Water-based architectural heat insulation coatings were studied to overcome the drawbacks of conventional inorganic silicate heat insulation coatings. The heat insulation coatings were prepared with the method of mech...Water-based architectural heat insulation coatings were studied to overcome the drawbacks of conventional inorganic silicate heat insulation coatings. The heat insulation coatings were prepared with the method of mechanical agitation when the mixed organic polymer emulsions were used as binder of the coatings and the mixed heat insulating aggregates were applied as powder, and some assistants were also added. Water temperature difference in the plastic container, which was coated with heat insulation coatings, represented the heat-insulating property of the coatings. The influences of components of mixed polymer emulsion, mass ratio of polymer emulsion to powder, particle size of heat insulating aggregates, added amount of air entraining admixture and the match of thickeners on the properties of the coatings were studied. The experimental results show that the heat insulation coatings with good finishing, heat-insulation property and artificial weathering can be prepared when the binder is composed of 66.92% styrene-acrylic emulsion, 16.59% elastic emulsion and 16.49% silicone-acrylic emulsion, the mass ratio of polymer emulsion to powder is 0.45, the particle size of heat insulating aggregates is in the rang of 200 and 250 mesh size, the added amount of sericite is 15%, and the added amount of air entraining admixture is in the range of 1.0% and 1.5% and the thickeners are the mixtures of ASE-60 and RM-5000.展开更多
It is necessary to develop burn-resistant and thermal barrier complex functional coatings on the titanium alloys surface due to the poor high temperature performance for titanium materials and the problem of“titanium...It is necessary to develop burn-resistant and thermal barrier complex functional coatings on the titanium alloys surface due to the poor high temperature performance for titanium materials and the problem of“titanium fire”which is easily happened.MTU Aero Engines GmbH has developed a complex functional coating which has great performance of burn resistant and sealing,the coatings has already been applied on compressor blades and casing for aero-engines and showed great performance.In this study,the complex functional coating which is composed of an electro-spark deposited amorphous Ti40Zr25Ni3 burn-resistant layer and a high-energy plasma spraying prepared YSZ thermal barrier layer was prepared on titanium alloys surface.Then the heat insulation ability,burn resistant performance and the bonding strength were investigated.The experimental results showed that the interface between the coating and the matrix was typical metallurgical bonded,and the average bonding strength was 36.335 MPa;when the temperature of the flame on the one side of the specimen reached 600℃,the average insulated temperature of the coating samples was 70.67℃;when the flame temperature was 350℃,the titanium samples without the complex functional coatings were burned,while the samples with the coating showed great performance of burn resistant even when the temperature was 750℃.This indicates that the new functional coating has good heat-insulating and burn-resistant performance.展开更多
Waste shell stacking with odor and toxicity is a serious hazard to our living environment. To make effective use of the natural resources, the shell powder was applied as a filler of outdoor thermal insulation coating...Waste shell stacking with odor and toxicity is a serious hazard to our living environment. To make effective use of the natural resources, the shell powder was applied as a filler of outdoor thermal insulation coatings. Sodium stearate(SS) was used to modify the properties of shell powder to reduce its agglomeration and to increase its compatibility with the emulsion. The oil absorption rate and the spectrum reflectance of the shell powder show that the optimized content of SS as a modifier is 1.5wt%. The total spectrum reflectance of the coating made with the shell powder that is modified at this optimum SS content is 9.33% higher than that without any modification. At the optimum SS content of 1.5wt%, the thermal insulation of the coatings is improved by 1.0℃ for the cement mortar board and 1.6℃ for the steel plate, respectively. The scouring resistance of the coating with the 1.5wt% SS-modified shell powder is three times that of the coating without modification.展开更多
The objective of this review is to present the results on the production techniques, process parameters and compositions of heat-resistant coatings for graphite and carbon-carbon composites. The data reported concern ...The objective of this review is to present the results on the production techniques, process parameters and compositions of heat-resistant coatings for graphite and carbon-carbon composites. The data reported concern the resistance of such protective coatings in air at temperatures up to 2273 K and in the high-speed flows of oxidizing gas media taking place in the spacecraft equipment. Coatings of this type, generally, have a multilayer structure based on the refractory compounds such as carbides, borides, silicides of transition metals and oxides with a high melting temperature. An efficient heat-resistant coating for carbon-based materials should be composed of three layers from which each fulfills its own function. The paper presents a new complex method for formation of heat-resistant coatings on the carbon-based materials. The method combines the vacuum-activated diffusion saturation in the presence of a liquid-phase and self-propagating high-temperature synthesis (SHS) simultaneously.展开更多
PEO ceramic coatings including ZrO_2-Al_2O_3-SiO_2 in three phases were prepared on an Al-12.5%Si alloy in electrolyte solutions containing ZrO_2 nanoparticles. The microstructures and phases of the coatings were anal...PEO ceramic coatings including ZrO_2-Al_2O_3-SiO_2 in three phases were prepared on an Al-12.5%Si alloy in electrolyte solutions containing ZrO_2 nanoparticles. The microstructures and phases of the coatings were analyzed by SEM and XRD, and the heat insulation performance and the thermal shock resistance of the coatings were investigated. The compactness of the coating increased significantly and the hindrance of the Si element on plasma electrolytic oxidation process was effectively weakened. The growth rate of the coating was improved substantially with the addition of ZrO_2 nanoparticles. The PEO ceramic coatings are primarily composed of SiO_2 and high temperature steady phases such as a-Al_2O_3 and c-ZrO_2. Both the content of c-ZrO_2 and the heat-insulating property of the coating increased significantly. The ceramic coatings with special microstructure and composition formed in the solutions containing ZrO_2 nanoparticles possess excellent heat insulation performance and thermal shock resistance.展开更多
WC-(W,Cr)2C-Ni coating was prepared on 1Cr18Ni9Ti stainless steel and C-276 Ni-base Hastelloy by high velocity oxy-fuel(HVOF)spraying.The effect of post heat treatment in air atmosphere on the microstructure,phase com...WC-(W,Cr)2C-Ni coating was prepared on 1Cr18Ni9Ti stainless steel and C-276 Ni-base Hastelloy by high velocity oxy-fuel(HVOF)spraying.The effect of post heat treatment in air atmosphere on the microstructure,phase composition,microhardness,fracture toughness,and wear resistance of HVOF-sprayed WC-(W,Cr)2C-Ni coating was investigated.The microstructure and phase composition of the coatings were analyzed by means of field emission scanning electron microscopy(FESEM)and X-ray diffraction(XRD).The microhardness and fracture toughness of the coatings were measured using a microhardness tester and a Vickers hardness tester.Moreover,dry friction and wear behavior of the coatings sliding against Si3N4 ball was investigated using an oscillating friction and wear tester;and the worn surfaces of the coatings were analyzed by means of scanning electron microscopy(SEM).It was found that heat treatment within 500-800°C resulted in crystallization of amorphous phase in as-sprayed coating,generating nanoscale new phases such as NiWO4,CrWO4 and Cr2WO6.Besides,heat treatment led to increase of the microhardness of as-sprayed coating,and the highest microhardness was obtained after heat treatment at 800°C.The fracture toughness and wear resistance of the as-sprayed coating increased with increasing heat treatment temperature up to 700°C but tended to decrease with further elevating temperature.In other words,the mechanical properties and wear resistance of the as-sprayed coatings were worsened owing to excessive growth of oxidation grains and depletion of ductile Ni binder after heat treatment above 700°C.Thus it was suggested that as-sprayed ceramic composite coating should be post heat treated in air at a moderate temperature of 700°C so as to achieve the optimized mechanical properties and wear resistance.展开更多
Selective laser melting of nickel-titanium alloy(SLM-NiTi)can precisely control the size of the sample molding structure and has attracted extensive attention due to its special superelasticity and shape memory effect...Selective laser melting of nickel-titanium alloy(SLM-NiTi)can precisely control the size of the sample molding structure and has attracted extensive attention due to its special superelasticity and shape memory effect.However,the biological inertness and poor corrosion resistance of SLM-NiTi alloy limit their wide application as biomedical implant materials.In this study,polycaprolactone(PCL)coating was prepared on SLM-NiTi alloy by dipping and pulling method,and the effects of alkali heat pretreatment on the morphology,adhesion,corrosion resistance,long-term stability and biomineralisation of the PCL coatings were investigated.The results showed that PCL coating can substan-tially improve the performance of SLM-NiTi alloy,and the PCL coating after alkali heat pretreatment has higher adhesion(increased from 1,747 to 2,498 mN)and lower corrosion current density(reduced by about an order of magnitude compared to PCL coating alone).In addition,the necessary stability,biomineralisation and biocompatibility ability of coatings were also further improved.Therefore,the alkali heat pretreated PCL-coated SLM-NiTi alloy has good application prospects in implants due to its superior properties.展开更多
Inconel 718 and Waspaloy, Nickel-based super-heat-resistant alloy, are high-strength, thermal-resistant and corrosion-resistant alloy that are widely used in parts of gas turbines and airplane engines. Due to their ex...Inconel 718 and Waspaloy, Nickel-based super-heat-resistant alloy, are high-strength, thermal-resistant and corrosion-resistant alloy that are widely used in parts of gas turbines and airplane engines. Due to their extremely tough and thermal-resistant nature, they are well known as materials that are difficult to cut. Shape holes on a disc of an aircraft engine, made of Ni-based super-heat-resistant alloy, are required with good surface integrity and geometric accuracy. This kind of shape hole is produced by EDM (Electro-discharge machining) currently. It is necessary to investigate an alternative machining process to reduce the process time and improve the surface quality. This paper presents an experimental study on the machining methods for the shape hole of Ni-base super-heat-resistant alloy Inconel 718 and Waspaloy. The feasibility using milling or/and grinding as an alternative for currently EDM process to machine shape holes is assessed by observing the wear and breakage of the cutting tools and grinder and analyzing the hole surface integrity and geometric accuracy. The results show that the milling process of Inconel 718 and Waspaloy can produce shape holes with acceptable surface roughness and geometric accuracy efficiently. The machined Waspaloy shape holes reveal a slight decrease tendency in section dimension from the top of the its bottom. There is a larger deviation from the nominal profile at the segment with smaller radius. A thin softened surface layer with thickness smaller than 60 μm occurs on the machined Waspaloy shape holes. The softening and work hardening become remarkable with the progress of tool wear.展开更多
The cutting friction, cutting deformation, producing heat, conducting heat, temperature field of TiN coated HSS tools in the cutting process are discussed profoundly. In order to make clear the heat property of TiN co...The cutting friction, cutting deformation, producing heat, conducting heat, temperature field of TiN coated HSS tools in the cutting process are discussed profoundly. In order to make clear the heat property of TiN coated tools, from the micromechanism angle, the relationship of the heat property and the crystal structure of TiN compound is analyzed, and the regularity of TiN compound crystal structure changing with temperature rising is sought. The difference of the wear resistance and heat resistance of TiN coated tools deposited by c1 and c2 depositing techniques is proved by tests. The conclusions will offer the theoretical basis for correct design of geometrical parameters of TiN coated tools, rational selection of cutting regimes and optimization of the depositing technique.展开更多
非固化橡胶沥青防水涂料高温性能较低,无法应用于立面、坡屋面等位置,且130℃时黏度高,需加热到160℃以上才可进行施工,消耗大量能源和废气的排放。开发了特种非固化橡胶沥青防水涂料的配方。并分析SBS、SBR、橡胶粉、沥青和软化油、无...非固化橡胶沥青防水涂料高温性能较低,无法应用于立面、坡屋面等位置,且130℃时黏度高,需加热到160℃以上才可进行施工,消耗大量能源和废气的排放。开发了特种非固化橡胶沥青防水涂料的配方。并分析SBS、SBR、橡胶粉、沥青和软化油、无机填料、分散助剂和C5石油树脂等原材料对其性能的影响。结果表明:特种非固化橡胶沥青防水涂料相对普通非固化橡胶沥青防水涂料软化点提高35℃,耐热性提高30℃,130℃黏度降低1810 m Pa·s,90℃时与防水卷材不发生滑移,具有高耐热性、低黏度的特点,可用于立面、坡屋面防水,可在130℃施工,降低能源消耗。展开更多
基金Funded by the Scientific Research Foundation for Postdoctor(20061023)
文摘Water-based architectural heat insulation coatings were studied to overcome the drawbacks of conventional inorganic silicate heat insulation coatings. The heat insulation coatings were prepared with the method of mechanical agitation when the mixed organic polymer emulsions were used as binder of the coatings and the mixed heat insulating aggregates were applied as powder, and some assistants were also added. Water temperature difference in the plastic container, which was coated with heat insulation coatings, represented the heat-insulating property of the coatings. The influences of components of mixed polymer emulsion, mass ratio of polymer emulsion to powder, particle size of heat insulating aggregates, added amount of air entraining admixture and the match of thickeners on the properties of the coatings were studied. The experimental results show that the heat insulation coatings with good finishing, heat-insulation property and artificial weathering can be prepared when the binder is composed of 66.92% styrene-acrylic emulsion, 16.59% elastic emulsion and 16.49% silicone-acrylic emulsion, the mass ratio of polymer emulsion to powder is 0.45, the particle size of heat insulating aggregates is in the rang of 200 and 250 mesh size, the added amount of sericite is 15%, and the added amount of air entraining admixture is in the range of 1.0% and 1.5% and the thickeners are the mixtures of ASE-60 and RM-5000.
文摘It is necessary to develop burn-resistant and thermal barrier complex functional coatings on the titanium alloys surface due to the poor high temperature performance for titanium materials and the problem of“titanium fire”which is easily happened.MTU Aero Engines GmbH has developed a complex functional coating which has great performance of burn resistant and sealing,the coatings has already been applied on compressor blades and casing for aero-engines and showed great performance.In this study,the complex functional coating which is composed of an electro-spark deposited amorphous Ti40Zr25Ni3 burn-resistant layer and a high-energy plasma spraying prepared YSZ thermal barrier layer was prepared on titanium alloys surface.Then the heat insulation ability,burn resistant performance and the bonding strength were investigated.The experimental results showed that the interface between the coating and the matrix was typical metallurgical bonded,and the average bonding strength was 36.335 MPa;when the temperature of the flame on the one side of the specimen reached 600℃,the average insulated temperature of the coating samples was 70.67℃;when the flame temperature was 350℃,the titanium samples without the complex functional coatings were burned,while the samples with the coating showed great performance of burn resistant even when the temperature was 750℃.This indicates that the new functional coating has good heat-insulating and burn-resistant performance.
文摘Waste shell stacking with odor and toxicity is a serious hazard to our living environment. To make effective use of the natural resources, the shell powder was applied as a filler of outdoor thermal insulation coatings. Sodium stearate(SS) was used to modify the properties of shell powder to reduce its agglomeration and to increase its compatibility with the emulsion. The oil absorption rate and the spectrum reflectance of the shell powder show that the optimized content of SS as a modifier is 1.5wt%. The total spectrum reflectance of the coating made with the shell powder that is modified at this optimum SS content is 9.33% higher than that without any modification. At the optimum SS content of 1.5wt%, the thermal insulation of the coatings is improved by 1.0℃ for the cement mortar board and 1.6℃ for the steel plate, respectively. The scouring resistance of the coating with the 1.5wt% SS-modified shell powder is three times that of the coating without modification.
文摘The objective of this review is to present the results on the production techniques, process parameters and compositions of heat-resistant coatings for graphite and carbon-carbon composites. The data reported concern the resistance of such protective coatings in air at temperatures up to 2273 K and in the high-speed flows of oxidizing gas media taking place in the spacecraft equipment. Coatings of this type, generally, have a multilayer structure based on the refractory compounds such as carbides, borides, silicides of transition metals and oxides with a high melting temperature. An efficient heat-resistant coating for carbon-based materials should be composed of three layers from which each fulfills its own function. The paper presents a new complex method for formation of heat-resistant coatings on the carbon-based materials. The method combines the vacuum-activated diffusion saturation in the presence of a liquid-phase and self-propagating high-temperature synthesis (SHS) simultaneously.
基金Funded by the National Natural Science Foundation of China(Nos.51401155 and 51771140)Key Research and Development Plan in Shaanxi(No.2018GY-111)+1 种基金Shaanxi Provincial Department of Education Industrialization Cultivation Project(No.17JF009)Yulin Science and Technology Project(No.2016-16-4)and Shaanxi Science and Technology Co-ordination Innovation Project(No.2016KTZDGY-04-01)
文摘PEO ceramic coatings including ZrO_2-Al_2O_3-SiO_2 in three phases were prepared on an Al-12.5%Si alloy in electrolyte solutions containing ZrO_2 nanoparticles. The microstructures and phases of the coatings were analyzed by SEM and XRD, and the heat insulation performance and the thermal shock resistance of the coatings were investigated. The compactness of the coating increased significantly and the hindrance of the Si element on plasma electrolytic oxidation process was effectively weakened. The growth rate of the coating was improved substantially with the addition of ZrO_2 nanoparticles. The PEO ceramic coatings are primarily composed of SiO_2 and high temperature steady phases such as a-Al_2O_3 and c-ZrO_2. Both the content of c-ZrO_2 and the heat-insulating property of the coating increased significantly. The ceramic coatings with special microstructure and composition formed in the solutions containing ZrO_2 nanoparticles possess excellent heat insulation performance and thermal shock resistance.
基金Innovative Group Foundation from National Natural Science Foundations of China(50421502)National"973"Project(2007CB607601)
文摘WC-(W,Cr)2C-Ni coating was prepared on 1Cr18Ni9Ti stainless steel and C-276 Ni-base Hastelloy by high velocity oxy-fuel(HVOF)spraying.The effect of post heat treatment in air atmosphere on the microstructure,phase composition,microhardness,fracture toughness,and wear resistance of HVOF-sprayed WC-(W,Cr)2C-Ni coating was investigated.The microstructure and phase composition of the coatings were analyzed by means of field emission scanning electron microscopy(FESEM)and X-ray diffraction(XRD).The microhardness and fracture toughness of the coatings were measured using a microhardness tester and a Vickers hardness tester.Moreover,dry friction and wear behavior of the coatings sliding against Si3N4 ball was investigated using an oscillating friction and wear tester;and the worn surfaces of the coatings were analyzed by means of scanning electron microscopy(SEM).It was found that heat treatment within 500-800°C resulted in crystallization of amorphous phase in as-sprayed coating,generating nanoscale new phases such as NiWO4,CrWO4 and Cr2WO6.Besides,heat treatment led to increase of the microhardness of as-sprayed coating,and the highest microhardness was obtained after heat treatment at 800°C.The fracture toughness and wear resistance of the as-sprayed coating increased with increasing heat treatment temperature up to 700°C but tended to decrease with further elevating temperature.In other words,the mechanical properties and wear resistance of the as-sprayed coatings were worsened owing to excessive growth of oxidation grains and depletion of ductile Ni binder after heat treatment above 700°C.Thus it was suggested that as-sprayed ceramic composite coating should be post heat treated in air at a moderate temperature of 700°C so as to achieve the optimized mechanical properties and wear resistance.
基金The Natural Science Foundation of Shandong Province,Grant/Award Number:ZR2021QE263The Open Project Program of Key Laboratory for Cross‐Scale Micro and Nano Manufacturing,Minstry of Education,Changchun University of Science and Technology,Grant/Award Number:CMNM‐KF202109+5 种基金The Ascl‐zytsxm,Grant/Award Number:202013The Interdisciplinary Research Fund for Doctoral Postgraduates of Jilin University,Grant/Award Number:101832020DJX052National Natural Science Foundation of China,Grant/Award Number:51975246The Program for JLU Science and Technology Innovative Research Team,Grant/Award Number:2019TD‐34Science and Technology Development Program of Jilin Province,Grant/Award Number:YDZJ202101ZYTS134The Interdisciplinary Cultivation Project for Young Teachers and Students,Grant/Award Number:415010300078。
文摘Selective laser melting of nickel-titanium alloy(SLM-NiTi)can precisely control the size of the sample molding structure and has attracted extensive attention due to its special superelasticity and shape memory effect.However,the biological inertness and poor corrosion resistance of SLM-NiTi alloy limit their wide application as biomedical implant materials.In this study,polycaprolactone(PCL)coating was prepared on SLM-NiTi alloy by dipping and pulling method,and the effects of alkali heat pretreatment on the morphology,adhesion,corrosion resistance,long-term stability and biomineralisation of the PCL coatings were investigated.The results showed that PCL coating can substan-tially improve the performance of SLM-NiTi alloy,and the PCL coating after alkali heat pretreatment has higher adhesion(increased from 1,747 to 2,498 mN)and lower corrosion current density(reduced by about an order of magnitude compared to PCL coating alone).In addition,the necessary stability,biomineralisation and biocompatibility ability of coatings were also further improved.Therefore,the alkali heat pretreated PCL-coated SLM-NiTi alloy has good application prospects in implants due to its superior properties.
文摘Inconel 718 and Waspaloy, Nickel-based super-heat-resistant alloy, are high-strength, thermal-resistant and corrosion-resistant alloy that are widely used in parts of gas turbines and airplane engines. Due to their extremely tough and thermal-resistant nature, they are well known as materials that are difficult to cut. Shape holes on a disc of an aircraft engine, made of Ni-based super-heat-resistant alloy, are required with good surface integrity and geometric accuracy. This kind of shape hole is produced by EDM (Electro-discharge machining) currently. It is necessary to investigate an alternative machining process to reduce the process time and improve the surface quality. This paper presents an experimental study on the machining methods for the shape hole of Ni-base super-heat-resistant alloy Inconel 718 and Waspaloy. The feasibility using milling or/and grinding as an alternative for currently EDM process to machine shape holes is assessed by observing the wear and breakage of the cutting tools and grinder and analyzing the hole surface integrity and geometric accuracy. The results show that the milling process of Inconel 718 and Waspaloy can produce shape holes with acceptable surface roughness and geometric accuracy efficiently. The machined Waspaloy shape holes reveal a slight decrease tendency in section dimension from the top of the its bottom. There is a larger deviation from the nominal profile at the segment with smaller radius. A thin softened surface layer with thickness smaller than 60 μm occurs on the machined Waspaloy shape holes. The softening and work hardening become remarkable with the progress of tool wear.
文摘The cutting friction, cutting deformation, producing heat, conducting heat, temperature field of TiN coated HSS tools in the cutting process are discussed profoundly. In order to make clear the heat property of TiN coated tools, from the micromechanism angle, the relationship of the heat property and the crystal structure of TiN compound is analyzed, and the regularity of TiN compound crystal structure changing with temperature rising is sought. The difference of the wear resistance and heat resistance of TiN coated tools deposited by c1 and c2 depositing techniques is proved by tests. The conclusions will offer the theoretical basis for correct design of geometrical parameters of TiN coated tools, rational selection of cutting regimes and optimization of the depositing technique.
文摘非固化橡胶沥青防水涂料高温性能较低,无法应用于立面、坡屋面等位置,且130℃时黏度高,需加热到160℃以上才可进行施工,消耗大量能源和废气的排放。开发了特种非固化橡胶沥青防水涂料的配方。并分析SBS、SBR、橡胶粉、沥青和软化油、无机填料、分散助剂和C5石油树脂等原材料对其性能的影响。结果表明:特种非固化橡胶沥青防水涂料相对普通非固化橡胶沥青防水涂料软化点提高35℃,耐热性提高30℃,130℃黏度降低1810 m Pa·s,90℃时与防水卷材不发生滑移,具有高耐热性、低黏度的特点,可用于立面、坡屋面防水,可在130℃施工,降低能源消耗。
