157 results about "Volume expansion" patented technology

The invention belongs to the technical field of infrastructure structures and materials, and discloses an intrinsic self-prestress ECC material, a surface layer structure prepared from the intrinsic self-prestress ECC material and application of the intrinsic self-prestress ECC material. A low-dosage volume expansion component and a building and curing combined strategy are utilized, the bottleneck that self-stress and a construction window period are not coordinated is broken through, the highest free expansion deformation of the intrinsic self-prestress ECC material in the temperature and humidity curing process is controlled to range from 1500 mu epsilon to 10000 mu epsilon, the later-period service free volume deformation is kept to be 55% higher than the early-period highest free expansion deformation, and the service life of the intrinsic self-prestress ECC material is prolonged. And the dual requirements of intrinsic self-prestress and construction windows are innovatively met. The maintenance-free seamless ultrathin target of the ECC surface layer structure is achieved through high-performance intrinsic self-prestress and self-healing. The method is widely applied to the fields of ocean ultra-thin large-buoyancy floating bodies, road surfaces, bridge floors, airport runways, ultra-thin box culverts, concrete panels, pumped storage power station panels, anti-seepage panels, floor panels, canal linings, tunnel linings, old structure updating and repairing and the like.

The invention discloses a silicon-tin-carbon composite material as well as a preparation method and application thereof, and the silicon-tin-carbon composite material sequentially comprises a porous silicon core, a first coating layer and a second coating layer from inside to outside, the first coating layer comprises a porous carbon material and tin located in pores of the porous carbon material, and the second coating layer comprises an amorphous carbon coating layer; pores of the porous silicon core contain tin and a porous carbon material. Tin of the silicon-tin-carbon composite material is located in pores of the porous carbon layer, so that the problem of tin expansion and the problem of tin agglomeration in the subsequent high-temperature carbonization process are buffered; meanwhile, a porous composite layer formed by tin and a porous carbon material is compounded to the surface and pores of the porous silicon core, so that the surface defects of porous silicon are repaired, and the expansion of silicon is limited to a certain extent; and on one hand, the outermost coated carbon layer can inhibit the volume expansion of silicon and tin in the charging and discharging process and increase the conductivity of the composite material.

The invention provides a phase change compensation low-thermal expansion coefficient resin formula and a preparation and use method of a composite prepreg tape of the phase change compensation low-thermal expansion coefficient resin. Tin micro-powder subjected to surface capsule coating treatment is added into a resin system, and heat absorption and low-temperature phase change volume expansion principles of the tin micro-powder are utilized; the resin system for the composite material has the characteristics of low heat release, low shrinkage and low thermal expansion coefficient. And by controlling the addition amount of the tin micro powder, the thermal expansion coefficient of the material is accurately regulated and controlled, generation and expansion of matrix microcracks are reduced or even inhibited, and the material performance is improved. Through microcapsule surface treatment and control of the particle size and shape of the tin micro powder, the interface compatibility problem can be solved, and resin toughening is realized. The method for producing the prepreg tape by the hot infiltration and cold demolding continuous drawing method is suitable for continuous and efficient production of the prepreg tape for high-performance fiber dry winding. The method has important economic, technical and social values, lays a foundation for scientific exploration and technical progress in the livelihood field, and improves the market competitiveness of products.

Disclosed are a substrate support device and a method of controlling prevention of leakage of temperature control fluid. In a substrate support device that controls temperature through supply of temperature control fluid, a sealing member configured to be actively controlled in volume expansion taking into consideration a difference in coefficient of expansion between a fluid supply block supplying the temperature control fluid and an electrostatic chuck due to the materials thereof is employed, thereby preventing leakage of the temperature control fluid.

The invention discloses a double-component reinforced 5Y-PSZ dental ceramic material and a preparation method thereof, and relates to the technical field of ceramic material preparation. The method comprises the following steps: mixing ZrCl4 and deionized water, and dropwise adding an ammonia water solution to prepare m-ZrO2 nano ceramic powder; zrOCl2. 8H2O, Y (NO3) 3.6 H2O and deionized water are mixed, the m-ZrO2 nano ceramic powder and polyethylene glycol 2000 are added, and the material is prepared through calcination, spray granulation, hot-pressing presintering and high-temperature sintering. According to the 5Y-PSZ dental ceramic material disclosed by the invention, the nano-scale m-phase ZrO2 is adopted as a reinforcing material and is dispersed and distributed inside the 5Y-PSZ, and through volume expansion generated by t-m phase change of the m-phase ZrO2, the anti-aging performance is guaranteed, and meanwhile, the reinforcement of the 5Y-PSZ dental ceramic material is realized. The invention solves the problem of insufficient strength of the 5Y-PSZ dental ceramic material in the prior art.

The invention discloses a marine concrete self-repairing material which is of a microcapsule structure and comprises a repairing core material and an environment triggering response wall material wrapping the repairing core material. In parts by weight, the weight ratio of the repairing core material to the environment triggering response wall material is (3-5): (1-2); the environment triggering response wall material is prepared from a water swelling material; the repairing core material comprises a material which generates an expansive hydration product when encountering water. When the concrete system has cracks, the environment-triggered response wall material absorbs water, swells and breaks; and water molecules enter the surface of the repairing core material to react to generate an expansive hydration product, so that the environment-triggered response wall material is further broken due to volume expansion of the repairing core material. After the repairing core material is released, an expansion reaction can be quickly generated, micro-cracks in the concrete are repaired in real time, and the penetration resistance of the concrete is improved.

The invention discloses a method for improving cloth lines after hot pressing of an epoxy glass fiber composite material, and the method comprises the steps of resin glue solution blending, glass fiber cloth presoaking, gradient pre-drying, hot pressing molding, cooling demolding and the like. The volume expansion rate is accurately matched with the resin curing shrinkage rate, interface stress caused by shrinkage difference is directly counteracted, meanwhile, gradient pre-drying and staged hot pressing processes are combined, and the resin fluidity and interface bonding strength are optimized. The resin conversion rate is controlled in two stages through gradient pre-drying, and flow blocking caused by premature curing is avoided; and secondly, through the chemical compensation mechanism of the expansion monomer, the mechanical property of the material is maintained while the cloth lines are eliminated.

The invention discloses a recycled aggregate close packing method established based on a volume expansion and contraction putting principle, belongs to the technical field of building material preparation, and is mainly applied to grading optimization and close packing treatment of recycled aggregate in production of building materials such as concrete. Comprising the following steps: S1, constructing a recycled aggregate three-dimensional particle model; S2, constructing a recycled aggregate accumulation model; and S3, performing grading optimization. The three-dimensional morphology characteristics of irregular shape, protruding edges and corners and the like of the recycled aggregate are fully considered, the volume expansion and shrinkage putting principle is combined, efficient collaborative accumulation of the coarse and fine aggregate is achieved, the accumulation density is improved by 8%-12% compared with that of a traditional method, and the accumulation structure is remarkably improved; the optimal feeding proportion and sequence of the aggregates of different particle sizes are accurately determined, the advantages of all the particle sizes are fully played, and the filling effect in the concrete is improved.

The invention belongs to the technical field of hydrogen storage materials, and particularly relates to a hydrogen storage material, a preparation method thereof and a hydrogen storage system. The hydrogen storage material comprises the following raw material components in percentage by mass: 90%-97.5% of hydrogen storage alloy powder, 1%-5% of a volume expansion buffering agent, 1%-5% of a heat conduction material and 0.5%-3% of an additive, the additive comprises at least one of a silane coupling agent and polyimide; the preparation method comprises the following steps: mixing the raw material components, carrying out cold press molding, carrying out heat treatment for 4-12 hours in an inert atmosphere at the temperature of 110-150 DEG C, and cooling to obtain the hydrogen storage material.

The invention provides a gas phase change rock breaking device and method based on an aluminothermic reaction, and belongs to the technical field of rock blasting. The rock breaking device comprises a graphite excitation pipe, a liquefied air bag and a sealing cover, the excitation pipe is filled with thermite, and thermite reaction can be carried out to release heat; the liquefied air bag is hermetically sleeved outside the excitation tube, is filled with liquid oxygen or liquid nitrogen and is changed into gas under the action of heat released by the excitation tube, and rock mass fracture is realized by volume expansion. By arranging a multi-section excitation pipe serial connection structure, adopting the industrial graphite excitation pipe, designing a liquid oxygen or liquid nitrogen double-medium system and using the polyethylene degradable material bag body, the safety, the economical efficiency and the environmental adaptability of open-air rock mining are remarkably improved.

According to the mullite porous ceramic and the preparation method thereof provided by the invention, solid waste fly ash is used as a raw material, andalusite is introduced as a silicon source regulator, alumina or calcined alumina is used as an aluminum source, and proportioning is carried out according to the chemical composition of near mullite; meanwhile, the structure of the mullite ceramic is regulated and controlled by combining the particle size of the raw material, a compression molding process and segmented sintering preparation. In the process, the preparation of the near-net-size mullite porous ceramic can be effectively realized through particle accumulation and volume expansion accompanied by mullite generation in the sintering process, the sintering shrinkage rate is less than or equal to 1%, the open porosity is more than or equal to 40%, the pore size distribution is unimodal distribution, and the bending strength is gt; and meanwhile, good gas flux is achieved.

The invention belongs to the technical field of grouting materials, and particularly relates to a quick-setting early-strength self-stress functional grouting material and an expansibility testing method. The existing cement-based anchoring agent or mine filling body top-contacting agent and fractured rock mass grouting reinforcing agent have the phenomena of poor coupling effect, volume shrinkage and the like. The grouting material is composed of a component A and a component B, the component A mainly comprises sulphoaluminate cement, a water reducing agent, a retarder, a sodium salt accelerator and fibers, and the component B mainly comprises anhydrite, quicklime, a water reducing agent, an early strength agent, aluminum powder, a retarder and fibers. When in use, the mass ratio of the main components of the component A to the component B is (0.85-1.15): 1, and the water-cement ratio is (0.6-1.2): 1. When the water cement ratio is low (0.6-0.8: 1), the material can be used as an anchoring agent of an anchor rod; when the water-cement ratio is high (0.8-1.2): 1, the grouting agent can be used as a mine filling body top-contacting agent and a fractured rock mass grouting reinforcing agent; the invention further provides a simple testing method for the volume expansion rate and the expansion stress. And the method has obvious engineering application value.

A gas leakage rate testing apparatus and method for a nonmetal hydrogen conveying pipeline, and a nonmetal hydrogen conveying pipeline volume expansion amount testing method. The gas leakage rate testing apparatus comprises: a test member (1), in which a test cavity (16) adapted to place a pipeline (31) to be tested is formed, wherein a sealed test cavity (11) is formed after said pipeline (31) is placed in the test cavity (16); a calibration cavity (21) selectively communicated with the test cavity (11); a first gas filling assembly (10) selectively communicated with the calibration cavity (21) so as to be adapted to inject gas of a first set pressure into the calibration chamber (21); a measurement unit (9) configured to measure the pressure and temperature in the calibration cavity (21) and the pressure and temperature in the test cavity (11), and calculate the volume of the test cavity (11); and a leakage rate test unit configured to acquire a pressure change value of the test cavity (11) within a preset time interval, and calculate the gas leakage rate of said pipeline (31). The technical problem that gas leakage rate testing is inaccurate due to the measurement of the volume of the test cavity (11) being difficult or inaccurate is solved. In the nonmetal hydrogen conveying pipeline volume expansion amount testing method, after gas leakage rate testing is ended, a measurement unit (9) calculates a second volume of a test cavity (11) on the basis of a second formula, and on the basis of the difference between a first volume and the second volume, calculates the volume expansion amount of a pipeline (31) to be tested.

The invention relates to the technical field of geotechnical engineering and slope reinforcement, and discloses a foam concrete-based expansive soil slope reinforcement structure which comprises a slope body and a foam concrete prefabricated reinforcement assembly mounted on the slope body through anchor rods, and the reinforcement assembly comprises a first reinforcement layer and a second reinforcement layer which are sequentially arranged on the slope surface of the slope body; the first reinforcing layer comprises a plurality of first reinforcing units arranged in the length direction of the slope body. By means of the double-layer design of the first reinforcing layer and the second reinforcing layer, the first prefabricated slab is longitudinally connected in an inserted mode through a dovetail or T-shaped tenon-and-mortise structure to achieve seamless attachment, the second prefabricated slab presses and covers tenon-and-mortise joints and is clamped and locked through the annular connecting piece, a latticed system of transverse restraining and longitudinal locking is formed, the structure can resist volume expansion of expansive soil by 30% or above, and the expansive soil is not prone to deformation. A soil body loss channel is effectively blocked, and the linkage problem of loosening-cavity-instability of a traditional prefabricated part is solved.

Method and apparatus to enable detection, count, and recordation of properties of particles of ultrafine particle sizes (<0.1 micron) as well as particle of larger sizes with the use of a condensation nuclei counter configured to enable multiple stages of volume expansion with the use of an array of fluidly connectable chambers.

The invention provides a long-term expansion prediction method and device for an aged steel slag asphalt mixture, and relates to the field of material testing. The method comprises the following steps: manufacturing a standard steel slag test piece through a preset treatment method, and respectively obtaining a plurality of target masses corresponding to the standard steel slag test piece under different experimental conditions according to preset steps; calculating the corresponding first bulk density of the standard steel slag test piece before expansion according to the multiple target masses; placing the standard steel slag test piece in a target constant-temperature and constant-pressure environment for stacking operation; obtaining a plurality of target aging masses corresponding to the standard steel slag test piece under different experimental conditions according to preset steps after a preset time period; according to the multiple target aging masses, the corresponding second bulk density of the standard steel slag test piece after expansion is calculated; calculating volume expansion rate data corresponding to the standard steel slag test piece according to the first bulk density and the second bulk density; acquiring volume expansion rate data of the standard steel slag test piece in a plurality of different times according to the selected time; and inputting the volume expansion rate data at different times into the prediction model, and outputting the predicted expansion rate corresponding to the standard steel slag test piece through the prediction model. According to the method, the problems that the long-term expansion behavior prediction of the steel slag asphalt mixture is insufficient and the change trend of the expansion rate along with time cannot be accurately mastered due to the lack of effective data fitting in the traditional method are solved.

The application discloses a graphene-diamond composite coating and a preparation method and application thereof, and belongs to the technical field of materials. The graphene-diamond composite coating comprises a diamond coating and a graphene coating; graphene sp2 bond structure is covalently combined with diamond sp3 bond structure; and the graphene coating has a graphene structure with non-parallel growth mainly in a vertical direction. The graphene-diamond composite coating has small lattice mismatch between the diamond and the graphene, avoids volume expansion caused in a friction heat process, and has the advantages that the diamond coating can provide a support layer for the graphene, forms super-strong C-C covalent bonds at an interface, and significantly improves the adhesion strength of the graphene; the graphene can avoid brittle fracture of the diamond, and significantly improves the lubricating performance of the surface of the diamond coating. The composite coating has better wear resistance, a low friction coefficient and excellent oxidation resistance, and can remain stable under high-temperature and high-load working conditions, so that the service life and processing efficiency of wear-resistant parts are improved.

This invention discloses a secondary chemically strengthened UFG glass and its preparation method, relating to the field of ultrathin flexible glass technology. The secondary chemically strengthened UFG glass, by molar percentage, comprises the following raw materials: SiO2: 59.85%~69.43%, Al2O3: 11.81%~18.45%, Na2O: 7.5%~10.48%, Li2O: 6.7%~9.0%, B2O3: 0~3.7%, MgO: 0~3.65%, P2O5: 0~4.59%, and SnO2: 0.9%. After the UFG glass undergoes two chemical strengthening processes, the volume expansion rates of the first and second regions of the UFG glass, which have varying thicknesses, are equal. This avoids problems such as distortion, deformation, and wrinkles that easily occur in the strengthened cover glass, improving the yield and facilitating large-scale production.

The invention relates to the field of metal nano material preparation, and discloses a supersonic gas atomization preparation method of high-dispersity spherical nano aluminum powder, which comprises the following steps: establishing a constant-temperature aluminum melt flow, and constructing a supersonic gas-solid two-phase atomization jet flow; nitrogen with the temperature lower than the melting point of the particles is used for carrying flow, solid zinc stearate particles are carried and accelerated to supersonic speed, and the aluminum melt flow is impacted; solid rigid momentum of the particles penetrates through an aluminum liquid interface to enter liquid drops, thermal relaxation time difference is used for inducing the particles to generate phase change decomposition in the liquid drops, the liquid drops are broken from the inside through volume expansion, and a carbon-zinc composite isolation layer is formed in situ through decomposition products. And high-efficiency nanocrystallization crushing under low energy consumption is realized.

The invention discloses a preparation method of an asphalt coated silicon-graphite composite negative electrode material, and aims to solve the problems of volume expansion and the like of a silicon-based material in circulation so as to prolong the cycle life of the silicon-based negative electrode material. The process is mainly characterized in that a target coating material is used for carrying out multi-time layered coating treatment on a silicon-graphite precursor to obtain the silicon-carbon negative electrode material with a'coating material-silicon-graphite 'spherical sandwich structure. The preparation method has the advantages that the graphite is used as a carbon material supporting framework and is mixed with the nanometer silicon for layered asphalt coating, stress change generated by volume expansion of the silicon is relieved by utilizing a cavity between the graphite and the silicon and a buffering effect of the elastic coating layer, and meanwhile, a complete carbon coating layer is formed by utilizing multiple times of coating; the content of free nano silicon in the material is reduced, the problem of failure caused by volume expansion of a solid electrolyte membrane is reduced, and high stability of the silicon-carbon composite negative electrode material is finally realized.

The application relates to the technical field of fluid control valve devices, in particular to a parallel multi-stage check valve which is characterized in that a plurality of groups of check valve assemblies which are vertically distributed are connected in parallel at the outlet end of a main flow pipe, the opening threshold of each group of the check valve assemblies increases from top to bottom, and the outlet ends of all the check valve assemblies are fixedly connected in common with a discharge pipe; each group of the check valve assemblies comprises a main valve body which is integrally fixedly connected by a liquid inlet section, a volume expansion section and a liquid outlet section in sequence, the left end of an elastic connecting piece is coaxially fixedly connected with an umbrella-shaped valve flap, the outer edge of the umbrella-shaped valve flap is coaxially fixedly connected with a conical cover which is matched with a conical inner wall, a waterproof hammer cylinder is coaxially slidably abutted with a vertical rod, the waterproof hammer cylinder is coaxially provided with an elastic buffer piece which is fixedly connected with the vertical rod, the lower end of a mounting disc is coaxially fixedly connected with a main sealing plug which is movably abutted with the inner wall of the waterproof hammer cylinder, and the vertical rod is fixedly connected with an outer sealing assembly which is used in cooperation with a sealing groove.

The invention relates to a metal-based composite material and a preparation method and application thereof, and belongs to the technical field of composite materials. The metal-based composite material comprises a substrate material and an active material loaded on the substrate material, the active material comprises a metal matrix and nano diamond particles distributed in the metal matrix; the nano diamond particle comprises a diamond inner core and an amorphous carbon layer, and the amorphous carbon layer coats at least part of the surface of the diamond inner core. The nano-diamond particles containing the amorphous carbon layer and the diamond core are utilized, so that the wettability of an interface electrolyte can be effectively improved, the structural stability of the material is improved, cracks and structural damage caused by volume expansion of the material are inhibited, the structural stability of the composite material is effectively improved, and the service life of the composite material is prolonged. And the transmission path of metal cations is optimized, and the cycle performance and high-rate charge-discharge performance of the material are improved.

This invention discloses a preparation method and application of Al2O3 self-reinforced zirconia medical ceramic material, belonging to the field of bioceramic material preparation. The preparation method includes the following steps: first, aluminum particles are surface passivated, then mixed with Y2O3-ZrO2 ceramic powder, a dispersant, and a binder to prepare a slurry; the slurry is obtained through spray granulation and dry pressing; finally, the finished product is obtained through atmosphere sintering, oxygen absorption reaction, and high-temperature sintering. This invention utilizes the volume expansion effect of in-situ generated Al2O3 to artificially introduce a beneficial local compressive stress field into the zirconia matrix, effectively compensating for the phase transformation strengthening effect lost due to increased yttrium oxide content. This achieves a synergistic improvement in the mechanical properties and anti-aging properties of zirconia all-ceramic materials, solving problems such as insufficient anti-aging performance of existing zirconia all-ceramic materials, significant strength decrease after adding yttrium oxide, and insufficient strengthening effect of traditional Al2O3 second-phase addition.

The invention discloses an axle laser cladding repairing method and structure based on gradient phase change regulation, and the method comprises the following steps: cladding an interface layer, a transition layer and a surface layer in sequence through a laser cladding method to form a gradient cladding structure; cladding the first mixed powder on the surface of the axle base body by adopting a low-heat input cladding process to form an interface layer; wherein high-Cr and Ni powder is adopted in the first mixed powder, and the first mixed powder is used for expanding the temperature interval of an austenite phase region; cladding the second mixed powder on the surface of the interface layer by adopting a slightly high heat input cladding process to form a transition layer; wherein the second mixed powder contains trace metal elements B and Mo; cladding the third mixed powder on the surface of the transition layer by adopting a rapid cooling cladding process to form a surface layer; wherein low-C and high-Si alloy powder is adopted as the third mixed powder, a lath martensite structure is formed, martensite phase change volume expansion is achieved, and surface pressure stress is introduced.

A composite material bonding assembly induced debonding method based on expansible graphite belongs to the technical field of sustainable application of composite materials, and comprises the following steps: adopting a shell-core structure preparation method, dissolving thermoplastic resin in a solvent, then uniformly dispersing expansible graphite in a mixed solution, filtering to obtain thermoplastic coating expansible graphite particles, and drying the thermoplastic coating expansible graphite particles to obtain the composite material bonding assembly. After surface treatment, filtration and drying, coupled thermoplastic coating expandable graphite particles are obtained through mechanical grinding; and dispersing the coupled thermoplastic coating and expandable graphite particles containing different particle sizes in an adhesive, and combining with a cementing assembly to complete cementing curing. When the glue joint assembly needs to be disassembled, the glue joint structure is heated, and the glue layer is cracked through volume expansion of the composite material to achieve debonding. By optimizing the expansion time-temperature design, the influence of too high expansion temperature on the performance of the assembly body in the glue joint structure is avoided, and obvious thermal damage to the body structure is avoided while induced debonding is achieved.

The invention relates to the technical field of steel production, and discloses a method for regulating and controlling residual stress of additive high-strength steel through cooperation of thermal cycle and martensite phase transformation, and the method comprises the following steps: S1, collecting process information; s2, establishing a digital twinborn model according to the process information and predicting a residual stress field; s3, cooperative control parameters are generated through a control algorithm; s4, the heat source output device is controlled to melt the raw materials to form a new layer of geometric structure; and S5, on the basis of the cooperative control parameters, residual stress generated by thermal shrinkage is compensated or counteracted through the volume expansion effect of martensite phase transformation. According to the method, the residual stress is predicted through the digital twinborn model, the control parameters are generated to control non-melting thermal cycle to trigger martensite phase transformation at a precise time-space point, thermal shrinkage stress is compensated through phase transformation volume expansion, and therefore the precision and predictability of stress regulation and control are improved.

The present invention discloses a method for predicting the mechanical properties of irradiated concrete based on ABAQUS, comprising the following steps: considering concrete as a composite material composed of three-phase mesoscopic materials: cement mortar, aggregate, and interface transition zone; adopting a CDP model based on field variables to consider the degradation law of the mechanical properties of the mesoscopic materials as their volume changes; establishing a finite element model of the concrete mesoscopic three-phase material in an ABAQUS static implicit solver and assigning material properties; setting an uneven temperature field and neutron fluence field based on the UTEMP subroutine and the USFLD subroutine, and controlling the volume expansion of the mesoscopic material over time based on the UEXPAN subroutine, thereby simulating the process of radiation-induced macroscopic volume change of concrete; and predicting the degradation law of the elastic properties and uniaxial compressive strength of the concrete through restart analysis.

The utility model discloses a novel water meter anti-freezing connecting pipe assembly which comprises an anti-freezing connecting pipe, a set of through holes are formed in the middle section of the anti-freezing connecting pipe in a winding mode, and an anti-explosion sleeve is arranged outside the through holes in a wrapping mode and made of tough materials. The explosion-proof sleeve is matched with the through hole to achieve bearing of volume expansion in a frozen state, due to the fact that the explosion-proof sleeve is made of tough materials, after the temperature rises and thawing is conducted, the explosion-proof pipe directly returns to the original position, the reutilization effect is achieved, resources are saved, meanwhile, the explosion-proof sleeve is composed of the upper wrapping sleeve and the lower wrapping sleeve, disassembly and assembly are convenient, and cost is low. The problem that an existing ultrasonic water meter cannot prevent freezing and explosion in a cold region is solved.

Provided is a heat exchanger that suppresses refrigerant leakage when water freezes and expands in volume. A heat exchanger (100) performs heat exchange between water and a refrigerant. A heat exchanger (100) is provided with a first flow path (111) through which water flows and a second flow path (121) through which a refrigerant flows. The member forming the first flow path (111) or the portion where the members forming the first flow path (111) are joined to each other functions as a fragile portion (190) having a lower strength than other portions. In a heat exchanger (100), when water freezes and expands in volume, members forming a first flow path (111) or portions where the members forming the first flow path (111) are joined, which function as fragile portions (190), break earlier than other portions. Therefore, according to the heat exchanger (100), when water freezes and the volume expands, the condition of refrigerant leakage caused by cracking of the parts or the joint parts forming the second flow path (121) can be inhibited.

A composite molded article in which thermoplastic resin expanded beads are bonded via a thermosetting resin binder, wherein the composite molded article has a density of 0.05 to 0.5 g / cm3, and when heated at 100° C. for 20 minutes, the composite molded article has a volume expansion rate of 15 to 200%.