8results about How to "Low corrosion current density" patented technology

The invention relates to a preparation method of a magnesium alloy stent composite coating, and belongs to the technical field of biomedical materials. The composite coating with the piezoelectric-pH synergistic protection function is provided for solving the technical problems that an existing polyester coating is degraded to produce acid, and corrosion of a magnesium alloy stent is accelerated. The coating comprises a PVDF (Polyvinylidene Fluoride)-g-APTES ( The pH regulation and control middle layer is composed of PVDF, PDLLA and alkaline nanoparticles; and a drug-loaded PDLLA outer coating layer. The pH value of the interface is actively increased to a passivation region through on-demand release of the alkaline nanoparticles, and a positive feedback mechanism that protection is achieved when stress is increased is achieved through the piezoelectric effect. Compared with the prior art, the dynamic corrosion resistance is enhanced by 40% or above, the protection effect is improved by 60% or above through the synergistic effect, piezoelectric and alkaline synergistic protection is achieved, and a comprehensive solution with long-acting corrosion resistance and intelligent response is provided for a degradable magnesium alloy implantation instrument.

The invention relates to the technical field of permanent magnet preparation, and particularly discloses a high-temperature-resistant neodymium-iron-boron magnet and a preparation method thereof. The high-temperature-resistant neodymium-iron-boron magnet comprises the following elements in percentage by mass: 17.4%-19.5% of Nd, 0.66%-0.72% of B, 38.37%-41.19% of Fe, 0.36%-4.8% of Dy, 0.18%-0.3% of Nb, 0.18%-0.3% of Al, 0.03%-0.09% of Cu, 29.1%-34.8% of an alloy rapid hardening sheet and the balance of unremovable impurities, wherein the alloy rapid hardening sheet contains Pr, Tb, Bi and Sn; the preparation method comprises the following steps: grinding the surface of an alloy rapid hardening sheet to be bright, mixing the alloy rapid hardening sheet with a pretreated magnet block, adding zirconium oxide balls, putting into a reaction kettle of a rotary diffusion furnace, vacuumizing the reaction kettle, introducing argon, rotating at the rotating speed of 4-6r / min, keeping the temperature at 700-704 DEG C for 3-7h, and carrying out rotary diffusion, so as to obtain the zirconium oxide-based composite material. And then carrying out heat preservation at 850-950 DEG C for 2-4 hours for high-temperature diffusion and heat preservation at 450-550 DEG C for 2-4 hours for tempering heat treatment by using a vacuum tube furnace in a vacuum environment. The high-temperature-resistant neodymium-iron-boron magnet has the advantage that the defect that heat resistance of a conventional neodymium-iron-boron magnet is still insufficient is overcome.

The application discloses a low-density corrosion-resistant thin-gauge high-aluminum medium-manganese steel, and chemical components and mass percentages of the low-density corrosion-resistant thin-gauge high-aluminum medium-manganese steel include the following: C: 0.1-0.4%, Mn: 3-12%, Al: 2-5%, and the balance of Fe and inevitable impurities. The application has the advantages that a stirring friction processing method is used to introduce a microstructure feature of a phase and a grain size in a matrix in a gradient distribution into the medium-manganese steel, so that the surface modification purpose is achieved, and then the corrosion resistance is effectively improved.

The invention discloses an epoxy resin coating based on a fluorine-containing alternating polymer and a preparation method thereof, and the preparation method comprises the following steps: carrying out polymerization reaction on alpha, omega-non-conjugated diene containing a benzene ring structure and alpha, omega-diiodo perfluoroalkane in the presence of a catalyst and an organic solvent to obtain the fluorine-containing alternating polymer; the surface of a base material is coated with a composite coating obtained by dispersing the fluorine-containing alternating polymer, epoxy resin, a curing agent and auxiliaries in a solvent, and the epoxy resin coating based on the fluorine-containing alternating polymer is obtained after curing treatment. According to the invention, the excellent strong acid resistance and strong gamma ray irradiation resistance of the coating can be synchronously realized through the single-component modifier (fluorine-containing alternating polymer), meanwhile, the mechanical property of the coating is guaranteed, and the service cycle of the coating is remarkably prolonged.

The present application relates to a kind of preparation methods of modified graphene oxide polyurethane composite, modified graphene oxide polyurethane composite prepared using the method and its application.The preparation method of the present application includes: graphene oxide is reacted with 4-(trifluoromethoxy) phenyl isocyanate to obtain modified graphene oxide;Toluene group-2,4-diisocyanate end-capped poly (propylene glycol), adipic acid dihydrazide is mixed with four hydrogen bond monomers, to obtain polyurethane base material;Modified graphene oxide is added to polyurethane base material and mixed uniformly, to prepare modified graphene oxide polyurethane material.By the method of the present application, functionalized graphene polymer composite anticorrosive material with self-repairing, strong mechanical properties can be prepared.The preparation method of the present application is simple, and the modified graphene oxide polyurethane composite prepared has higher self-repairing anticorrosive efficiency.

The application relates to the technical field of zinc oxide materials, and discloses zinc-based isomeric zinc oxide as well as a preparation method and application thereof. The zinc-based isomeric zinc oxide is used for ship antifouling paint, and the zinc-based isomeric zinc oxide comprises a crystal nucleus layer, the chemical general formula of the crystal nucleus layer is: [(ZnO) x (Si a , Mg b , Zn c , Ni d )Al2O 4z ] y , x=0.5-1.2, a=0.1-0.3, b=0.05-0.15, c=0.2-0.4, d=0.02-0.08, z=0.8-1.2, and y=0.9-1.1. The zinc-based isomeric zinc oxide contains zinc oxide phases and zinc-based spinel solid solution phases, the two phases form low-energy coherent interfaces through interface reconstruction, the release rate of zinc ions can be controlled, marine toxicity caused by explosive release can be avoided, marine organism adhesion can be reduced, the powdering degree of the antifouling paint coating can be reduced, and the corrosion current density can be reduced, and therefore the zinc-based isomeric zinc oxide is suitable for environmentally-friendly ship antifouling paint.

The application relates to a preparation method of a magnesium alloy stent composite coating and belongs to the technical field of biomedical materials. In view of the technical problem that an existing polyester coating produces acid by degradation, and accelerates corrosion of a magnesium alloy stent, a composite coating with piezoelectric-pH synergistic protection function is provided. The coating comprises a PVDF-g-APTES primer layer, a pH regulating intermediate layer composed of PVDF, PDLLA and alkaline nanoparticles, and a drug-loaded PDLLA outer coating. The application actively increases the interface pH to the passivation zone by on-demand release of alkaline nanoparticles, and realizes the positive feedback mechanism of "the more stress, the more protection" by using the piezoelectric effect. Compared with the prior art, the dynamic corrosion resistance of the application is increased by more than 40%, the synergistic effect makes the protection effect increased by more than 60%, the piezoelectricity and alkalinity are synergistically protected, a long-acting corrosion-resistant and intelligent response comprehensive solution is provided for the degradable magnesium alloy implant device.

The application discloses a buckle type square tube for a semiconductor frame and a production process thereof, relates to the technical field of buckle type square tubes, and discloses a buckle type square tube for a semiconductor frame and a production process thereof, which is aimed at the problems of easy corrosion and abrasion of Q345 square tubes in a semiconductor workshop, corrosion dust pollution of components and devices, adopts a base material step-by-step polishing pretreatment, an aluminate system plasma electrolytic oxidation to prepare a ceramic bottom layer, and a composite process of a multiphase joint surface layer prepared through hydrothermal and liquid phase deposition, and has excellent wear resistance and all-weather corrosion resistance. The application solves the defects of weak bonding force of single surface treatment, and the incapability of corrosion resistance and wear resistance to cooperate, is suitable for complex working conditions of the semiconductor frame, has no dust pollution, and greatly improves the service life.