The fundamentals of coating tribology is presented in a generalised holistic approach to friction and wear mechanisms of coated surfaces in dry sliding contacts. It is based on a classification of the tribological con...The fundamentals of coating tribology is presented in a generalised holistic approach to friction and wear mechanisms of coated surfaces in dry sliding contacts. It is based on a classification of the tribological contact process into macromechanical, micromechanical, tribochemical contact mechanisms and material transfer. The tribological contact process is dominated by the macromechanical mechanisms, which have been systematically analysed by using four main parameters: the coating-to-substrate hardness relationship, the film thickness, the surface roughness and the debris in the contact. In this paper special attention is given to the microlevel mechanisms, and in particular new techniques for modelling the elastic, plastic and brittle behaviour of the surface by finite element (FEM) computer simulations. The contact condition with a sphere sliding over a plate coated with a very thin hard coating is analysed. A three dimensional FEM model has been developed for calculating the first principal stress distribution in the scratch tester contact of a diamond spherical tip moving with increased load on a 2 thick titanium nitride (TiN) coated steel surface. The model is comprehensive in that sense that it considers elastic, plastic and fracture behaviour of the contact surfaces. By identifying from a scratch experiment the location of the first crack and using this as input data can the fracture toughness of the coating be determined.展开更多
Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportati...Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportation,manufacturing,power generation,and residential.Previously published four case studies on passenger cars,trucks and buses,paper machines and the mining industry were included in our detailed calculations as reference data in our current analyses.The following can be concluded:-In total,～23％ (119 EJ) of the world's total energy consumption originates from tribological contacts.Of that 20％ (103 EJ) is used to overcome friction and 3％ (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.-By taking advantage of the new surface,materials,and lubrication technologies for friction reduction and wear protection in vehicles,machinery and other equipment worldwide,energy losses due to friction and wear could potentially be reduced by 40％ in the long term (15 years)and by 18％ in the short term (8 years).On global scale,these savings would amount to 1.4％ of the GDP annually and 8.7％ of the total energy consumption in the long term.-The largest short term energy savings are envisioned in transportation (25％) and in the power generation (20％) while the potential savings in the manufacturing and residential sectors are estimated to be ～10％.In the longer terms,the savings would be 55％,40％,25％,and 20％,respectively.-Implementing advanced tribological technologies can also reduce the CO2 emissions globally by as much as 1,460 MtCO2 and result in 450,000 million Euros cost savings in the short term.In the longer term,the reduction can be 3,140 MtCO2 and the cost savings 970,000 million Euros.Fifty years ago,wear and wear-related failures were a major concern for UK industry and their mitigation was considered to be the major contributor to potential economic savings by as much as 95％ in ten years by the development and deployment of new tribological solutions.The corresponding estimated savings are today still of the same orders but the calculated contribution to cost reduction is about 74％ by friction reduction and to 26％ from better wear protection.Overall,wear appears to be more critical than friction as it may result in catastrophic failures and operational breakdowns that can adversely impact productivity and hence cost.展开更多
文摘The fundamentals of coating tribology is presented in a generalised holistic approach to friction and wear mechanisms of coated surfaces in dry sliding contacts. It is based on a classification of the tribological contact process into macromechanical, micromechanical, tribochemical contact mechanisms and material transfer. The tribological contact process is dominated by the macromechanical mechanisms, which have been systematically analysed by using four main parameters: the coating-to-substrate hardness relationship, the film thickness, the surface roughness and the debris in the contact. In this paper special attention is given to the microlevel mechanisms, and in particular new techniques for modelling the elastic, plastic and brittle behaviour of the surface by finite element (FEM) computer simulations. The contact condition with a sphere sliding over a plate coated with a very thin hard coating is analysed. A three dimensional FEM model has been developed for calculating the first principal stress distribution in the scratch tester contact of a diamond spherical tip moving with increased load on a 2 thick titanium nitride (TiN) coated steel surface. The model is comprehensive in that sense that it considers elastic, plastic and fracture behaviour of the contact surfaces. By identifying from a scratch experiment the location of the first crack and using this as input data can the fracture toughness of the coating be determined.
文摘Calculations of the impact of friction and wear on energy consumption,economic expenditure,and CO2 emissions are presented on a global scale.This impact study covers the four main energy consuming sectors:transportation,manufacturing,power generation,and residential.Previously published four case studies on passenger cars,trucks and buses,paper machines and the mining industry were included in our detailed calculations as reference data in our current analyses.The following can be concluded:-In total,～23％ (119 EJ) of the world's total energy consumption originates from tribological contacts.Of that 20％ (103 EJ) is used to overcome friction and 3％ (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.-By taking advantage of the new surface,materials,and lubrication technologies for friction reduction and wear protection in vehicles,machinery and other equipment worldwide,energy losses due to friction and wear could potentially be reduced by 40％ in the long term (15 years)and by 18％ in the short term (8 years).On global scale,these savings would amount to 1.4％ of the GDP annually and 8.7％ of the total energy consumption in the long term.-The largest short term energy savings are envisioned in transportation (25％) and in the power generation (20％) while the potential savings in the manufacturing and residential sectors are estimated to be ～10％.In the longer terms,the savings would be 55％,40％,25％,and 20％,respectively.-Implementing advanced tribological technologies can also reduce the CO2 emissions globally by as much as 1,460 MtCO2 and result in 450,000 million Euros cost savings in the short term.In the longer term,the reduction can be 3,140 MtCO2 and the cost savings 970,000 million Euros.Fifty years ago,wear and wear-related failures were a major concern for UK industry and their mitigation was considered to be the major contributor to potential economic savings by as much as 95％ in ten years by the development and deployment of new tribological solutions.The corresponding estimated savings are today still of the same orders but the calculated contribution to cost reduction is about 74％ by friction reduction and to 26％ from better wear protection.Overall,wear appears to be more critical than friction as it may result in catastrophic failures and operational breakdowns that can adversely impact productivity and hence cost.
