Energy enhanced process for treating a conductive surface and products formed thereby

#The instant invention relates to process for forming a deposit on the surface of metallic or conductive surfaces. The process employs an electrolytic process to deposit, for example, a mineral containing coating or film upon a metallic, metal containing or an electrically conductive surface.

#Silicates have been used in electrocleaning operations to clean steel, tin, among other surfaces. Electrocleaning is typically employed as a cleaning step prior to an electroplating operation. Using “Silicates As Cleaners In The Production of Tinplate” is described by L. J. Brown in February 1966 edition of Plating; hereby incorporated by reference.

#Processes for electrolytically forming a protective layer or film by using an anodic method are disclosed by U.S. Pat. No. 3,658,662 (Casson, Jr. et al.), and United Kingdom Patent No. 498,485; both of which are hereby incorporated by reference.

#FIG. 1 is a schematic drawing of the circuit and apparatus which can be employed for practicing an aspect of the invention.

#FIG. 2 is a schematic drawing of one process that employs the inventive electrolytic method.

#The instant invention relates to a process for depositing or forming a beneficial surface (e.g., a mineral containing coating or film) upon a metallic or an electrically conductive surface. The process employs a silicate medium, e.g., containing soluble mineral components or precursors thereof, and utilizes an electrically enhanced method to treat an electrically conductive surface (e.g., to obtain a mineral coating or film upon a metallic or conductive surface). By “mineral containing coating”, “mineralized film” or “mineral” it is meant to refer to a relatively thin coating or film which is formed upon a metal or conductive surface wherein at least a portion of the coating or film comprises at least one metal containing mineral, e.g., an amorphous phase or matrix surrounding or incorporating crystals comprising a zinc disilicate. Mineral and Mineral Containing are defined in the previously identified Copending and Commonly Assigned Patents and Patent Applications; incorporated by reference. By “electrolytic” or “electrodeposition” or “electrically enhanced”, it is meant to refer to an environment created by introducing or passing an electrical current through a silicate containing medium while in contact with an electrically conductive substrate (or having an electrically conductive surface) and wherein the substrate functions as the cathode. By “metal containing”, “metal”, or “metallic”, it is meant to refer to sheets, shaped articles, fibers, rods, particles, continuous lengths such as coil and wire, metallized surfaces, among other configurations that are based upon at least one metal and alloys including a metal having a naturally occurring, or chemically, mechanically or thermally modified surface. Typically a naturally occurring surface upon a metal will comprise a thin film or layer comprising at least one oxide, hydroxides, carbonates, sulfates, chlorides, among others. The naturally occurring surface can be removed or modified by using the inventive process.

#The electrolytic environment can be established in any suitable manner including immersing the substrate, applying a silicate containing coating upon the substrate and thereafter applying an electrical current, among others. The preferred method for establishing the environment will be determined by the size of the substrate, electrodeposition time, applied voltage, among other parameters known in the electrodeposition art. The effectiveness of the electrolytic environment can be enhanced by supplying energy in the form of ultrasonic, laser, ultraviolet light, RF, IR, among others. The inventive process can be operated on a batch or continuous basis.

#The silicate containing medium can be a fluid bath, gel, spray, among other methods for contacting the substrate with the silicate medium. Examples of the silicate medium comprise a bath containing at least one silicate, a gel comprising at least one silicate and a thickener, among others. The medium can comprise a bath comprising at least one of potassium silicate, calcium silicate, lithium silicate, sodium silicate, compounds releasing silicate moieties or species, among other silicates. The bath can comprise any suitable polar carrier such as water, alcohol, ethers, among others. Normally, the bath comprises sodium silicate and de-ionized water and optionally at least one dopant. Typically, the at least one dopant is water soluble or dispersible within an aqueous medium.