centrifugal force.

[0052] In an alternative embodiment, the particles are ejected onto the metal surface in a discontinuous manner with the aid of the driving force of a rod and crank system. This allows the particles to be ejected in a discontinuous manner with a system that is highly configurable with respect to the speed and volume of each shot.

[0053] In an alternative embodiment, the particles are ejected onto the metal surface in a continuous manner with the aid of the driving force of the worm. This allows for the creation of a continuous and compacted stream of particles, thereby facilitating the mechanism of electrical transmission through contact.

[0054] The exiting flow of particles through the nozzle can be controlled by means of valves and timers so that it is continuous or pulsed.

[0055] The way in which the particles are sprayed onto the surface can be adapted to the needs of the part to be treated. For example, if it is desired to treat a flat surface within a production chain, a nozzle can be used that allows the particles to be sprayed onto the surface in the form of a curtain, allowing the entire width of the surface of the part moving under the curtain to be covered.

[0056] In an alternative embodiment, the spraying can be performed using a nozzle in the form of an application hose, through which the driven particles will exit. Such an application hose can be configurable, for example, with respect to the direction or size of the exit needle. Such hoses can be moved in an automated manner (e.g., within a spraying cabin), or they can be applied manually against the surface to be treated. In the case of particle spraying with the aid of compressed gas, these hoses can incorporate an air dissipator element in their final section at the particle delivery point to compact the particles and maintain high electrical conductivity.

[0057] The particle flow exiting through the nozzle can be controlled by means of a valve and a timer so that the particle flow is continuous or pulsed.

[0058] The way in which the particles are sprayed onto the surface can be adapted to the needs of the part to be polished. For example, if it is desired to process a flat surface within a production chain, a nozzle can be used that allows the particles to be sprayed onto the surface in the form of a curtain, which allows covering the width of the surface of the part moving under the curtain.

[0059] In an alternative embodiment, the spraying can be performed using a nozzle in the form of an application hose, through which the propelled particles will exit. Such an application hose can be configurable, for example, with respect to the direction or size of the exit needle. Such hoses can be moved in an automated manner (e.g., within a spraying cabin), or they can be applied manually against the surface to be polished. In the case of particle spraying with the aid of compressed gas, these hoses can incorporate air dissipator elements at the particle delivery point at the end of their length to compact the particles and maintain high electrical conductivity.

[0060] The surface to be treated can be isolated, grounded, or connected to a power source. Preferably, the surface to be treated is connected to the electrodes of the power source. This allows for greater control over the applied potential difference and allows for measurement of the current flowing between the particles leaving the electrodes and the surface to be treated.

[0061] The surface to be treated must be electrically conductive. Preferably, the surface to be treated is metallic. This includes parts made of plastic material with metallized surfaces. Metals and alloys that can be treated include, but are not limited to, any type of iron, steel, chromium-cobalt alloys, nickel and nickel alloys (e.g., nitinol), zinc and zinc alloys (e.g., Zamak), aluminum and aluminum alloys, titanium and titanium alloys, copper and copper alloys, tungsten carbide, and the like.

[0062] The versatility of the system allows processing of large flat surfaces, large-sized parts, immovable surfaces (such as building structures), etc.

[0063] The electrical parameters applied to the power supply determine the effect of the particles on the surface. The potential difference applied for producing a polishing effect is in the large range of 1V to 50kV, which is a feature of the electrical transport mechanism. The current applied to the electrode can be DC, AC or pulsed current. For example, a 30kV DC source at a distance of 18cm between the electrode and the surface to be processed, in which particles are ejected by gravity pulses and not compacted, produces a polishing effect on the metal surface. Moreover, for example, a 30V DC source at a distance of 2cm between the electrode and the surface to be processed, in which particles are compacted and continuously ejected by gravity, produces a polishing effect on the metal surface. Moreover, for example, a 50Hz to 2kV AC source at a distance of 18cm between the electrode and the surface to be processed, in which particles are ejected by gravity pulses and not compacted and ejected and driven by 5 bar air, produces a visible arc and a polishing effect on the metal surface. The greater relative proportions of the various charge transport mechanisms explained before can be assigned to each of these examples in a qualitative manner.

[0064] The electroactive solid particles can transfer electric charge from a power source to the metal surface to be treated. Preferably, the solid particles can retain a liquid. The retained liquid can partially dissolve rust and salts formed by the passage of electric current, which improves surface cleanliness. Preferably, the electroactive solid particles are manufactured in a polymer gel because it provides a compromise between physical integrity and the ability to retain liquid in its structure. Preferably, the electroactive particles are made of sulfonated polystyrene-divinylbenzene gel because it facilitates the process due to its reversible ability to retain dissolved metal ions. Preferably, the liquid retained in the electroactive particles is an acidic aqueous solution because most rust, hydroxides and metal salts are more soluble in acidic media. Preferably, the acidic aqueous solution includes one or more strong acids (pK a<2), due to their greater dissociation, strong acids increase electrical transport, while they improve the solubility of rust, hydroxides and metal salts, which leads to optimal surface cleaning.

[0065] Other elements that improve the operation of the present invention are:

[0066] - a pre-deposition section for conveying particles;

[0067] - a particle collector. This collector and the pre-deposition unit may be the same element;

[0068] - a particle recirculation system from the collector to the delivery deposit (in the case where they are not the same element); and

[0069] - Vibrators at the storage or circulation points of the particles, to facilitate their transport and transmit the vibrations to the surface to be treated.

[0070] Preferably, the device comprises a solid particle delivery deposit prior to electrical contact and injection. Such a deposit ensures that the particles are delivered to the system in a constant manner and avoids stop moments.

[0071] Preferably, the device includes a solid particle collector after the particles have been driven onto the surface to be treated. This collector is designed in a specific manner for each embodiment and can take several shapes, as can be seen in the examples. This element prevents the particles from being scattered around while allowing them to be recycled.

[0072] In the embodiment that allows, preferably, the delivery deposit part and the collector are the same element. This allows simplifying the design of the device and preventing redundancy of elements, which results in lower costs while maintaining the same functionality.

[0073] In the case where the transport deposit and the collector are not the same element, a particle recycling system can be present between the solid particle collector and the transport deposit. This system allows the particles to be automatically reused, thus avoiding the necessary manpower and increasing the level of automation.

[0074] The apparatus preferably includes one or more vibrators that vibrate the particles to facilitate their movement. The vibrators may preferably be located in the conveyor-deposit section and / or the collector. The movement of granular material (such as the particles used in this process) may be blocked by arc formation. The use of vibrators in the deposit section and the circulation line significantly reduces arc formation, which prevents blockages in the circulation point.

[0075] Therefore, the following steps of the improved process (object of the present invention) were identified, which are:

[0076] - recycling of particles from the collector to the transport-settling section, in the case where the collector and the transport-settling section are not the same element; and

[0077] - causing electroactive solid particles to vibrate.

[0078] This new technology is believed to have a large number of possible end applications. For example, for non-limiting purposes, some applications are proposed. One application is polishing a separate unit to treat large structural parts (such as aircraft wings) to improve their aerodynamics. The end application is to treat metal surfaces in a continuous online process after the metal surface is produced or as a previous step for other treatments.

[0079] Another end application is the polishing of stand-alone portable equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 is an exemplary view of an apparatus for achieving the polishing method according to the present invention.

[0081] Figure 2A An outline diagram of the mechanism by which electricity is transferred between a power source and a metal surface by means of the net charge of the particles.

[0082] Figure 2B An outline diagram of the mechanism by which electricity is transferred between a power source and a metal surface by means of conductivity achieved through contact.

[0083] Figure 2C An outline diagram of the mechanism by which electricity is transferred between a power source and a metal surface by means of conductivity achieved by an electric arc.

[0084] Figure 3 It is an outline drawing of equipment used for online surface treatment.

[0085] Figure 4 is an outline drawing of a portable device for surface treatment.

[0086] Figure 5 is an outline drawing of a device having a cabin for surface treatment. DETAILED DESCRIPTION

[0087] In the following, several exemplary scenarios are presented without limitation.

[0088] Example 1

[0089] An apparatus comprising a particle 9 transporting and depositing section 7, the outlet of which is connected to a copper tube serving as an electrode 3, which is connected to a power supply 2. The particles 9 fall continuously by gravity onto a surface to be treated 1, which is connected to the power supply 2 via a counter electrode. The particles 9 that have previously come into contact with the part fall into a collector 6, so that they can be subsequently recycled with the aid of a recycling system 5. The particle transporting and depositing section 7, as well as the collector 6, has a vibrator 8 available. Figure 1A schematic diagram can be seen in .

[0090] In the exemplary case, the particles used are microporous gel particles of sulfonated polystyrene-divinylbenzene filled with an electrolyte solution containing 4% sulfuric acid. This prototype has been demonstrated with different types of current: DC from 1V to 60V; C at 50Hz at 50,000Hz from 0V to 220V.

[0091] With these parameters, a polishing method for treating steel 316 surfaces has been demonstrated with different types of current: DC up to 35 kV, AC up to 15 kV at 50 Hz.

[0092] The DC results show a linear behavior of the intensity with respect to the potential difference. It was observed that after a 5-minute treatment at 30 kV, the R a Reduced from 0.37μm to 0.34μm.

[0093] The results using 50 Hz AC show linear performance in the range of 0 kV to 5 kV. Increasing the voltage from this point does not produce a proportional increase in intensity. This effect clearly indicates a change in the mechanism of charge transport.

[0094] Equipment for online surface treatment

[0095] It includes equipment for in-line surface treatment. Figure 3 A schematic diagram is shown in FIG. In this example, without limiting the scope of the invention, a metal plate is treated. The device comprises a power supply 3, a "curtain" system for applying particles 9, a support system for the plate to be treated, and a recycling system 5 that collects the particles and deposits them in a conveyor-deposit section 7.

[0096] The metal plate to be treated is located on a conveyor belt that provides vibrations and is connected to an electrical power source. At one point in the path of the conveyor belt there is a curtain-type particle ejector 9. A linear applicator generates a linear jet of particles 9 covering the entire width of the plate to be treated on the surface to be treated 1. The plate moves through the particle curtain at a suitable speed that provides it with treatment time to obtain the desired finish. This curtain-type particle ejector includes a vibrator 8 to facilitate the flow of particles. In the narrow slot where the particles leave there is a metal element that is connected to the negative pole of the power source used as electrode 3. The particles contact the electrode 3 before reaching the surface to be treated 1. Near the point of contact, a recirculation system 5 is applied, which sucks the particles after they come into contact with the surface and deposits them in the conveyor-depositing section 7.

[0097] Portable equipment for surface treatment

[0098] It comprises a portable device 1 for treating a surface. Figure 4 A schematic diagram is shown in . The device utilizes wheels, for example, to facilitate intermodal transport.

[0099] The apparatus comprises a compressor and pressurized air deposition section, a power source 2 , a particle transport deposition section 7 , and a recirculation system 5 .

[0100] The device can be connected to a plug, or alternatively, it can include a battery sufficient to provide energy. A particle 9 delivery and deposition section 7 has an outlet at its lower portion toward a particle delivery hose. This section may be equipped with a vibrator 8 to facilitate the flow of particles 9. The particles 9 are propelled through the application hose by compressed air from a compressor. The required pressure depends on the length and position of the application hose, with pressures of 3 to 10 bar providing good results. The application hose terminates in a diffuser that allows some air to escape, forcing the particles 9 to compact. The particles are released through or in contact with an electrode 3, which can be made of, for example, copper, 316 stainless steel, or radiated titanium. The electrode 3 is connected to a power source 2, preferably the positive terminal, and preferably has an ammeter for tracking the intensity. The application electrode 3 is located at a distance of 0.5 to 10 cm from the surface, so that there is a flow of particles between the electrode and the surface, creating a path for the current. The final portion of the particle outlet is contained within a collection collector 6 that is very close to or in contact with the surface 1 to be treated. These collectors 6 for collecting the particles are connected to a recycling system 5 comprising a second hose provided with a suction section which collects the particles from the collectors 6 after they have come into contact with the surface and ejects them anew to the particle transport and deposition section 7. The surface to be treated 1 is connected to the power supply 1, preferably at the positive pole, by means of, for example, an electric clamp. The system may include the use of a robotic arm in order to polish surfaces that are inaccessible to workers or to increase accuracy.

[0101] The design of the system is considered to occupy a compact volume and it comprises elements that make it load-bearing (such as wheels or sliding elements).

[0102] The current applied depends on the composition of the surface to be treated and the composition of the particles 9 used. For example, for treating steel 316 surfaces, good results are achieved using sulfonated polystyrene-divinylbenzene particles containing 4% sulfuric acid with 12 V DC.

[0103] Equipment for treating surfaces in cabins

[0104] It comprises an apparatus for treating a surface 1 in a closed chamber 4. Figure 5A schematic diagram can be seen in Figure 1. The device comprises a power supply 2, one or more outlets for electroactive particles 9 with electrodes 3, a system for anchoring the part to be polished, a closed chamber 4 for the treatment, and a recirculation system 5 that sucks the particles from a collector 6, which in this example also serves as a transport deposit 7, towards the particle outlet.

[0105] The metal parts to be polished are placed on a frame inside the chamber with the aid of suitable anchors so that they are connected to the power supply 2. The chamber 4 is provided with several particle outlets which are connected in their rear part to the electrodes 3. The injection of the particles 9 is carried out by using compressed air, preferably in the range of 2 to 10 bar, preferably between 4 and 6 bar.

[0106] There is a slope at the bottom of the chamber 4 which serves as a delivery deposit 7 and as a collector 6 , and the particles 9 are collected by a recirculation system 5 which transports them to a particle outlet.

[0107] The applied current depends on several factors, such as the type of material, the total area to be treated, the distance between the exit point of the particles and the surface. For example, to polish steel 316 at a distance of 4 cm, the total area is 25 cm 2 .

Claims

1. A method for treating a metal surface by ion transport, the method comprising: spraying a plurality of electroactive solid particles holding a liquid electrolyte toward a metal surface, wherein spraying the plurality of electroactive solid particles includes generating chains of electroactive solid particles extending between an electrode and the metal surface being treated; Adjacent solid particles in the chain of electroactive solid particles are electrically connected by a medium providing electrical conductivity between the adjacent solid particles, the medium comprising solid and / or liquid units suspended in a gas; charging the plurality of electroactive solid particles by coupling the electrode to one pole of a power source and connecting the other pole of the power source to the treated surface, such that the plurality of electroactive solid particles transfer charge to the treated metal surface when in contact with the treated metal surface; as well as The metal surface is treated by ion transport via a liquid electrolyte held by the plurality of electroactive solid particles.

2. The method for treating a metal surface according to claim 1, wherein: During spraying of the plurality of electroactive solid particles, electrical transfer between the power source and the metal surface is via the net electrical charge of the plurality of electroactive solid particles.

3. The method for treating a metal surface according to claim 1, wherein: A direct current (DC) is applied to the electrodes.

4. The method for treating a metal surface according to claim 1, wherein: A current is applied to the electrodes, the current comprising a positive component and a negative component.

5. The method for treating a metal surface according to claim 1, wherein: The medium is selected from the group consisting of carbon, iodine and talc. 6 . The method for treating a metal surface according to claim 1 , further comprising treating the metal surface with abrasive particles, and simultaneously or continuously spraying the plurality of electroactive solid particles toward the metal surface.

7. The method for treating a metal surface according to claim 1, wherein: The plurality of electroactive solid particles include microporous gel particles of sulfonated polystyrene-divinylbenzene.

8. The method for treating a metal surface according to claim 7, wherein: The microporous gel particles of the sulfonated polystyrene-divinylbenzene contain sulfuric acid.

9. A system for treating a metal surface by ion transport, the system comprising: a plurality of electroactive solid particles holding a conductive solution; a power source having electrodes configured to transfer electrical charge to the plurality of electroactive solid particles; and A device for spraying the plurality of charged electroactive solid particles onto the metal surface to be treated, wherein the charge carried by the particles is transferred to the metal surface to be treated when in contact with the metal surface to be treated, thereby achieving ion transport.

10. The system for treating a metal surface according to claim 9, wherein: The power source has a positive pole and a negative pole, the electrode is coupled to the negative pole and the metal surface is coupled to the positive pole.

11. The system for treating a metal surface according to claim 9, wherein: The electroactive solid particles are propelled towards the metal surface solely by gravity.

12. The system for treating a metal surface of claim 9, further comprising a centrifugal system configured to propel the electroactive solid particles toward the metal surface.

13. The system for treating a metal surface of claim 9, further comprising a compressed gas source configured to propel the electroactive solid particles toward the metal surface.

14. The system for treating a metal surface of claim 9, further comprising a rod and crank system or annular screw system configured to propel the electroactive solid particles toward the metal surface.

15. The system for treating a metal surface of claim 9, further comprising means for moving the metal surface during said treating.

16. The system for treating a metal surface according to claim 9, further comprising a transport and deposition portion for storing the plurality of electroactive solid particles at a location remote from the electrode.

17. The system for treating a metal surface of claim 16, further comprising a collector, wherein the plurality of electroactive solid particles are collected in the collector after being sprayed onto the metal surface.

18. The system for treating a metal surface of claim 17, further comprising a recycling system configured to transport the plurality of electroactive solid particles from the collector to the transport deposition portion.

19. The system for treating a metal surface of claim 16, further comprising a vibrator physically coupled to the conveyor deposition portion.

20. The system for treating a metal surface of claim 17, further comprising a vibrator physically coupled to the collector.

21. The method for treating a metal surface according to claim 1, wherein: The liquid units are liquid droplets.

22. The method for treating a metal surface according to claim 1, wherein: The solid units are microparticles or nanoparticles.

23. The method for treating a metal surface according to claim 22, wherein: The microparticles or nanoparticles include carbon.

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