96 results about "Chromate conversion coating" patented technology

A corrosion-resistant antifriction bearing is disclosed that includes a multi-layer corrosion protection system over a metallic substrate. The corrosion-resistant system may be applied to a single or multiple components of the bearing, including inner and outer rings, bearing elements, collars, and so forth. The system includes a nickel-phosphorous alloy plating layer applied by an autocatalytic process after surface preparation of the protected component. The surface preparation aids in adherence of the nickel-phosphorous alloy plating layer to the substrate. The preparation may include the application of rust inhibitors, liquid vapor honing, acid neutralizing, and so forth. Additional topcoat layers may be applied to the nickel-phosphorous alloy plating layer. These may include a chromate conversion coating and a polymeric topcoat layer. The polymeric topcoat layer, such as polytetrafluoroethylene, may include a UV marker to enable identification of the bearing when placed in service and throughout its useful life.

A pretreatment before phosphating conversion coating is effected by contacting a metal substrate to be coated with a pretreatment composition that has a pH from 4 to 13 and contains dispersed fine particle size alkali metal or ammonium salts and divalent or trivalent metal phosphates. The conditioning achieved is as good as with conventional Jernstedt salts and the pretreatment compositions according to the invention are more storage stable.

The invention relates to a composite phosphating solution of P-Ca-V on the surface of a magnesium alloy and a method for chemical conversion treatment. The solution is characterized in that each liter of the composite phosphating solution comprises the following compositions: 4 to 20 milliliters of 85 percent phosphoric acid of, 5 to 30 grams of sodium dihydrogen phosphate, 10 to 40 grams of calcium nitrate, 0.5 to 10 grams of benzene sulfonic acid sodium salt, 0.5 to 5 grams of ammonium metavanadate, and the balance being water. The method comprises the following steps: pre-degreasing, degreasing, secondary water washing, acid washing, secondary water washing, alkaline etching, secondary water washing, chemical transformation, secondary water washing, pure water washing, and drying. Taking an AZ91D magnesium alloy as an example, 48 hours after a corrosion resistance salt spray test after the treatment by the method of the invention, the corrosion area of the AZ91D magnesium alloy is less than 1 percent; the paint film adhesive force is at 0 level by a grid method and is obviously superior to the performance of a chromate conversion coating; and the formed chemical conversion coating does not contain crystal water. The composite phosphating solution has the synergistic reaction of Ca and V, as well as the functions of a corrosion inhibitor and a wetting agent of the benzene sulfonic acid sodium salt.

Biodegradable magnesium alloy implantable medical devices are protected to delay onset of corrosion, and thus biodegradability, or to corrode more uniformly. The protection allows for extended effective use of the devices while maintaining biodegradability. Examples of protective coatings include conversion coatings that at least partially remove exposed second phases from a surface of the magnesium alloy and coatings that provide a barrier between water and the surface of the magnesium alloy.

A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises: trivalent chromium and oxalic acid in a molar ratio ranging from 0.5/1 to 1.5/1, wherein the trivalent chromium is present in the form of a water-soluble complex with oxalic acid; and cobalt ions, which do not form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation; wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating. The film is quite thin, free of any hexavalent chromium, has corrosion resistance identical to or higher than that achieved by the conventional hexavalent chromium-containing film and can be formed using a processing solution having a quite low concentration.

The invention discloses a low chromium anticorrosive chemical conversion treating fluid on the surface of constructive aluminium profile and a use method thereof; the technology comprises placing constructive aluminium profile in a tank liquor to treat with a pH value of 1.8-2.2 at 5-40 DEG C for 3-5min or 0.5-1.5min to form a layer of compact and uniform golden to irisated chromate conversion film with a film thickness of 1-2mu m on the surface of the constructive aluminium profile; wherein, the tank liquor comprises 0.6-2.0g/L of chromate, 0.3-0.9g/L of fluorine compound, 0.1-0.6g/L of zinc salt, 0.2-0.8g/L of nitrate, 0.1-0.5g/L of salts from rare earth metals and 0.3-1.0g/L of stabilizer. The invention has simple process and contains no potassium ferricyanide and low chromate; the solution is stable with little sediment; the service cycle is long; the cost of environment pollution and wastewater treatment is low; the treated waste solution can meet the relative discharge standards and the invention has other advantages of room temperature use, energy saving, low comprehensive cost and the like.

A steel pipe has a multi-layer coating including: a plating film formed on the surface of the steel pipe; a chemical conversion coating covering the plating film; a primer coating covering the chemical conversion coating and formed from a curable epoxy resin composition composed mainly of an epoxy compound and having an amide or imide bond introduced; and a polyamide resin coating covering the primer coating. The multi-layer coating can significantly enhance the adhesion force of the polyamide coating compared to the conventional pipe.

The present invention relates to a pickling agent for the chemical conversion coating of a heat exchanger which is capable of cleaning the complicated structure comprising fins and tubes of a heat exchanger in preparation for the successful formation of a chemical conversion film, a method of pickling a heat exchanger, a method of treating a heat exchanger comprising said pickling method, and a heat exchanger produced by using said treating method. The present invention provides pickling agent for the chemical conversion coating of a heat exchanger which comprises an acidic aqueous solution containing nitric acid and/or sulfuric acid and at least one metal and/or metal oxoanion salt derived from any metal selected from the group consisting of iron, nickel, cobalt, molybdenum and cerium.

There is provided a screw treated by a chemical conversion coating of trivalent chromium having a torque characteristic approximately equivalent to a screw of a hexavalent chromate treatment. For the purpose, on a surface of a bolt, a zinc plating layer is formed by a zinc plating treatment. On the layer, a chemical conversion coating of trivalent chromium is also formed by a treatment of chemical conversion coatings of trivalent chromium. The coating is formed to be thin and soft so that the zinc-based plating layer can be exposed on the surface due to rubbing off of the chemical conversion coating of trivalent chromium at a contact portion to a fastened member of the bolt by tightening the bolt.

A corrosion resistant roller chain which exhibits protection against corrosion for a long period of time under corrosive conditions such as saltwater, acid, alkali or the like comprises outer plates 110 and inner plates 130 which comprise a zinc-aluminum system alloy coating which is thinner than required by JIS and a chemical conversion coating which covers the zinc-aluminum system alloy coating.

The invention relates to a novel water-based rust conversion coating and a preparation method thereof. The coating comprises the following components in parts by weight: 30-70 parts of water-based epoxy emulsion, 5-20 parts of a rust conversion agent, 0.5-5 parts of a penetrating agent, 5-10 parts of aluminum triphosphate, 10-20 parts of barium sulfate and 0.6-5 parts of a functional additive, wherein the water-based epoxy emulsion is a cationic water-based acidic modified epoxy emulsion. According to the invention, the cationic water-based acidic epoxy emulsion is selected as a film-forming substance and has good compatibility with an acidic rust conversion agent; based on single-component normal-temperature curing, compared with a modified water-based acrylic acid system, a paint film ofthe coating is good in water resistance and salt water resistance, good in salt spray resistance, high in adhesive force, high in hardness and excellent in storage stability. The coating is high in rust conversion rate and can chemically react with rust to generate a black compact and stable chelate, so that the purposes of rust removal, rust prevention and rust stabilization are achieved.

The invention relates to the surface prevention technology of steel fasteners, in particular to a TiZr conversion coating/organic coating double-layered prevention method applied to the steel fasteners, and aims to solve the problems of poor anticorrosion performance and serious pollution of surface protection of a plurality of single-layered or composite electroplated, chemically plated or organic coatings. The method comprises the following steps: deoiling and derusting the fasteners; soaking the steel fasteners in diluted Ti/Zr conversion liquid for 2 to 10 min to generate a layer of Ti/Zr conversion coating; carrying out water washing; and coating a layer of organic coating material, so as to form an organic coating. Through the adoption of the TiZr conversion coating/organic coating double-layered surface prevention technology, the problem that the fasteners are poor in corrosion resistance and seriously polluted under relatively harsh marine environment is solved; and under the premise that the thinness of coating is smaller than and equal to 15 Mum and the basal body bonding strength is high, the neutral salt mist corrosion resistance and the wear resistance of the coating are improved to a large extent.

Aqueous acidic coating solutions containing a water soluble divalent zinc compound, a complex fluoride compound, and an organic inhibitor for improving the corrosion resistance and adhesive bonding characteristics of aluminum, aluminum alloys, anodic coatings and sacrificial coatings, are disclosed. Suitable organic inhibitors include oximes, such as salicylaldoxime, and/or quinolines, particularly 8-hydroxyquinoline, and mixtures thereof.

A method employing oxide film conversion coatings prepared using ferrate (VI) as the oxidizing agent is disclosed. Metal substrates or surfaces, such as aluminum, aluminum alloys or other metals, are contacted with an aqueous solution comprising ferrate (VI) anions to form a corrosion resistant conversion coating on the surface thereof. The ferrate anion concentration is preferably between about 0.0166% and about 1.66% by weight. The coating process is carried out by dipping, spraying, or painting at temperatures ranging from 25° C. to 100° C. for a period of time ranging from about 1 second to about 5 minutes.

PROBLEM TO BE SOLVED: To provide a pretreatment method which imparts a chromium-free chemical conversion coating adhesiveness to a paint film and corrosion resistance equivalent to or better than those of a chromating conversion coating containing hexavalent chromium ions, when an aluminum-based substrate is subjected to the chromium-free chemical conversion treatment as an alternative method for the chromate conversion treatment.SOLUTION: A surface treatment method for the aluminum-based substrate comprises the steps of: subjecting the aluminum-based substrate to a treatment process including the chemical conversion treatment; and then painting it. The method also includes treating the aluminum-based substrate with a strongly alkaline aqueous solution or electrolyzed alkaline water before the step prior to the painting step including the chemical conversion treatment to enhance a cleanliness degree of the surface of the aluminum-based substrate.