The work in this study is focused on the investigation of the structure and properties of ductile cast iron with nanoparticle additives： TiN （titanium nitride）, TiN ＋ TiCN （titanium carbonitride） and cBN （cubic...The work in this study is focused on the investigation of the structure and properties of ductile cast iron with nanoparticle additives： TiN （titanium nitride）, TiN ＋ TiCN （titanium carbonitride） and cBN （cubic boron nitride）. The nanoparticles are coated with nickel prior to addition to the iron melt to improve their wetting and uniform distribution in the volume of the casting. The metallographic observation and wear test are performed to study the influence of the nanoparticle additives on the microstructure and and cast iron tribological properties.展开更多
Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface....Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface. Nowadays environmental protection has been gaining significance and becoming highly important for the various innovation strategies. In rubber industry the concept of environmental protection is more often associated with the maximum use of elastomers and ingredients from renewable sources in the manufacture of rubber products. The aim of this work is to investigate the possibilities of using elastomers and ingredients from renewable sources—epoxidized natural rubber, silica obtained by rice husks incineration and microcrystalline cellulose—as fillers and rapeseed oil as a process additive in compositions, intended for the manufacture of soles for winter footwear having an increased coefficient of friction to icy surfaces. The tribological tests based on the coefficient of friction evaluated the adhesion of the composites to the icy surfaces at different temperatures. The complex evaluation of developed composites revealed those containing microcrystalline cellulose and biogenic amorphous silica at a 1:1 ratio as the most suitable for making footwear soles because of the best combination of physicо-mechanical properties and coefficient of friction.展开更多
Metal matrix nanocomposites(MMnCs)comprise a metal matrix filled with nanosized reinforcements with physical and mechanical properties that are very different from those of the matrix.In ZA-27 alloy-based nanocomposit...Metal matrix nanocomposites(MMnCs)comprise a metal matrix filled with nanosized reinforcements with physical and mechanical properties that are very different from those of the matrix.In ZA-27 alloy-based nanocomposites,the metal matrix provides ductility and toughness,while usually used ceramic reinforcements give high strength and hardness.Tested ZA-27 alloy-based nanocomposites,reinforced with different types(Si C and Al2O3),amounts(0.2 wt.%,0.3 wt.%,and 0.5 wt.%)and sizes(25 nm,50 nm,and 100 nm)of nanoparticles were produced through the compocasting process with mechanical alloying pre-processing(ball milling).It was previously shown that the presence of nanoparticles in ZA-27 alloy-based nanocomposites led to the formation of a finer structure in the nanocomposites matrix and an improvement in the basic mechanical properties(hardness and compressive yield strength)through the enhanced dislocation density strengthening mechanism.Solid particle erosive wear testing demonstrated that these improvements were followed with an increase in the erosive wear resistance of tested nanocomposites,as well.Additionally,by analyzing the influences of type,amount,and size of nanoparticles on the erosive wear resistance of nanocomposites,it was demonstrated that there is an optimal amount of nanoparticles,which in our case is 0.3 wt.%,and that the presence of SiC nanoparticles and smaller nanoparticles in nanocomposites had more beneficial influence on erosive wear resistance.展开更多
文摘The work in this study is focused on the investigation of the structure and properties of ductile cast iron with nanoparticle additives： TiN （titanium nitride）, TiN ＋ TiCN （titanium carbonitride） and cBN （cubic boron nitride）. The nanoparticles are coated with nickel prior to addition to the iron melt to improve their wetting and uniform distribution in the volume of the casting. The metallographic observation and wear test are performed to study the influence of the nanoparticle additives on the microstructure and and cast iron tribological properties.
文摘Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface. Nowadays environmental protection has been gaining significance and becoming highly important for the various innovation strategies. In rubber industry the concept of environmental protection is more often associated with the maximum use of elastomers and ingredients from renewable sources in the manufacture of rubber products. The aim of this work is to investigate the possibilities of using elastomers and ingredients from renewable sources—epoxidized natural rubber, silica obtained by rice husks incineration and microcrystalline cellulose—as fillers and rapeseed oil as a process additive in compositions, intended for the manufacture of soles for winter footwear having an increased coefficient of friction to icy surfaces. The tribological tests based on the coefficient of friction evaluated the adhesion of the composites to the icy surfaces at different temperatures. The complex evaluation of developed composites revealed those containing microcrystalline cellulose and biogenic amorphous silica at a 1:1 ratio as the most suitable for making footwear soles because of the best combination of physicо-mechanical properties and coefficient of friction.
基金the projects TR 34028, TR 35021, and OI 172005supported by the Republic of Serbia, Ministry of Education, Science and Technological Development+1 种基金the project LO1202, funded by the MEYS under the National Sustainability Programme Ithe project AН 07/28-15.12.2016, funded by the National Science Fund of the Ministry of Education and Science, Bulgaria
文摘Metal matrix nanocomposites(MMnCs)comprise a metal matrix filled with nanosized reinforcements with physical and mechanical properties that are very different from those of the matrix.In ZA-27 alloy-based nanocomposites,the metal matrix provides ductility and toughness,while usually used ceramic reinforcements give high strength and hardness.Tested ZA-27 alloy-based nanocomposites,reinforced with different types(Si C and Al2O3),amounts(0.2 wt.%,0.3 wt.%,and 0.5 wt.%)and sizes(25 nm,50 nm,and 100 nm)of nanoparticles were produced through the compocasting process with mechanical alloying pre-processing(ball milling).It was previously shown that the presence of nanoparticles in ZA-27 alloy-based nanocomposites led to the formation of a finer structure in the nanocomposites matrix and an improvement in the basic mechanical properties(hardness and compressive yield strength)through the enhanced dislocation density strengthening mechanism.Solid particle erosive wear testing demonstrated that these improvements were followed with an increase in the erosive wear resistance of tested nanocomposites,as well.Additionally,by analyzing the influences of type,amount,and size of nanoparticles on the erosive wear resistance of nanocomposites,it was demonstrated that there is an optimal amount of nanoparticles,which in our case is 0.3 wt.%,and that the presence of SiC nanoparticles and smaller nanoparticles in nanocomposites had more beneficial influence on erosive wear resistance.
