855 results about "Chromic acid" patented technology

The invention comprises a process of preparing a non-conductive substrate for subsequent metalization. The process replaces the traditional chromic acid etching step with an etching solution comprising a permanganate and a mineral acid. The process also includes a novel activation solution comprising a palladium salt and an amine complexor. The new process of the invention is more environmentally friendly than the traditional chromic acid etching solutions but achieves a comparable result on most non-conductive substrates.

The invention relates to an intensive anodic oxidation process to prepare porous anodic alumina film. An aluminum sheet is as an anode; a platinum sheet as a cathode; argon as shielded gas; mixed solution of perchloric acid with absolute alcohol as electrochemical polishing compound for the aluminum sheet; mixed solution of oxalic acid, absolute alcohol and deionized water as electrolyte; and mixed solution of phosphoric acid, chromic acid and deionized water as alumina film corrodent. Through aluminum sheet annealing, purging, electrochemical polishing, mild anodic oxidation, corrosion on aluminum sheet oxide film, intensive anodic oxidation and stripping oxide film, and finally, pale yellow, high purity and ordered porous-structured nanometer-leveled alumina film is achieved; The alumina film pore is in circular shape sized in 30 to 35nm, pore distance in 80 to100nm and pore depth in 162.4 micrometers; growth rate of the alumina film is 54 micrometers/h, which is 27 times higher than 2 micrometers/h of growth rate of anodic oxidation aluminum film prepared through mild anodic oxidation process.

The invention discloses a preparation method of a superhydrophobic/superoleophilic sponge, belonging to the technical field of functional materials. The method comprises the following steps: pretreating the sponge, preparing a chromic acid washing liquid, preparing a polyperfluoroalkylsiloxane-ethanol mixed solution, corroding by immersing the sponge in the chromic acid washing liquid, modifying by immersing the sponge in the polyperfluoroalkylsiloxane-ethanol mixed solution, taking out, drying and the like. The preparation method disclosed by the invention has the advantage of simple process; and by using the chromic acid corrosion and fluorosilane modification, a superhydrophobic/superoleophilic surface is formed on the surface of the polyurethane sponge. By the means of chemical reaction, the polyurethane sponge is firstly corroded by the chromic acid washing liquid and then modified by the polyperfluoroalkylsiloxane-ethanol solution to lower the surface energy, so that the sponge is superhydrophobic and superoleophilic, thereby enhancing the oil-water separation effect. The surface contact angle of gasoline is 0 degree, and the surface contact angle of water is greater than 150 degrees.

The invention belongs to the field of chromite hydrometallurgy and chromium chemical industry, and in particular relates to a method for the pollution-free production of sodium chromate by pressure leaching of chromite. The method comprises the following steps of: 1) reacting the chromite with oxidizing gas in solution of NaOH; 2) diluting the product obtained by the step 1) and making subcrystalline sodium chromate to fully enter a liquid phase; 3) performing solid-liquid separation on the solid-liquid mixed slurry obtained by the step 2); 4) adding calcium oxide into the obtained diluent for removing impurities; and 5) evaporating and crystallizing the obtained solution without the impurities to obtain a sodium chromate crystal and crystallization mother solution; after the solid-liquid separation, rinsing the sodium chromate crystal by using saturated solution of sodium chromate; and drying to obtain a qualified sodium chromate product. The method has the advantages of simple reaction system component, no difficultly separated phase introduced in the system, contribution to high-efficiency separation of the sodium chromate, great reduction in reaction temperature, low energy consumption, effective reduction in production cost of the sodium chromate, and high chromium leaching yield.

A thermoplastic resin coated aluminum alloy sheet has excellent processing adhesion and high adhesion after retort processing such that laminated thermoplastic resin layers do not peel off even when the alloy sheet is subjected to severe processing such as stretching after deep drawing and furthermore, ironing. A production method and a production apparatus for the alloy sheet are also described. A treatment by an alkaline solution and a treatment by an acidic solution are sequentially applied to bring the surface of an aluminum alloy sheet into a specific surface state and then electrolytic chromic acid treatment is carried out by a known method so as to laminate a thermoplastic resin to an aluminum alloy sheet having a two-layered film which comprises metallic chromium as the lower layer and a chromium hydrate as the upper layer and has a specific surface condition. As a result, a thermoplastic resin coated aluminum alloy sheet having excellent processing adhesion capable of withstanding molding and processing can be obtained.

The invention discloses a manufacturing method of a high-superposition low-loss metal magnetic powder core, aiming to solve the problem of poor direct-current superposition performance of an inductor using metal magnetic powder cores in the prior art. The manufacturing method includes performing surface passivation on Fe (iron)-Si (silicon)-Al (aluminum) magnetic powder by a phosphoric acid acetone solution; adopting a secondary insulation process, in which a chromic acid solution is used for surface film formation and coating liquor is used for surface coating, on Fi-Ni (nickel) magnetic power; mixing the Fe-Si-Al magnetic powder and the Fi-Ni magnetic powder and adding a demolding lubricant; obtaining the finished metal magnetic powder core after dry pressing, secondary annealing and surface painting. The manufacturing method is simple in process procedure; as binding strength between a passivation film on the surface of the magnetic powder and the magnetic powder is high, the passivation film is not easy to separate from the magnetic powder; insulating materials are evenly coated on the surface of the magnetic powder and are not easy to crack or shed; the metal magnetic powder core obtained by the manufacturing method has good current superposition performance, low loss and excellent mechanical property.

The invention relates to a method for extracting vanadium and chromium from a vanadium chromate mixed solution. The method has the characteristics that the vanadium in the vanadium chromate mixed solution is separated and recycled through the crystallization precipitation method or the hydrolysis precipitation method or the calcium salt precipitation method at first, then the chromium in the enrichment solution is separated through the copper salt precipitation method or the barium salt precipitation method, an obtained chromium precipitation enrichment product is then transformed into chromium enrichment liquid, the chromium enrichment liquid is further processed into products of chromic acid and chromate, and production of vanadium-chromium reducing slag and ammonia-nitrogen wastewater in the separation and recycling process of the vanadium and the chromium in the solution is effectively avoided. The method for extracting the vanadium and the chromium from the vanadium chromate mixed solution has the advantages of being good in vanadium and chromium separation effect, short in technological process, high in metal recycling rate, easy and convenient to operate, low in production cost, environmentally friendly and the like and is suitable for industrial production and application.

An aluminum or aluminum alloy member superior in liquid and gaseous corrosion resistance and plasma resistance, which has an anodized film formed thereon which is composed of a porous layer and a non-porous barrier layer whose structure is at least partly boehmite or pseudo-boehmite. Said anodized film is characterized by that the film dissolving rate measured by the test for immersion in a mixture of phosphoric acid and chromic acid (conforming to JIS H8683-2) is less than 120 mg/dm<2>/15 min, the ratio of area in which corrosion occurs after standing for 2 hours in an atmosphere of argon containing 5% chlorine (at 300° C.) is less than 15%, and the hardness (Hv) of the film is no lower than 420.

The invention discloses a method for preparing a nano-size catalyst of copper chromite and copper ferrite, and belongs to the technical field of nano-size catalyst preparation. The method of the invention comprises a sol-gel process and a vacuum freezing drying (VFD) process. Firstly, a mixed solution is prepared from a soluble copper salt and a soluble chromium salt or iron salt, added with a surface active agent, and mixed uniformly, and then the system is added with a precipitating agent to carry out precipitation reaction under the condition that the pH value is between 6.8 and 9.5, then is kept stand, aged, washed and melted in a water bath for 2 to 8 hours at a temperature of between 70 and 95 DEG C, thus sol is obtained; then the sol is subjected to freezing drying in a vacuum freezing dryer to obtain dried gel which is a precursor of the catalyst; finally, the dried gel is roasted to obtain the nano-size catalyst of copper chromite (CuCr2O4) or copper ferrite (CuFe2O4). The catalyst prepared by the method has the advantages of high purity, small grain diameter, good dispersivity, high catalytic activity, and the like.

The invention discloses an electroplating solution for preparation of a nanocrystalline nickel alloy plating. The electroplating solution comprises, in terms of mass concentration, 30 to 80 g/L of a nickel salt, 1 to 10 g/L of a grain-refining agent, 10 to 20 g/L of a complexing agent and 0.1 to 1 g/L of a surfactant. The invention also discloses an electroplating method for preparation of a nanocrystalline nickel alloy plating by using the electroplating solution and the prepared nanocrystalline nickel alloy plating which contains a certain amount of at least one inorganic element selected from the group consisting of nitrogen, carbon and boron besides the metallic element of nickel, wherein the inorganic element is introduced by the grain-refining agent. Compared with the prior art, the nanocrystalline nickel alloy plating prepared in the invention has a crystal grain size of less than 10 nm, a hardness of more than 800 Hv and good wear resistance; compared with conventional preparation methods for chromic acid plated hard chromium, the electroplating method provided by the invention has the advantages of simple equipment and process, easy operation, no pollution caused by hexavalent chromium and the like and has good market application prospects and research values.

The invention relates to a method of electroless Ni-P alloy on surface of magnesium alloy, comprising following steps: (1) degreasing: the magnesium alloy is degreased in non-phosphate alkaline degreasing solution with a temperature of 55 deg C to 65 deg C; (2) acid cleaning: a mixture of organic acid and anionic surfactant is used as magnesium alloy acid cleaning solution instead of traditional chromic acid solution to remove oxide film of the surface of the magnesium alloy; (3) surface conditioning: the acid cleaned magnesium alloy is processed surface conditioning in alkaline surface conditioning solution with a temperature of 80 deg C to 100 deg C; (4) activating: the surface conditioned magnesium alloy is processed activation in HF solution; (5) acid dipping zinc; (6) nickel plating: in a condition that the temperature is 80 deg C to 90 deg C and ph value is in the range of 5 to 6, a brightener is added into electroless nickel solution to process nickel plating reaction Ni-P alloy coating. The invention has following beneficial effects: (1) reducing pollution for environment and damage for bodies of operators, and at the same time, easily controlling the operation and uneasily losing control for process parameters; (2) improving appearance of the Ni-P alloy coating, and being provided with better decorative.

The invention discloses a preparation method of a high-frequency high-magnetic-permeability low-loss iron nickel molybdenum metal magnetic powder core. According to the traditional method, during magnetic powder insulated costing, the quantity of on-magnetic substances is more, and the high density and high magnetic permeability of the iron nickel molybdenum magnetic powder core can not be realized. The preparation method provided by the invention comprises the following steps: firstly screening selected iron nickel molybdenum magnetic powder subjected to water atomization or iron nickel molybdenum magnetic powder subjected to gas atomization; secondly reacting the iron nickel molybdenum magnetic powder in a chromic acid aqueous solution, thus generating an insulation film on the surface of the magnetic powder; drying for two hours, and solidifying and stabilizing the insulation film on the surface of the magnetic powder; then adding zinc stearate serving as a lubricating agent into the iron nickel molybdenum magnetic powder, mixing and pressing the magnetic powder to obtain the iron nickel molybdenum magnetic powder core and carrying out annealing heat treatment under N2 atmosphere; and finally spraying epoxy paint on the iron nickel molybdenum magnetic powder core. The preparation method provided by the invention can be used for uniformly and firmly generating hundreds of nanometers of the insulation film on the surface of the iron nickel molybdenum magnetic powder, the insulated coating effect is good, the consumption of the non-magnetic insulants is reduced, and the purpose of improving the density and magnetic permeability of the magnetic core is achieved.

The invention relates to a detection method of plated layer corrosion rate in a steel wire or a steel wire rope. The method comprises the process steps that: 1, a sample is prepared, wherein a plated steel wire or steel wire rope is cut into N segments; the surfaces are cleaned by using alcohol cotton; and the ends are sequentially sealed by using a solid sealant (AB composite adhesive), such that N samples are prepared; 2, the samples are weighed; 3, a salt spray test is carried out, wherein the weighed samples are subjected to a neutral salt spray test in a salt spray box; 4, the surfaces of the samples are cleaned, wherein the samples after the salt spray test are washed in a container with a prepared chromic acid cleaning agent, such that residual salt and corrosives on the surface of the samples are completely removed; the samples are washed by using water, and are dried; and 5, weighing and calculation are carried out, wherein the dried samples are weighed, and the weights are adopted as after-test weights; and the corrosion rate is calculated according to the weight loss before and after the test. With the method provided by the invention, corrosion-resistant rates of various plated layers can be easily determined, and the service lives of the plated layer samples in the environment can be inferred.

The invention discloses an environment-friendly technology for copper and copper alloy surface treatment. The environment-friendly technology includes the following steps of (1) ultrasonic degreasing, (2) rinsing with clear water, (3) magnetic force polishing, (4) rinsing with clear water, (5) surface sealing, (6) centrifugal drying and (7) inspecting and packaging. A magnetic force polishing method is adopted to replace traditional three-acid pickling so as to conduct surface oxide skin removing operation on a copper alloy workpiece, and steel needles continuously collide and rub copper and the copper alloy workpiece so that surface oxide layers and tiny burrs can be removed and the purpose of surface smoothness can be achieved. The size of the copper alloy workpiece is not changed at all before and after treatment, and the poor size problem of the workpiece due to overpickling in the acid pickling process does not exist. A water-soluble environment-friendly sealing agent is adopted, the copper and the copper alloy workpiece with the smoothness surfaces after magnetic force polishing are subjected to sealing treatment, an organic closing membrane is used for replacing a chromic acid passivation membrane so that surface protection can be performed on the copper alloy workpiece, the adopted sealing agent is up to the ROSH standard and does not contain toxic and harmful substances, and the thickness of the surface closing membrane is controllable in the process; and moreover, the product has high fingerprint resistance, high salt spray resistance and high anti-tarnish performance.

The invention discloses an anticorrosive environment-friendly spray paint formula, and relates to the field of chemical industries. The anticorrosive environment-friendly spray paint formula comprises the following components in parts by weight: 28 to 35 parts of glacial acetic acid, 3 to 7 parts of organic fluorine epoxy resin, 7 to 12 parts of epoxy modified organic silicon resin, 2 to 6 parts of glycol monomethyl ether, 6 to 9 parts of dimethyl sulfoxide, 8 to 13 parts of zinc phosphate, 8 to 13 parts of barium chromate, 1 to 4 parts of ethanol, 2 to 7 parts of polyacrylate, 1 to 4 parts of alcohol soluble resin, 7 to 13 parts of diacetone alcohol, 6 to 9 parts of zinc oxide, 8 to 13 parts of toluene diisocynate, 3 to 7 parts of n-butyl acetate, 12 to 16 parts of benzophenone, 9 to 13 parts of triethanolamine and 3 to 7 parts of diphenyl polysiloxane. The paint is bright in color and good in air-curing resisting effect, can substitute medium chrome yellow in inorganic pigment, is applicable to the outer wall paint, and has no harm of heavy metals, no harmful substances, good environment protection effect, little odor, no peculiar smell after being smeared on the wall, good mechanical performance, excellent electric insulation performance, dampness and water resistance, rust and cold resistance and ozone aging resistance.

The invention discloses a multifunctional gaseous phase anti-rust oil which mainly comprises No. 25 transformer oil, oil-soluble vapor phase corrosion inhibitor, cosolvent dibutyl phthalate, defoamingagent polydimethylsiloxane, antioxidant zinc dialkyl dithiophosphate, mildewproof agent di-n-octyl-4-isothiazolin-3-ketone and the like; wherein the oil-soluble vapor phase corrosion inhibitor is prepared by mixing 10-40% of octadecyl butanedioic acid, 10-30% of 2-ethylamino heptadecenyl imidazoline, 2-20% of lanolin, 5-20% of zinc naphthenate and 15-30% of chromic acid tert-butyl ester. The gaseous phase anti-rust oil not only has the contact anti-rust property of the anti-rust oil, but also has the superior vapor phase anti-rust performance of the vapor phase corrosion inhibitor. The multifunctional gaseous phase anti-rust oil can be widely applied to long-term rust protection of military hardware and metal materials for civil use, more particularly, used for rust prevention of engines,large compressors, special gear boxes and the like, and mainly applicable to preventing a closed cavity system from rusting. The anti-rust oil not only can prevent black metal steel-made parts from rusting, but also has the function of rust prevention for multiple non-ferrous metal parts, thus effectively preventing metals such as steel, copper, zincification, chrome-plate and the like as well asalloy materials thereof from being corroded.

It is an object of the present invention to provide an anticorrosive coating composition which uses a pollution-free (heavy metal-free) rust preventive pigment and exhibits anticorrosive performances equal or superior to those of lead compounds or chromic acid compounds even if the pigment is blended in various binder resins and also to provide an anticorrosive coating composition having excellent storage stability. The present invention relates to an anticorrosive coating composition comprising a binder resin and a pollution-free (heavy metal-free) rust preventive pigment containing a condensed calcium phosphate produced by baking a single substance or mixture of a calcium component and a phosphorous component in the following atomic ratio (Ca/P=m): 0.50<m<1.00, at 180 to 350° C.

The invention relates to a method for directly preparing adipic acid and diacid from cyclohexane bionic oxidation mixture by nitric acid oxidation. The invention is characterized in that in the presence of 1-10mg/L metalloporphyrin catalyst, at 140-160DEG C and 0.8-1.2MPa, cyclohexane is oxidized by air, and the cyclohexane oxidation mixture is directly prepared into adipic acid and diacid by nitric acid oxidation. Compared with prior adipic acid preparation, the invention can simultaneously improve single-pass conversion of cyclohexane and total yield of diacid respectively more than 10% and 80%. At the same level of adipic acid yield, the circulation quantity of cyclohexane is reduced more than 50%, nitric acid consumption is reduced about 10%, to reduce the load on cyclohexane distillation system, reduce energy consumption, and reduce production cost. The invention can be directly used in prior industrial unit that prepares adipic acid from cyclohexane, to reduce production cost and improve yield. The invention can simplify prior production that prepares adipic acid by cyclohexane oxidation, to eliminate washing, cyclohexyl hydrogen dioxide decomposition, and cyclohexanone-and-cyclohexanol distillation systems, and avoid tert-butyl chromic acid catalyst.

The invention provides a process method for recovering chromium and aluminum by comprehensively utilizing waste aluminum residues, and relates to a novel method for recovering sodium chromate and aluminum oxide from industrial waste chromium-containing aluminum residues. The waste chromium-containing aluminum residues serve as a raw material and are separated with beating, water washing, electroosmosis and other processes, so that the sodium chromate solution is obtained and used for producing sodium dichromate products; the aluminum residues after dechroming processing are dissolved with a NaOH solution, and then a high-purity metallurgical grade aluminum oxide product is obtained with repeated continuous carbonation decomposition methods. With the adoption of the process method, hexavent chromium in the chromium-containing aluminum residues can be recovered, valuable metal aluminum in the aluminum residues is extracted, the qualified aluminum oxide product is produced, and meanwhile, the environment is effectively protected.

A process for preparing Cr2O3 by continuous thermodecomposition of chromic acid includes such steps as proportionally mixing chromic acid, coarse Cr2O3 as returning charge and additive chosen from boric acid (preferable), ammonium chloride, starch and saw dust; after uniformly mixing under a computer control, parallel-flow combustion of the said mixture and liquefied gas as fuel in an insulated rotary furnace, thermodecomposition reaction to generate Cr2O3, keeping the temp. for a certain time, cooling and pulverizing to obtain the product. The unpulverized material is used as the said returning charge.