63 results about "Adhesive wear" patented technology

The invention relates to the technical field of taping machine equipment, and particularly discloses a self-adhesive wear-resistant aluminum foil mylar tape longitudinal wrapping taping machine which is used for solving the problems of poor wear resistance and poor taping quality in the prior art. Comprising a base, a supporting vertical plate is vertically arranged at the upper end of the base, a winding penetrating hole allowing a cable A to penetrate through conveniently is formed in the supporting vertical plate, a winding disc is rotationally arranged on the outer side of the winding penetrating hole, the winding disc is connected with a winding driving piece used for driving the winding disc to rotate, and an aluminum foil belt roller is arranged at the end of the winding disc; an aluminum foil belt is wound on the aluminum foil belt roller, and an installation assembly used for fixing the aluminum foil belt roller is arranged on the winding disc. The aluminum foil tape is designed according to existing requirements, the wear-resistant layer is arranged on the outer side face of the aluminum foil tape, and the bonding layer is arranged on the inner side of the aluminum foil tape, so that the aluminum foil tape better wraps the outer side of the cable A, and the protection effect of the cable A is improved.

The invention belongs to the technical field of rubber sealing tests, and relates to a gap leakage analysis-based aviation dynamic sealing ring service life prediction method, which comprises the following steps: S1, carrying out an aviation dynamic sealing ring service life pre-test, carrying out sealing ring service life exploration, and determining a sealing ring failure criterion; s2, carrying out an aviation dynamic sealing ring service life model correction test, and recording service life correction parameters in the test process; s3, according to Archard adhesion wear analysis and gap leakage analysis, obtaining a wear loss variable of the aviation dynamic sealing ring; s4, the abrasion loss of the aviation movable sealing ring is calculated, a standard equation for judging the sealing state of the aviation movable sealing ring is established, and the working state is determined; and S5, establishing an aviation dynamic sealing ring aging prediction model of the target working condition, and completing service life prediction evaluation. According to the invention, traditional sealing ring size measurement is replaced by the leakage amount, so that a complex sealing ring dismounting experiment is avoided, non-experimental wear of the sealing ring is reduced, and an accurate service life prediction model is established.

The invention discloses a pump body assembly, a compressor and refrigeration equipment, and relates to the technical field of compressors, the pump body assembly comprises an air cylinder, a pump body, a pump body, a pump body, a pump body and a pump body, and the air cylinder is provided with a working cavity and a sliding groove communicated with the working cavity; the piston is eccentrically and rotatably arranged in the working cavity; the sliding piece comprises a sliding piece body and a hinge portion arranged at one end of the sliding piece body, the sliding piece body is arranged in the sliding groove in a sliding mode, the hinge portion is hinged to the piston and provided with a first opposite-grinding face, the piston is provided with a second opposite-grinding face in contact with the first opposite-grinding face, and the second opposite-grinding face is provided with a second opposite-grinding face in contact with the second opposite-grinding face. The surface hardness of the first counter-grinding surface is at least 30% higher than that of the second counter-grinding surface. According to the technical scheme, adhesive abrasion can be effectively reduced, and the problem that abrasion of a hinge structure is aggravated is solved.

The invention provides a light wear-resistant polyester fiber and a preparation method thereof, the polyester fiber has a skin-core structure, a skin layer component in the skin-core structure is modified mica, modified silicon dioxide and polyester, and a core layer component in the skin-core structure is polyester. The modified mica and the modified silicon dioxide are added into the skin layer polyester fiber, the modified silicon dioxide forms a hydrophobic layer with a low friction coefficient on the surface of the fiber, and adhesive wear is reduced through the'molecular ball 'effect; the modified mica sheet prolongs a crack propagation path through crack deflection and a bridging mechanism so as to disperse macroscopic stress, and the modified mica sheet and the macroscopic stress cooperate with each other to improve the wear resistance of the polyester fiber.

The invention relates to the field of saw blades, in particular to an efficient sawing band saw blade and sawing machining equipment. According to the band saw blade, the special arc liquid storage groove structure is arranged on the tooth groove outline, so that cutting liquid can effectively enter saw seams and infiltrate the rake face of the saw teeth, the cutting temperature is reduced, adhesive abrasion is delayed, and the saw cutting service life is remarkably prolonged. The tooth-shaped structure of the band saw blade comprises a plurality of continuous arc sections, the optimized cutter angle and the optimized diversion trench design, and the cooling effect and the cutting performance are further enhanced. Practical application shows that the efficient sawing band saw blade shows excellent cooling and wear-resisting performance under the high-linear-speed sawing working condition.

The invention provides a tensile testing machine for testing a basalt fiber super-viscous wearing layer, and belongs to the technical field of pavement material tensile testing devices.The tensile testing machine comprises a base component, clamping head assemblies, a constant-temperature cover assembly, a bottom driving assembly and a cooling and heating all-in-one machine, and the clamping head assemblies are arranged in the base component in pairs; constant-temperature covers are screwed to the two sides of one end of a base component in pairs, a clamping base in a clamping head assembly at the bottom is fixedly connected with the inner bottom of the base component, clamping heads are slidably connected to the inner side face of a trapezoidal groove formed in the head end of the clamping base in pairs, an inner sliding block is transversely slidably connected to the tail ends of the two sets of clamping heads jointly, and an adjusting bolt is vertically connected to a main body of the clamping base in a threaded mode. The head end of the adjusting bolt is screwed with the inner sliding block, so that when the bottom driving assembly drives the clamping head assembly at the bottom to carry out clamping, the constant-temperature cover can be driven to form a rotary closing action, and the constant-temperature cover can be communicated with the cold and hot all-in-one machine only after the constant-temperature cover is closed in place and a closed space is formed for a test piece between the outer surfaces of the two groups of clamping seats, so that safety and reliability are realized.

The invention belongs to the technical field of drilling tools, and discloses a coating drilling tool and a machining method.The coating drilling tool comprises a drill tip part, the drill tip part comprises a front tool face and two tool end faces, the two tool end faces intersect to form a chisel edge, each tool end face comprises a first rear tool face, and the first rear tool faces intersect with the front tool face to form a main cutting edge; the drill tip part further comprises a first machining area, the first machining area is arranged on the front tool face and intersects with the main cutting edge, a first micro-texture is arranged in the first machining area, and / or the drill tip part further comprises a second machining area, the second machining area is arranged on the first rear tool face and intersects with the chisel edge and the main cutting edge, and a second micro-texture is arranged in the second machining area. A second microstructure is arranged in the second machining area. The first microtextures and the second microtextures can improve the surface roughness of the front tool face and the first rear tool face, improve the coating binding force, slow down tool abrasion, improve the cutting performance and reduce abrasive particle abrasion and bonding abrasion between interfaces.

The application discloses a high-speed current-carrying friction in-situ test system and relates to the technical field of precision instruments, which comprises a macro-micro power loading module, a constant force loading module, a current loading module, a force monitoring module and an in-situ detection module. The macro-micro power loading module controls the relative motion of the friction pair to be tested. The current loading module is used for loading current between friction amplitudes. The in-situ monitoring module comprises three in-situ monitoring means, namely acoustic emission, infrared thermal imaging and a high-speed camera. The application can support the test of high-speed current-carrying friction conditions such as multi-angle and multi-posture macro-micro-motion-static coupling, and can simultaneously acquire time sequence information of temperature fields, optics, acoustics and vibration, and further acquire time sequence information of thermal energy, arc intensity, adhesive wear degree, fatigue wear degree and deformation energy of the friction pair, which helps to deeply understand the failure mechanism and modification mechanism of high-speed multi-condition current-carrying friction amplitude and accelerates the optimization work of the current-carrying friction performance of the current-carrying friction pair.

The present invention relates to a high temperature wear resistant dry brake friction plate material and a preparation method thereof, belonging to the technical field of alloy friction materials. The material strengthens the iron-copper alloy matrix by precisely controlling the addition amount of Mo and Y2O3; adds a high entropy alloy strengthening phase (Al‑Cr‑Fe‑Ni‑Ti) to the iron-copper alloy to improve the wear resistance; adopts a composite lubricating phase (CaF2+BaF2+Ag), and adjusts its ratio so that CaF2‑BaF2 weakens the two-body wear effect and Ag weakens the three-body wear effect, thereby achieving the improvement of lubrication performance under high temperature and room temperature conditions; adds a high entropy alloy strengthening phase (Al‑Cr‑Fe‑Ni‑Ti) and a composite lubricating phase (CaF2+BaF2+Ag) at the same time, and adjusts its ratio so that (CaF2+BaF2+Ag) weakens the adhesive wear effect and (CaF2+BaF2+Ag) weakens the abrasive wear effect, thereby reducing the friction coefficient and wear rate.

The present invention discloses a two-stage decay prediction method for the preload force of a ball screw pair, and belongs to the technical field of research on the service performance of a ball screw pair. The present invention combines macroscopic geometric errors and microscopic contacts to model the decay process of the preload force of a ball screw pair, describes the geometric errors and calculates the wear depth of the first stage (rapid decay stage), corrects the formula for calculating the adhesive wear volume based on fractal theory, corrects the distribution function of the number of micro-convex bodies, calculates the volume of abrasive wear, and can more accurately describe the actual situation of the decay of the preload force, and more accurately predict the decay process of the preload force of a ball screw pair.

The present invention belongs to the technical field of metal ceramics, and specifically relates to a metal ceramic with a strong grain growth orientation on the surface and a preparation method thereof, wherein an oxygen atmosphere is introduced into the sintering process to form a Ti(O,C,N) surface region with a face-centered cubic crystal structure that is poor in bonding phase, dense, and has more than 80% uniform orientation and large aspect ratio grains on the surface of the material. Titanium carbides and nitrides have extremely high hardness and wear resistance, and the compactness and self-lubricating property of titanium oxides make the organizational structure have good resistance to bonding and wear, relatively stable chemical properties, heat resistance, corrosion resistance, and oxidation resistance, thereby improving the processing performance of the material.

The application belongs to the technical field of rubber seal test, and relates to a method for predicting the service life of an aviation dynamic sealing ring based on gap leakage analysis, which comprises the following steps: S1, performing a service life pre-test of the aviation dynamic sealing ring, performing a sealing ring life investigation, and determining a sealing ring failure criterion; S2, performing a sealing ring life model correction test, and recording life correction parameters in the test process; S3, obtaining an aviation dynamic sealing ring wear variable according to Archard adhesive wear analysis and gap leakage analysis; S4, calculating the wear of the aviation dynamic sealing ring, establishing a sealing state judgment standard equation of the aviation dynamic sealing ring, and determining a working state; and S5, establishing an aging prediction model of the aviation dynamic sealing ring under a target working condition, and completing service life prediction and evaluation. The application replaces the traditional sealing ring size measurement with leakage to avoid complex disassembly and assembly of the sealing ring test, reduces non-experimental wear of the sealing ring, and establishes an accurate life prediction model.

The invention discloses alloy powder for repairing an H13 steel piercing needle and a repairing method of the alloy powder, and belongs to the technical field of extrusion die repairing. The alloy powder is a Co-based high-temperature alloy and comprises the following components in percentage by mass: 45.0 to 50.0 percent of Co, 15.0 to 20.0 percent of Cr, 26.0 to 29.0 percent of Mo, 0.1 to 0.3 percent of Ni, 2.0 to 4.0 percent of Si, 1.0 to 3.0 percent of B and 0.05 to 0.1 percent of C. During repairing, firstly, the surface of the perforating needle is pretreated, then the GH4169 alloy transition layer and the Co-based alloy functional layer are sequentially cladded through the laser cladding technology, and a hard-soft-hard three-layer gradient structure is formed. Through special alloy component design and gradient structure innovation, cracking of a repairing layer is effectively restrained, high-strength metallurgical bonding of the repairing layer and a base body is achieved, the repaired perforating needle has excellent high-temperature resistance, adhesive wear resistance and deformation resistance, the service life of the perforating needle is remarkably prolonged, and the repairing cost is reduced. The method is suitable for repairing and strengthening the copper alloy extrusion die.

The invention relates to the field of tools for machining, and discloses a tool for machining a turbine disc and a preparation method of the tool for machining the turbine disc, the magnetic axis complexity of a hard alloy blank is reduced by adjusting WC-Co hard alloy element components of a base material, and the magnetic axis orientation distribution in the hard alloy blank is changed by using magnetic lines of force in an external polar region, so that the machining precision of the turbine disc is improved. The hard alloy blank is soft and smooth and shows single-orientation distribution of magnetic lines; a drift diffusion mode is combined, low-pressure non-equilibrium plasma nitrogen migration is guided, a wear-resistant phase with higher hardness is formed on the surface of the cutter without affecting the geometrical shape of the cutter, and therefore nitrogen ion directional guiding is achieved, and a nitrogen element gradient distribution structure is achieved on the surface of the hard alloy cutter; therefore, the surface hardness and the high-temperature resistance of the hard alloy cutter material are improved, and adhesive abrasion and groove abrasion generated in the machining process of the turbine disc alloy material by the hard alloy cutter are reduced.

The embodiment of the invention discloses a workpiece combined machining method. The workpiece combined machining method comprises the steps that a to-be-sulfurized area on the surface of a nitriding layer of a prefabricated workpiece is covered with a sulfurizing agent; the surface, covered with the sulfurizing agent, of the prefabricated workpiece is ground at the preset temperature, so that a sulfurizing layer is generated on the prefabricated workpiece, and a composite workpiece is obtained; the prefabricated workpiece is a workpiece containing a nitriding layer. According to the embodiment of the invention, the sulfurizing layer is generated on the surface of the nitriding layer of the prefabricated workpiece, so that the adhesive wear resistance of the surface of the workpiece is effectively improved. Meanwhile, sulfurizing and grinding are combined, so that the production efficiency is improved, and the process complexity is effectively reduced.

A run channel for a vehicular door includes a corner section and adhesive wear tape. The corner section includes window surfaces facing interiorly to the corner section, door structure surfaces facing exteriorly to the corner section, and a wear spot on a door structure surface. The adhesive wear tape is applied to the wear spot, and includes a backing configured to shield the wear spot from wear.

The invention discloses a repairing method for quickly repairing the surface of a bearing. The repairing method comprises the following steps: providing a composite bearing to be repaired; the abrasion type of the composite material layer of the composite bearing to be repaired is analyzed; when the abrasion type is adhesive abrasion, the repairing structure comprises two layers, namely a bottom coating and an abrasion-resistant layer; when the abrasion type is abrasive grain abrasion, the repairing structure comprises a bottom coating and an abrasion-resistant layer. When the abrasion type is fatigue abrasion, the repairing structure comprises a bottom coating, a reinforcing layer and an antifriction lubricating layer. According to different abrasion types, the composite bearing to be repaired is coated with the repairing material in a blade coating mode, and then all layers are subjected to light curing; and after curing, abrasive paper is used for surface polishing treatment, and the convex points are removed. According to the repairing method, the surface of the lining can be quickly repaired according to different abrasion types of the lining, so that the shutdown maintenance time can be shortened, the service life of the original lining is prolonged, and the stable performance of the lining is kept.

The invention discloses a nano alternating coherent growth composite coating special for honeycomb composite material processing and a preparation method thereof. The nano alternating coherent growth composite coating sequentially comprises an AlTiSiN / ZrN alternating layer, an AlTiSiN functional layer and a TiAlN transition layer from outside to inside. The mismatch degree mismatch value between the ZrN layer and the AlTiSiN layer is delta < lt >; the formed AlTiSiN / ZrN alternating layer coating has the characteristics of high surface toughness, excellent adhesion resistance and excellent wear resistance; the TiAlN transition layer is deposited in a gradient mode, the coating structure is in continuous gradient transition through gradient target current, matrix bias voltage and gas flow, the residual stress of the coating is low, and the bonding strength is high; the high Al and Zr elements are doped in the coating, the oxidation resistance of the coating can be guaranteed, the friction coefficient of the coating can be reduced, in the honeycomb composite material cutting process, adhesive abrasion is reduced, the TiAlN transition layer and the AlTiSiN functional layer which are of a compact continuous gradual change structure serve as supports of the multiple nanometer alternating layers AlTiSiN / ZrN, and therefore the honeycomb composite material cutting performance is improved. And the bonding strength, fracture toughness, wear resistance and oxidation resistance of the coating are improved, so that the service life of the cutter is prolonged.

This application provides a control method for a stick-slip piezoelectric actuator throughout its entire lifecycle, comprising: obtaining a contact force reference value using the equation of the driving characteristic surface; acquiring contact force data from a database; calculating a contact force compensation value and converting it into a compensation voltage for the vertical piezoelectric stack; acquiring step displacement and actual contact force data; obtaining the total wear volume using the Archard adhesive wear model based on the step displacement and voltage data of the vertical piezoelectric stack; proportionally allocating the total wear volume to the slider and driving foot using a wear distribution method based on material hardness; storing the obtained slider wear data, driving foot wear data, and actual contact force data in a contact force database; and predicting contact force data for non-cyclic working ranges based on slider wear data and driving foot wear data within the cyclic working range, and storing this prediction in the database. This method can effectively improve the driving stability of the stick-slip piezoelectric actuator throughout its entire working stroke and lifecycle.

An end face anti-sticking torque sucker rod comprises a rod body, rod heads, couplings, threaded portions and shoulders, the rod heads are arranged at the two ends of the rod body, the couplings are connected to the rod heads in a screwed mode, the threaded portions are arranged in the couplings, and the shoulders are arranged at the positions, close to the rod heads, of the rod body. The torque sucker rod has the advantages that adhesion abrasion of the contact surface is reduced, abrasion of the end surface is reduced, the service life of the torque sucker rod is prolonged, the reliability of rod-column connection is improved, the end surface of the external thread shoulder of the torque sucker rod is hardened, a phosphating film on the end surface of the coupling is removed, and the adhesion abrasion of the contact surface can be reduced.

The application discloses a kind of automobile wear pad assembly and process method, including universal joint, wear pad assembly, universal joint axle, wheel hub axle;Ball cage bearing is installed in the inside of universal joint, universal joint axle on universal joint passes through wheel hub, and wear pad assembly is arranged in the contact position of the end of universal joint axle and wheel hub, universal joint axle is connected with wheel hub spline, and universal joint axle is locked by lock nut;When universal joint is subjected to instantaneous torque, torque is transmitted to wheel hub by spline, at this time, it will generate adhesive friction on wear pad assembly at the contact of wheel hub bearing and fixed end universal joint end face.Can guarantee the durability of its product performance, effectively reduce the friction coefficient between its and contact surface, reduce adhesive wear, and then play the noise reduction effect, can effectively improve the wear resistance and reduce noise generated between the contact surface of the fixed end universal joint end face of automobile transmission shaft / drive shaft and wheel hub bearing.

The invention discloses a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy and a preparation method thereof. A Ti-Zr-C / Ti-Zr wear-resistant modified layer is prepared on the surface of the TA15 alloy through the double glow plasma metallurgy technology, the coating is mainly composed of a Ti-Zr-C deposition layer on the outer layer and a Ti-Zr transition layer on the inner layer, the transition layer is a gradient structure layer, the content of the Zr element is continuously decreased from the surface to the inside, and the content of the Ti element is continuously increased from the surface to the inside. Under the action of 5.3 N, the lubricating oil shows a stable and lower friction coefficient, and by observing the shape of a grinding crack, the lubricating oil mainly shows slight abrasive wear and slight adhesive wear. Meanwhile, firm metallurgical bonding is formed between the coating and the base body through preparation and high-temperature diffusion of the transition layer, excellent bonding strength is shown, large external force can be borne, the service life of the TA15 alloy base body is effectively prolonged, and good application prospects are achieved.

The present invention discloses a cobalt-based high-temperature alloy, a key shaft, and a method for preparing the alloy that are resistant to adhesive wear, and belongs to the technical field of alloy processing. The present invention solves the problems in the prior art that cobalt-based high-temperature alloys are prone to forming banded structures, have poor wear resistance, and have large amounts of adhesive wear on friction pairs. The preparation method comprises: performing homogenization heat treatment on a cobalt-based alloy ingot; performing multi-directional forging on the cobalt-based alloy ingot that has undergone homogenization heat treatment to obtain a rod; performing secondary homogenization heat treatment on the rod; hot rolling the rod after the secondary homogenization heat treatment to obtain a rod; and performing finished product processing on the rod to obtain a cobalt-based high-temperature alloy rod with excellent adhesive wear resistance. The present invention can effectively eliminate the banded structure of the alloy through multi-directional forging and secondary homogenization heat treatment, obtain a uniform and fine grain structure and uniformly distributed carbides, improve the uniformity of the alloy structure, and at the same time improve the wear resistance of the alloy, especially reduce the amount of adhesive wear on the friction pair.

The invention belongs to the technical field of surface engineering, and particularly relates to an electrode for electric spark deposition, application of the electrode, a wear-resistant coating and a preparation method and application of the wear-resistant coating. According to the electrode provided by the invention, the coating is prepared by adopting an electric spark deposition method, and the Mo element in the coating can improve the lubricating performance and reduce the friction coefficient between the coating and a metal mold; the rare earth elements in the coating can refine grains, so that the coating has good mechanical properties, good metallurgical bonding is formed between the coating and a matrix, and the hardness and the adhesive wear resistance of the coating are further improved. Furthermore, the invention also provides a preparation method of the wear-resistant coating, an ultrasonic process is applied in the deposition process, and ultrasonic impact is utilized to generate pressure stress, so that the deposited tensile stress is counteracted, the residual stress of the coating is eliminated, and the hardness and wear resistance of the coating are further improved. The wear-resistant coating is applied to the surface treatment of the rim mold, so that the service life of the mold can be further prolonged.

The present application relates to the field of tribology and material cross, in particular to a kind of surface structure preparation method for improving the wear resistance of B4C ceramic to realize self-lubrication.Firstly, B4C and Al2O3 powder are weighed, ball-milled, dried and sieved to obtain mixed powder;Then the mixed powder is hot-pressed and sintered to obtain a block;The block is ground and polished to obtain the final B4C-Al2O3 composite ceramic.The B4C-Al2O3 composite ceramic prepared by the present application can form a concave-convex relief structure in situ on the wear surface during dry sliding due to the hardness difference between B4C and Al2O3 two phases.On the one hand, the relief structure can trap the nanoscale wear debris generated during sliding, reducing abrasive wear;On the other hand, the relief structure can reduce the real contact area between B4C ceramic and the counterbody, thereby effectively reducing the adhesive wear of B4C ceramic, improving the wear resistance of B4C ceramic and realizing self-lubrication.

The present invention relates to the technical field of coated cutting tools, and provides a composite coated cutting tool, a preparation method thereof and an application. The multi-layer composite coating not only has good high-temperature oxidation resistance and bonding strength, but also has good anti-adhesion. At the same time, the substrate also has high hot hardness, high toughness and high wear resistance. By exerting the mutual synergistic effect of the multi-layer composite coating and the substrate, the problems of severe oxidation wear, adhesive wear and chipping of the cutting tool during the machining of titanium alloy materials can be solved.

The invention discloses a titanium carbide wear-resistant composite plate for a valve and a preparation method of the titanium carbide wear-resistant composite plate, and relates to the technical field of metallurgy and steel rolling. The titanium carbide wear-resistant composite plate for the valve comprises a composite plate, a titanium carbide-based metal ceramic plate is arranged on one side of the composite plate, and a carbon steel-based plate is arranged on the other side of the composite plate. According to the titanium carbide wear-resistant composite plate for the valve and the preparation method of the titanium carbide wear-resistant composite plate, the titanium carbide-based metal ceramic and the carbon steel-based plate are combined to manufacture the composite plate, and the titanium carbide-based metal ceramic has extremely high hardness and excellent abrasive wear resistance, adhesive wear resistance and erosive wear resistance; wherein the ceramic layer of the titanium carbide-based metal ceramic can resist abrasion caused by an abrasion medium in the using process of the valve, the service life can be prolonged, the maintenance and replacement frequency of the valve can be reduced, meanwhile, the attached faces of the two plates are cleaned through the cleaning mechanism, the influence caused by impurities can be avoided, and the service life of the valve is prolonged. And the service life of the valve made of the composite board is further prolonged.

The application discloses a kind of oxidized coal pitch nanocarbon material modified water-related polymer friction pair materials and preparation method, belong to polymer material technical field.The water-related polymer friction pair material of the present application is made of soluble oxidized pitch nanomaterial of formic acid / hydrogen peroxide oxidation system oxidation coal pitch and ultra-high molecular weight polyethylene matrix.The present application utilizes the gap of polymer molecular chain of soluble oxidized pitch nanomaterial of ultra-small structure, and plastic rheology and adhesive wear of material are reduced in friction process by steric hindrance and interface anchoring effect;Combination of the "nanometer reinforcing network" formed by uniform dispersion can effectively transfer friction stress, avoid the matrix cracking caused by local stress concentration;While the nanometer size of soluble oxidized pitch nanomaterial and carbon-based characteristics give it unique dynamic lubrication function, its surface abundant functional groups can form high density, strong adhesion transfer film, significantly improve the wear resistance and service life of composite material.

A powder mixture for manufacturing sintered engine parts, such as valve seat inserts, comprising a first iron-based powder and a second iron-based powder wherein the first iron-based powder has a higher hardness than the second iron-based powder, the first iron-based powder comprising, in weight percent, 1-2% C, 10-25% Cr, 5-20% Mo, 15-25% Co, and 30-60% Fe; the second iron-based powder comprises a vanadium-free tool steel powder, such as a vanadium-free tool steel, comprising, in weight percent, 1-1.5% C, 3-15% Cr, 5-7% Mo, 3-6% W and 60-85% Fe; the second iron-based powder further includes vanadium carbide particles in an amount sufficient to reduce adhesive wear. The powder mixture may be sintered to form a sintered engine part optionally infiltrated with copper.

Provided is a ball screw in which the occurrence of adhesive wear can be reduced and stable driving can be maintained even in severe environments for lubricating, such as an underwater environment or an environment constantly exposed to water. The ball screw includes: a stainless steel screw shaft (21) having an outer circumferential screw groove (21a) formed in the outer circumferential surface; a stainless steel nut (22) having an inner circumferential screw groove (22a) formed in the inner circumferential surface; a plurality of balls (23) accommodated in a rolling path formed with the outer circumferential screw groove (21a) and the inner circumferential screw groove (22a); and a circulation part for circulating the plurality of balls (23) in the rolling path. The plurality of balls (23) includes a plurality of load balls (23a) and spacer balls (23b) disposed between adjacent load balls (23a). The load balls (23a) are made of ceramic. The spacer balls (23b) are made of stainless steel having a hardness lower than the material constituting the load balls. The diameter of the spacer balls (23b) is smaller than the diameter of the load balls (23a).