Equipment for oxidation of planar metallic surfaces, such as sheet, fabric or metal net and method of application of the treatment

Abstract

An oxidation apparatus of planar metal surfaces, comprises: a tank within which the planar metal surface being treated is laid; an electrical power supply circuit with the two heads of the electrical power supply of the circuit placed in contact with electrodes with high electrical conductivity; a first planar electrode is placed below the metal surface being treated on a bottom of the aforementioned tank; an electrolyte is placed in the tank to close the electrolytic oxidation circuit; a second electrode is placed sliding and spaced on the planar metal surface under treatment in an immersed position at the level of the electrolyte in the tank; and it has the second electrode constituted by a conductive roller placed so as to roll on the planar metal surface being treated, avoiding contact between the cylindrical surface of the roller electrode and the planar metal surface being treated by means of the interposition of a permeable spacer element; the permeable spacer element is made of material resistant to the electrolytic action of oxidation and at least placed on one of the two surfaces, the cylindrical one of the roller electrode or the planar metallic one being treated, neither of which must come into contact.

1 . An oxidation apparatus of planar metal surfaces, comprising a tank within which the planar metal surface being treated is laid; an electrical power supply circuit with the two heads of the electrical power supply of the circuit placed in contact with electrodes, with high electrical conductivity; a first planar electrode is placed below the metal surface being treated on a bottom of the aforementioned tank; an electrolyte is placed in the tank to close the electrolytic oxidation circuit; a second electrode is placed sliding spaced apart on the planar metal surface being treated in a position immersed at the level of the electrolyte in the tank; characterized in that it presents the second electrode consisting of a conductive roller placed so as to roll on the planar metal surface being treated, avoiding contact between the cylindrical surface of the roller electrode with the planar metal surface being treated by the interposition of a permeable spacer element; the permeable spacer element is made of material resistant to the electrolytic action of oxidation and at least placed on one of the two surfaces, the cylindrical one of the roller electrode or the planar metallic one (2) being treated, neither of which must come into contact. 
     
     
         2 . Planar metal surface oxidation apparatus according to  claim 1 , wherein the spacer element is applied to the cylindrical surface of the roller of the roller electrode and is made of absorbent and insulating material to form a coating sheath of said cylindrical surface. 
     
     
         3 . Planar metal surface oxidation apparatus, according to  claim 1 , wherein the spacer element is made with a passage printing screen positioned before treatment on the planar metal surface to be treated, in contact therewith and to make the spacer with the thickness of the screen itself between said cylindrical surface of the roller electrode and the planar metal surface being treated. 
     
     
         4 . Planar metal surface oxidation apparatus, according to  claim 2 , wherein masks resistant to electrolytic action are shown on the planar metal surface being treated, to make decorations, images or lettering on the planar metal surface with oxidation treatment. 
     
     
         5 . Planar metal surface oxidation apparatus according to  claim 3 , wherein masks resistant to electrolytic action are shown on the passage printing screen to make decorations, images or lettering on the planar metal surface with oxidation treatment. 
     
     
         6 . Planar metal surface oxidation apparatus according to  claim 5 , wherein the passage printing screen with masks, for making decorations, images or lettering on said planar metal surface with the oxidation treatment, is laid against the planar metal surface being treated with the mask facing up and in contact with said planar metal surface, while the electrolytic oxidation action of the roller electrode with its cylindrical surface, is applied from the upper side of the passage printing screen. 
     
     
         7 . Planar metal surface oxidation apparatus according to  claim 1 , wherein the first planar electrode consists of a graphite planar plate or graphite mesh placed on the bottom of the tank and on which the planar metal surface being treated is placed. 
     
     
         8 . Planar metal surface oxidation apparatus according to  claim 1 , wherein the roller electrode is made of a cylindrical graphite tube wherein an axial metal pin is connected to the ends with a head of the electrical circuit: the rotating support between the central pin and the graphite tubular roller is made of a conical turning pair, in metallic material, close to each end of the roller. 
     
     
         9 . A method of applying the electrolytic oxidation action on planar metal surfaces, carried out by an apparatus defined according to  claim 1 , wherein:
 the planar metal surface to be treated is placed in a tank in an electrolyte bath with a level sufficient to cover the planar surface being treated and part of the aforementioned roller electrode;   the two power supply heads of the circuit are positioned, a first head in contact with the first planar electrode and the second head with the second electrically conductive roller electrode;   the electrolytic surface oxidation action is applied with unidirectional or bidirectional back and forth rotation, rolling the roller electrode on the planar metal surface being treated with a permeable spacer element interposed, consisting of a sheath applied to the cylindrical surface of the electrode roller;   the electrolytic action is activated with either a direct or alternating electric current, generated by the electric power supply circuit, with a voltage of between 5 and 25 Volts and current between a minimum of 1.0 A/cm2 and a maximum of 20.0 A/cm2, calculated on the surface facing the electrode treatment;   the electrolytic action is achieved by rolling the roller electrode on the metal surface being treated, so as to achieve a rapid uniform distribution of the desired oxidation on the metal surface being treated.   
     
     
         10 . A method of applying the electrolytic oxidation action on planar metal surfaces, carried out by an apparatus defined according to  claim 1 , wherein:
 the planar metal surface to be treated is placed in a tank in an electrolyte bath having a level sufficient to cover the planar surface being treated and part of the above-mentioned roller electrode;   the two power supply heads of the circuit are positioned, a first head in contact with the first planar electrode and the second head with the second electrically conductive roller electrode;   the electrolytic surface oxidation action is applied with unidirectional or bidirectional back and forth rotation rolling the roller electrode on the planar metal surface being treated with a permeable spacer element interposed which consists of a printing screen placed on the planar metal surface being treated and in contact with the cylindrical surface of the electrode roller;   the electrolytic action is activated with either a direct or alternating electric current, generated by the electric power supply circuit, with a voltage of between 5 and 25 Volts and current between a minimum of 1.0 A/cm2 and a maximum of 20.0 A/cm2, calculated on the surface facing the electrode treatment;   the electrolytic action is achieved by rolling the roller electrode on the metal surface being treated, so as to achieve a rapid uniform distribution of the desired oxidation on the metal surface being treated.   
     
     
         11 . Planar metal surface oxidation apparatus, according to  claim 3 , wherein masks resistant to electrolytic action are shown on the planar metal surface being treated, to make decorations, images or lettering on the planar metal surface with oxidation treatment. 
     
     
         12 . Planar metal surface oxidation apparatus according to  claim 2 , wherein the first planar electrode consists of a graphite planar plate or graphite mesh placed on the bottom of the tank and on which the planar metal surface being treated is placed. 
     
     
         13 . Planar metal surface oxidation apparatus according to  claim 3 , wherein the first planar electrode consists of a graphite planar plate or graphite mesh placed on the bottom of the tank and on which the planar metal surface being treated is placed.