395 results about "Corrosion potential" patented technology

Hundreds of thousands of concrete bridges, buildings etc. and hundreds of billions of tons of concrete require characterization throughout the process from manufacture to pouring and curing and on throughout service life. The characterization may relate to initial concrete properties, projected concrete properties, framework removal, corrosion, failure etc. Accordingly, a variety of measurements such as water content, electrical resistivity, and half-cell corrosion potential for example would be beneficially implemented as easy to use field test equipment or embedded sensors allowing lifetime monitoring to be performed rather than discrete assessments when issues become evident.

Improved shape and strength of the weld in a welded structure are obtained by use of a weldable aluminum product comprising a structural component which is a sheet, a plate or an extruded body and is made of an aluminum alloy containing not more than 1.5 wt % Zn. This component has, adhered on at least one side, a cladding layer made of an AA7xxx-series alloy having a corrosion potential lower than that of the alloy of the structural component. The alloy of the structural component is preferably an AA5xxx-series alloy containing Mg in the range 2 to 6 wt %.

The invention provides a preparation method of a magnesium alloy surface micro-arc oxidation/spray coating compound film, which relates to a preparation method of a magnesium alloy surface compound film. The invention solves the problems that film layers obtained by chemical composition coating, anodic oxidation and vapor deposition in the existing magnesium alloy surface treatment method are thin and have poor corrosion resistance performance, the ion injection has high cost and is difficult to realize large-area processing, the combining force between coating layers and the magnesium alloy is poor, and organic coating layers has the defect of easy aging. The preparation method has the following steps: firstly, using micro-arc oxidation for preparing ceramic films on the surface of the magnesium alloy; then, adopting air spray coating for spraying and coating inorganic paint onto the ceramic films; and then, carrying out heat treatment to obtain the micro-arc oxidation/spray coating compound film. The method is simple, and the cost is low. The air spray coating uses porous structures of the micro-arc oxidation ceramic films, so the combination of the inorganic coating layers and the ceramic films is firm, the thickness of the compound films is between 20 and 40 mum, the self corrosion electric potential is positively moved to -1.02 V, the corrosion current density is lowered by 5 orders through being compared with that of the magnesium alloy, the magnesium alloy surface micro-arc oxidation/spray coating compound film has no damage after 72 to 144h of salt spray tests, and the corrosion resistance performance is good.

The invention provides a corrosion detection method for a grounding net, as well as a system. The method comprises the steps as follows: the corrosion potential of detected grounding net metal is measured, constant current step signals are applied to the detected grounding net metal, and the constant current step response signals are collected; the wavelet filter treatment is performed to the collected grounding net soil corrosion electrochemical detection data; and the corrosion electrochemical parameter analysis processing is performed to the grounding net soil corrosion electrochemical detection data after the wavelet filter treatment, thereby generating the grounding net soil corrosion detection result. The grounding net corrosion status is detected accurately and conveniently by the electrochemical detection method.

The invention discloses a high-strength, corrosion-resistant and medium-entropy alloy and a preparation method thereof. The component of the medium-entropy alloy is (CoCrNi)(100-x)Mnx, the atomic ratio of Co to Cr to Ni is (0.5-1):(0.5-1):(0.5-1), the value range of x is 1at%-10at%, , the alloy is formed through mixing, smelting, homogenizing treatment, rolling and heat treatment machining, the grain size of the alloy ranges from 30 mu m to 200 mu m, the manganese-rich phase is separated out of the grain boundary, the tensile strength of the alloy is higher than 1,200 MPa, the ductility is higher than 10%, the corrosion potential ranges from negative 0.43 V to negative 0.26 V, and the medium-entropy alloy is applicable to marine engineering equipment. The preparation process route of the alloy includes vacuum smelting, suction casting, homogenizing annealing, cold rolling and heat treatment. Co, Cr and Ni with the purity being 99% or higher are selected and weighed according to the proportion and are smelted repeatedly in a vacuum smelting furnace, suction casting forming is performed after the component is uniform, multi-pass cold rolling is adopted after annealing treatment, a plate which is 1-2 mm thick is obtained, the tensile strength of the plate is higher than 1,200 MPa, the ductility is higher than 10%, and the corrosion potential ranges from negative 0.43 V to negative0.26 V.

Disclosed are methods of treating a metal to improve the metal's corrosion resistance. In one such method, the method is carried out by applying, to the surface of the metal, a coating which includes magnesium powder and a UV-curable or other radiation-curable binder. In another such method, the method is carried out by applying, to the surface of the metal, a coating which includes magnesium powder and an inorganic binder. In another such method, a coating that includes a magnesium alloy powder and a binder is applied to the surface of the metal. The magnesium alloy powder is selected such that it has a corrosion potential that is from about 0.01 volt to about 1.5 volt more negative than the metal's corrosion potential. Also disclosed are methods of treating a ferrous metals and magnesium alloys to improve the corrosion resistance of these materials.

The present invention discloses a preparation process of polyaniline anticorrosive coating, and includes the following steps: mixing epoxy rsin, polyaniline and diluent uniformly, grinding, then mixing them with phenol aldehide amine, polyamide and diluent uniformly according to the ratio of 10-20:1, cuating on the metal surface and solidifying at room temp. so as to implement said invention. Said anticorrosive coating can form a layer of compact film on the steel surface, can raise corrosion potential of steel, reduce corrosion current and can prevent and relieve corrosion of steel, and said coating layer possesses high harndess and excellent abrasive resistance, after said coating layer is scratched, a passive film can be formed so as to can protect metal from corrosion.

An aluminum alloy fin stock of lower (more negative) corrosion potential and higher thermal conductivity is produced by a process, which comprises continuously strip casting the alloy to form a strip, cold rolling the strip to an intermediate gauge sheet, annealing the sheet and cold rolling the sheet to final gauge. Lower corrosion potential and higher thermal conductivity are imparted by carrying out the continuous strip casting while cooling the alloy at a rate of at least 300 DEG C./second, e.g. by conducting the casting step in a twin-roll caster.

Disclosed herein is an apparatus for use downhole comprising an expandable component; a support member that has a selected corrosion rate; wherein the support member is disposed on the expandable component; where the support member comprises a plurality of particles fused together; the particles comprising a core comprising a first metal; and a first layer disposed upon the core; the first layer comprising a second metal; the first metal having a different corrosion potential from the second metal; the first layer comprising a third metal having a different corrosion potential from the first metal.

The invention particularly relates to a preparation method of a polyaniline/graphene water-based epoxy anticorrosive paint by blending a polyaniline composite material and a water-based epoxy resin, belonging to the technical field of anticorrosive paints. In order to solve the problems of lower water resistance and lower corrosion resistance of the coating due to abundant hydrophilic groups in the water-based epoxy resin paint which uses water as the solvent, the invention provides a preparation method of a polyaniline water-based epoxy resin anticorrosive paint. By using the characteristic of large specific area in the graphene, a polymerization-reduction process is utilized to prepare the large-specific-area high-dispersity polyaniline/graphene composite material, and the composite material is blended with the water-based epoxy resin to prepare the anticorrosive coating. The polyaniline/graphene composite material added into the water-based epoxy resin enhances the metallic corrosion potential, quickly conducts electrons formed in the corrosion process, and separates the cathode and anode reaction; a metal passivation layer is formed on the matrix surface to decelerate the metal corrosion; and the composite material with large specific area prolongs the seepage path of oxygen and water molecules to the carbon steel surface, and thus, has excellent barrier properties.

A method of binode polarization curve which is used to test the metallographic electrochemistry property and the corrosion resisting property is disclosed, The metal sample to be measured is immersed into the aqueous solution, the open-circuit potential that is the corrosion potential Ecorr of the sample is recorded, then the forward scan from the activating area to the inactivating area of the metal sample can be done beginning with the corrosion potential, the density of current which goes by the sample is be recorded at the same time; the scanning direction of electric potential is changed when the electric potential reaches the assigned value Et, the backward scan from the inactivating area to the activating area of the metal sample is started, a new corrosion potential E'corr is obtained, the anode polarization curve F of the forward scan and the anode polarization curve B of the backward scan that metal sample is in aqueous solution are run with the logarithm of electric potential and current density measured. The invention can make the measured results have perfect correlation with the true causticity of metal to gain one times information more than current technology. It will be the very effective tools for research of the metallographic electrochemistry property and the corrosion resisting property of metal in aqueous solution.

The invention discloses a Ti-Mg alloy material applied as human tissue bone repair materials and a preparing method thereof. Phase composition of the alloy comprises Ti, Mg, TiO and MgO. The alloy comprises 70-80% of the Ti, 0-10% of the Mg, 8-20% of the TiO and 2-5% of the MgO. The Ti-Mg alloy is prepared by utilization of mechanical alloying and spark plasma sintering. The porosity of the alloy is smaller than 1%, the Vickers hardness of the alloy is HV400-HV500, the compressive strength of the alloy is 1600-1700 MPa, the elasticity modulus of the alloy is 12-13 GPa, the self-corrosion potential of the alloy ranges from -900 mV to -800 mV, the self-corrosion current density is 50-90 [mu]A/cm<2>. The alloy has characteristics of uniform structure, high compactness, good mechanical compatibility, capability of being biodegradable, and good corrosion resistance.

An improvement in the corrosion resistance of a magnetoresistive head is aimed for, and a high magnetoresistivity ratio is maintained. In a magnetoresistive head equipped with, as a magnetic sensor element for detecting magnetic signals while in contact with a magnetic recording medium, a spin-valve film, which has a structure where an anti-ferromagnetic layer, a pinned layer in which the direction of magnetization is pinned in a predetermined direction by an exchange-coupling magnetic field at work between itself and the anti-ferromagnetic layer, a free layer in which the direction of magnetization changes in accordance with an external magnetic field, and a non-magnetic layer for magnetically isolating the pinned layer and the free layer are layered, the corrosion potential of the spin-valve film relative to a standard hydrogen electrode measured while immersed in a NaCl solution of a concentration of 0.1 mol/L is specified at +0.4 [V vs. SHE] or above.

The invention relates to a method for preparing a biodegradable magnesium alloy surface modification fluoridated hydroxyapatite coating. The method comprises the following steps of: pretreating a magnesium alloy substrate, wherein the adopted transfer solution is prepared from sodium dihydrogen phosphate dehydrate and calcium nitrate tetrahydrate; soaking a substrate sample obtained by pretreatment in the transfer solution for 5-100 hours, thus obtaining a calcium-phosphorus coating; soaking a calcium-phosphorus coating sample in an alkali fluoridated transfer solution for 10-48 hours, so as to obtain a fluoridated calcium-phosphorus coating, wherein the alkali fluoridated transfer solution is prepared from sodium hydroxide and sodium fluoride, the concentration of the sodium hydroxide is 3-4g/L, the concentration of the sodium fluoride is 4-5g/L, and heat treatment is not performed; performing heat treatment on the fluoridated calcium-phosphorus coating at the temperature of 300-350 DEG C for 2-5 hours, thus obtaining the fluoridated hydroxyapatite. According to performance detection, the fluoridated hydroxyapatite (FHA) coating prepared by combining a heat treatment process is shaped like a slender sheet and is divergently arranged from the center to the periphery; the electrochemical test proves that the self-corrosion potential of the substrate is improved through the FHA coating; the immersed corrosion experiment proves that an actual protective effect of the FHA coating on the magnesium alloy substrate is better than that of a fluoridated apatite (FA) coating.

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 relates to a method for preparing a novel conductive polypyrrole/polyaniline composite anticorrosive coating. The method comprises the following steps of: dissolving p-toluenesulfonic acid into water, regulating the pH value of a solution to be an appropriate value, and adding pyrrole and aniline monomers to obtain a mixed solution; performing electrochemical synthesis by using a three-electrode system, wherein copper is taken as a working electrode, a platinum sheet is taken as an auxiliary electrode, and a reference electrode is a saturated calomel electrode; and performing electrochemical polymerization under certain electrical parameters by cyclic voltammetry to obtain a layer of conductive polypyrrole/polyaniline composite anticorrosive coating on the surface of the copper electrode. The conductive polymer coating generated on the surface of the copper has high adhesion and is uniform and compact; medium corrosion ions can be effectively hindered from penetrating the coating and permeating into the surface of a metal matrix for a long time; the composite coating effectively improves the corrosion potential of a copper matrix and reduces corrosion current; and in addition, after the prepared coating is damaged, a layer of passivating film can be quickly generated on the surface of the matrix so as to ensure that metal is free of corrosion.

The invention discloses an electrochemical test method of steel bar corrosion in the concrete of coastal area. The test method comprises the following steps: (1) under the concrete condition of the temperature of 0 to 50 DEG C and the relative humidity of 50 percent to 85 percent, the resistance rate R of the concrete is detected; if the estimated value of R is more than or equal to 20kilo-ohm, the passive film of the steel bar in the concrete is not damaged; if the estimated value of R is less than 20kilo-ohm, the second step is adopted; (2) a silver-silver chloride electrode is used for further determining the corrosion potential of the steel bar; if the estimated value of the corrosion potential of the steel bar is more than or equal to minus 119mV, the passive film of the steel bar in the concrete is not damaged; if the estimated value is less than 119mV, the passive film of the steel bar in the concrete is not damaged. The corrosion current density Jcorr of the steel bar in the concrete is further determined; the average corrosion depth and the average section loss rate of the steel bar are calculated. The guarantee rate of the estimated values is 95 percent. The electrochemical test method has the targeted characteristic and comprehensive criteria, and is in particular suitable for estimating the corrosion of the steel bar in the concrete structure without obvious cracking and rust on the surface.

A potential testing method of deep-sea corrosion on metal material includes preparing test device to be a unified and sealed structure, setting test device in deep-sea of selected sea area, realizing automatic measurement and automatic conversion as well as automatic storage by utilizing battery carried by itself and control of monolithic computer, using interface to guide data into computer to carry out analysis and treatment to obtain test result after recovery, enabling to carry 30-50 metal test-pieces on one test device and laying test device in deep-sea of 100-3000 metres for 1-6 months.

The invention discloses a detection and evaluation method of simulation acceleration metal acid atmospheric environment corrosion. The method comprises the steps of preparing test specimens, wherein the size and the surface roughness of the test specimens must be identical; 2, preparing a simulation acid atmospheric environment corrosion solution, wherein a test solution needed by a high-low-temperature alternation damp and heat experiment test and electrochemical polarization curve corrosion is prepared; 3, determining a corrosion condition, wherein the high-low-temperature alternation damp and heat experiment test is conducted on the specimens in sequence; 4, determining evaluation indexes, wherein a weight increment, a corrosion velocity, a surface topography and a corrosion potential are adopted as corrosion performance indexes. According to the detection and evaluation method of the simulation acceleration metal acid atmospheric environment corrosion, through the high-low-temperature alternation damp and heat experiment test, a simple, convenient, fast and efficient detection and evaluation method of the simulation acceleration metal acid atmospheric environment corrosion is designed, the method is high in practicability, the corrosion which occurs in an outdoor acid atmospheric environment can be better represented, and a method is provided for a related metal material corrosion performance study.

The invention relates to a method for the stray current corrosion test of a buried steel pipeline under the tensile stress action, and belongs to the material corrosion and protection fields. A system used by the method comprises a stress loading test system, a soil environment simulation system, a stray current simulation system, a cathode protection system and an electrochemical test system. The stress loading test system generates a pressure required by a sample test, the soil environment simulation system stimulates the soil environment in which a buried metal is positioned to prepare soil solutions having different pH values and conductivities, the stray current simulation system generates direct current, alternate current and direct and alternate mixed stray currents, the cathode protection system provides a cathode protection potential for the sample, and the electrochemical test system tests the corrosion potentials of the sample under different influence factors. The system used by the method can measure the weight loss, can obtain the corrosion morphology, can generate the direct current, alternate current and direct and alternate mixed stray currents, can provide the stress required by the test according to the practical running condition, can stimulate the cathode protection, and can realize the corrosion rule experiments under different influence factors.