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Tribology in Japan — some personal impressions
Tribology in Japan some personal impressions D. TABOR* INTRODUCTION
Recently I spent nearly three weeks in Japan as a Royal Society-Japan Academy visiting Fellow. I was a guest of the Japan Society of Mechanical Engineers (JSME) and the Japan Society of Lubrication Engineers (JSLE) and it was largely through their good offices that my tour was arranged. My main contact was Dr. K. Matsubara who runs the Tribology Group in the Government Mechanical Engineering Laboratory and Mr. Beatty of the British Council. The organisation of the trip which included lectures, laboratory visits, cultural outings, sightseeing tours and general hospitality was first rate. It is not my purpose in this article to describe my general impressions of Japan or of Japanese life. I wish merely to record, in note form, some of the people I met, the laboratories 1 visited and the work I saw. The account is by no means complete and the coverage is probably a reflection of my own interests which include surface physics as well as tribology itself. But it may provide readers with some ideas of the range and quality of work which I saw.
LABORATORIES AND SCIENTISTS The following are the main laboratories I visited:
Mechanical Engineering Laboratory, Director, Dr. Masao Kubota. This is a Government Laboratory. It is supported by the Government department of trade and industry but it is significant that the relevant Japanese department is called the Ministry of International Trade and Industry, abbreviated to MITI and pronounced Mitchi. Annual budget about $6 000 000. The Tribology group is supervised by Dr. K. Matsubara. He has a small but very able team including the first Japanese woman Ph.D. in tribology - Dr. Yuko Tsuya. Dr. Tsuya with K. Nakayama is studying the role of the brittle ductile transition in junction growth, dry film lubrication, friction and wear in high vacuum at elevated temperatures. There is also work on the lubrication of rolling bearings, strength of high speed gears, the protective role of metal films formed by ion plating, elastic loss process in the friction of polymers. There is practically no sponsored research supported by industry.
The Electrochemical Laboratories (MITI). In the Extreme Technology Division I met Dr. H. Shimuzu who has developed a host of electron-optical techniques for studying surfaces and surface reactivity. The work shows great ability and drive. Hitachi Central Laboratory. This is a modern laboratory of a company which in many ways resembles G.E. in America. The group I met were working mainly on surface phenomena involving the use of a whole range of sophisticatrd electronoptical devices: a LEED and micro-beam scanning, AUGER spectroscopy (K. Hayakawa), * Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE.
b extremely high resolution electron microscopy - about 1.2 A for specimens 50 )k thick - (Dr. F. Nagata), c scanning electron microscope of extremely high resolution (Dr. F. Nagata), d scanning ion microscope. Here the ion is used to sputter away the surface as well as to examine it, e ESCA for the study of chemically bonded oxides on metal surfaces, particularly the influence of A1203 in influencing the adhesion of evaporated films (Dr. Iwata). Most of these techniques have been developed as a means of studying different aspects of solid-state electronic devices. It is clear that the electronics industry has had a tremendous influence on the technology of surface studies.
Institute of Industrial Science, University of Tokyo. I met Professor Masahisa Matsunaga who is very much concerned with the friction of solid lubricants in vacuum. He believes that the edge friction of MoS2 plays a very important role just as it does for graphite.
University of Tokyo Engineering Department. Professor Yukio Hori and Professor Tsuneo Someya are actively engaged in problems of hydrodynamic lubrication, oil-whip, vibrational stability and cativation. These are largely associated with problems of vibration in propeller shafts of large container ships. University of Kyushu, Fukuoka. Professor Fujio Hirano runs an active tribology group. Dr. K. Kazuaki has been studying the motion of balls in bearings by incorporating a magnet in one ball and observing the various magnetic effects produced during running. Professor Hirano himself is greatly interested in the Marangoni effect which is concerned with the influence of temperature on surface tension and the way in which, as a result, surface temperature gradients can cause retraction of a liquid film. He believes surface temperature gradients to be a primary factor in producing scuffing. Dr. Akira Ura has been investigating the effect of the hardness of solids on abrasive wear by hard abrasive particles. He finds that the wear is least when both surfaces are of equal hardness since this leads to a more effective smearing of a protective film over the abrasive particles. Dr. M. Kaneta is carrying out a theoretical and experimental study of seals. Professor Yutaro Wakuri is studying the lubrication between the piston ring and liner of an internal combustion engine using optical interference techniques by using a cylinder with a glass wall. He spent a year with Professor Cameron in London and is developing the ideas he saw there.
Hiroshima University, Dr. Kaizo Kuwahara, Professor of Precision Engineering. Professor Kuwahara was originally a physicist and his main field of interest was the electrical properties of thin films. He is now studying the adhesion and lubricating properties of such films.
Osaka University. Professor Tsukizoe in the Department of Engineering has a team working on tribological problems.
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Dr. Hisakado is interested in profilometry and contact mechanisms both theoretical and experimental. Dr. Sakamoto is studying the failure of the 'bourrelet frontal' when a hand slider ploughs its way through a softer metal. Dr. Ohmae is studying friction properties of composite materials and also the effect of ion plated films on fretting corrosion. The best film material for reducing fretting corrosion of steel is boron carbide. In the Metallurgy Department we were shown the 'world record' high voltage electron microscope. It works regularly at 2 MeV and for short periods at 3 MeV. In the Electronics Department Professor Hanawa showed some beautiful electron-optical equipment he has developed to study the epitaxial growth of films. His latest device enables the LEED diffracted electrons to be directed into a special cylindrical analyser.
Kanazawa University. This is a small university. Professor Tanaka in the Engineering Department directs a small team working on various aspects of polymer friction. The work is well integrated and its combined weight is substantial. With Dr. Yoshitaka Uchiyama he has particularly studied the wear properties of polymers at engineering speeds and has concluded that if surface melting can occur on a polymer during sliding it will give low wear. With Dr. Miyoshi he has been looking at the wear and the wear anisotropy of hard crystalline solids. This is relevant to the wear of videotape devices. He has a scanning electron microscope and a good transmission electron microscope incorporating an X-ray detector.
Toyota Central Research Laboratory, Nagoya. Dr. Nakajima runs a group working on fundamental friction and wear problems. The outstanding feature of his work in his use of modern surface techniques to elucidate the various mechanisms involved. Dr. Yasunori Taga is using Auger and electron probe analysis to study the surface changes occurring in C u - Z n alloys when they rub against stainless steel (dezincification and oxidation). Dr. Yoshiyuku Mizutan is studying the effect of heat treatments on the formation of MoSx in Fe-Mo-S alloys and the influence of this material on the frictional properties. His X-ray studies show that x ~ 1.8 and that the structure of the sulphide resembles MoS 2. A surface film of MoSx is often formed during the sliding process itself by the migration of Mo and S atoms to the interface. Dr. Kenichi Suzuki is studying the effect of cathode honing on the structure of nickel electro deposits. Such honing enables higher current densities to be used. This leads to finer grain deposits, greater hardness and compressive stresses in the film. Dr. Masuhiko Kawamura is using electrical resistance methods to study the amount of 'metallic' contact in lubricated systems. Using a four-ball arrangement he has examined the effect of base oil viscosity and the role of tricresyl phosphate, chlorine and sulphur additives. The synergistic effects of mixtures of additives can be negative as well as positive. Other scientists
Amongst other scientists 1 met the following but did not discuss their work in detail.
136
TRIBOLOGY international June 1975
a Professor Kozo Kawata. Institute of Space and Aeronautical Science, Tokyo. (High velocity elastic and plastic deformation). b Associate Professor Tadashi Sasada. Tokyo Institute of Technology. (Agglutinative mechanism of wear particle formation). c Professor S. Hyodo and Dr. A. Kohno, Institute of Physical and Physical Chemical Research. (Adhesion at very small loads showing the rule of surface energy). d Dr. H. Doi. Central Research Laboratory (Mitsubishi). (The applied problems of carbide cutting tools and the role of thin TiC and A1203 coatings). e Professor T. Sakurai. Tokyo Institute of Technology. (Effect of oxidation of base oils on the phases in greases). f Dr. Y. Miyakawa. National Aerospace Laboratory. (High temperature solid lubricants use of oxide and ion deposited metal films). g Professor H. Kitagawa. Institute of Industrial Science, Tokyo. (Interaction of cracks in inducing catastrophic failure).
CONCL USI ONS
Most of the tribological work 1 saw was concerned with friction, wear, the action of dry film lubrication, the role of ion-plated films in reducing friction, wear, fretting, cracking, etc. (almost everybody seemed to be 'having a go' at this). There did not seem to be very much work on conventional hydrodynamic lubrication and practically nothing on elastohydrodynamic lubrication. There is interest in E.P. lubricants, in boundary lubrication and in the friction and wear behaviour of polymers. The work is all of a high standard. The greater part is carried out in Engineering Department or industrial laboratories. Practically all of them make very good and effective use of optical and electron optical devices. Amidst all the wealth of Japanese equipment 1 was glad to see a Talysurf and Talyrond but in the field of electron microscopy there does not seem to be any imported equipment. The doyen of Japanese tribology is Professor Norimune Soda who translated the Oxford monograph on 'Friction and Lubrication of Solids' by Bowden and Tabor. He now runs a tribology department in the Institute of Physics and Chemical Research, a non-profit making research organisation. It is situated some distance from the centre of Tokyo. I greatly regret that although I met him on three occasions I somehow missed the opportunity of visiting his laboratory. Surface science studies, involving LEED, RHEED, AUGER and ESCA follow most of the conventional lines that are being investigated in other countries. The work is of a high calibre and some of the equipment is truly impressive and innovatory. My trip enabled me to visit Fukuoka, Osaka, Kanazawa, Kyoto, Nagoya; to see many ancient shrines, temples and castles; to cruise in the Inland Sea, to visit art exhibitions and to see something of the beautiful Japanese countryside with its shallow cultivated valleys, its tree-covered hills and snow capped mountains. All this was a new and exhilarating experience. But most of all l was able to meet and speak with Japanese scientists working in fields of mutual interest and to appreciate their human as well as their professional qualities.
Recently I spent nearly three weeks in Japan as a Royal Society-Japan Academy visiting Fellow. I was a guest of the Japan Society of Mechanical Engineers (JSME) and the Japan Society of Lubrication Engineers (JSLE) and it was largely through their good offices that my tour was arranged. My main contact was Dr. K. Matsubara who runs the Tribology Group in the Government Mechanical Engineering Laboratory and Mr. Beatty of the British Council. The organisation of the trip which included lectures, laboratory visits, cultural outings, sightseeing tours and general hospitality was first rate. It is not my purpose in this article to describe my general impressions of Japan or of Japanese life. I wish merely to record, in note form, some of the people I met, the laboratories 1 visited and the work I saw. The account is by no means complete and the coverage is probably a reflection of my own interests which include surface physics as well as tribology itself. But it may provide readers with some ideas of the range and quality of work which I saw.
LABORATORIES AND SCIENTISTS The following are the main laboratories I visited:
Mechanical Engineering Laboratory, Director, Dr. Masao Kubota. This is a Government Laboratory. It is supported by the Government department of trade and industry but it is significant that the relevant Japanese department is called the Ministry of International Trade and Industry, abbreviated to MITI and pronounced Mitchi. Annual budget about $6 000 000. The Tribology group is supervised by Dr. K. Matsubara. He has a small but very able team including the first Japanese woman Ph.D. in tribology - Dr. Yuko Tsuya. Dr. Tsuya with K. Nakayama is studying the role of the brittle ductile transition in junction growth, dry film lubrication, friction and wear in high vacuum at elevated temperatures. There is also work on the lubrication of rolling bearings, strength of high speed gears, the protective role of metal films formed by ion plating, elastic loss process in the friction of polymers. There is practically no sponsored research supported by industry.
The Electrochemical Laboratories (MITI). In the Extreme Technology Division I met Dr. H. Shimuzu who has developed a host of electron-optical techniques for studying surfaces and surface reactivity. The work shows great ability and drive. Hitachi Central Laboratory. This is a modern laboratory of a company which in many ways resembles G.E. in America. The group I met were working mainly on surface phenomena involving the use of a whole range of sophisticatrd electronoptical devices: a LEED and micro-beam scanning, AUGER spectroscopy (K. Hayakawa), * Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE.
b extremely high resolution electron microscopy - about 1.2 A for specimens 50 )k thick - (Dr. F. Nagata), c scanning electron microscope of extremely high resolution (Dr. F. Nagata), d scanning ion microscope. Here the ion is used to sputter away the surface as well as to examine it, e ESCA for the study of chemically bonded oxides on metal surfaces, particularly the influence of A1203 in influencing the adhesion of evaporated films (Dr. Iwata). Most of these techniques have been developed as a means of studying different aspects of solid-state electronic devices. It is clear that the electronics industry has had a tremendous influence on the technology of surface studies.
Institute of Industrial Science, University of Tokyo. I met Professor Masahisa Matsunaga who is very much concerned with the friction of solid lubricants in vacuum. He believes that the edge friction of MoS2 plays a very important role just as it does for graphite.
University of Tokyo Engineering Department. Professor Yukio Hori and Professor Tsuneo Someya are actively engaged in problems of hydrodynamic lubrication, oil-whip, vibrational stability and cativation. These are largely associated with problems of vibration in propeller shafts of large container ships. University of Kyushu, Fukuoka. Professor Fujio Hirano runs an active tribology group. Dr. K. Kazuaki has been studying the motion of balls in bearings by incorporating a magnet in one ball and observing the various magnetic effects produced during running. Professor Hirano himself is greatly interested in the Marangoni effect which is concerned with the influence of temperature on surface tension and the way in which, as a result, surface temperature gradients can cause retraction of a liquid film. He believes surface temperature gradients to be a primary factor in producing scuffing. Dr. Akira Ura has been investigating the effect of the hardness of solids on abrasive wear by hard abrasive particles. He finds that the wear is least when both surfaces are of equal hardness since this leads to a more effective smearing of a protective film over the abrasive particles. Dr. M. Kaneta is carrying out a theoretical and experimental study of seals. Professor Yutaro Wakuri is studying the lubrication between the piston ring and liner of an internal combustion engine using optical interference techniques by using a cylinder with a glass wall. He spent a year with Professor Cameron in London and is developing the ideas he saw there.
Hiroshima University, Dr. Kaizo Kuwahara, Professor of Precision Engineering. Professor Kuwahara was originally a physicist and his main field of interest was the electrical properties of thin films. He is now studying the adhesion and lubricating properties of such films.
Osaka University. Professor Tsukizoe in the Department of Engineering has a team working on tribological problems.
TRIBOLOGY international June 1975
135
Dr. Hisakado is interested in profilometry and contact mechanisms both theoretical and experimental. Dr. Sakamoto is studying the failure of the 'bourrelet frontal' when a hand slider ploughs its way through a softer metal. Dr. Ohmae is studying friction properties of composite materials and also the effect of ion plated films on fretting corrosion. The best film material for reducing fretting corrosion of steel is boron carbide. In the Metallurgy Department we were shown the 'world record' high voltage electron microscope. It works regularly at 2 MeV and for short periods at 3 MeV. In the Electronics Department Professor Hanawa showed some beautiful electron-optical equipment he has developed to study the epitaxial growth of films. His latest device enables the LEED diffracted electrons to be directed into a special cylindrical analyser.
Kanazawa University. This is a small university. Professor Tanaka in the Engineering Department directs a small team working on various aspects of polymer friction. The work is well integrated and its combined weight is substantial. With Dr. Yoshitaka Uchiyama he has particularly studied the wear properties of polymers at engineering speeds and has concluded that if surface melting can occur on a polymer during sliding it will give low wear. With Dr. Miyoshi he has been looking at the wear and the wear anisotropy of hard crystalline solids. This is relevant to the wear of videotape devices. He has a scanning electron microscope and a good transmission electron microscope incorporating an X-ray detector.
Toyota Central Research Laboratory, Nagoya. Dr. Nakajima runs a group working on fundamental friction and wear problems. The outstanding feature of his work in his use of modern surface techniques to elucidate the various mechanisms involved. Dr. Yasunori Taga is using Auger and electron probe analysis to study the surface changes occurring in C u - Z n alloys when they rub against stainless steel (dezincification and oxidation). Dr. Yoshiyuku Mizutan is studying the effect of heat treatments on the formation of MoSx in Fe-Mo-S alloys and the influence of this material on the frictional properties. His X-ray studies show that x ~ 1.8 and that the structure of the sulphide resembles MoS 2. A surface film of MoSx is often formed during the sliding process itself by the migration of Mo and S atoms to the interface. Dr. Kenichi Suzuki is studying the effect of cathode honing on the structure of nickel electro deposits. Such honing enables higher current densities to be used. This leads to finer grain deposits, greater hardness and compressive stresses in the film. Dr. Masuhiko Kawamura is using electrical resistance methods to study the amount of 'metallic' contact in lubricated systems. Using a four-ball arrangement he has examined the effect of base oil viscosity and the role of tricresyl phosphate, chlorine and sulphur additives. The synergistic effects of mixtures of additives can be negative as well as positive. Other scientists
Amongst other scientists 1 met the following but did not discuss their work in detail.
136
TRIBOLOGY international June 1975
a Professor Kozo Kawata. Institute of Space and Aeronautical Science, Tokyo. (High velocity elastic and plastic deformation). b Associate Professor Tadashi Sasada. Tokyo Institute of Technology. (Agglutinative mechanism of wear particle formation). c Professor S. Hyodo and Dr. A. Kohno, Institute of Physical and Physical Chemical Research. (Adhesion at very small loads showing the rule of surface energy). d Dr. H. Doi. Central Research Laboratory (Mitsubishi). (The applied problems of carbide cutting tools and the role of thin TiC and A1203 coatings). e Professor T. Sakurai. Tokyo Institute of Technology. (Effect of oxidation of base oils on the phases in greases). f Dr. Y. Miyakawa. National Aerospace Laboratory. (High temperature solid lubricants use of oxide and ion deposited metal films). g Professor H. Kitagawa. Institute of Industrial Science, Tokyo. (Interaction of cracks in inducing catastrophic failure).
CONCL USI ONS
Most of the tribological work 1 saw was concerned with friction, wear, the action of dry film lubrication, the role of ion-plated films in reducing friction, wear, fretting, cracking, etc. (almost everybody seemed to be 'having a go' at this). There did not seem to be very much work on conventional hydrodynamic lubrication and practically nothing on elastohydrodynamic lubrication. There is interest in E.P. lubricants, in boundary lubrication and in the friction and wear behaviour of polymers. The work is all of a high standard. The greater part is carried out in Engineering Department or industrial laboratories. Practically all of them make very good and effective use of optical and electron optical devices. Amidst all the wealth of Japanese equipment 1 was glad to see a Talysurf and Talyrond but in the field of electron microscopy there does not seem to be any imported equipment. The doyen of Japanese tribology is Professor Norimune Soda who translated the Oxford monograph on 'Friction and Lubrication of Solids' by Bowden and Tabor. He now runs a tribology department in the Institute of Physics and Chemical Research, a non-profit making research organisation. It is situated some distance from the centre of Tokyo. I greatly regret that although I met him on three occasions I somehow missed the opportunity of visiting his laboratory. Surface science studies, involving LEED, RHEED, AUGER and ESCA follow most of the conventional lines that are being investigated in other countries. The work is of a high calibre and some of the equipment is truly impressive and innovatory. My trip enabled me to visit Fukuoka, Osaka, Kanazawa, Kyoto, Nagoya; to see many ancient shrines, temples and castles; to cruise in the Inland Sea, to visit art exhibitions and to see something of the beautiful Japanese countryside with its shallow cultivated valleys, its tree-covered hills and snow capped mountains. All this was a new and exhilarating experience. But most of all l was able to meet and speak with Japanese scientists working in fields of mutual interest and to appreciate their human as well as their professional qualities.