118 results about "Anodic dissolution" patented technology

In chloride media, copper anodic dissolution is a mature process for producing cuprous oxide (Cu2O); and based on the preparation process, the invention provides a method for directly growing a one-dimensional nanometer Cu2O array on an anode metal copper substrate through adding a surface active agent to an anode slot, and controlling the concentration of electrolyte chloride salt in the anode slot, the concentration of alkali in a cathode slot, electric quantity of electrolysis and electrolysis temperature. The array has controllable appearance, and consists of a nanometer belt, a nanometer plate and a nanometer line, wherein the top end of the one-dimensional array can be acicular, circular, and the like. The one-dimensional nanometer Cu2O array directly growing on the copper substrate has excellent effect of field emission performance and visible light catalysis, and has wide application prospect in technical fields of vacuum microelectronic devices, panel display, advanced oxidation and other aspects.

It is a task of the present invention to provide an electrolytic apparatus for producing fluorine or nitrogen trifluoride by electrolyzing a hydrogen fluoride-containing molten salt, the electrolytic apparatus being advantageous in that the electrolysis can be performed without the occurrence of the anode effect even at a high current density and without the occurrence of an anodic dissolution. In the present invention, this task has been accomplished by an electrolytic apparatus for producing fluorine or nitrogen trifluoride by electrolyzing a hydrogen fluoride-containing molten salt at an applied current density of from 1 to 1,000 A / dm2, the electrolytic apparatus using a conductive diamond-coated electrode as an anode.

The invention relates to online preparing system and method for an electrochemical grinding micro tool for a line electrode, belonging to the field of micro electrochemical machining. A microscale line electrode is fixed in an electrolyte tank and is tensioned by a micro tension device, and a tool electrode is connected onto a numerical-control rotary main shaft; the electrolyte tank is filled with electrolyte, the microscale line electrode and the tool electrode are immersed in the electrolyte, both the microscale line electrode and the tool electrode maintain a machining gap, and a pulse width power supply is connected; and by utilizing a principle that metal generates electrochemical anodic dissolution in the electrolyte, the tool electrode is corroded for molding. In the machining process, the numerical-control rotary main shaft is utilized to enable the tool electrode to generate rotation of certain angular speed or perform indexing, meanwhile a three-axis motion platform is utilized to generate uniform-speed feeding in a Z-axis direction so as to obtain the micro tool with a needed section shape. In size control, a current sensor is used for collecting and machining current in a loop, the size change of tungsten filaments in the corrosion process is reflected by utilizing the corresponding relationship of machining current and tungsten filament resistance, and therefore the size is accurately controlled.

The invention relates to an electrolytic milling-grinding machining tool cathode with efficiency and precision and an electrolytic milling-grinding method, and belongs to the field of electrolytic milling-grinding composite machining. According to the electrolytic milling-grinding machining tool cathode and the electrolytic milling-grinding method, a plurality of arc-shaped grooves at equal intervals are formed in the lower end of the side wall of the tool cathode, the side walls of the grooves are insulated, and diamond abrasive particles are inlaid in the wall surfaces of the portions, except for the grooves, of the side wall of a cathode base body through a resin binder, so that electrochemical anodic dissolution only exists in the surfaces of the portions, opposite to the grooves, of aworkpiece, at the moment, the depths of the grooves become a part of a machining gap, accordingly the contact depth between the diamond abrasive particles in the portions, except for the grooves, ofthe side wall of the cathode base body and the machining surface of the workpiece is increased, then the grinding effect of the diamond abrasive particles on the workpiece in the electrolytic milling-grinding process is enhanced, and the precision and the surface quality of the electrolytic milling-grinding machining can be improved; and moreover, compared with the electrolytic milling-grinding finish machining under the low current density in the past, the tool cathode can adopt higher current density, and the machining efficiency can be improved.

The invention discloses an electrochemical machining device and method for an internally-oblique micro line segment gear. The electrochemical machining device comprises a power system, a PLC control system, an electrolyte circulating filtration system, a numerical control rotary table, a cathode system and a workpiece clamp. According to the method, a sheet-shaped cathode which is machined by a high-precision linear cutting machine and has the thickness of 1mm is used, and the gear outline shape on a tool cathode is obtained by the fact that a workpiece inner gear shape to be machined and formed is offset to the inner side by a machining gap delta in the radial direction; in the machining process, the tool cathode makes rotating movement around a shaft while being fed downwards in the radial direction, and workpieces are machined according to an electrochemical anodic dissolution principle; the spiral angle of an inner gear is guaranteed by the speed ratio of axial feeding and rotary feeding around the shaft, and when the spiral angle of the gear is changed, corresponding angle machining can be achieved through change of the speed ratio of the axial feeding and the rotating movement around the shaft. The electrochemical machining device and method are beneficial to improving the machining efficiency and the gear forming precision.

The invention relates to an inserted sheet type composite tool and an electrochemical and mechanical composite machining device and a machining method thereof. The composite tool of the invention comprises an inserted sheet and a substrate. The inserted sheet is fixed on the substrate. The composite tool of the invention has the advantages of simple fabrication, easy replacement of the inserted sheet, adjusting the inter-electrode gap and the ratio of the electrolysis area and the grinding area of the machining process by adjusting the geometric parameter of the inserted sheet and the substrate, simultaneously adopting the little grinding particle as possible according to the material to be machined, and consequently achieving the higher surface roughness. The composite machining device of the invention comprises a mechanical movement mechanism, a control system and an electrolyte supply system, wherein the mechanical movement mechanism comprises a mechanism enabling the composite tool to do the self-rotation motion, and a mechanism enabling the composite tool to do the upward and downward, front and back, and left and right motion relative to the workpiece. The machining process of the invention utilizes the principle of electrochemical anode dissolution and the mechanical film scraping to remove the metal. For the difficult-machining material, the machining method has the advantages of small tool loss, high machining efficiency and high machining accuracy.

The invention relates to a preparation method of Al-based Pb-WC-CeO2 inert composite anode material. The Al (aluminium alloy) -based Pb-WC-CeO2 inert composite anode material which is doped with micron tungsten carbide (WC) and nano ceric oxide particles is prepared by methods of chemical plating and composite plating. The anode material takes on gray black on the surface and has the plating thickness of 100-200mu m. Compared with the traditional lead and lead-based alloy anode, the composite anode material increases the surface roughness so as to enlarge the specific surface area, and improves the using efficiency of the anode; when being used for non-ferrous metal electrowinning, the electrode material reduces the bath voltage by 0.2-0.4V, improves the current efficiency by 1.5-2.5% and effectively reduces the power consumption; meanwhile, the anodic dissolution speed is slowed down by half, so that the pollution for cathode products caused by anodic lead dissolution is effectively reduced; and the invention is added with tungsten carbide particles with good electro-catalysis activity and electrical conductivity, thus not only guaranteeing the performance of material, but also improving the hardness and the wear resistance of an anode plate and enhancing the mechanical strength.

The invention relates to a glass processing method and a glass processing system. According to the method, a glass workpiece is soaked into a chemical solution so as to be positively charged, a tool electrode is negatively charged, rotatably moves, ultrasonically vibrates and acts on the glass workpiece, the chemical solution becomes a discharge channel between a positive electrode and a negative electrode, and hydraulic impact waves generated by the thermodynamic effect and the ultrasonic vibration of a discharge moment and electrochemical anodic dissolution co-act on the action part of the tool electrode to form a processing surface. The glass processing system comprises a direct current power supply, the tool electrode which is connected with the negative electrode of the direct current power supply, an ultrasonic vibrator which is connected with the tool electrode, an adjusting supporting seat which drives the ultrasonic vibrator to move up and down, an additional electrode which is connected with the positive electrode of the direct current power supply and positively charges the glass workpiece, and a chemical solution tank which is used for holding the glass workpiece. The glass processing method and the glass processing system have the advantages that higher-accuracy and higher-efficiency glass micro-pore groove processing can be realized; meanwhile, an implementation method is low in cost, and an implementation system is simple in structure and is easy to mount and maintain.

The invention provides a preparation method of a stainless steel-based beta-PbO2-SnO2-CeO2-ZrO2 inertia composite anode material. The preparation method comprises the steps of: firstly pre-processing a stainless steel based material, then immersing the stainless steel based material in an acidic system for etching and activating the stainless steel based material, and finally preparing the stainless steel-based beta-PbO2-SnO2-CeO2-ZrO2 inertia composite anode material through electrolytic deposition. The inertia composite anode material has an ash black surface, compact surface crystallization and plating thickness of 120-170mu m, and the binding force between the plating and a substrate is excellent. According to the method, the pollution of traditional lead and lead-base alloy anodic dissolution to a cathode chromium plating is avoided, and the quality of cathode products is improved; the electro-catalysis activation of the electrode material is improved due to addition of tin dioxide with good electro-catalytic activity and electrical conductivity, the cell voltage is stable, and power consumption is effectively reduced; the oxidization of trivalent chromium in an electroplating surface is effectively inhibited due to addition of zirconium dioxide, so that the stability of a plating solution is greatly improved, and the service life of the plating solution is greatly prolonged; and grains of the anode material can be refined due to addition of rear-earth oxide CeO2 so that the plating is more compact, and the corrosion resistance of the anode material can be effectively improved.

Anode applicators include consumable anodes, that can be operated in a non-stationary mode and are insensitive to orientation, are used in selective plating / brush electrodeposition of coatings or free-standing components. The flow-through dimensionally-stable, consumable anodes employed are perforated / porous to provide relatively unimpeded electrolyte flow and operate at low enough electrochemical potentials to provide for anodic metal / alloy dissolution avoiding undesired anodic reactions. The consumable anodes include consumable anode material(s) in high surface area to reduce the local anodic current density. During electroplating, sufficient electrolyte is pumped through the consumable anodes at sufficient flow rates to minimize concentration gradient and / or avoid the generation of chlorine and / or oxygen gas and / or undesired reaction such as the anodic oxidation of P-bearing ions in the electrolyte. The active consumable anode material(s) can have a microstructure which is fine-grained and / or amorphous to ensure a uniform anodic dissolution.

The invention relates to the technical field of water purification and particularly relates to a method for efficiently removing sulfide in water and a special device for the method. Two-stage electrochemical treatment is carried out by using a two-stage chemical treatment device, and iron or iron alloy is used as an anode in the two-stage electrochemical treatment, wherein high-concentration sulfide in water is treated in the first-stage electrochemical treatment stage by means of the oxidation effect of the anode and the sedimentation effect of ferrous irons generated by dissolving iron anodes, and low-concentration sulfide in water is rapidly and thoroughly removed through adding a proper amount of hydrogen peroxide before second-stage electrochemical treatment by means of ferrous ions generated by uniformly dissolving the hydrogen peroxide and the anode, fenton reaction generated by electrochemical effects and an electrocatalytic effect. When the method is used for treating sulfide-contained wastewater or domestic drinking water, the removal rate of sulfide can be more than 99.9%. Generally speaking, after sulfide-contained wastewater and domestic drinking water are treated by using the method provided by the invention, the content of sulfide can be respectively up to the discharging standard and the drinking water standard.

Pad-assisted electropolishing of the substrate is conducted by performing anodic dissolution of metal at a first portion of the substrate and simultaneously mechanically buffing a second portion of the substrate with a buffing pad. Anodic dissolution includes forming a thin liquid layer of electropolishing liquid between the anodic substrate and a cathodic electropolishing head. The location of electrical contacts between the substrate and power supply allow peripheral edge regions of the substrate to be mechanically buffed with the pad. Preferably, a substrate is further planararized using an isotropic material-removal technique. An apparatus includes an electropolishing head that is movable to a position proximate to a first portion of a substrate to form a thin gap, and a buffing pad that mechanically buffs a second portion of the substrate using minimal pressure.

The invention relates to a preparation method and application of an organic sulfur conversion catalyst. With use of an electrochemical synthesis method, metal ions dissolved through an anode and an organic ligand 1,3,5-benzenetricarboxylic acid in a solution are self-assembled to form a metal-organic framework material (MOF). The method can avoid introduction of metal salt anionic impurities, the synthesis conditions are mild, the reaction is rapid, and the consumed time is short. The preparation of the catalyst is simple and convenient and comprises the steps: taking a metal Cu elementary substance as an electrode, placing in an ethanol-water solution containing the 1,3,5-benzenetricarboxylic acid (H3BTC) organic ligand and a tetrabutylammonium perchlorate (TBAP) support electrolyte, communicating a circuit, carrying out an electrolytic reaction, and thus generating a pure Cu-MOF (HKUST-1) material. The prepared HKUST-1 has an octahedral structure, has the advantages of geometric symmetry, high utilization ratio and relatively high catalytic activity at a temperature of 150 DEG C, and is suitable for medium-low temperature catalytic hydrolysis of carbonyl sulfide gas.

The invention relates to a method for preparing a solution of tin methane sulfonate for electroplating. The method is characterized by comprising the following steps that: 1) an anion exchange membrane is used for dividing an electrolytic cell into a cathode chamber and an anode chamber, wherein the electrolyte used in the anode chamber is a solution of methane sulfonic acid with the mass concentration of between 20 and 40 percent, and the electrolyte used in the cathode chamber is a solution of methane sulfonic acid with the mass concentration of between 10 and 50 percent; the anode in the anode chamber is made of a tin plate or tin flower, and the cathode in the cathode chamber is made of a tin plate or copper plate; and 2) the anode and the cathode are connected with a DC power supply for electrolysis, the electrolytic temperature is between 20 and 60 DEG C, and under the action of the DC with the voltage of 1.8 to 3V, the anode is subjected to anodic dissolution and enters the anode chamber; and when the concentration of tin ion in the anode chamber reaches between 100 and 130g / L, the electrolysis stops, and the electrolyte in the anode chamber is taken out and filtered, and the filtrate is subjected to vacuum concentration at a temperature of between 40 and 120 DEG C, so that the solution of tin methane sulfonate, of which the content of tin ion is 300 to 310g / L, can be obtained. The method has the advantages of less equipment investment, simple process and high product purity.

The invention relates to a surface roughening method of a metal material. According to the method, the metal material is subjected to anodic polarization in an electrolyte; the surface roughness of the metal material is increased by the anodic dissolution effect; the electrolyte is a water-based solution of sodium chloride of 0.02 to 100 g / L; and the anodic polarization mode is to externally add current or couple a cathodic dissimilar metal material. The method has the biggest advantages of environmental friendliness, high efficiency, energy conservation and low cost.

The invention discloses a device for processing metallic workpiece, which comprises a machine tool, a servo mechanism, an electrolyte tank, electrolyte, a workpiece, a tool, a workbench, a feeding spindle, a power supply and an agitator. The workbench is arranged on a base of the machine tool; the electrolyte tank is arranged on the workbench; electrolyte is arranged inside the electrolyte tank; the workpiece and the tool are immerged into the electrolyte; two ends of the feeding spindle are respectively connected with the workpiece and the servo mechanism; the servo mechanism is arranged at the upper end of the machine tool; the workpiece is connected with a cathode of the power supply; and the tool is connected with the cathode of the power supply. According to the method disclosed by the invention, grinding and polishing are processed by utilizing a metal electrochemical anodic dissolution principle; electrochemical pre-polishing and mechanical precise polishing are organically combined together without limitation of material hardness and toughness; various workpieces with complicated shapes can be polished, and the device has high polishing efficiency, low cost, simple operation and easiness of industrialization.

The invention provides a method for preparing a ceramic film layer with high corrosion resistance and stress corrosion resistance. Potassium oxide 1-7 g / L, sodium tetraborate 1-10 g / L, EDTA 1-10 g / L, glycerin 10-20 g / L; Micro-arc oxidation is performed on the surface of high-strength aluminum alloy, the current density is 5‑15 A / dm2, the temperature is controlled at 20‑30 °C, and the constant current micro-arc oxidation time is 10‑30 min under constant stirring. Two kinds of additives, EDTA and glycerin, are added to the electrolyte of the present invention, which greatly improves the compactness of the ceramic film layer, making it difficult for the corrosive medium to anodically dissolve the material matrix through the micro-arc oxidation film layer; greatly improving the charge migration resistance on the surface of the alloy, corrosion and The electrochemical process in the stress corrosion process is inhibited, which significantly improves the corrosion resistance and stress corrosion resistance of the 7XXX series high-strength aluminum alloy surface; the surface of the ceramic film is smooth and has a high bonding force with the substrate.

The invention provides a preparation method of a cerium-doped zinc oxide photocatalyst. The preparation method comprises the following steps that zinc is taken as the positive pole, a noble electrodeis taken as the negative pole, an aqueous solution containing conducting salt, Ce<3+> and 2-methylimidazole is taken as a conducting solution for electrolysis, and Ce / ZIF-8 is obtained; the Ce / ZIF-8 is calcined to obtain the cerium-doped zinc oxide photocatalyst. According to cerium-doped zinc oxide photocatalyst and the preparation method thereof, the zinc is taken as the positive pole, anodic dissolution occurs under the action of a certain current, Zn<2+> enters an electrolyte to react with the 2-methylimidazole to generate ZIF-8 with a porous structure, the Ce<3+> in the solution is loadedin the porous ZIF-8 structure, and calcination is carried out to prepare a Ce / ZnO photocatalyst, and the Ce / ZnO photocatalyst is applied to the field of organic pollutants of photocatalytic degradation, has good application prospects, and has a good degradation effect on methyl orange, methylene blue and the like.

The invention discloses a cutting-in type centerless grinding machining method for a ceramic material stepped shaft part. A dressing wheel is arranged at the side part of a guide wheel, tool electrodes are correspondingly arranged on the side part of a grinding wheel and the side part of the dressing wheel, when in machining, an electrolytic mode is adopted to enable a metal bonding agent on the surface of the grinding wheel and the dressing wheel to occur anodic dissolution so as to realize online synchronous dressing and the grinding wheel and the dressing wheel are enabled to be dressed onthe same reference, and then higher dressing precision is guaranteed on a mechanical structure; and in addition, online electrolytic dressing can avoid surface passivation and blockage of the grindingwheel, the grinding wheel can maintain good grinding performance for a long time, meanwhile, the online dressing of the guide wheel stabilizes the contact friction coefficient of the guide wheel anda workpiece, thereby obtaining higher workpiece machining precision and guaranteeing the surface quality of the workpiece, and meanwhile, higher machining efficiency is obtained. Correspondingly, theinvention further provides a cutting-in type centerless grinding machining device for the ceramic material stepped shaft part. The device can realize efficient and high-precision grinding machining ofthe ceramic material stepped shaft part.

The invention provides a method for making holes through electric spark-electrolysis combination via matching of thread pipe electrode with inner and outer liquid flushing. At the electric spark high-speed hole making machining stage, an electric spark pulse power source is connected, the inner liquid flushing manner is adopted for leading in of deionized water, in cooperation with rotation of thethread pipe electrode, meanwhile, downward feeding is carried out, when the interpolar distance is up to the electric spark discharge gap, a pulse electric spark is generated, a workpiece material issubjected to corrosion removing, through thread rotation disturbance and upward action force of a thread groove on electric corrosion solid small particles, the electric corrosion solid small particles can be rapidly and upwards discharged, when a workpiece is subjected to breakdown, the electrode station is kept unchangeable, an electrolysis power source is connected, outer liquid flushing is replaced, an outer nozzle is aligned with the gap to spray an electrolyte, in cooperation with reverse rotation of the thread pipe electrode, the thread groove can contain more electrolyte to enter thenarrow and small gap, the workpiece has the anodic dissolution reaction, electrolytic flocs can be rapidly and downwards discharged under extrusion of the thread groove, micro hole manufacturing highprecision and high efficiency can be ensured, and the hole wall non-micro-crack and non-recast-layer machining needs can be achieved.

The invention belongs to the field of renewable resources and particularly relates to a Nd-Fe-B waste solution electrolysis regeneration method. The Nd-Fe-B waste solution electrolysis regeneration method comprises the steps of firstly, removing an anticorrosive layer on the surface of a Nd-Fe-B dismantled waste material; gathering the waste materials into a whole through the Nd-Fe-B magnetism toserve as an anode of an electrolysis system, wherein in the electrolytic process, the anode is dissolved, rare earth and iron ions go into a solution, the iron ions are separated out at a cathode to become high-purity iron, and the rare earth is enriched in electrolyte in an ionic state; and recycling rare earth elements in the electrolyte in a solvent extraction mode after completion of electrolysis and producing rare earth oxides or further producing rare earth metals. Through the Nd-Fe-B waste solution electrolysis regeneration method, a high-purity electrolytic iron product can be directlyrecycled in the electrolytic process, Nd, La, Dy and other rare earth ions left in the electrolyte are separated through extraction, the technological process has the requirement for the temperatureand can be implemented at normal temperature, and the high value-added utilization of iron and rare earth is realized.

The invention relates to a preparation method of an ordered mesoporous carbon-tungsten coating for proton exchange membrane fuel cell stainless steel bipolar plate protection. The preparation method comprises the following steps: dissolving a surfactant in absolute alcohol, and stirring; adding a phenol formaldehyde resin ethanol solution in a dropwise manner, and uniformly stirring to provide a spare use; dissolving silicotungstic acid in absolute alcohol, and stirring to obtain a solution to provide a spare use; uniformly mixing the two solutions to obtain a transparent yellowish carbon-tungsten solution; adding the carbon-tungsten solution on a stainless steel sheet in a dropwise manner drop-to-drop, and carrying out treatments such as glue adding in a dropwise manner and glue uniformization; carrying out solvent evaporation on the solution-coated stainless steel sheet for at least 8 h at a temperature of 25 DEG C, and then carrying out thermal polymerization for at least 24 h at a temperature of 70-120 DEG C to form a yellowish coating on the surface of the stainless steel; and finally carrying out carbonization to obtain the black ordered mesoporous carbon-tungsten coating. According to the preparation method, the ordered mesoporous carbon-tungsten electric conduction coating is formed on the surface of the stainless steel bipolar plate so as to protect stability of a passivation film, inhibit anode dissolution of the stainless steel bipolar plate, and improve output power and a service life of a proton exchange membrane fuel cell.

The invention relates to a method for preparing iron-aluminum hydrotalcite through a sacrificial anode method. The method for preparing the iron-aluminum hydrotalcite comprises the steps that an ironelectrode and an aluminum electrode are arranged in an electrolytic tank, an electrolyte solution in added into the electrolytic tank, then direct current is introduced for an electrolysis reaction, and after precipitation and drying, the iron-aluminum hydrotalcite is obtained. Compared with the prior art, the iron electrode and aluminum electrode are used as anodes, the iron-aluminum hydrotalciteis prepared through the one-step reaction by means of the sacrificial anode method, ompared with a commonly used coprecipitation method, metal salt is completely made from anodic dissolution, metal salt and strong alkali do not need to be added additionally, the anaerobic environment does not need to be controlled, the pH of the solution does not need to be adjusted, the reaction is mild, the operation is simple, and a large amount of the high-purity iron-aluminum hydrotalcite can be prepared, and the method has good development prospect.

Anode applicators include consumable anodes, that can be operated in a non-stationary mode and are insensitive to orientation, are used in selective plating / brush electrodeposition of coatings or free-standing components. The flow-through dimensionally-stable, consumable anodes employed are perforated / porous to provide relatively unimpeded electrolyte flow and operate at low enough electrochemical potentials to provide for anodic metal / alloy dissolution avoiding undesired anodic reactions. The consumable anodes include consumable anode material(s) in high surface area to reduce the local anodic current density. During electroplating, sufficient electrolyte is pumped through the consumable anodes at sufficient flow rates to minimize concentration gradient and / or avoid the generation of chlorine and / or oxygen gas and / or undesired reaction such as the anodic oxidation of P-bearing ions in the electrolyte. The active consumable anode material(s) can have a microstructure which is fine-grained and / or amorphous to ensure a uniform anodic dissolution.

In advanced electrolytic polish (AEP) method, a metal wafer (10) acts as an anodic electrodes and another metal plate (65) is used as a cathodic electrode. A voltage differential is applied to the anode and cathode under a predetermined anodic dissolution current density. This causes a reaction that provides a planarized surface on the metal wafers. Additives are included in the electrolyte solution (55) which adsorb onto the wafer surface urging a higher removal rate at higher spots and a lower removal rate at lower spots. Also, in another embodiment of the present invention is a pulsed-electrolytic process (260) in which positive and negative potentials are applied to the anodic and cathodic electrodes alternately, further encouraging surface planarization. AEP can be used either as a first step followed by a mechanical polish or a second step between initial CMP polish and a third step mechanical polish. The present invention may also be added as a last step of copper electroplating process and so may be used in the manufacture of all kinds of patterned metal wafers.

Pad-assisted electropolishing of the substrate is conducted by performing anodic dissolution of metal at a first portion of the substrate and simultaneously mechanically buffing a second portion of the substrate with a buffing pad. Anodic dissolution includes forming a thin liquid layer of electropolishing liquid between the anodic substrate and a cathodic electropolishing head. The location of electrical contacts between the substrate and power supply allow peripheral edge regions of the substrate to be mechanically buffed with the pad. Preferably, a substrate is further planararized using an isotropic material-removal technique. An apparatus includes an electropolishing head that is movable to a position proximate to a first portion of a substrate to form a thin gap, and a buffing pad that mechanically buffs a second portion of the substrate using minimal pressure.

The invention relates to an electrolytic rotating ultrasonic magnetic composite plane polishing device. The device comprises a manipulator, an insulating horizontal processing platform, a rotating ultrasonic device clamped by the manipulator, and a magnetic particle grinding and polishing device connected under an ultrasonic generator; one side of the rotating ultrasonic device is connected with an electrolytic polishing device through a fixed clamp holder; a to-be-processed workpiece is clamped on the insulating horizontal processing platform; the rotating ultrasonic device, the electrolyticpolishing device and the magnetic particle grinding and polishing device simultaneously polish the plane of the to-be-processed workpiece; firstly, the material on the surface of the to-be-processed workpiece is softened through an electrochemically anodic dissolution reaction, so as to generate a passivation film, the hardness of which is lower than that of a matrix of the to-be-processed workpiece; the passivation film weakens the anodic dissolution reaction and then the passivation film is removed by using a magnetic particle grinding method, so as to continue the dissolution of the electrolytic anode; and the rotating ultrasonic device provides intermittent grinding pressure to achieve the polishing of the to-be-processed workpiece. The device has good surface polishing effect for cemented carbide.

The invention provides a preparation method of a low-valence halide of a variable-valence metal. The preparation method comprises the steps that a high-purity simple substance of variable-valence metal or an aluminum alloy of the variable-valence metal serves as an anode, AlX3-MX is used as a molten salt electrolyte, the molten salt electrolyte is heated and molten, then constant-temperature electrolysis is conducted so as to obtain the low-valence halide of the variable-valence metal, wherein X is one of I<->, Br<-> and Cl<->, and M is one of K<+>, Na<+> and Li<+>. A preparation method provided by the invention has universality and can be used for preparing the low-valence halide of most transition metal elements in the periodic table of elements; the problems of complex preparation and high cost of the low-valence halide in the prior art are solved, and the preparation rate of the low-valence halide can be increased by controlling reaction conditions; the low-valence halide of metalor alloy can be directly prepared through anodic oxidation, only the electrolytic voltage needs to be controlled in the anodic dissolution process, and the purity can be improved through reduced pressure distillation. The method has advantages of simple operation, mild reaction condition, low equipment requirement, good economy and high practicability.