116 results about "Chromate and dichromate" patented technology

The disclosure relates to a method of producing a multi-metal catalyst film and of producing a reactor system for catalytic removal of a wide variety of contaminants (for example, nitrate, nitrite, perchlorate, chlorate, chromate, selenate, chlorophenols, 2,4-D, dicamba, atrazine, trichloroacetic acid, bromochloroiodomethane, NDMA, TCE, TCA, chloroform, freons, RDX, HMX, TNT, PFOA, and PFOS) from water and wastewater. The disclosure also relates to a method of using the multi-metal catalyst for the removal of such contaminants and a system comprising the multi-metal catalyst film for removing such contaminants.

The invention belongs to the field of catalysts for oxygen production through seawater electrolysis, and particularly discloses a chromium-doped ferronickel sulfide nanorod array material, a preparation method thereof and application of the chromium-doped ferronickel sulfide nanorod array material to oxygen evolution through seawater electrolysis. The material is a chromium-doped ferronickel sulfide grown in situ on a foamed ferronickel substrate, has components of NiFe, Ni3S2 and (Fe, Ni) 3S4, and is of a nanorod array structure. The preparation method comprises the following steps: putting the cleaned foam ferronickel into a solution containing a sulfur source and chromate, and obtaining the chromium-doped ferronickel sulfide nanorod array material by utilizing a hydrothermal method. As an alkaline water and seawater oxidation electrode, the composite material shows extremely excellent catalytic activity and stability, and has potential application value in the aspect of developing a transition metal OER catalyst for electrolyzing seawater to evolve oxygen.

The invention discloses a heat storage unit and an assembling method and application thereof. The heat storage unit comprises a metal heat storage shell and a phase change layer, a heat storage space in the metal heat storage shell is filled with the phase change layer, and a phase change material of the phase change layer comprises the following components: 85.0 wt.%-95.0 wt.% of a phase change base material, 1.0 wt.%-3.0 wt.% of a nucleating agent, 2.0 wt.%-4.0 wt.% of a thickening agent and 0.5 wt.%-2.0 wt.% of a corrosion inhibitor; the phase-change base material comprises one of saturated fatty acid, an alcohol compound or an inorganic phase-change base material; the corrosion inhibitor comprises at least one of a nitrogen-containing heterocyclic compound, an oxygen-containing heterocyclic compound, molybdate, chromate and tungstate. A phase change base material and a corrosion inhibitor are selected for combined use, the corrosion inhibitor dissociates and forms substances with negative charges such as BTA <->, MnO4 < 2-> and CrO4 < 2->, a metal shell is in contact with the phase change material to lose electrons to form metal ions with positive charges, and the metal ions are combined with the substances with negative charges such as BTA <->, MnO4 < 2-> and CrO4 < 2-> to generate a compact long-chain complex. Further contact between other corrosion ions and metal is inhibited, so that the purpose of corrosion prevention is achieved.

The invention discloses a modified polyaniline synergistic flaky zinc-aluminum waterborne epoxy anticorrosive coating and a preparation method thereof. The anticorrosive coating comprises a component A and a component B in a mass ratio of (4-5): 1, the component A is prepared from the following components in parts by weight: 8 to 16 parts of waterborne epoxy resin, 55 to 75 parts of zinc powder, 5 to 10 parts of flaky zinc-aluminum powder, 0.3 to 0.6 part of a dispersing agent, 0.5 to 1 part of an anti-settling agent, 0.1 to 0.3 part of dodecylbenzene sulfonic acid doped polyaniline, 1 to 2 parts of an adhesion promoter and 6 to 10 parts of a first solvent; and the component B comprises the following components in parts by weight: 3-7 parts of a water-based amine curing agent, 1-2 parts of an anti-flash-rust auxiliary agent, 5-10 parts of a second solvent and 2-5 parts of deionized water. The obtained coating is compact, excellent in corrosion resistance, good in adhesive force, few in organic volatile matter, easy to prepare, convenient to operate and completely free of chromate, and the corrosion resistance far beyond that of conventional paint is achieved.

The invention belongs to the technical field of precision part machining, and discloses a precision part corrosion-resistant coating process, electrochemical treatment is chromic acid treatment, coating materials comprise epoxy resin coating, polyurethane coating and polytetrafluoroethylene coating, and a spraying technology comprises electrostatic spraying, air spraying and airless spraying. Hydrochloric acid is used for removing oxides on the surface of steel, phosphoric acid is used for removing rust on the surface of metal, through cooperation of acid pickling, passivation and electroplating, acid pickling and passivation can remove the surface oxides, the hardness and friction resistance of the surface of the metal can be improved, and electroplating can improve the surface hardness of parts, improve abrasion resistance and prevent corrosion; a protective film is formed through passivation treatment, further oxidation is prevented, chromate passivation soaking time is 10-30 minutes, phosphate passivation soaking time is 5-15 minutes, nitric acid passivation soaking time is 5-10 minutes, and durability, corrosion resistance and surface hardness of the precision part are improved.

The invention relates to the technical field of chemical mechanical polishing solutions, in particular to a chemical mechanical polishing solution for silicon carbide and a preparation method thereof, the polishing solution comprises a catalyst, abrasive particles, a dispersing agent, an oxidizing agent, a surfactant, an acid-base regulator and deionized water; the catalyst is nano platinum particles; the abrasive particles are aluminum oxide; the dispersing agent is at least one of sodium polyacrylate, sodium hexametaphosphate, hexadecyl trimethyl ammonium bromide and the like. The oxidizing agent is at least one of permanganate, pypocholoride, dichromate and the like; the surfactant is at least one of sodium dodecyl benzene sulfonate, organic bentonite and the like; the pH regulator is at least one of phosphoric acid, nitric acid, oxalic acid and citric acid. The polishing solution can effectively improve the removal rate of silicon carbide, and meanwhile, a polished silicon carbide wafer is high in flatness and free of scratches.

Provided is a tin-plated steel sheet for containers, said steel sheet having a zirconium-containing coating layer, without having to undergo conventional chromate treatment. The tin-plated steel sheet has further excellent yellowing resistance. A tin-plated steel sheet having: a steel sheet; a tin plating layer on at least one surface of the steel sheet; and a coating layer that is positioned on the tin plating layer and contains zirconium oxide and tin sulfide, the amount of tin plating layer deposited in the coating layer being 0.1 g / m2 to 15 g / m2 in terms of the amount of metal Sn, the amount of zirconium oxide deposited in the coating layer being 0.2 mg / m2 to 50 mg / m2 in terms of the amount of metal Zr, and the amount of tin sulfide deposited in the coating layer being 0.1 mg / m2 to 5 mg / m2 in terms of the amount of sulfur.

The present invention relates to a high-entropy rare earth chromate high-temperature negative temperature coefficient thermistor material, belonging to the field of semiconductor sensors, and aims to solve the existing perovskite structure high-temperature NTC material. Under high temperature environment, the Cr element in the system will volatilize in the form of gaseous CrO3, showing poor high-temperature aging stability. The high-temperature negative temperature coefficient thermistor material uses lanthanum trioxide, neodymium trioxide, samarium trioxide, europium trioxide, gadolinium trioxide and chromium trioxide as raw materials, and undergoes wet three-dimensional vibration ball milling, powder calcination, cold isostatic pressing, and high-temperature sintering to obtain a perovskite structure (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 G 0.2 )CrO3 thermosensitive material. The electrical performance parameters of this series of materials are: B 0℃ / 1300℃ =2044±1.42%K,ρ 1300℃ =1.45×10 3 ±1.73%Ω·cm. The high-entropy rare earth chromate high-temperature negative temperature coefficient thermistor (La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 G 0.2 )CrO3 has excellent negative temperature coefficient characteristics in the temperature range of 0~1300℃, and shows good high temperature aging stability at high temperatures (the resistance drift rate is only 4.35% after aging for 500 hours at 1300℃).

A method for manufacturing a cover member for electronic devices according to certain embodiments of the present disclosure may comprise: a step for forming a magnesium plate; a step for performing primary CNC processing on the magnesium plate using a predetermined cutting oil; a step for performing a primary pretreatment on the magnesium plate using chromate or micro arc oxidation (MAO); a step for performing a primary surface-treatment on the magnesium plate by bake-coating or electrodeposition coating; a step for performing secondary CNC processing on a first region of the magnesium plate using an alcohol-containing cutting oil; a washing and drying step; a step for performing a secondary pretreatment for preventing oxidation on the first region; and a step for performing a secondary surface-treatment on the first region by bake-coating or electrodeposition coating.