141 results about "Localised corrosion" patented technology

By enhancing a stress corrosion cracking resistance in a leadless brass alloy, specifically by suppressing a velocity of propagation of corrosion cracks in the brass alloy, a straight line crack peculiar to the leadless brass alloy is suppressed, a probability of cracks coming into contact with γ phases is heightened and local corrosion on the brass surface is prevented to suppress induction of cracks by the local corrosion, thereby providing a leadless brass alloy contributable to enhancement of the stress corrosion cracking resistance. The present invention is directed to an Sn-containing Bi-based, Sn-containing Bi+Sb-based or Sn-containing Bi+Se+Sb-based leadless brass alloy excellent in stress corrosion cracking resistance, having an α+γ structure or α+β+γ structure and having γ phases distributed uniformly therein at a predetermined proportion to suppress local corrosion and induction of stress corrosion cracks.

The invention discloses a method for the antiseptic protection of a cable system of a suspension bridge. The cable system comprises a main cable consisting of steel wire bundles formed by multi-strands of high-strength zinc-plated steel wires, a main saddle on the top part of a cable tower, a loosening-cable saddle on the near anchorage end, a plurality of cable clips fixed on the main cable and suspension cables fixed on the cable slips, wherein the main cable comprises a wire wound section main cable section and a non-wire wound section main cable section; the wire wound section main cable orderly undergoes the following treatments: (A) the main cable undergoes the pre-sealing dehumidification treatment; (B) the outer surface of the main cable undergoes the inner-layer antiseptic treatment; (C) a layer of steel wires or a belt material winding layer is wound; (D) the outer surface of the winding layer undergoes the outer layer protective treatment. In the invention, before steel wire bundles of the main cable are coated, the main cable system undergoes the pre-sealing dehumidification treatment, thereby removing water and moistures already existed in the main cable, eliminating the local corrosion phenomenon of the steel wires of the main cable started from the inner part caused by water originally existed in the main cable and ensuring the achievement of expected effects in the protection of the main cable.

The invention relates to a system and a method for testing local corrosion of a multi-electrode coupled inhomogeneous structure. Three testing systems including a classic electrochemical comprehensive testing system, a micro-area electrochemical testing system and a micro-electrode array testing system are arranged in the system; the three testing systems can be used for testing separately and any two testing systems also can be combined together; by using a micro-electrode array as a bridge and a bond, the three testing systems are coupled and combined, three tests of a classic electrochemistry test, a micro-electrode array test and a micro-area electrochemistry test can be carried out, and overall average information such as self-corrosion potential, self-corrosion current density, polarization property and electrochemical impedance spectroscopy, local distribution information such as galvanic potential and galvanic current having certain statistical characteristics, and micro-area distribution information of local cathode and anode areas in a local corrosion process of an inhomogeneous structure can be acquired and effectively associated on aspects of large scale, middle scale and small scale.

The invention provides an economic biphase stainless steel with high mechanical property and superior corrosion resistance, which comprises the following components in percentage by weight: less than or equal to 0.03% of C, 21.5-23.0% of Cr, 1.50-2.50% of Ni, 0.20-0.40% of N, 0.20-0.40% of Mo, 0.20-0.50% of Cu, 0.5-2.0% of Mn, less than 0.005% of S, less than 0.005% of P, and the balance Fe and unavoidable impurities. After the steel product is thermally treated at the temperature range of 980-1080 DEG C, the contents of ferrite and austenite in the obtained biphase structure are approximately same, the local corrosion resistant capacity and the uniform corrosion resistant capacity are superior to those of 304 austenitic stainless steel, the mechanical property is similar to that of 316L austenitic stainless steel, and the steel product can be used as an alternate material for the currently extensively used 304 austenitic stainless steel and 316L austenitic stainless steel.

The invention relates to a pickling solution capable of removing hot-rolled corrosion-resisting alloy oxide skin and a pickling method thereof. The pickling solution comprises 10 g/L-60 g/L of sulfuric acid, 90 g/L-120 g/L of hydrochloric acid, 25 g/L-75 g/L of nitric acid and the balance of water by proportioning. The pickling method comprises the following steps of: I. soaking corrosion-resisting alloy which is annealed and is subjected to shot blasting in the pickling solution capable of removing the hot-rolled corrosion-resisting alloy oxide skin and comprising 10 g/L-60 g/L of sulfuric acid, 90 g/L-120 g/L of hydrochloric acid, 25 g/L-75 g/L of nitric acid and the balance of water by proportioning, wherein the soaking temperature is 20-90 DEG C, and the soaking time is 120-1 minute; and II. cleaning the pickled corrosion-resisting alloy by using a nylon brush or a roll brush, and then washing and airing. The pickling solution reduces environmental pollution caused by hydrofluoric acid; and due to application of the pickling method, local corrosion is not easy to generate on the surface of a pickled surface.

The invention discloses a flame-retardance-type multi-layer wrapping anticorrosion system. The system comprises anticorrosion paste, a flame-retardance-type anticorrosion band, an oil separation basecoating, a flame-retardance-type nonmetal protection cover and a dirt-adhesive-resistance surface coating along the metal structure surface towards outside in sequence. The flame-retardance-type multi-layer wrapping anticorrosion system has excellent construction tolerance and adaptability, a long-acting and lasting anticorrosion effect, flame retardance, excellent dirt-adhesive-resistance and weather resistance and is attractive in appearance, wide in application field and particularly suitable for steel structure connection parts, local severe-corrosion parts, facilities of splash areas in ocean and the like, the anticorrosion effect can last for above 20 years, maintenance is not needed within the anticorrosion validity period, and the system has remarkable economic benefits and wide popularization prospects.

The invention relates to super-martensitic stainless steel and a preparation method thereof, and belongs to the field of steel materials. The super-martensitic stainless steel comprises the following chemical components in percentage by mass: 0 to 0.03 percent of C, 0 to 0.03 percent of N, less than 0.015 percent of S, less than 0.020 percent of P, less than 1 percent of Si, less than 1 percent of Mn, 13 to 16 percent of Cr, 4 to 6 percent of Ni, 1 to 2 percent of Mo, 0.05 to 0.15 percent of Nb, 0.001 to 0.01 percent of Ti and the balance of Fe. The preparation method comprises the following steps of: smelting by using a vacuum induction furnace to obtain a casting blank which meets the requirements of chemical component ranges, performing hot forging at the temperature of 1,200 DEG C, performing hot rolling at the temperature of between 1,100 and 1,200 DEG C, performing solid solution treatment at the temperature of between 1,050 and 1,100 DEG C for 0.5 to 1 hour, performing air cooling and normalizing treatment, tempering at the temperature of between 550 and 700 DEG C for 2 to 4 hours, and performing oil cooling to room temperature. The super-martensitic stainless steel has high strength and toughness and high local corrosion resistance.

The invention discloses a neodymium-iron-boron magnet surface composite corrosion-resistant coating and a preparation method thereof. The composite corrosion-resistant coating sequentially comprises acold spraying aluminum coating, an aluminum oxide passivation layer obtained through surface passivation treatment and a hole sealing ceramic paint layer from the surface of a neodymium-iron-boron magnet to the outside. The preparation method comprises the following steps of: (1) surface treatment of a neodymium-iron-boron substrate; (2) treatment of aluminum powder; (3) cold spraying of an aluminum coating; (4) passivation treatment to obtain an aluminum oxide passivation layer; and (5) hole sealing treatment to obtain a hole sealing ceramic paint layer. The prepared neodymium-iron-boron magnet surface composite corrosion-resistant coating has excellent local corrosion resistance, the corrosion-resistant coating is formed by well combining with the neodymium-iron-boron magnet, the defects that a pure aluminum coating is low in strength and hardness and micropores exist in the surface are overcome, and the service life of the corrosion-resistant coating is prolonged when the corrosion-resistant coating is used as a sintered neodymium-iron-boron magnetic material surface corrosion-resistant process.

The invention discloses a copper-plated layer washing degreaser applied in the electroplating industry. The copper-plated layer washing degreaser comprises the following ingredients in percentage by weight: 10-15 percent of sodium carbonate, 20-25 percent of sodium metasilicate, 20-25 percent of trisodium phosphate, 10-12 percent of anhydrous sodium sulfate, 5-8 percent of an anionic surfactant, 3-5 percent of a nonionic surfactant and 10-30 percent of a grinding material. A preparation method comprises the following steps: sieving the raw materials through a 20-mesh vibration sieve; respectively weighing the raw materials according to the percentage, and pouring the raw materials into a horizontal mixer for mixing; adding the anionic surfactant and the nonionic surfactant according to the percentage and mixing; adding the grinding material and mixing. The copper-plated layer washing degreaser disclosed by the invention can be used for rapidly removing the dirt such as grease, residual polishing paste, dust, fingerprints and the like from the surface of a copper layer before chroming and also has the function of roughening a copper-plated layer; an oxide layer on the surface of the copper layer is removed and the Ra value of the roughness of a copper polished layer is reduced to 0.10-0.12 micrometer from 0.06-0.08 micrometer, thus the binding force between the copper layer and a subsequent chromed layer is increased, the problems of partial corrosion of the chromed layer and the like are solved, reworking is reduced, the roller printing quality is improved and the service life is prolonged.

The invention relates to a heat exchanger electrochemically-induced film formation method in a circulating cooling water micro-alkalifying transition period. The method comprises the following steps: connecting a circulating cooling water system heat exchanger with an active metal zinc block to constitute a primary cell, regulating the pH value of circulating water to 2-4, monitoring the metal ion content of the circulating water in the operation process, and after 2-3 days, finishing cleaning when the rise trend slows down; as for a brass heat exchanger, regulating the system to alkality, adding an oxidizer, and forming a Cu2O passivating film on the surface after some time, wherein after the cathode protection is removed, the Cu2O passivating film is gradually converted into a stable CuO passivating film, and afterwards, the brass corrosion rate is less than 0.005 mm/a; and as for the a carbon steel heat exchanger, adding Fe<2+> at one time, circulating for some time, regulating the solution to alkality, adding an oxidizer, removing cathode protection after some time, and forming a compact ferric oxide passivating film on the surface, wherein the corrosion rate is less than 0.01mm/a. The method prevents local corrosion and completes the circulating cooling water micro-alkalifying transition period.

The invention provides a corrosion evaluation method for a corrosion-resistant alloy surfacing welding layer of an underwater oil and gas facility. The method is used for quantitatively evaluating thecorrosion resistance of a surfacing welding layer by comprehensively characterizing the structure state, the mechanical property, the comprehensive corrosion rate and the local corrosion risk of thesurfacing welding layer. According to the invention, quantitative indexes are provided mainly for the corrosion resistance of the corrosion-resistant alloy surfacing welding layer of the underwater oil and gas facility, corrosion resistance evaluation can be conducted on surfacing welding materials applied under corresponding working conditions, and material selection, welding process evaluation and corrosion control are guided.

A substitution gold plating solution for performing uniform gold plating directly on copper wiring of a printed circuit board is provided and a gold plating method using the same is provided, the solution comprising a purine-based compound or a pyrimidine-based compound having a carbonyl oxygen used as a localized corrosion inhibitor, a water-soluble gold compound, an aminocarboxylic acid as a complexing agent, a dicarboxylic acid as a conductivity improving agent, an α-hydroxycarboxylic acid and heteroaryl carboxylic acid as a base metal elution and re-precipitation preventing agent, a sulfite compound as a gold ion stabilizer, an axole compound as a surface corrosion inhibitor, other surfactants, crystal regulators, pH adjuster, and buffers.

The substitution-type electroless gold plating solution according to the present invention prevents the localized corrosion of the copper surface, which is the base metal, and thus the gold plating film produced is excellent in solder mounting reliability.

The invention discloses a metal-organic/inorganic hybrid coating capable of promoting bone regeneration and regulating and controlling corrosion on a degradable metal surface and a preparation method thereof, and the metal-organic/inorganic hybrid coating capable of promoting bone regeneration and regulating and controlling corrosion and degradation is prepared in an alternate liquid phase deposition mode in combination with a chemical coordination chelation principle. According to the coating, the problem that degradable metal, especially zinc-based metal, is insufficient in bone integration and regeneration promoting activity is solved in a targeted mode, and the purpose of promoting bone healing and regeneration is achieved from three aspects of promoting bone generation, promoting angiogenesis and inhibiting osteoclast differentiation at the same time. And the problem of non-uniform corrosion of the zinc-based metal is solved, the corrosion degradation mode of the zinc metal is changed, local corrosion and small hole corrosion are avoided, and the zinc metal can be effectively prevented from being broken and losing efficacy in advance.

The invention discloses a Mannich base acidizing corrosion inhibitor and a preparation method thereof, and belongs to the technical field of corrosion inhibitor preparation. A two-step synthesis process is adopted. Firstly, paraformaldehyde, N,N-dimethyl ethylenediamine and acetophenone are subjected to a Mannich base reaction, and then benzyl chloride, 2-(chloromethyl)naphthalene or 9-chloromethyl anthracene are added to perform a quaternization reaction. Problems of excessive by-products and incomplete reaction are avoided and the yield of corrosion inhibitor products is improved. The prepared corrosion inhibitor has good solubility in an acid solution system, and can reach the first-class industry standard under the conditions of medium temperature and high temperature. A tested hangingpiece is flat in surface and free of obvious pitting corrosion, and the corrosion inhibitor has a good inhibitory effect on uniform corrosion and local corrosion.

The invention provides corrosion inhibitor for carbon steel in the oil field acid environment, and particularly relates to preparation and application of low-toxicity and efficient corrosion inhibitor for restraining corrosion of carbon steel and products of the carbon steel in oil field acid pickling liquid or a saturated CO2 medium. According to the preparing method of the corrosion inhibitor, 3-phenylpropionic acid and diethylenetriamine are subjected to the dehydration reaction, and the phenylpropionic acid imidazoline ramification is obtained. According to the product, comprehensive corrosion and local corrosion is prevented from being generated in the process that the carbon steel makes contact with the acid pickling liquid or the CO2 medium. The compound does not serve as metal corrosion inhibitor at current. By adoption of the corrosion inhibitor, production is simple and convenient, toxicity is small, the inhibition rate is high, corrosion damage to the carbon steel from the acid pickling liquid or CO2 can be effectively restrained, and wide application prospects are achieved. The steps are simple, operation is convenient, and practicability is high.