58results about How to "Reduced cracking tendency" patented technology

Provided are a gradient wear-resistant coating and a method for preparing the same. Co50+0.15% CeO2 powder, Co50+0.25% CeO2+6% Ni/Wc powder and Co50+0.4% CeO2+12% Ni/WC powder are used for preparing the gradient wear-resistant coating with the structure of a bottom layer, a transition layer and a wear-resistant layer on the surface of a workpiece in a coaxial powder supply manner and a laser cladding manner, and the wear resisting performance of the work surface of a part is improved. An ultrasonic vibration device and a contour tracing electromagnetic induction heating device are adopted in the cladding process. Ultrasonic oscillation of a certain degree is applied to the area close to a cladded area of the workpiece, the grain size of a cladding layer can be remarkably refined, residual stress can be remarkably eliminated, and therefore generated cracks are reduced, and a cladding layer structure with good performance is obtained. The contour tracing electromagnetic induction heating device can be utilized for effectively reducing thermal stress brought by the temperature gradient of the cladding layer and relieving the cracking tendency. According to the technological parameters of the ultrasonic vibration device, the work frequency ranges from 10 kHz to 20 kHz, the maximum output power is 1,000 W, and the pneumatic pressure ranges from 0.3 MPa to 0.6 MPa. According to the technological parameters of the contour tracing electromagnetic induction heating device, the voltage is 380 V, the frequency is 60 Hz, and the heating temperature ranges from 150 DEG C to 1,000 DEG C.

The invention relates to a SiC nanowire toughened high temperature ablation resistant ZrB2-SiC composite coating and a preparation method thereof. The preparation method comprises the steps of firstly, preparing an internal SiC coating on the surface of a C/C (Carbon/Carbon) composite material; then, preparing a SiC nanowire toughened ZrB2-SiC ceramic coating on the internal SiC coating by using a chemical vapor deposition and supersonic plasma spraying combined process; obtaining a ceramic coating with a compact structure through increasing the toughness of the ceramic coating and reducing the cracking tendency of the coating by means of the toughening effect of a nanowire. Known from the drawing 3, the SiC nanowire toughened ZrB2-SiC coating is relatively compact and free of cracks and holes on the surface; known from the drawing 4, a ZrB2-SiC coating which is not toughened by using the nanowire has obvious cracks and more defects on the surface. A SiC nanowire toughened test sample has the linear ablative rate of 8.7mu m/s and the mass ablative rate of 1.5*10<-3>g/s when eroded at the temperature of 2200 DEG C by oxyacetylene, and a test sample which is not toughened by using the SiC nanowire has the linear ablative rate of 16.4mu m/s and the mass ablative rate of 3.3*10<-3>g/s when eroded at the temperature of 2200 DEG C by oxyacetylene.

The invention discloses a method for preparing a nanowire-toughened carbon/carbon composite material ceramic coating. The method aims to solve the technical problem that the ceramic coating prepared by a conventional method has poor denseness. The method adopts the following technical scheme that: the nanowire-toughened carborundum (SiC)-molybdenum disilicide (MoSi2)-chromium silicide (CrSi2) ceramic coating is prepared by chemical vapor deposition, the cracking trend of the coating is reduced, and the ceramic coating with a dense structure is prepared by means of the toughening effect of nanowires. The effective anti-oxidization time of the prepared ceramic coating in atmosphere at the temperature of 1,500 DEG C is improved to 140 and 155 hours from 50 hours in background technology.

The invention provides a hafnium carbide nanowire-toughened ceramic coating layer of the surface of carbon/carbon composites and a preparation method thereof. The HfC nanowire-toughened SiC ceramic coating layer is prepared by adopting a chemical vapor deposition and embedding two-step method, the toughness of the coating layer can be increased in virtue of nanowire pulling-out, bridging and crack steering mechanisms, and a cracking tendency of the coating layer is decreased. The preparation method has the beneficial effects that the HfC nanowire-toughened SiC ceramic coating layer is prepared by adopting the chemical vapor deposition and embedding two-step method, the toughness of the coating layer can be increased in virtue of the nanowire pulling-out, bridging and crack steering mechanisms, and the ceramic coating layer with a dense structure is prepared. The preparation method of the HfC nanowire-toughened SiC ceramic coating layer is simple, and as seen from figure 2, the HfC nanowire-toughened SiC ceramic coating layer is more dense and complete than an SiC ceramic coating layer, and the crystal particle size in the coating layer is also more uniform.

The invention discloses a high-temperature resistant and abrasion-resistant white cast iron piece and a production method to solve the problem in hardness of white cast iron. The high-temperature resistant abrasion-resistant white cast iron piece is characterized in that the white iron casting comprises the following chemical compositions by mass percent: 3.0 to 3.5 percent of C, 30 to 36 percent of Cr, 1.8 to 2.5 percent of Mo, smaller than or equal to 1 percent of Si, 1.0 to 2.0 percent of Ni, 1.05 to 1.5 percent of Mn, 0.5 to 1.0 percent of B, smaller than or equal to 0.10 percent of P, smaller than or equal to 0.08 percent of S, and Fe in balancing amount; and the chromium carbon ratio of the white cast iron is 8.5 to 12. The method comprises the steps of smelting, casting, thermal insulation and cooling. The white cast iron piece has the advantages that casting-state thermal insulation slow cooling hardness HRC is larger than or equal to 61, the hardness HRC after quench tempering is larger than or equal to 66, the hardness HRC can still keep larger than or equal to 61 at 700 DEG C, the corrosion resistance of the white cast iron piece is superior to that of the existing white cast iron piece, and the white cast iron piece is particularly suitable to serve as a wear-resistant part operating under high-temperature condition.

The invention discloses mechanized construction plastering mortar and a preparation method thereof. The plastering mortar is formed by mixing powder, aggregate and water, and a mass ratio of the powder, the aggregate and the water is (200-300):(700-800):(160-250); the powder is formed by mixing portland cement clinker, plaster, granulated blast-furnace slag, coal ash, limestone powder and a chemical addition agent, and a mass ratio of the portland cement clinker, the plaster, the granulated blast-furnace slag, the coal ash, the limestone powder and the chemical addition agent is (100-300): (50-100): (50-200): (100-400): (100-400): (2-5). According to the invention, after the detection in a factory according to a quality requirement and the measuring packing, the powder and the aggregate are respectively sent to a construction site or a dedicated distributing bin for burdening, and the mechanized construction is performed; compared with dry-mixed mortar, the aggregate is not required to be dried, so that the drying cost and a part of transportation cost of the aggregate are reduced, and the material cost is substantially lowered; and simultaneously the advantages that the dry-mixed mortar quality can be controlled and the construction site environment is good are maintained.

The invention discloses a method and a device for alloying composite processing of a laser surface through mechanical vibration assisted induction heating. The method comprises the steps of delivering alloy powder to a purified and activated metal matrix surface by adopting a preset material method or synchronous powder delivery method; under the protection of argon, assisting laser scanning of a sample surface through induction heating, and performing mechanical vibration at the same time to perform auxiliary processing so as to prepare an alloyed layer. A high-frequency induction heater is connected with an induction heating coil, the induction heating coil is fixed on a laser head, the laser emitted by the laser head is positioned in the center of a heating area of the induction heating coil, and the laser head is connected with a laser. The method and the device disclosed by the invention can achieve the effects of refining grains, improving the completeness of a crystal structure, uniformizing structures, improving the efficiency of alloying the laser surface, increasing the depth of the alloyed layer and reducing the tracking trend of the alloyed layer, and has the advantages of stable processing, high efficiency, high quality of the alloyed layer and the like; therefore, the method and the device are beneficial to industrial popularization and application of the alloying of the laser surface.

A tonneau cover for use on a vehicle bed can have a multilayer construction. The multilayer tonneau cover can include an upper layer and a reinforcing layer. The tonneau cover can also have a lower layer. The reinforcing layer can include a reinforcing beam to reduce the potential for cracking of the upper layer. The reinforcing beam can be elongate and non-intersecting along its path.

The invention relates to a branched silyl ester copolymer comprising repeating units of (A) one or more monomers containing one polymerisable ethylenically unsaturated bond, of which at least one monomer is containing silyl ester functionality, (B) one or more monomers containing two or more polymerisable ethylenically unsaturated bonds, and (C) one or more chain transfer agents. Furthermore, theinvention relates to the use of said branched silyl ester copolymer as a component in an antifouling coating composition, as well as to an antifouling coating composition comprising said branched silyl ester copolymer and one or more other components.

The invention relates to the technical field of additive shaft repairing, and provides a shaft surface repairing system and method for additive composite micro-rolling. The system comprises a frame, a plurality of groups of spinning units evenly distributed in the circumferential direction are arranged on the frame, and a middle wear shaft repairing area is constructed; each of the spinning units comprises a first driving device, a first guide rail, a first sliding block and a roller, wherein the first driving device and the first guide rail are fixed to the frame, an output end of the first driving device is connected with the first sliding block, the first sliding block is movably arranged on the first guide rail, the roller is connected with the first sliding block, and the roller surface of the roller is opposite to the circumferential surface of a wear shaft in the middle wear shaft repairing area; and a heating mechanism and an additive printing mechanism are arranged on the frame. According to the shaft surface repairing system for the additive composite micro-rolling provided by the invention, additive shaft repairing and micro-rolling of a repaired part are synchronously achieved, the microstructure and the mechanical property of the repaired shaft are comprehensively improved, the overall performance of the repaired shaft is improved, and the repaired shaft can be put into use again.

The invention relates to a preparation method of a beaded nanowire toughened and reinforced ceramic coat. A beaded SiC nanowire toughened and reinforced Si-Cr ceramic coat is prepared through adopting an in-situ synthesis process, and the combination of the special toughening efficacy possessed by the in-situ synthesized beaded nanowire and a strong interface formed between the nanowire and an internal coat reduces the cracking trend of the coat to make the ceramic coat have a compact structure, so the effective anti-oxidation time of the prepared ceramic coat in 1500DEG C static air is prolonged to 165-185h from 40h of a background technology.

The invention discloses an Yb modified CMAS prevention composite structure thermal barrier coating and a preparing method thereof. A CMAS corrosion prevention layer adopts Yb modified rare earth zirconate to form a compact layered structure, at the high temperature, the layered structure can have a reaction with CMAS to form a compact blocking layer, permeation of molten CMAS to the interior of the thermal barrier coating can be prevented, a first heat insulation layer adopts Yb modified rare earth zirconate to form a columnar structure, enough heat insulation performance and high strain tolerance can be provided for the thermal barrier coating, the thermal shock property of the thermal barrier coating is improved, the service life of the thermal barrier coating can be prolonged, the CMAScorrosion prevention layer and the first heat insulation layer are made of materials of the same elements, heat mis-match stress between the two layers can be relieved, combining strength of the two layers can be improved, the thermal barrier coating has the advantages of being low in heat conduction rate, stable in phase, high in combining strength, and high in sintering resisting capacity, the service life under the high-temperature service condition is long, combination strength between dual layers of ceramic can be high, and combination strength between a ceramic layer and a metal bondinglayer is high.

The invention provides a preparation process of an aviation aluminum alloy ingot. The preparation process of the aviation aluminum alloy ingot comprises the following steps: (A) mixing a Cu source, an Mg source, a Zn source, a Ti source, a Zr source and an Al source, then smelting to obtain a smelted product; (B) sequentially degassing, filtering and refining the smelted product obtained in the step (A) on line to obtain an on-line processed product; (C) casting the on-line processed product obtained in the step (B) to obtain an aviation aluminum alloy ingot blank, wherein the casting rate is 8-14mm/min; (D) carrying out homogenizing treatment on the aviation aluminum alloy ingot blank obtained in the step (C) to obtain the aviation aluminum alloy ingot. According to the preparation process, the proper casting rate is adopted; the flaw detection eligibility rate of the aluminum alloy can be increased; experimental results show that the flaw detection eligibility rate of aluminum alloy 7050 and aluminum alloy 7A85 prepared by the preparation process of the aviation aluminum reaches 97-99%.

The invention provides a hot top casting process of a 7050 aluminum alloy. The process comprises the following steps: (A) mixing a Cu source, a Mg source, a Zn source, a Ti source, a Zr source and a Al source, and then performing smelting to obtain a smelted material; (B) sequentially performing online degassing, online filtration and online refining on the smelted material obtained in the step (A) to obtain an online treatment product; and (C) performing casting on the online treatment product obtained in the step (B) to obtain the 7050 aluminum alloy, wherein the casting speed is 8-14mm/min. The hot top casting process provided by the invention adopts an appropriate casting speed and can be used for improving the flaw detection qualified rate of the aluminum alloy, and experimental results show that the flaw detection qualified rate of the 7050 aluminum alloy prepared by the hot top casting process of aviation aluminum, provided by the invention, is 97-99%.

The invention provides a 7A85 aluminium alloy hot-top casting process which comprises the following steps: (A) mixing a Cu source, a Mg source, a Zn source, a Zr source and a Al source, and then smelting to obtain a smelted material; (B) sequentially performing on-line degassing, on-line filtering and on-line refining on the smelted material obtained in the step (A) to obtain an on-line processed product; (C) casting the on-line processed product obtained in the step (B) to obtain a 7A85 aluminium alloy, wherein the casting speed is 8-14 mm/min. The 7A85 aluminium alloy hot-top casting process has the advantages that an appropriate casting speed is adopted, so that the nondestructive inspection qualification rate of the aluminium alloy can be improved. Experimental results show that the nondestructive inspection qualification rate of the 7A85 aluminium alloy prepared by adopting the aviation aluminium hot-top casting process is 97-99 percent.

The invention discloses wear-resistant ultra-high performance concrete and a preparation method thereof. The wear-resistant ultra-high performance concrete comprises the following raw materials in parts by weight: 600-650 parts of a special cementing material; 120-150 parts of silica fume; 600-650 parts of steel slag aggregate; 300-350 parts of iron tailing sand; 240-260 parts of quartz sand; 15-18 parts of a water reducing agent; 80-100 parts of steel fiber; and 160-180 parts of water. The special cementing material is prepared by uniformly dry-mixing the following raw materials in parts by weight: 65-75 parts of Portland cement clinker powder; 20-30 parts of high iron and high belite sulphoaluminate cement clinker powder; and 5-10 parts of gypsum powder. According to the present invention, the strength generation is rapid, the compressive strength and the breaking strength are high, the impact resistance is strong, the 1d compressive strength can achieve 70 MPa, the breaking strength can achieve 15 MPa, the 28d compressive strength can achieve 180 MPa or more, and the breaking strength can achieve 35 MPa or more; the abrasion value is less than 4.0 cm < 3 >, and the preparation cost is reduced by about 80%.

A bionic gradient antifouling composite coating comprises a base body, a metal bonding layer is deposited on the base body, and a gradient composite coating with the ceramic content gradually increased and the metal content gradually reduced from the surface of the base material to the surface of the coating is deposited on the bonding layer; and the gradient composite coating is of a block-like compact layered structure. A preparation method of the bionic gradient antifouling composite coating comprises the following steps that (1) the surface of the metal base body is polished and subjected to sand blasting treatment; (2) a metal bonding layer is deposited on the surface of the base body through gas hood protection plasma spraying; (3) an atmosphere plasma spraying method is adopted, the powder proportion during spraying is adjusted, and a gradient composite coating with the ceramic content gradually increased and the metal content gradually reduced from the surface of the base material to the surface of the coating is deposited on the surface of the metal bonding layer. According to the gradient composite interface structure, the interface bonding strength can be improved, the density of the coating is improved, the corrosion resistance and toughness of the coating are improved, and the biofouling resistance can be achieved through adjustment of a metal phase.

The invention relates to a glow plug comprising a housing, a ceramic pencil-type glow element which projects from the housing with a first end and is arranged inside the housing with a second end, a feed line which is arranged in the housing and leads to the pencil-type glow element, and a sleeve-type element which surrounds a section of the pencil-type glow element projecting from the housing. The invention is characterized in that the pencil-type glow element has a section surrounded by the housing which section tapers towards the second end, the pencil-type glow element is encircled by a contact element in the housing, which contact element has a section that narrows towards the second end of the pencil-type glow element, said narrowing section encircling at least a subsection of the tapered section of the pencil-type glow element. The invention further relates to a method for producing said glow plug.