1195 results about "Plasma electrolytic oxidation" patented technology

The invention discloses a composite wear-resistant antifriction coating on a titanium alloy surface and a preparation method thereof. The coating comprises a laser texturing surface, an oxide ceramic layer and a self-lubricating coating which are connected in sequence, wherein micropore arrays are uniformly distributed on the laser texturing surface; the oxide ceramic layer is a hard oxide ceramic coating; and the self-lubricating coating is a MoS2 coating, PTFE (polytetrafluoroethylene) coating or graphite coating. In the invention, the laser surface texturing technology is combined with the plasma electrolytic oxidation technology, and a texturing / ceramization composite coating is prepared on the titanium alloy surface which is then coated with a solid lubricant to improve the friction performance of the surface.

The invention provides a method for processing the surface of magnesium-lithium alloy. The technique of micro-arc oxidation is successfully applied to processing the surface of the magnesium-lithium alloy. Direct current / DC pulse / alternating current pulse multiplex power supply is used and the magnesium-lithium alloy with different lithium contents in a compound electrolyte system of sodium polyphosphate, sodium silicate, calgon and sodium hydroxide is carried out by micro-arc oxidation for 2-120min. A ceramic oxide film of 10-100Mum with a rigidity higher than 200Hv is formed in situ on the surface of the magnesium-lithium alloy, thus remarkably improving corrosion resistant property compared with an alloy matrix, solving the problem known at home and abroad concerning processing the surface of the magnesium-lithium alloy and broadening the application in the fields of aviation, aerospace, car, electronic, etc.

The invention discloses a method for preparing an environment-friendly micro-arc oxidation black ceramic film on an aluminum alloy surface, and the method comprises the following steps: firstly, pouring deionized water into an oxidation tank, weighing 1-10g / L of sodium hexametaphosphate, 1-3g / L of sodium silicate, 0.5-2g / L of potassium hydroxide, 0.2-2g / L of sodium fluoride and 0.5-20g / L of ferric ammonium oxalate in terms of the volume of the added deionized water, and uniformly stirring and mixing the sodium hexametaphosphate, the sodium silicate, the potassium hydroxide and the sodium fluoride to obtain a micro-arc oxidation base electrolyte; adding the weighed ferric ammonium oxalate into the base electrolyte, and stirring and mixing uniformly to obtain an aluminum alloy micro-arc oxidant solution; and then, sequentially carrying out surface deoiling and cleaning, water washing, aluminum alloy micro-arc oxidation, sealing and drying on the aluminum alloy to prepare the environment-friendly micro-arc oxidation black ceramic film on the aluminum alloy surface. By means of the preparation method disclosed by the invention, the problems of single color, limited application range, and environment pollution caused by a vanadate electrolyte, of the existing aluminum alloy ceramic film layer, are solved.

The invention discloses a method for preparing an antisepsis and antiwear ceramics coating layer on the surface of alloy through microarc oxidation. The method includes three steps of collocating electrolyte, arranging power electric parameters and microarc oxidation treatment; wherein, the component concentrations of the electrolyte are sodium silicate of 20 to 100g / L, sodium hydroxide of 5 to 10g / L and organic amine additive of 5 to 15ml / L; the current density of unit area is 50 to 100A / centiare; the pulse frequency is 100 to 700Hz; the pulse dutyfactor is 20 to 90 percent; the temperature of the electrolyte in the microarc oxidation treatment is not higher than 45 DEG C. The method needs lower unit power density and has fast film forming speed to prepare the ceramics coating layer on the surface of aluminum and magnesium alloys; the method adopts 100KVA power which can treat at least 2 centiares of the surface area of the aluminum alloy for one time; the growing speed of the ceramics coating layer can reach 1 to 1.5 micron / min. The formed ceramics coating layer is uniform and compact; the rigidity of the aluminum alloy can reach 1200 to 1300Hv.

The invention discloses a method for preparing biomedical titanium and titanium alloy surface antibacterial coatings. The method comprises steps of firstly, processing the surface of a biomedical titanium or titanium alloy sample to be processed, immersing the biomedical titanium or titanium alloy sample in a glycol aqueous solution containing soluble fluoride and performing an anode oxidation treatment; secondly, immersing the biomedical titanium or titanium alloy sample after being subjected to the anode oxidation treatment in a silver nitrate solution, taking out the biomedical titanium or titanium alloy sample, using ultraviolet light radiation to process the biomedical titanium or titanium alloy sample and obtaining the silver-carrying biomedical titanium or titanium alloy sample; and performing a micro-arc oxidation treatment for the silver-carrying biomedical titanium or titanium alloy sample, performing ultrasonic cleaning and vacuum drying and obtaining the antibacterial coatings. The nano precoating layer preparation, the silver-carrying treatment and a micro-arc oxidation technology are combined, then a large amount of silver can be fixed on the biomedical titanium and titanium alloy sample surfaces and can be released slowly for a long time, the antibacterial performance of titanium and titanium alloys is greatly improved, the antibacterial effect can be kept for a long time, and the bacterial infection caused by the fact that a titanium and titanium alloy apparatus is embedded in a human body is greatly reduced or avoided.

The invention relates to a new method for preparing an antibiotic bioactive coating material on the surface of titanium alloy and magnesium alloy by ultrasonic-microarc oxidation composite technology, which can be used for obtaining a biological coating material which is compact at the bottom layer and is porous at the surface layer, wherein Ca, P and Ag contained in the coating can improve the bioactivity and the corrosion resistance of magnesium and titanium, and reduce bacterial infection caused by implantation. The invention can meet the requirements of bearing bones of human beings for mechanical properties of implanted materials, and can overcome disadvantages of the traditional surface modification method for biologic materials. In the coating composite material, the coating thickness of titanium alloy is 50-85 mu m, the surface hole diameter is 4-25 mu m, the porosity is 20-30%, and the bonding strength between the coating and the matrix is 23-40 MPa. The coating thickness of magnesium alloy is 16-22 mu m, the surface hole diameter is 5-28 mu m, the porosity is 21-30%, and the bonding strength between the coating and the matrix is 8-20 MPa.

The invention relates to an aluminum alloy which comprises an aluminum alloy matrix and a micro-arc oxide ceramic membrane formed on the surface of the matrix, wherein the ceramic membrane comprises a bottom transition layer, a middle compact layer and a surface compact layer. The preparation method of the aluminum alloy, which is used for forming the micro-arc oxide ceramic membrane without a loose layer on the surface of the aluminum alloy, comprises the following steps: putting the aluminum alloy matrix in an oxidation tank containing electrolyte; carrying out initial oxidation treatment for the aluminum alloy matrix by adopting constant current; and continuously applying oxidation treatment to the aluminum alloy matrix by adopting positive and negative bidirectional pulse voltage, wherein positive and negative voltage keeps constant after rising to the maximum value, wherein the maximum constant positive voltage is 450V-650V, the maximum constant negative voltage is 30V-200V, the width of positive and negative pulse is 1000-10000mus, the pulse interval is 300-2000mus, the continuous oxidation treatment time is 30-180min, and the treatment temperature is between 20 DEG C and 50DEG C.

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 belongs to the field of micro-arc oxidation, and relates to micro-arc oxidation electrolyte. The electrolyte comprises the aqueous solution of film former and toner, and has the pH value of 6.0 to 12, wherein the film former is phosphate and / or silicate; the toner is a titanium compound; and the film former content is 5 to 50 g / L, and the toner content is 5 to 30 g / L. When used for performing micro-arc oxidation on light metals, the micro-arc oxidation electrolyte provided by the invention can form blue ceramic films on the surfaces of the light metals so as to break the limitation of the conventional micro-arc oxidation technology to colors, expand grey-black and grey-white tones to colorful fields with uniform colors and achieve the decoration effect of a light-metallic product. Moreover, by the invention, the erosion resistance, the pollution resistance and the compactability of the micro-arc oxidized film are enhanced, and the surface of the micro-arc oxidized film has a ceramic texture. The invention further discloses a micro-arc oxidation method.

The invention discloses a micro-arc oxidation electrolyte and a micro-arc oxidation method. The micro-arc oxidation electrolyte comprises the following components: a basic solution, a wear-resisting agent, a pore sealing agent and a dispersing agent, wherein the basic solution is phosphate and silicate aqueous solution of pH 8-12, the wear-resisting agent is graphite powder, the pore sealing agent is silica powder or alumina powder, and the dispersing agent is polyoxyethylenealkylphenol ether. The micro-arc oxidation electrolyte of the invention is simple in composition, and easy in control. Light metal parts to be plated are subjected to micro-arc oxidation using the micro-arc oxidation electrolyte of the invention, and are directly subjected to pore sealing treatment in the micro-arc oxidation process without after-treatment. The process of the invention is simple, and obtained micro-arc oxide film layer is high in hardness, and is good in abrasion resistance and corrosion resistance.

The present invention relates to a process for preparing hydroxylapatite bio-ceramic membranes at titanium or titanium alloy surfaces by utilizing differential arc oxidation process. Firstly, preparing electrolytic solution A by using calcium ion salts and phosphate radical ion-containing salts, or preparing electrolytic solution B by adding metal silver ions to the electrolytic solution A; or preparing electrolytic solution C by adding metal silicon ions to the electrolytic solution A; and then, selecting titanium or titanium alloy as anodes and putting them respectively into the electrolytic solution A, B and C, selecting the non-corrodible steel container for containing the electrolytic solutions as cathodes, controlling conditions such as impulse electrical source positive phase voltage, frequency for differential arc oxidation of titanium or titanium alloy, then hydroxylapatite bio-ceramic membrane layers possessing different performances are prepared. Said titanium based bio-ceramic compound material prepared according to said process possesses not only intensity and toughness of metals but also biological activity of hydroxylapatites, and is capable of being applied in the fields such as jackstraw chirurgery implantation body and tooth planting body.

The invention discloses a method for preparing magnesium alloy super-hydrophobic surface. The method comprises: cleaning the magnesium alloy after conventional pretreatment, adopting the micro-arc oxidation technique to form a roughening micro / nano porous surface on the surface of a sample in a phosphate electrolyte, treating the surface in an acrylic acid solution, performing spin coating of ethylene dimethyl silicone polymer on the surface, and drying the processed sample to prepare the magnesium alloy super-hydrophobic surface.

The invention relates to an environmentally-friendly magnesium alloy chemical conversion film, microarc oxide film hole sealing solution and a hole sealing method. The hole sealing solution comprises phytate or phytic acid and one or more following substances of alkali metal hydroxide, silicate, phosphoric acid or phosphate. The hole sealing method is operated according to the following steps: preliminary treatment; chemical conversion or micro-arc oxidation; post treatment: in phytate, one of or several kinds of silicate, phosphoric acid or phosphate are added, the pH value of solution is adjusted by the alkali metal hydroxide or ammonia water, solution temperature is controlled at 30-100 DEG C, and hole sealing treatment is carried out. The hole sealing solution used by the invention does not contain Cr6 and F-, thus causing no pollution to environment. After sealing holes, the size of the crack or the micropore of the chemical conversion film or oxide film is obviously decreased, and corrosion resisting property is improved; meanwhile, the film layer and the organic coating obtained by next-step painting have favourable adhesive force.

There is disclosed a process and apparatus for carrying out plasma electrolytic oxidation of metals and alloys, forming ceramic coatings on surfaces thereof at a rate of 2-10 microns per minute. The process comprises the use of high-frequency current pulses of a certain form and having a given frequency range, combined with the generation of acoustic vibrations in a sonic frequency range in the electrolyte, the frequency ranges of the current pulses and the acoustic vibrations being overlapping. The process makes it possible to introduce ultra-disperse powders into the electrolyte, with the acoustic vibrations helping to form a stable hydrosol, and to create coatings with set properties. The process makes it possible to produce dense hard microcrystalline ceramic coatings of thickness up to 150 microns. The coatings are characterised by reduced specific thickness of an external porous layer (less than 14% of the total coating thickness) and low roughness of the oxidised surface, Ra 0.6-2.1 microns.

The invention relates to the means of active biological film, especially the titanium radicel porous nanometer Strontium hydroxyapatite active biological film and the Process for the manufacture. The differential arc oxidation technology is used in the method, the film is generated in the surface of titanium and titanium alloy, a electrolyte solution with phosphate radical ion, calcium ion and Strontium ion is supplied; the titanium and titanium alloy is the anode and the rustless steel or the titanium is the cathode, the direct current power supply or the direct current impulsing power source is applied to differential arc oxygenize the titanium and titanium alloy; the oxidate time is 3-60min; the temperature of electrolyte is not above 50DEG C. There is no interface between the porous hydroxyapatite containing Strontium film produced by the invention and the basal body, the modulus of elasticity is approximate with the sclerotin, the porous hydroxyapatite containing Strontium film produced by the invention which has perfect bioactivity can be the alternate material of several parts with heavy load, such as femur, hip joint and teeth root.

The invention discloses a corrosion-resistant magnesium alloy bracket and a preparation method thereof, which relate to a magnesium alloy bracket with a corrosion-resistant coating and the preparation method thereof. The bracket and the method solve the problems of low bonding strength between the coating and a substrate, poor corrosion-resistant lasting stability, low mechanical bearing capacity and poor bracket coordination and deformation ability of the traditional magnesium alloy bracket. The corrosion-resistant magnesium alloy bracket is prepared by growing a ceramic coating in situ on the surface of the magnesium alloy by a micro-arc oxidation process. The method of the invention comprises the following steps: 1, processing the magnesium alloy to make a net-like bracket and removing oil to obtain the magnesium alloy bracket; 2, performing the micro-arc oxidation reaction; and 3, cleaning and drying the bracket to obtain the corrosion-resistant magnesium alloy bracket. The product of the invention is high in hardness and relatively high in tenacity and can coordinate with a substrate bracket to deform; and the ceramic coating is insusceptible to falling off and is high in body fluid corrosion resistance, so life cycle of the embedded bracket can be prolonged to a maximum extent. The method is simple and low in cost and can realize mass production. The product of the invention is suitable for implants with complex shapes, such as brackets, and is convenient to promote and use.

The invention provides a magnesium alloy microarc oxidation-electrophoresis composite coating which consists of a ceramic layer and a deposition layer. The ceramic layer is covered on the surface of magnesium alloy through microarc oxidation treatment and the deposition layer deposits on the surface of the ceramic layer through electrophoresis treatment. The thickness of the ceramic layer is 15micrometers-35 micrometers, the surface roughness Ra is 2.0 micrometer -4.5 micrometer and the porosity factor is 15%-40%. The thickness of the deposition layer is 20 micrometers -45micrometers. The invention further provides a preparation method of the composite coating, which includes the following steps: firstly, carrying out microarc oxidation treatment on the magnesium alloy to obtain the ceramic layer on the magnesium alloy surface; and secondly, carrying out electrophoresis treatment on the magnesium alloy which is coated with the ceramic layer on the surface to obtain the microarc oxidation-electrophoresis composite coating. The magnesium alloy microarc oxidation- electrophoresis composite coating has excellent comprehensive performances and can fully satisfy the requirements for corrosion resistance and resistances to heat, humidity and the like of magnesium alloy coatings in China national defense military industry and aviation fields.

A surface treatment method of a light metal material comprises the following steps of forming a micro-arc oxide film on the surface of the light metal material, and sequentially subjecting the surface of the light metal material with the micro-arc oxide film to laser etching and anode oxidization. The light metal material obtained by the method in the invention has the advantages of very high hardness, abrasion resistance, corrosion resistance and electrical insulation, strong appearance decoration, bright and diversified color and three-dimensional pattern, thus greatly improving the additional value of the light metal material.

The present invention features that the composite ceramic film consists of two layers, the inner layer film of silicon-containing composite Mg-Al oxide and the outer layer film of Mg-Al silico-oxide of 5-70 micron thickness each. The composite ceramic film is formed through surface treatment, degreasing, neutralizing, water washing, micro-arc anodizing, water washing, drying, closing treatment or painting. The composite ceramic film has no holes and cracks, high corrosion resistance, high wear resistance and smooth surface.

The present invention relates to a magnesium alloy surface microarc oxidation method. Said method includes the following steps: (1), pretreatment; (2), preparing alkaline silicate electrolyte or alkaline aluminate electrolyte; and (3), placing the pretreated magnesium alloy in the alkaline silicate electrolyte or alkaline aluminate electrolyte and making microarc oxidation; applying DC current, continuously rising voltage, constant current, current density is 1-15 A / sq.dm, galvanization time is 5-90 min and electrolyte temperature is less than 40 deg.C.

The invention discloses pure-titanium metal surface micro-arc oxidation treatment electrolyte and an antimicrobial bioactive coating preparation method thereof, belongs to a medical titanium metal surface modification technology, and aims to provide a micro-arc oxidation treatment electrolyte which can remarkably improve pure-titanium metal surface bioactivity and coating bonding strength and a coating preparation method thereof. The electrolyte comprises a compound system including the components of calcium acetate, sodium phosphate and a zinc oxide precursor, wherein the phosphorous ion concentration is 0.5 to 1.0 M, the molar ratio of Ca to P is 0.2 to 1.0, and the designed Zn<2+> concentration accounts for 10 to 20 percent of the total concentration. A biological composite coating is directly generated on the surface of a titanium metal surface in-situ by adopting the electrolyte and a micro-arc oxidation technology. The coating has high bonding strength with a substrate, dense inner layer, coarse and porous outer layer, high bioactivity and high antibacterial property; moreover, the used raw materials are easy to obtain; the process is simple and easy to operate; and the electrolyte has stability, reusability, and low production cost and is suitable for industrial production.

The invention discloses a method for preparing a dense enhancement type ceramic membrane based on micro-arc oxidizing and laser remelting, and relates to a method for preparing a dense enhancement type ceramic membrane on the surfaces of light metals such as magnesium, aluminium and titanium and other alloys. The method is used for solving the problems that a micro-arc oxidizing surface treatment technology for preparing the dense enhancement type ceramic membrane on the surfaces of light metals such as magnesium, aluminium and titanium and other alloys cannot have low energy consumption and high membrane performance at the same time. The method comprises steps of: 1, pretreatment of basic materials; 2, working liquid preparation treatment; 3, micro-arc oxidation; and 4, laser remelting treatment of the micro-arc oxidation (MAO) membrane, and thus obtaining a sample piece of the dense enhancement type ceramic membrane. The prepared membrane has good binding force with a base body, dense tissues, low porosity, high hardness and good corrosion resistance and wear resistance; and the porosity of the membrane can be reduced to below 3%, the harness number can be improved by double times of the original MAO membrane which is not subjected to laser remelting treatment. The method can be used for preparing the dense enhancement type ceramic membrane on the surfaces of light metals such as magnesium, aluminium and titanium and other alloys.

The invention discloses a method for preparing a magnesium-based ceramic coating by micro-arc oxidation-electrophoretic deposition. The method comprises the following steps of: immersing preheated magnesium alloy taken as an anode in an electrolyte, taking a micro-arc oxidation stainless steel electrolytic cell as a cathode, adopting a direct-current pulsed micro-arc oxidation device, carrying out micro-arc oxidation for 10-25 minutes under the conditions that the electric current is 10-20A / dm<2>, the duty ratio is 37.5-50%, and the temperature of the electrolyte is 20-30 DEG C, taking out the anode, naturally drying, thus obtaining magnesium alloy subjected to micro-arc oxidation; immersing the magnesium alloy subjected to micro-arc oxidation and taken as the anode in electrophoretic deposition liquid, taking the stainless steel electrolytic cell as the cathode, adopting a pulsed power supply, carrying out electrophoretic deposition treatment for 10-30 minutes under the conditions that the voltage is 250-350V, and the duty ratio is 37.5-50%, naturally cooling, thus obtaining the magnesium-based ceramic coating. The adhesive force of the biological nanometer coating is obviously enhanced, the toughness and the corrosion resistance of the coating are improved, and the coating has certain biological activity.

The invention discloses a micro-arc oxidation-electrodeposition preparation method of a magnesium-based bioactive coating. The preparation method comprises the following steps: putting a magnesium-based base material in micro-arc oxidation electrolyte after pretreatment to perform micro-arc oxidation reaction to obtain a micro-arc oxidation coating sample; then, putting the micro-arc oxidation coating sample in electrodeposition electrolyte to perform electrodeposition reaction; and after electrodeposition, taking the sample out, and washing and drying the sample. The micro-arc oxidation-electrodeposition preparation method has the advantages that a biologic coating prepared by the method has high binding property with a base material; and the entire biologic coating has excellent corrosion resistance, bioactivity and compatibility; moreover, the formed bioactive coating is a composite coating (comprising HA, OCP, Mg3(PO3)2 and MgO); and because the composite coating comprises OCP, problems that the degradation of pure HA is difficult are avoided and only an HA crust is left after the degradation of formed magnesium alloy can be avoided.

A prorous nanometre titanium oxide based heterogeneous bioactive surface layer is prepared by micro-arc oxidizing process, that is, the aqueous solution containing Ca and P is used as electrolyte andthe Ti or Ti-alloy is oxidized by micro-arc generated by high-voltage pulse power supply. The said bioactive surface layer is composed of TiO2, calcium titanate, alpha-calcium phosphate and beta-calcium pyrophosphate and has a thickness of over 30 microns, no interface with the matrix, multi-porous nm-crystalline structure on morphology, high bonding strength, good plastic toughness, capability of inducing the formation of apatite and good bioactivity. Its advantages are more than 30 micros for thickness, no interface with matrix, high adhesion, good plastic, toughness and bioactivity, and the elastic modulus close to that of bone.

The invention belongs to the technical field of surface treatment, and relates to a preparation method of a ceramic film through chemical conversion and micro-arc oxidation of aluminum and aluminum alloy. The preparation method comprises: cleaning aluminum and aluminum alloy, and then carrying out chemical conversion treatment on the cleaned aluminum and aluminum alloy to generate chemical conversion film containing metal ions; and then placing the chemical conversion film in a micro-arc oxidation electrolyte and carrying out micro-arc oxidation treatment on the chemical conversion film to obtain dark micro-arc oxidized ceramic film. In the preparation method provided by the invention, different metal cations such as Mn<7+>, Mo<6+>, Ni<2+>, Ce<2+>, Co<2+> and Zr<2+> are introduced to formthe chemical conversion film containing the corresponding metal ion on the surfaces of the aluminum and aluminum alloy, then the chemical conversion film is placed in different micro-arc oxidation electrolytes, the micro-arc oxidized ceramic film with improved corrosion resistance is obtained by virtue of micro-arc oxidation treatment, and simultaneously the film is colored.

The invention provides an electrolyte used for micro-arc oxidation of light metal. The electrolyte is aqueous solution containing sodium hexametahposphate and sodium silicate, wherein, the electrolyte also contains cobalt sulfate and ammonium metavanadate. The invention also provides a method of micro-arc oxidation by adopting the electrolyte. By adopting the electrolyte and the micro-arc oxidation method provided by the invention, light metal products with good pollution resistance, scrape resistance and compactness can be obtained.

The invention discloses a method for preparing a microarc oxidation composite film with high corrosion resisting surface of magnesium alloy. The method utilizes the absorption and the mechanical capture effect of micropores of TiO2 sol particles in a microarc oxidation film and the instantaneous high temperature and high pressure produced by arc discharge in the microarc oxidation process to calcine and solidify the TiO2 sol particles to finally realize in-situ hole sealing effect and obtain the compact microarc oxidation composite film by introducing the prior process for preparing nano-particles, namely sol-gel into the microarc oxidation treatment on the surface of the magnesium alloy, and directly adding TiO2 sol into a microarc oxidation electrolyte.