The hardness values and the wear resistance of Al2O3P/ Zn-Al composite, prepared by means of rheological casting technology,are investigated separately in this work. The results show that the addition of Al2O3P increa...The hardness values and the wear resistance of Al2O3P/ Zn-Al composite, prepared by means of rheological casting technology,are investigated separately in this work. The results show that the addition of Al2O3P increases the hardness values of the matrix at both room and high temperature and improves the wear resistance of the material.The hardness values and the wear resistance of the composite rise with the increase of the particle volume fraction or the decrease of the particle size.The raising of test temperature results in a rapid descending of its hardness values.However, the addition of Al2O3P improves the property of high temperature resistance of Zn-Al alloys significantly.Moreover,the effect of quenching, tempering or cycling heat treatment on the hardness values of the composite is also studied.展开更多
WC-Co reinforced C276 alloy composite coatings are fabricated on Q235 steel by laser melting deposition.The microstructure,hardness,wear performance,and electrochemical corrosion behavior of composite coating are stud...WC-Co reinforced C276 alloy composite coatings are fabricated on Q235 steel by laser melting deposition.The microstructure,hardness,wear performance,and electrochemical corrosion behavior of composite coating are studied.The results show that WC-Co particles are mostly uniformly distributed in the coating and provide favorable conditions for heterogeneous nucleation.The microstructure of C276/WC-Co composite coatings is composed of γ-Ni solid solution dendrites and MoNi solid solution eutectics.The WC-Co particles can effectively improve the hardness and wear resistance of C276 alloy.The average hardness of the composite coating containing 10-wt% WC-Co(447 HV_(0.2)) are 1.26 times higher than that of the C276 alloy(356 HV_(0.2)).The wear rate of composite coating containing 10-wt% WC-Co(6.95 ×10^(-3) mg/m) is just 3.5% of that of C276 coating(196.23 × 10^(-3) mg/m).However,comparing with Hastelloy C276,the corrosion resistance of C276/WC-Co composite coating decreases.展开更多
Metal matrix self-lubricating materials lie at the core of cutting-edge aerospace,mechanical,and electrical industries,which demand technological performances that cannot be met by traditional liquid lubricants.Rapid ...Metal matrix self-lubricating materials lie at the core of cutting-edge aerospace,mechanical,and electrical industries,which demand technological performances that cannot be met by traditional liquid lubricants.Rapid innovation in nanocarbon materials in recent years enabled rapid development of advanced nanocomposites for applications in structural engineering and functional devices.Carbonous materials(e.g.,graphite,graphene and carbon nanotubes),exhibit a wide range of unique electrical,mechanical,and thermal properties,which are also considered ideal lubricating reinforcements for metal matrix nanocomposites(MMCs)with superior mechanical and tribological properties.In this review,we first showcase the distinctive features of the constituents commonly employed in self-lubricating MMCs,encompassing the high-strength metallic matrix and nano-carbonous reinforcement.Then,we present a comprehensive overview of the recent advancements in preparation techniques for these advanced MMCs,followed by an in-depth discussion on their corresponding tribological properties and wear mechanisms.We close this review by outlining key problems to be solved and the future trend of the development in self-lubricating MMCs.展开更多
TiN films were deposited on 2A12 aluminum alloy by arc ion plating (AIP). The Vickers hardness of the films deposited at different bias voltages and different nitrogen gas pressures, and that of the substrate were mea...TiN films were deposited on 2A12 aluminum alloy by arc ion plating (AIP). The Vickers hardness of the films deposited at different bias voltages and different nitrogen gas pressures, and that of the substrate were measured. The surface roughness of the TiN films diposited at –30 V and –80 V respectively and at different nitrogen gas pressure was measured also. The mass loss of TiN films deposited at 0 V, –30 V and –80 V respectively were analyzed in dry sand rubber wheel abrasive wear tests and wet ones in comparison with uncoated Al alloy and austenitic stainless steel (AISI 316L). It is revealed that the highest hardness of the TiN film is obtained at a bias voltage of –30 V and a N2 gas pressure of 0.5 Pa. The surface roughness of the film is larger at –80 V than that at –30 V and reduces as the increase of the N2 gas pressure. The mass loss of TiN-film coated 2A12 aluminum alloy is remarkably less than that of uncoated Al alloy and also that of AISI 316L, which indicates that the abrasive wear rate is greatly reduced by the application of TiN coating. TiN coating deposited by arc ion plating (AIP) technique on aluminum alloy can be a potential coating for machine parts requiring preciseness and lightness.展开更多
In this paper, the influeuce of B on mechanical properties and microstructure of weld metal from B4C surfacing alloy is studied’ Results show that increasing boron content leads to sharp increasing of harduess and we...In this paper, the influeuce of B on mechanical properties and microstructure of weld metal from B4C surfacing alloy is studied’ Results show that increasing boron content leads to sharp increasing of harduess and wear-resistance of weld metal’ And micrestructure transforms gradually from hypoeutectoid to hypereutectic with Fe3C-type carbide transforming into Fe3 (C, B)- and Fe23 (C, B ),-type carbon-boride. And in hypereutectic micrestructure even segregates out high-hardness phase Fe2B. As eutectic mainly consists of a phase and Fe23 (C,B),’ Fe3 (C,B) and distributes homogenously in network, which makes surfaced alloy have kigh impact resistance.展开更多
Severe production conditions in coal mines cause damage and failure problems with the oriented sliding boots of the mechanical shearer. Wear has been an especially vexing problem. Plasma cladding methods were used to ...Severe production conditions in coal mines cause damage and failure problems with the oriented sliding boots of the mechanical shearer. Wear has been an especially vexing problem. Plasma cladding methods were used to study optimized sliding boot design. By cladding the substrate steel the surface may be made of a material more resistant to wear. The iron based alloy Cr4MnTi was coated onto a modified 45 steel matrix material in these tests. The results show that the alloy cladding layer is high strength, has high hardness, and is highly resistant to wear. After hardening and tempering, 45 steel substrate has great tenacity so the combined structure meets the performance requirements for the construction of shearer sliding boots.展开更多
： Successful co-deposition of fine particulate matter within an Electroless Nickel-Phosphorous （ENi-P） matrix is dependent on various factors like bath composition, particle compatibility with metallic matrix, bath...： Successful co-deposition of fine particulate matter within an Electroless Nickel-Phosphorous （ENi-P） matrix is dependent on various factors like bath composition, particle compatibility with metallic matrix, bath reactivity （pH）, particle size and their distribution. ENi-P deposits incorporating Al2O3/ Alumina in a disperse phase have varied effects on properties and attributes like surface roughness （Ra／ microhardness, wear resistance, corrosion resistance and surface morphology of the deposits obtained. This paper experimentally investigates the effect of alumina （1.55 g/L） on Ra, microhardness, surface morphology, deposition rate, wettability, wear resistance and corrosion resistance of ENi-P-Al2O3 composite deposits on mild steel substrates at bath pH 5, 7 and 9. Study reveals that optimum deposit parameters and deposition rates are achieved with bath pH. However, not much study has been undertaken concerning composite deposits obtained from higher bath pH or basic bath. This is attributable to the fact that at higher bath pH or alkaline baths, the bath gets unstable and eventually degrades or decomposes, thereby resulting in sub optimal or poor deposition. Hence, experimental investigations carried out by preparing suitable baths, operating under optimum conditions, and enabling successful composite deposition in acidic and alkaline baths have revealed that there is a significant improvement in the above mentioned properties of the as-deposited composite deposits, as the pH is increased from pH 5 to pH 9. This aspect can therefore be advantageously utilized for preparing various marine components like fasteners, nuts, bolts, washers, pipes, cables, components having relative motion etc.展开更多
Nb/Ta multilayer films deposited on Ti6A14V substrate with Nb and Ta monolayer thicknesses of 30 nm, 120 nm, and 240 nm were irradiated by a high current pulse electron beam （HCPEB） to prepare Nb-Ta alloyed layers. ...Nb/Ta multilayer films deposited on Ti6A14V substrate with Nb and Ta monolayer thicknesses of 30 nm, 120 nm, and 240 nm were irradiated by a high current pulse electron beam （HCPEB） to prepare Nb-Ta alloyed layers. The mi- crostructure and the composition of the outmost surface of melted alloyed layers were investigated using a transmission electron microscope （TEM） equipped with an X-ray energy dispersive spectrometer （EDS） attachment. The Ta content of the alloyed surface layer prepared from the monolayer of thickness 30 nm, 120 nm, and 240 nm was- 27.7 at.%, 6.37 at.%, and 0 at.%, respectively. It was found that the Ta content in the alloyed layer plays a dominant role in the microstructure of the films. The hardness and the wear rate of the alloyed layers decrease with the increasing content of Ta in the surface laver.展开更多
Based on the structure,working principle,and working conditions of conductance water cut sensor,it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well ...Based on the structure,working principle,and working conditions of conductance water cut sensor,it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well fluid erosion,electrochemical corrosion,and oil pollution during its long-term service in the downhole.A technology for electrode surface treatment is proposed using boron-doped diamond(BDD)films to improve the service performance of the modified electrode.The hot wire chemical vapor deposition method was adopted to fabricate BDD film,the boron doping concentration and deposition time were optimized,and fluorination treatment was applied to improve the wear resistance,electrochemical corrosion resistance,and oleophobic property of the BDD film comprehensively.The results showed that BDD film with boron doping concentration of 6×10^(-3) exhibited high wear resistance and good electrochemical corrosion resistance,and endowed the modified electrode with superior erosion resistance and corrosion resistance.The friction coefficient and wear rate of BDD modified electrode were 92%and 78%lower than those of Invar alloy,also,the low-frequency impedance modulus value of the modified electrode was higher than 1×10^(4) Ω·cm^(2).The BDD film prepared with a deposition time of 8 h had a favorable micro-nano structure owing to small grain size and uniform distribution.Such morphology was conducive to enhancing the oleophobic performance of the modified electrode,and its contact angle in the simulated well fluid was high to 102°.The engineering applicability of BDD film modified electrode under simulated working conditions indicated that,the modified electrode had excellent comprehensive performances of erosion resistance,electrochemical corrosion resistance and oil adhesion resistance,and can realize the long-term stable operation of the conductance water cut sensor under harsh downhole conditions.展开更多
文摘The hardness values and the wear resistance of Al2O3P/ Zn-Al composite, prepared by means of rheological casting technology,are investigated separately in this work. The results show that the addition of Al2O3P increases the hardness values of the matrix at both room and high temperature and improves the wear resistance of the material.The hardness values and the wear resistance of the composite rise with the increase of the particle volume fraction or the decrease of the particle size.The raising of test temperature results in a rapid descending of its hardness values.However, the addition of Al2O3P improves the property of high temperature resistance of Zn-Al alloys significantly.Moreover,the effect of quenching, tempering or cycling heat treatment on the hardness values of the composite is also studied.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFB1103604)the Industrial Transformation and Upgrading Funds of the Ministry of Industry and Information Technology,China(Grant No.RZJC-XM19-004)+2 种基金the Tianjin Municipal Special Program of Talents Development for Excellent Youth Scholars,China(Grant No.TJTZJH-QNBJRC-2-15)the National Natural Science Foundation of China(Grant No.61475117)the Scientific Research Program of Tianjin Municipal Education Commission,China(Grant No.2018KJ206)。
文摘WC-Co reinforced C276 alloy composite coatings are fabricated on Q235 steel by laser melting deposition.The microstructure,hardness,wear performance,and electrochemical corrosion behavior of composite coating are studied.The results show that WC-Co particles are mostly uniformly distributed in the coating and provide favorable conditions for heterogeneous nucleation.The microstructure of C276/WC-Co composite coatings is composed of γ-Ni solid solution dendrites and MoNi solid solution eutectics.The WC-Co particles can effectively improve the hardness and wear resistance of C276 alloy.The average hardness of the composite coating containing 10-wt% WC-Co(447 HV_(0.2)) are 1.26 times higher than that of the C276 alloy(356 HV_(0.2)).The wear rate of composite coating containing 10-wt% WC-Co(6.95 ×10^(-3) mg/m) is just 3.5% of that of C276 coating(196.23 × 10^(-3) mg/m).However,comparing with Hastelloy C276,the corrosion resistance of C276/WC-Co composite coating decreases.
基金support by the National Key Research and Development Program of China(2022YFB3809000)the Natural Science Foundation of China(No.52175188)+2 种基金Key Research and Development Program of Shaanxi Province(2023-YBGY-434)the Open Fund of Liaoning Provincial Key Laboratory of Aero-engine Materials Tribology(Grant No.LKLAMTF202301)State Key Laboratory for Mechanical Behavior of Materials(20222412).
文摘Metal matrix self-lubricating materials lie at the core of cutting-edge aerospace,mechanical,and electrical industries,which demand technological performances that cannot be met by traditional liquid lubricants.Rapid innovation in nanocarbon materials in recent years enabled rapid development of advanced nanocomposites for applications in structural engineering and functional devices.Carbonous materials(e.g.,graphite,graphene and carbon nanotubes),exhibit a wide range of unique electrical,mechanical,and thermal properties,which are also considered ideal lubricating reinforcements for metal matrix nanocomposites(MMCs)with superior mechanical and tribological properties.In this review,we first showcase the distinctive features of the constituents commonly employed in self-lubricating MMCs,encompassing the high-strength metallic matrix and nano-carbonous reinforcement.Then,we present a comprehensive overview of the recent advancements in preparation techniques for these advanced MMCs,followed by an in-depth discussion on their corresponding tribological properties and wear mechanisms.We close this review by outlining key problems to be solved and the future trend of the development in self-lubricating MMCs.
文摘TiN films were deposited on 2A12 aluminum alloy by arc ion plating (AIP). The Vickers hardness of the films deposited at different bias voltages and different nitrogen gas pressures, and that of the substrate were measured. The surface roughness of the TiN films diposited at –30 V and –80 V respectively and at different nitrogen gas pressure was measured also. The mass loss of TiN films deposited at 0 V, –30 V and –80 V respectively were analyzed in dry sand rubber wheel abrasive wear tests and wet ones in comparison with uncoated Al alloy and austenitic stainless steel (AISI 316L). It is revealed that the highest hardness of the TiN film is obtained at a bias voltage of –30 V and a N2 gas pressure of 0.5 Pa. The surface roughness of the film is larger at –80 V than that at –30 V and reduces as the increase of the N2 gas pressure. The mass loss of TiN-film coated 2A12 aluminum alloy is remarkably less than that of uncoated Al alloy and also that of AISI 316L, which indicates that the abrasive wear rate is greatly reduced by the application of TiN coating. TiN coating deposited by arc ion plating (AIP) technique on aluminum alloy can be a potential coating for machine parts requiring preciseness and lightness.
文摘In this paper, the influeuce of B on mechanical properties and microstructure of weld metal from B4C surfacing alloy is studied’ Results show that increasing boron content leads to sharp increasing of harduess and wear-resistance of weld metal’ And micrestructure transforms gradually from hypoeutectoid to hypereutectic with Fe3C-type carbide transforming into Fe3 (C, B)- and Fe23 (C, B ),-type carbon-boride. And in hypereutectic micrestructure even segregates out high-hardness phase Fe2B. As eutectic mainly consists of a phase and Fe23 (C,B),’ Fe3 (C,B) and distributes homogenously in network, which makes surfaced alloy have kigh impact resistance.
基金Financial support for this work, provided by the fundingsupport: the National Natural Science Foundation General Projects(No. 51075387)the National "Eleventh Five-Year" Plan Major Projects supported by the National Science and Technology (No.2008BAB36B02)
文摘Severe production conditions in coal mines cause damage and failure problems with the oriented sliding boots of the mechanical shearer. Wear has been an especially vexing problem. Plasma cladding methods were used to study optimized sliding boot design. By cladding the substrate steel the surface may be made of a material more resistant to wear. The iron based alloy Cr4MnTi was coated onto a modified 45 steel matrix material in these tests. The results show that the alloy cladding layer is high strength, has high hardness, and is highly resistant to wear. After hardening and tempering, 45 steel substrate has great tenacity so the combined structure meets the performance requirements for the construction of shearer sliding boots.
文摘： Successful co-deposition of fine particulate matter within an Electroless Nickel-Phosphorous （ENi-P） matrix is dependent on various factors like bath composition, particle compatibility with metallic matrix, bath reactivity （pH）, particle size and their distribution. ENi-P deposits incorporating Al2O3/ Alumina in a disperse phase have varied effects on properties and attributes like surface roughness （Ra／ microhardness, wear resistance, corrosion resistance and surface morphology of the deposits obtained. This paper experimentally investigates the effect of alumina （1.55 g/L） on Ra, microhardness, surface morphology, deposition rate, wettability, wear resistance and corrosion resistance of ENi-P-Al2O3 composite deposits on mild steel substrates at bath pH 5, 7 and 9. Study reveals that optimum deposit parameters and deposition rates are achieved with bath pH. However, not much study has been undertaken concerning composite deposits obtained from higher bath pH or basic bath. This is attributable to the fact that at higher bath pH or alkaline baths, the bath gets unstable and eventually degrades or decomposes, thereby resulting in sub optimal or poor deposition. Hence, experimental investigations carried out by preparing suitable baths, operating under optimum conditions, and enabling successful composite deposition in acidic and alkaline baths have revealed that there is a significant improvement in the above mentioned properties of the as-deposited composite deposits, as the pH is increased from pH 5 to pH 9. This aspect can therefore be advantageously utilized for preparing various marine components like fasteners, nuts, bolts, washers, pipes, cables, components having relative motion etc.
基金Project supported by the National Basic Research Program of China (Grant No. 2013CB632305)the Guangdong Province University-Industry Cooperation Project of the Ministry of Education, China (Grant No. 2010B090400444)+1 种基金the Guangdong International Cooperation Projects, China (Grant No. 2010B050900003)the Guangdong Science and Technology Plan Projects, China (Grant No. 2010A070500002)
文摘Nb/Ta multilayer films deposited on Ti6A14V substrate with Nb and Ta monolayer thicknesses of 30 nm, 120 nm, and 240 nm were irradiated by a high current pulse electron beam （HCPEB） to prepare Nb-Ta alloyed layers. The mi- crostructure and the composition of the outmost surface of melted alloyed layers were investigated using a transmission electron microscope （TEM） equipped with an X-ray energy dispersive spectrometer （EDS） attachment. The Ta content of the alloyed surface layer prepared from the monolayer of thickness 30 nm, 120 nm, and 240 nm was- 27.7 at.%, 6.37 at.%, and 0 at.%, respectively. It was found that the Ta content in the alloyed layer plays a dominant role in the microstructure of the films. The hardness and the wear rate of the alloyed layers decrease with the increasing content of Ta in the surface laver.
基金Supported by the Basic Science Center Project of National Natural Science Foundation of China(72088101)Scientific Research and Technology Development Project of CNPC(2021ZG12)National Key R&D Plan/Key Project of International Scientific and Technological Innovation Cooperation Between Governments(2018YFE0196000).
文摘Based on the structure,working principle,and working conditions of conductance water cut sensor,it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well fluid erosion,electrochemical corrosion,and oil pollution during its long-term service in the downhole.A technology for electrode surface treatment is proposed using boron-doped diamond(BDD)films to improve the service performance of the modified electrode.The hot wire chemical vapor deposition method was adopted to fabricate BDD film,the boron doping concentration and deposition time were optimized,and fluorination treatment was applied to improve the wear resistance,electrochemical corrosion resistance,and oleophobic property of the BDD film comprehensively.The results showed that BDD film with boron doping concentration of 6×10^(-3) exhibited high wear resistance and good electrochemical corrosion resistance,and endowed the modified electrode with superior erosion resistance and corrosion resistance.The friction coefficient and wear rate of BDD modified electrode were 92%and 78%lower than those of Invar alloy,also,the low-frequency impedance modulus value of the modified electrode was higher than 1×10^(4) Ω·cm^(2).The BDD film prepared with a deposition time of 8 h had a favorable micro-nano structure owing to small grain size and uniform distribution.Such morphology was conducive to enhancing the oleophobic performance of the modified electrode,and its contact angle in the simulated well fluid was high to 102°.The engineering applicability of BDD film modified electrode under simulated working conditions indicated that,the modified electrode had excellent comprehensive performances of erosion resistance,electrochemical corrosion resistance and oil adhesion resistance,and can realize the long-term stable operation of the conductance water cut sensor under harsh downhole conditions.
