146 results about "Metal binding" patented technology

The invention relates to the technical field of conductive copper paste, in particular to conductive copper paste prepared by combining liquid nonferrous metal with graphene and a preparation method of the conductive copper paste. The preparation method comprises the following steps: weighing nano-copper coated graphene composite powder, a liquid nonferrous metal, a binder, trifluoropropyltrimethoxysilane, an auxiliary agent and copper powder, and then preparing trifluoropropyltrimethoxysilane into a dilute solution; copper powder and the nano-copper coated graphene composite powder are mixed to obtain composite powder; the liquid nonferrous metal and the composite powder are stirred to obtain metal paste; and adding a resin solution and an auxiliary agent into the metal paste to form printing paste, and then standing and curing. According to the conductive copper paste, the liquid nonferrous metal serves as a main binding phase, the defect that the welding thrust is low due to a traditional resin system is overcome, the problems of dispersion and interface compatibility are solved through cooperation of the nano-copper-coated graphene and the silane coupling agent, and finally the conductive copper paste with extremely low resistance, high stability and ultrahigh welding thrust is obtained.

The invention relates to the field of material surface treatment, and discloses a silica gel and metal combined treatment process which comprises the following steps: S1, ultra-short pulse laser is adopted to machine a three-dimensional micro-nano composite structure on the surface of a titanium alloy, the structure comprises a periodic groove array and surface nano holes, and the surface roughness Ra of the titanium alloy is larger than or equal to 5 microns; and S2, a titanium nitride transition layer and a siloxane self-assembly molecular layer are sequentially formed on the roughened titanium alloy surface through atomic layer deposition, and a gradient chemical interface is formed. According to the method, the micro-nano composite structure is processed through ultra-short pulse laser, the interface mechanical embedding area is remarkably increased, the two-dimensional rough limitation of a traditional sand blasting process is broken through, deep barb-shaped anchoring is achieved, the anti-stripping capacity is greatly enhanced, gradient chemical bonding is formed by the atomic layer deposition titanium nitride transition layer and the amino self-assembly molecular layer, and the anti-stripping performance is improved. The thermal expansion difference is effectively buffered, and the interface high-temperature resistance is improved.

The invention belongs to the technical field of advanced metal ceramic composite materials, and particularly relates to high-toughness Ti (C, N)-based metal ceramic and a preparation method and application thereof. The high-toughness Ti (C, N)-based metal ceramic comprises the following components in percentage by weight: 50 to 70 percent of solid solution, 15 to 25 percent of metal binding phase, 0.1 to 0.5 percent of rare earth oxide or rare earth salt and 15 to 25 percent of carbide phase, the solid solution contains an amplitude-modulated decomposition structure. The solid solution hard phase with an amplitude modulation decomposition structure is reserved in the alloy containing a certain amount of metal binder, so that the metal ceramic material has higher fracture toughness, bending strength and high-temperature toughness compared with traditional Ti (C, N)-based metal ceramic under the condition that the hardness is kept unchanged.

The invention discloses a conductive paste, a metallized substrate and a metallization process for manufacturing the metallized substrate, the conductive paste comprises metal particles, the particle size of the metal particles is 0.1-10 [mu] m, and the mass ratio of the metal particles is 80-98%; in the metallization process, a copper layer is arranged on the hole wall of a through hole or a blind hole of a substrate, then conductive slurry is filled in the hole with the copper layer, heating sintering treatment is carried out, and after heating sintering is carried out in an inert gas atmosphere at the temperature of less than or equal to 300 DEG C, metal particles can be fused to form a connection structure or a eutectic structure. A reinforcing layer can be formed between the nano metal particles and the copper layer, and the reinforcing layer is a metal bonding layer or an intermetallic compound layer. The metallization mode is suitable for a through hole or a blind hole of a glass / silicon / ceramic substrate with a high aspect ratio and a micro aperture, and the technical problems that complete filling is difficult to achieve and filling defects exist in an existing electroplating process, the electrical resistivity of conductive paste is high, and the interface bonding force is insufficient can be solved.

The invention provides a steel member welding device, and relates to the technical field of welding, the steel member welding device comprises a fixing frame body, and a stabilizing support is installed at the position of the included angle of the bottom edge of the fixing frame body; a collecting cover is mounted at the bottom of the stable bracket; a collecting box is mounted at the bottom of the inner side of the collecting cover, and two collecting air pumps are mounted at the top of the collecting box; a positioning support plate is mounted at the top of the rear side of the fixed frame body; a driving motor is mounted on the front side of one end of the positioning supporting plate, and second rotating transmission rods are rotationally mounted at the two ends of the inner side of the positioning supporting plate correspondingly. The inner side of a welding seam is finely polished through the polishing wheel at the bottom of the bearing plate, dirt, rust and other impurities on the surface of the welding seam are effectively removed, it is ensured that the welding seam can contain more welding water, the welding firmness degree and the overall quality are improved, and the problems that the containing space of a molten pool is limited due to the fact that the local width of the welding seam blocked by impurities is usually narrow are solved. And metal combination in the welding seam is not sufficient.

The invention relates to the technical field of material protection, in particular to a lead-bismuth-resistant coating and a preparation method thereof.The coating is composed of a metal bonding layer, a functional transition layer and a corrosion-resistant layer, the metal bonding layer is formed by compounding a high-entropy alloy and a medium-entropy alloy, a component gradient transition structure is formed, the high-entropy alloy is a near-equal-atomic-ratio alloy of Fe, Co, Ni, Cr and Al, and the medium-entropy alloy is a near-equal-atomic-ratio alloy of Fe, Co, Ni, Cr and Al. %, and the medium-entropy alloy is a FeCoNiCr system quaternary alloy, and the content of the Al element is 5-10 at. The functional transition layer is a transition metal nitride layer; and the corrosion-resistant layer is an eutectic composite layer of rare earth oxide and stabilized oxide. Therefore, the problems of insufficient bonding strength, limited corrosion resistance, poor process stability and the like in the prior art are solved.

The invention provides a PCBN composite material and a preparation method thereof.The preparation method comprises the steps that two or more of zirconium oxide, titanium nitride, silicon nitride, titanium diboride, silicon carbide, titanium carbide, titanium carbonitride, aluminum oxide and aluminum nitride are mixed, and ceramic composite powder is prepared; the CBN micro powder and a metal binding agent are subjected to ball milling and mixing, and CBN pre-composite micro powder is prepared; mixing the CBN pre-composite micro powder with the ceramic composite powder to obtain a premix, placing the premix in a mold for pre-pressing to obtain a blank piece, and then assembling the blank piece for sintering to obtain a PCBN composite material; the mass percentage content of the ceramic composite powder is 5%-40%, the mass percentage content of the metal binding agent is 15%-30%, and the mass percentage content of the CBN micro powder is 45%-65%. According to the method, the toughness and the stability of the PCBN cutter can be improved on the premise of low content of CBN (Cubic Boron Nitride).

The invention belongs to the technical field of thermal power heating surface treatment, and provides a boiler heating surface high-temperature corrosion protective coating and a preparation method thereof in order to solve the technical problems that in the prior art, a nano ceramic coating and a metal alloy coating for treating thermal power boiler heating surface high-temperature corrosion are insufficient in adhesive force, prone to falling off and short in protection service life. Through multi-layer structure design and technological parameter optimization, a coating system has continuous thermal expansion coefficient gradient distribution in the interval of 500-900 DEG C, the metal bonding layer at the bottom layer has a pore structure which can effectively absorb thermal stress, the nano ceramic layer at the surface layer can maintain high-temperature stability, and it is verified that the overall bonding strength is larger than or equal to 35 MPa, and the thermal expansion coefficient is larger than or equal to 10%. Compared with a traditional single-layer coating, the adhesive force is improved by 200% or above, and therefore the technical problems that in the prior art, adhesive force is insufficient, thermal stress is not matched, and high-temperature softening fails can be effectively solved.

The invention relates to the technical field of grinding wheels, in particular to a copper-titanium-based aluminum oxide grinding wheel and a preparation method and application thereof. The preparation method comprises the following steps: mixing the aluminum oxide grinding material, the metal binding agent and the auxiliary binding agent to obtain a mixture; carrying out cold press molding on the mixture to obtain a green body; and sintering the green body to obtain the copper-titanium-based aluminum oxide grinding wheel. The metal binding agent comprises Cu powder, Ti powder, Nd powder and Y powder according to the mass ratio of (58-80): (20-40): (1-4): (1-4). The aluminum oxide grinding material reacts with titanium atoms in the metal binding agent to generate a titanium oxide compound and a copper-aluminum oxide compound, the holding effect of the metal matrix on aluminum oxide can be improved, the self-sharpening performance of the grinding wheel is improved, and the grinding efficiency of the grinding wheel is improved. And the Nd powder and the Y powder can effectively reduce the residual stress during sintering, inhibit hot cracks at the interface of the matrix and the aluminum oxide, and also can be used as a second phase to improve the strength of the copper-titanium matrix and improve the wear resistance of the aluminum oxide grinding wheel.

The invention discloses a precise TPI-copper-based metal composite binding agent grinding tool and a preparation method thereof. The grinding tool comprises the following components in parts by weight: 100 parts of a grinding material, 10-30 parts of a resin binding agent, 60-90 parts of a copper-based metal binding agent and 2 parts of a wetting agent. The thermoplastic polyimide TPI is added into the formula, a large number of ether bonds, alkyl groups and rigid group benzene rings are introduced into the molecular structure of the TPI, the processability of the TPI is improved, meanwhile, the defect of insufficient heat resistance is overcome, and therefore the TPI resin binding agent better in temperature matching performance with a copper-based metal binding agent is obtained. In the composite superhard grinding tool prepared from the copper-based metal binding agent and the TPI resin binding agent, the existence of the metal binding agent plays a role in supporting a framework, and the strength and hardness of the grinding tool are guaranteed; the TPI resin binding agent increases the elasticity and the self-sharpening property of the grinding tool, so that the self-sharpening property of the grinding tool in the working process is improved, and better workpiece processing surface quality can be obtained.

The utility model discloses a composite copper foil for a semi-solid lithium battery, which comprises a film layer, two sides of the film layer are respectively provided with a metal isolation layer, one side of the metal isolation layer far away from the film layer is provided with a metal combination layer, and one side of the metal combination layer far away from the metal isolation layer is provided with a conductive copper layer. And a metal protection layer is arranged on one surface, far away from the metal bonding layer, of the conductive copper layer. The weight of the semi-solid lithium battery can be reduced, the manufacturing cost of the semi-solid lithium battery can be reduced, and the service life of the semi-solid lithium battery can be prolonged.

This invention relates to the field of materials science, specifically to a method for preparing a high-bonding, ultrahard nanolayered thin film, the film itself, and its applications. The film comprises a Cr / Ti metal bonding layer, a CrTiN intermediate layer, a TiNC transition layer, and an a-C:Ti nanocomposite surface layer sequentially deposited on a substrate surface. The a-C:Ti ultrahard nanolayered thin film prepared by this invention achieves multi-layer stacking at the microscale by controlling the periodic modulation structure of the bonding layer, intermediate layer, and transition layer, effectively suppressing dislocation and crack propagation. Through Ti doping modification and gradient periodic modulation structure design, the internal stress of the film is reduced, improving its bonding strength, wear resistance, and toughness, reducing the risk of coating cracking or peeling, and enhancing the film's service stability. The a-C:Ti ultrahard nanolayered thin film of this invention is particularly suitable for applications such as precision machining tool coatings, surface strengthening of aero-engine gears and bearings, and wear protection of microelectromechanical systems (MEMS).

A coating on a process chamber component includes a metallic bond layer deposited on a surface of the component. A thermal barrier layer is deposited on the bonding layer. A substantially non-porous ceramic sealing layer is deposited on the thermal barrier layer. The sealing layer is substantially conformable to irregularities of the surface of the thermal barrier layer. The chemical composition of the sealing layer is selected to resist erosion from halogen-containing chemicals.

The invention relates to a method for preparing a structured grinding wheel through ultrasonic vibration assisted laser cladding. An ultrasonic vibration process and a laser cladding process are combined. The grinding wheel base body is connected with ultrasonic vibration equipment, and normal vibration is transmitted; metal binding agent powder and abrasive particles are mixed according to the proportion; and depositing a binding agent layer and an abrasive particle layer on the end face of the vibrating grinding wheel base body according to the determined process parameters by adopting laser cladding equipment according to the designed'impact-free track 'path. The method has the advantages of being short in period, simple in process, prominent in abrasive particle, high in abrasive particle holding force, low in grinding temperature, good in workpiece surface quality and the like, and by means of the cavitation effect of ultrasonic vibration and the acoustic streaming stirring effect, the defects that the number of defects in a laser cladding grinding wheel coating is large, and the mechanical performance is poor are avoided to the maximum extent; and meanwhile, the characteristic of high design freedom degree of the abrasive particle layer deposited through the laser cladding technology is exerted, different material binders and abrasive particles can be selected according to different scenes, the pattern of the abrasive particle layer is customized, and the method is suitable for machining difficult-to-machine materials with different requirements.

The invention discloses a water-tree-resistant ultra-high-voltage power cable which comprises a water-blocking conductor, an insulation shielding layer, a metal water-blocking layer and an outer protective layer which are sequentially arranged from inside to outside in a wrapping mode, and the insulation shielding layer comprises a wrapping conductor shielding layer, an extruded conductor shielding layer, an extruded insulation layer and an extruded insulation shielding layer which are sequentially arranged from inside to outside. The metal water-blocking layer comprises a longitudinal water-blocking layer, a metal shielding layer, a metal binding layer, a shielding wrapping layer and a radial water-blocking layer which are sequentially arranged from inside to outside, the water-blocking conductor comprises a plurality of stranded conductor units, the outer side of each conductor unit is provided with a longitudinal wrapping double-sided insulating water-blocking tape, water-blocking powder is filled among the conductor units, and the longitudinal wrapping double-sided insulating water-blocking tape is provided with a longitudinal wrapping double-sided insulating water-blocking tape. And the outer protective layer is formed by high-density polyethylene and a wear-resistant anti-termite nylon sheath through double-layer co-extrusion. The method has the advantages that water trees are reduced, the reliability and the long service life of the ultrahigh-voltage power cable are guaranteed, and the transverse size of the ultrahigh-voltage cable is reduced.

A electrical connection element includes a planar mating surface adapted for mating with a metal bonding surface, a rim that forms an enclosed shape around the planar mating surface, and a plurality of outgassing grooves formed in the planar mating surface, wherein each of the outgassing grooves comprises a proximal end that is spaced apart from the rim and a distal end that intersects the rim, and wherein a cross-sectional area of each of the outgassing grooves increases along a lengthwise direction going from the proximal end to the distal end.

A grinding wheel dressing tool with hollow spheres preferably includes a tool shank and a dressing portion. The tool shank preferably includes a shank portion and a tool body. The shank portion extends from one end of the tool body and a dressing portion cavity is formed in an opposing end. The dressing portion preferably includes a quantity of diamond grit, metal bond powder, binder and a plurality of hollow spheres. The dressing portion cavity is preferably filled to a top with metal bond powder. The diamond grit, the metal bond powder and the binder are mixed together to form a grit mixture. A tubular mold is slipped over a top of the tool body. The dressing portion is created by forming alternative layers of grit mixture and hollow spheres in the tubular mold. The tubular mold is heated and the grit mixture pressed with a plunger.

The utility model relates to a new energy lithium battery binding post, which comprises an installation seat, a metal binding post is installed on the installation seat, a knurling groove is arranged on the metal binding post, a dustproof cap is sleeved on the metal binding post, the metal binding post is matched with the dustproof cap, a positive electrode mark and a negative electrode mark are arranged on the dustproof cap, and the knurling groove is arranged on the metal binding post. Four metal rings are arranged on the mounting seat, the metal rings are symmetrically distributed around the center of the mounting seat, and threads are formed in the metal rings. According to the new energy lithium battery binding post, the knurling groove is additionally formed in the metal binding post, and the knurling groove is in contact with the inner wall of the dustproof cap, so that the friction force between the metal binding post and the dustproof cap is increased, the dustproof cap is prevented from falling off, and the stability is improved.

[Problem] To directly bond a metal layer in a thin line shape to a surface of a ceramic substrate.[Solution] A method for producing a ceramic-metal bonded object including irradiating a surface of a ceramic substrate with a laser beam while sweeping the laser beam, and simultaneously therewith, feeding a solid metal material toward a region irradiated with the laser beam on the surface of the ceramic substrate (hereinafter referred to as “irradiation area”), so that the metal material being fed is also brought into a state of being irradiated with the laser beam to melt the metal material while heating the surface of the ceramic substrate located in the irradiation area, and depositing the molten metal material on the surface of the ceramic substrate and then solidifying the metal material.

The present invention relates to the field of bacterial protein engineering and protein fibers applicable as metal-binding bionanomaterials. More specifically, the present invention relates to engineered bacterial endospore appendage (Ena) proteins modified to contain metal-binding polypeptide (MBP) inserts providing for stable, flexible and robust protein assemblies with metal-binding activity. In particular, the invention relates to methods for designing Ena-fusion proteins capable of self-assembling into fibers, and for recombinant production of said self-assembling Ena-MBP fusion protein subunits, assemblies and fibers, ensuring a sustainable source of biological material for use in metal mineralization, metal sequestration, and metal-removal applications such as waste water treatment, water softening, or bioremediation.

A method of manufacturing a fuel cell catalyst may include a method of manufacturing a carbon support for a fuel cell catalyst, wherein the carbon support has improved catalytic metal binding force and improved carbon durability. The carbon support may be coated with a carbon layer that is highly doped with heteroatoms. The carbon layer may be formed by uniformly compounding a conductive polymer containing heteroatoms with a carbon support and thermally treating the compounded mixture.

The invention relates to the technical field of hydrogen protection, in particular to a hydrogen-resistant wear-resistant coating as well as a preparation method and application thereof. The invention provides a hydrogen-resistant wear-resistant coating which comprises a Zr metal bonding layer, a periodic nano multilayer and a chromium nitride sealing top layer which are sequentially stacked from bottom to top, the periodic nano multilayer comprises CrN ceramic layers and Zr metal layers which are sequentially and alternately stacked on the surface of the Zr metal bonding layer; and the Zr metal bonding layer is made of Zr. The hydrogen-resistant wear-resistant coating has excellent hydrogen resistance and wear resistance at the same time.

This invention discloses a composite-bonded superhard grinding wheel for silicon carbide wafer thinning and its preparation method. The grinding wheel comprises, by mass ratio, 20%-35% diamond abrasive, 25%-50% metal binder, 10%-20% resin, 10%-15% pore-forming agent, and 3%-10% filler. The diamond abrasive has a particle size of 2000#-5000#. The preparation method includes S1, preparing porous diamond; S2, preparing porous diamond abrasive; S3, preparing grinding wheel raw material; and S4, preparing the grinding wheel. This invention ensures grinding efficiency and surface quality during silicon carbide wafer grinding, solving the problem of difficulty in balancing wafer damage and grinding efficiency. Compared with existing products, it guarantees wafer processing quality and improves wafer processing efficiency.

The invention provides a diamond grinding tool based on silicon carbide wafer processing and a preparation method and application, the diamond grinding tool comprises a grinding pellet piece and a grinding disc, the grinding pellet piece is provided with Ni powder, a metal binding agent, a ceramic binding agent, a pore forming agent and a wetting agent, diamond abrasive particles and the metal-ceramic binding agent are adopted as raw materials and are mixed with Ni, a certain amount of pore forming agent is added, and the mixture is stirred to be uniform; the preparation method comprises the following steps: sintering for 20 minutes at high temperature and high pressure in a high-temperature mold, removing pressure after sintering, cooling to 810 DEG C, preserving heat for 10 minutes, then cooling to 550 DEG C, and preserving heat for 10 minutes, so that sintering shrinkage can be effectively prevented; compared with a conventional metal-ceramic bond diamond grinding tool, the multi-nickel metal-ceramic bond diamond grinding tool has the advantages that the material removal rate is increased by 18.3%, the overall level of the grinding process and technology can be improved, the quality of a processed product is improved, the preparation period is short, the product cost can be greatly reduced, and the economic benefit is high.

The invention relates to the technical field of composite membrane material manufacturing, and discloses a preparation method of an electrolyte-resistant composite aluminum foil, which comprises the following steps: providing a polymer base membrane and carrying out surface pretreatment; synchronously constructing metal oxide interface layers on the two sides of the pretreated base membrane; depositing a first metal bonding layer on the metal oxide interface layer; and a second metal function layer is formed on the first metal bonding layer through vacuum evaporation, and the composite aluminum foil with the heterogeneous interface anchoring structure is formed. The preparation method of the electrolyte-resistant composite aluminum foil aims to prevent an electrolyte from entering a disintegration bonding interface by mutually anchoring the metal oxide layer, the metal layer and the metal layer which are plated after the macromolecular base film is pretreated, so that the electrolyte-resistant capability is enhanced.

The application discloses a metal binder diamond tool and a preparation method thereof, which is composed of the following components in parts by weight: 70-90 parts of a metal binder, 9-20 parts of diamond abrasive and 1-10 parts of nano-enhanced material, wherein the metal binder is prepared from Fe powder and Al powder, and the nano-enhanced material is one of nano-diamond, carbon nano-onion, nano-graphene and nano-carbon tube or a mixture of two or more thereof. The application uses low-cost Fe and Al elements as raw materials, mechanically alloyed in a certain proportion, and adds one kind of nano-enhanced material, so that the nano-enhanced material is uniformly dispersed in the binder as a reinforcing phase through a special rapid sintering process, thereby strengthening the strength and hardness of the binder, reducing the friction coefficient of the binder, and reducing the wear and grinding heat of the binder in the grinding process.

The application belongs to the technical field of precision cutting tools, and particularly relates to a metal bond cutting grinding wheel and a preparation method thereof. The metal bond cutting grinding wheel comprises a base body and an abrasive layer arranged on the surface of the base body; the abrasive layer is mainly made of main abrasives and a metal bond; the main abrasives are cubic boron nitride, the concentration of the main abrasives in the abrasive layer is 50%-125%, and the granularity of the main abrasives in the abrasive layer is B126-B251. The content of the metal bond and the content of other components in the formula of the grinding wheel are adjusted, so that the cutting performance and the cutting cooling effect of the grinding wheel are improved, and the grinding wheel has good cutting yield and processing efficiency when used for cutting a valve rod of a specific material. When the grinding wheel is used for cutting a valve rod, the valve steel workpiece after cutting has no burr and no burn, and the service life of the grinding wheel can reach 200,000 pieces.

Provided is a superabrasive cutting wheel comprising: a disk-shaped base metal made of cemented carbide; and a superabrasive layer provided on the outer peripheral part of the base metal. The superabrasive layer includes a superabrasive, a metal bond, and a filler. The difference between the coefficient of linear expansion of the superabrasive layer and the coefficient of linear expansion of the base metal is 0-15.0 × 10-6 (1 / °C) or less.

The invention discloses a high-binding-force low-temperature anti-cold-welding amorphous carbon-based film layer and a preparation method thereof, and belongs to the technical field of surface engineering. The film layer comprises a metal bonding layer, a metal carbide transition layer and a plurality of low-stress lubricating anti-cold-welding layers which are arranged in sequence. Wherein the low-stress lubricating anti-cold-welding multilayer is composed of a-C: H with higher hardness and a-C: H-SiOx with lower hardness in an alternating manner. The plasma enhanced chemical vapor deposition technology is adopted, the multi-layer structure with the a-C: H hard layers and the a-C: H-SiOx soft layers alternating is prepared in a deposition mode, the intrinsic stress of the amorphous carbon layer can be effectively regulated and controlled while the vacuum friction characteristic of the film layer is guaranteed, and therefore the film layer binding force is improved. A multi-layer composite structure film layer is deposited on the surface of a metal base material such as titanium alloy, aluminum alloy, stainless steel and bearing steel, and the requirement for the cold welding prevention and lubrication integration function of a valve dynamic sealing component under the low-temperature condition in deep space exploration is met.

The utility model relates to an external plug-in connection battery assembly with limiting and locking functions, which comprises a battery module and a battery module socket, the end part of a battery module shell comprises a second thread and a concave-convex second limiting part, and the end surface of the battery module shell comprises a battery module positive electrode metal sheet and a battery module negative electrode metal sheet; the end part of the battery module socket shell comprises a first thread and a first concave-convex limiting part, and the end surface comprises a battery cathode connecting metal binding post and a battery anode connecting metal binding post which are embedded with springs; and in a fixed connection state of the battery module and the battery module socket, the first concave-convex limiting part and the second concave-convex limiting part are matched with each other, the first thread and the second thread are screwed, and the battery module positive and negative electrode metal sheets are respectively connected and conducted with the battery module socket negative and positive electrode connection metal binding posts. Limiting is achieved through the axial limiting part, battery module connection is achieved in a threaded locking mode, and the battery module connecting structure has the technical effects of being simple in structure, convenient to disassemble and assemble and the like.