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Spherical artifacts on ferrograms
Wear, 37 (1976) 193 - 195 @ Elsevier Sequoia S.A., Lausanne - Printed in the Netherlands
193
Short Communication
Spherical artifacts on ferrograms
W. R. JONES, JR. Letvk Research
Center, Cleveland,
Ohio 44135
(U.S.A.)
(Received September 8, 1975)
The generation of metallic microspheres has been reported by a number of investigators [l - 61. Several mechanisms have been postulated for their generation. These include fretting [ 1, 21, abrasion [ 31, cavitation erosion [4] and fatigue-related processes [5, 61. It has been suggested that the detection of spheres in a bearing lubricant may allow the prediction of incipient bearing fatigue failure [ 71. Ferrographic analysis [ 81 is a technique for magnetically precipitating metallic wear particles from a used lubricant onto a glass slide. This slide with its associated particles is called a ferrogram. Recently, a ferrogram prepared from a short term sliding friction and wear test was found to contain several thousand small (approximately 1 - 2 E.trnin diameter) metallic spheres. It seemed highly unlikely that these spheres were produced by some mechanism associated with the friction and wear test. It soon became evident that they were a result of airborne contamination. This was confirmed when no spheres were detected on a second ferrogram prepared from the identical oil sample. The contaminating source was finally found to be the result of a routine grinding operation on a steel plate located over 20 ft from the uncovered ferrograph. A similar grinding operation was performed on a piece of low carbon steel a few feet from the ferrograph. An aluminum oxide abrasive disc at a maximum surface speed of 40 m s-l (8000 ft mix-‘) was used. After only 2 min of grinding, the resulting ferrogram contained thousands of particles of which more than 90% were spherical. These spheres ranged in size from less than 1 to more than 30 pm in diameter. An example of this debris is shown in Fig. 1. Further examination of this debris in an SEM (Fig. 2) revealed that many of the spheres were hollow. The spherical shape combined with the convoluted surface features on many of the particles indicates that melting followed by rapid cooling probably occurred. Komanduri and Shaw [9] have reported similar occurrences in grinding experiments. Because of the widespread occurrence of ordinary grinding operations, it seems prudent that those utilizing the ferrograph be cognizant of this type of artifact.
Fig. 1. Photomicrograph
of spherical
Fig. 2. Scanning
micrographs
electron
grinding
debris.
of hollow
spheres.
References P. Hurricks, The occurrence of spherical particles in fretting wear, Wear, 27 (1974) 319 - 328. I. F. Stowers and E. Rabinowicz, Spherical particles formed in the fretting of silver, J. Appl. Phys., 43 (1972) 2485. E. Broszeit and F. J. Hess, Discussion to a scanning electron microscope study of fracture phenomena associated with rolling contact fatigue failure, Wear, 17 (1971) 314 - 315. S. W. Doroff, R. S. Miller, A. Thiruvengadam and V. C. Westcott, Nature (London), 247 (1974) 363. B. Loy and R. McCallum, Mode of formulation of spherical particles in rolling contact fatigue, Wear, 24 (1973) 219 - 228.
195 6 D. Scott and G. H. Mills, Spherical debris .- its occurrence, formation and significance in rolling contact fatigue, Wear, 24 (1973) 235 - 242. 7 D. Scott, W. W. Seifert and V. C. Westcott, The particles of wear, Sci. Am., 230 (5) (1974) 88. 8 W. W. Seifert and V. C. Westcott, A method for the study of wear particles in lubricating oil, Wear, 21 (1972) 27. 9 R. Komanduri and M. C. Shaw, Formation of spherical particles in grinding, Philos. Mag., 1975, to be published.
Wear, 37 (1976) 197 - 200 0 Elsevier Sequoia S.A., Lausanne - Printed in the Netherlands
197
NOTES ON CONTRIBUTORS
S. E. Amundson: I. B. Atkinson:
(for biographic note see Wear, 36 (1976)
(for biographic note see Wear, 29 (1974)
R. G. Bayer: (for biographic note see Wear, 16 (1970)
131). 139).
468).
R. J. Bird: graduated in physics at London University in 1948 and joined Shell Research Limited in 1954. He has worked at Thornton Research Centre principally on physical methods of analysis, with emphasis on the characterization of solid surfaces by the techniques of electron microscopy, X-ray and electron emission. W. Bonfield: is Professor of Materials at Queen Mary College, University of London, and Executive Editor of the Journal of Materials Science. He obtained the degrees of B. SC. (Eng.) (1958) and Ph. D. (1961) in metallurgy at Imperial College, University of London, and is a Fellow of the Institution of Metallurgists. Prior to joining Queen Mary College in 1968, he was a senior principal research scientist at the Honeywell Research Center, Hopkins, Minnesota. His research interests include microplasticity, precipitation hardening, composite materials and biomechanics. Philip Cadman: graduated in chemistry from the University of Birmingham in 1962 and was awarded a Ph. D. in 1965 for a thesis on photochemistry and reaction kinetics. He held a postdoctoral fellowship at the University of Toronto until 1967 and is now a university lecturer in chemistry at the University College of Wales at Aberystwyth. A. Cameron: (for biographic note see Wear, 36 (1976)
267).
A. H. Demirci: born in Yesilhisar, Kayseri, Turkey, in 1945; graduated in mechanical engineering from the Technical University of Istanbul in 1969; employed in the State Company DSI in Ankara. Now employed as assistant scientist in the Department Abnutzung der Werkstoffe at the Technical University of Aachen, F.R.G. K. F. Dufrane: received his B. S. and M. S. degrees in metallurgical engineering from Michigan Technological University in 1963 and 1964. Joined Battelle’s Columbus Laboratories in 1964 and has been active in the fields of friction, wear and mechanical failure analysis. B. C. Edwards: graduated in physics (1969), and then obtained a Ph. D. in materials science (1973), both at Queen Mary College, University of London. He was subsequently a research assistant, studying crystallisation in polymers, at Queen Mary College, before joining the Metallurgy Division, A.E.R.E., Harwell, in 1975 as a Research Fellow, on an investigation of brittle fracture in steel. G. D. Galvin: works in the Lubrication Division of the Thornton Research Centre of Shell Research Limited. He has published papers on the effect of lubricants on metal fatigue, on the properties of lubricants at high pressures, on surface chemical effects in lubrication and on the cleaning and lubrication of gas bearings in gyroscopes. W. A. Glaeser: received his B.M.E. from Cornell University in 1949, and his M.S. in metallurgical engineering from Ohio State University in 1959. He joined the Battelle staff in 1951 and is presently a research leader in the Tribomechanics Section.
198 M. K. Gopalan: graduated from the University of Kerala (India) in 1961 in civil engineering; qualified for an appointment in the Central Engineering Services of the Government of India through the All India Competitive Engineering Services Examination; worked as a design engineer and evolved standard designs for right and skew highway bridges in steel, R.C.C. and prestressed concrete; won the fellowship (Dean’s Award) of the University of New South Wales in 1973 and is at present doing full-time research for his Ph. D. on the influence of surface texture on abrasion and friction of rubber. J. Halling:
(for biographic
T. Hisakado:
note see Wear, 24 (1973)
(for biographic
131).
note see Wear, 30 (1974)
283).
R. E. Jackson: received a Ph. D. degree in structural geology from the University of North Carolina, Chapel Hill, North Carolina, U.S.A., in 1973. After completing graduate studies on the frictional behavior of sliding rock surfaces, he was a post-doctorai fellow and research scientist at Martin Marietta Laboratories where he studied chemomechanical behavior in relation to rock drilling. He is currently employed by the U.S. Nuclear Regulatory Commission (formerly USAEC) where he is involved in solving problems relating to the safe siting of nuclear reactors. William R. Jones, Jr.: graduated with a B. S. degree in chemical engineering in 1962 from the University of Missouri at Rolla; spent a year of graduate study in the field of organic chemistry at the University of Wisconsin; completed two years with the United States Peace Corps as a lecturer at the Yaba Technical Institute in Lagos, Nigeria, West Africa; joined the Lubrication Branch of the NASA Lewis Research Center, Cleveland, Ohio, in 1965. His research areas of interest include: boundary lubrication, lubricant additives and ferrographic analysis. He is a member of ASLE. H. Krause: received a technical education at the Technical University of Aachen, F.R.G; obtained his doctor’s degree (Dr.-Ing.) in 1967; obtained habilitation and uenia legendi for the Friction and Wear Section (Tribology) in 1968; was nominated as a professor at the Technical University of Aachen, and is now bead of the Department Abnutzung der Werkstoffe at the Technical University of Aachen. His main interest is tribology, especially triboehemical reactions on metallic surfaces. R. C. Lokken: is a research supervisor at the Industrial Abrasives Division Laboratory of the 3M Company in St. Paul, Minnesota. He obtained his B.A. in mathematics and physics from Concordia College (Moorhead, Minnesota) in 1956 and did graduate work in mathematics at North Dakota State University during 1965 - 66. He is interested in the theory of grinding and wear and his primary research area has been new methods applications for various coated abrasive products. A. C. Mahanti:
(for biographic
note see Wear, 29 (1974)
275).
A. J. Markham: is experimental officer in the Department of Materials, Queen Mary College, University of London. A Fellow of the Royal Microscopical Society, her particular research interest is etectron microscope examination of ceramic whiskers and polymer sections. T. R. McGibbon: received his B. Mathematics degree in 1969 from the University of Minnesota. He has been employed by the 3M Company since 1962. His current position is Advanced Research Mathematician and his responsibilities include coated abrasives development work in the area of abrasive wear mechanisms, precision grinding technology and surface measurement and characterization. H. Nolle: (for biographic
note see Wear, 28 11974) 145).
199
K. A. Nuri: (for biographic
note see Weor, 30 (1974)
396).
P. C. Pandey: graduated in mechanicai engineering from the Banaras Hindu University in 1957. After completion of a one year apprenticeship with the Kanpur Electric Supply Administration he became a lecturer in the Department of Mechanical Engineering, Banaras Hindu University; he obtained the degree of Ph. D. (production engineering) in 1966 from Nottingh~ University. On returning to India he joined the Department of Mechanical and Industrial Engineering of the University of Roorkee. He is at present a professor and his fields of interest are material processing and machine tools. M. D. Pascovici:
(for biographic
note see Wear, 16 (1970)
Jon Pemberton: is a research student London. He is a graduate of Imperial
164).
in the Lubrication Laboratory at Imperial College, College with a mechanical engineering degree.
Geoffrey Pocock: graduated in chemistry from the University of Bristol in 1968 and was awarded a Ph. D. in 1971 for a thesis on molecular interactions in dilute gases. A one year research feiiowship in X-ray photoelectron spectroscopy at the Physical Chemistry Laboratory, Oxford, was followed by a return to Bristoi and a fellowship in the department of theoretical chemistry. Since 1973 he has worked in the tribology section of the Admiralty Materials Laboratory where he is mainly concerned with wear in oillubricated systems. G. Ramanaiah:
(for biographic
R. S. H. Richardson: E. Sacher:
note see Wear, 14 (1969)
(for biographic
(for biographic
220).
note see Wear, 28 (19743 146).
note see Wear, 32 (1975)
276).
H. S. Shan: graduated in mechanical engineering from Guru Nanak Engineering College, Ludhiana (Panjab University), in 1966. He obtained his master’s degree with honours in production engineering from the University of Roorkee in 1968 and his Ph. D. degree (mech. eng.) in 1972. Dr. Shan is at present a reader in the department of Mechanical and Industrial Engineering of the University of Roorkee. His current interests are in the field of metal machining and ergonomics. M. V. Swain: P. Swift:
(for biographic
(for biographic
note see Weor. 35 (1975)
note see Wear, 29 (1974)
204).
139).
R. M. Waghorne: studied at Imperial College, London, where he gained a B. SC. and D.I.C. in mathematical physics. Joined Fulmer Research Institute in 1960, where he has worked on a variety of research topics, including the structure of liquid metals and alloys. He is currently concerned with surface studies, mainly using X-ray photoelectron spectroscopy. J. R. White: following a B. SC. in physics (1964) and Ph. D. in chemical engineering (1968) at Imperial College, University of London, and periods at Morganite Research Ltd. and Johns Hopkins University in Baltimore, he joined the Department of Materials, Queen Mary College, University of London, in 1970 as a senior research assistant. His major research interests include electron microscopy and diffraction, and fatigue in polymers. In 1975 he was appointed as a lecturer in the Department of Metallurgy and Engineering Materials, University of Newcastle upon Tyne. W. 0. Yandetl: graduated from the University of New South Wales in 1962 in civil engineering; examined the effect of earthquake loads on stresses in earth and concrete dams at the Irrigation Commission of N.S. W. and studied scour, using hydraulic models.
200 He won a fellowship of the University of N.S.W. and obtained an M. Eng. degree in 1966 for his original practical work on the effect of cyclic loading on road making materials. While working in the Highway Schoof he designed a number of research devices including a road strength testing machine and a single-wheeled skid trailer. He anaiysed tbeoretically the stresses and friction in hysteretic materials and submitted his Ph. D. in 1970 on the effect of surface texture on skidding resistance. He is now senior lecturer and is continuing his research on road friction financed by the Australian Research Grants Commission.
193
Short Communication
Spherical artifacts on ferrograms
W. R. JONES, JR. Letvk Research
Center, Cleveland,
Ohio 44135
(U.S.A.)
(Received September 8, 1975)
The generation of metallic microspheres has been reported by a number of investigators [l - 61. Several mechanisms have been postulated for their generation. These include fretting [ 1, 21, abrasion [ 31, cavitation erosion [4] and fatigue-related processes [5, 61. It has been suggested that the detection of spheres in a bearing lubricant may allow the prediction of incipient bearing fatigue failure [ 71. Ferrographic analysis [ 81 is a technique for magnetically precipitating metallic wear particles from a used lubricant onto a glass slide. This slide with its associated particles is called a ferrogram. Recently, a ferrogram prepared from a short term sliding friction and wear test was found to contain several thousand small (approximately 1 - 2 E.trnin diameter) metallic spheres. It seemed highly unlikely that these spheres were produced by some mechanism associated with the friction and wear test. It soon became evident that they were a result of airborne contamination. This was confirmed when no spheres were detected on a second ferrogram prepared from the identical oil sample. The contaminating source was finally found to be the result of a routine grinding operation on a steel plate located over 20 ft from the uncovered ferrograph. A similar grinding operation was performed on a piece of low carbon steel a few feet from the ferrograph. An aluminum oxide abrasive disc at a maximum surface speed of 40 m s-l (8000 ft mix-‘) was used. After only 2 min of grinding, the resulting ferrogram contained thousands of particles of which more than 90% were spherical. These spheres ranged in size from less than 1 to more than 30 pm in diameter. An example of this debris is shown in Fig. 1. Further examination of this debris in an SEM (Fig. 2) revealed that many of the spheres were hollow. The spherical shape combined with the convoluted surface features on many of the particles indicates that melting followed by rapid cooling probably occurred. Komanduri and Shaw [9] have reported similar occurrences in grinding experiments. Because of the widespread occurrence of ordinary grinding operations, it seems prudent that those utilizing the ferrograph be cognizant of this type of artifact.
Fig. 1. Photomicrograph
of spherical
Fig. 2. Scanning
micrographs
electron
grinding
debris.
of hollow
spheres.
References P. Hurricks, The occurrence of spherical particles in fretting wear, Wear, 27 (1974) 319 - 328. I. F. Stowers and E. Rabinowicz, Spherical particles formed in the fretting of silver, J. Appl. Phys., 43 (1972) 2485. E. Broszeit and F. J. Hess, Discussion to a scanning electron microscope study of fracture phenomena associated with rolling contact fatigue failure, Wear, 17 (1971) 314 - 315. S. W. Doroff, R. S. Miller, A. Thiruvengadam and V. C. Westcott, Nature (London), 247 (1974) 363. B. Loy and R. McCallum, Mode of formulation of spherical particles in rolling contact fatigue, Wear, 24 (1973) 219 - 228.
195 6 D. Scott and G. H. Mills, Spherical debris .- its occurrence, formation and significance in rolling contact fatigue, Wear, 24 (1973) 235 - 242. 7 D. Scott, W. W. Seifert and V. C. Westcott, The particles of wear, Sci. Am., 230 (5) (1974) 88. 8 W. W. Seifert and V. C. Westcott, A method for the study of wear particles in lubricating oil, Wear, 21 (1972) 27. 9 R. Komanduri and M. C. Shaw, Formation of spherical particles in grinding, Philos. Mag., 1975, to be published.
Wear, 37 (1976) 197 - 200 0 Elsevier Sequoia S.A., Lausanne - Printed in the Netherlands
197
NOTES ON CONTRIBUTORS
S. E. Amundson: I. B. Atkinson:
(for biographic note see Wear, 36 (1976)
(for biographic note see Wear, 29 (1974)
R. G. Bayer: (for biographic note see Wear, 16 (1970)
131). 139).
468).
R. J. Bird: graduated in physics at London University in 1948 and joined Shell Research Limited in 1954. He has worked at Thornton Research Centre principally on physical methods of analysis, with emphasis on the characterization of solid surfaces by the techniques of electron microscopy, X-ray and electron emission. W. Bonfield: is Professor of Materials at Queen Mary College, University of London, and Executive Editor of the Journal of Materials Science. He obtained the degrees of B. SC. (Eng.) (1958) and Ph. D. (1961) in metallurgy at Imperial College, University of London, and is a Fellow of the Institution of Metallurgists. Prior to joining Queen Mary College in 1968, he was a senior principal research scientist at the Honeywell Research Center, Hopkins, Minnesota. His research interests include microplasticity, precipitation hardening, composite materials and biomechanics. Philip Cadman: graduated in chemistry from the University of Birmingham in 1962 and was awarded a Ph. D. in 1965 for a thesis on photochemistry and reaction kinetics. He held a postdoctoral fellowship at the University of Toronto until 1967 and is now a university lecturer in chemistry at the University College of Wales at Aberystwyth. A. Cameron: (for biographic note see Wear, 36 (1976)
267).
A. H. Demirci: born in Yesilhisar, Kayseri, Turkey, in 1945; graduated in mechanical engineering from the Technical University of Istanbul in 1969; employed in the State Company DSI in Ankara. Now employed as assistant scientist in the Department Abnutzung der Werkstoffe at the Technical University of Aachen, F.R.G. K. F. Dufrane: received his B. S. and M. S. degrees in metallurgical engineering from Michigan Technological University in 1963 and 1964. Joined Battelle’s Columbus Laboratories in 1964 and has been active in the fields of friction, wear and mechanical failure analysis. B. C. Edwards: graduated in physics (1969), and then obtained a Ph. D. in materials science (1973), both at Queen Mary College, University of London. He was subsequently a research assistant, studying crystallisation in polymers, at Queen Mary College, before joining the Metallurgy Division, A.E.R.E., Harwell, in 1975 as a Research Fellow, on an investigation of brittle fracture in steel. G. D. Galvin: works in the Lubrication Division of the Thornton Research Centre of Shell Research Limited. He has published papers on the effect of lubricants on metal fatigue, on the properties of lubricants at high pressures, on surface chemical effects in lubrication and on the cleaning and lubrication of gas bearings in gyroscopes. W. A. Glaeser: received his B.M.E. from Cornell University in 1949, and his M.S. in metallurgical engineering from Ohio State University in 1959. He joined the Battelle staff in 1951 and is presently a research leader in the Tribomechanics Section.
198 M. K. Gopalan: graduated from the University of Kerala (India) in 1961 in civil engineering; qualified for an appointment in the Central Engineering Services of the Government of India through the All India Competitive Engineering Services Examination; worked as a design engineer and evolved standard designs for right and skew highway bridges in steel, R.C.C. and prestressed concrete; won the fellowship (Dean’s Award) of the University of New South Wales in 1973 and is at present doing full-time research for his Ph. D. on the influence of surface texture on abrasion and friction of rubber. J. Halling:
(for biographic
T. Hisakado:
note see Wear, 24 (1973)
(for biographic
131).
note see Wear, 30 (1974)
283).
R. E. Jackson: received a Ph. D. degree in structural geology from the University of North Carolina, Chapel Hill, North Carolina, U.S.A., in 1973. After completing graduate studies on the frictional behavior of sliding rock surfaces, he was a post-doctorai fellow and research scientist at Martin Marietta Laboratories where he studied chemomechanical behavior in relation to rock drilling. He is currently employed by the U.S. Nuclear Regulatory Commission (formerly USAEC) where he is involved in solving problems relating to the safe siting of nuclear reactors. William R. Jones, Jr.: graduated with a B. S. degree in chemical engineering in 1962 from the University of Missouri at Rolla; spent a year of graduate study in the field of organic chemistry at the University of Wisconsin; completed two years with the United States Peace Corps as a lecturer at the Yaba Technical Institute in Lagos, Nigeria, West Africa; joined the Lubrication Branch of the NASA Lewis Research Center, Cleveland, Ohio, in 1965. His research areas of interest include: boundary lubrication, lubricant additives and ferrographic analysis. He is a member of ASLE. H. Krause: received a technical education at the Technical University of Aachen, F.R.G; obtained his doctor’s degree (Dr.-Ing.) in 1967; obtained habilitation and uenia legendi for the Friction and Wear Section (Tribology) in 1968; was nominated as a professor at the Technical University of Aachen, and is now bead of the Department Abnutzung der Werkstoffe at the Technical University of Aachen. His main interest is tribology, especially triboehemical reactions on metallic surfaces. R. C. Lokken: is a research supervisor at the Industrial Abrasives Division Laboratory of the 3M Company in St. Paul, Minnesota. He obtained his B.A. in mathematics and physics from Concordia College (Moorhead, Minnesota) in 1956 and did graduate work in mathematics at North Dakota State University during 1965 - 66. He is interested in the theory of grinding and wear and his primary research area has been new methods applications for various coated abrasive products. A. C. Mahanti:
(for biographic
note see Wear, 29 (1974)
275).
A. J. Markham: is experimental officer in the Department of Materials, Queen Mary College, University of London. A Fellow of the Royal Microscopical Society, her particular research interest is etectron microscope examination of ceramic whiskers and polymer sections. T. R. McGibbon: received his B. Mathematics degree in 1969 from the University of Minnesota. He has been employed by the 3M Company since 1962. His current position is Advanced Research Mathematician and his responsibilities include coated abrasives development work in the area of abrasive wear mechanisms, precision grinding technology and surface measurement and characterization. H. Nolle: (for biographic
note see Wear, 28 11974) 145).
199
K. A. Nuri: (for biographic
note see Weor, 30 (1974)
396).
P. C. Pandey: graduated in mechanicai engineering from the Banaras Hindu University in 1957. After completion of a one year apprenticeship with the Kanpur Electric Supply Administration he became a lecturer in the Department of Mechanical Engineering, Banaras Hindu University; he obtained the degree of Ph. D. (production engineering) in 1966 from Nottingh~ University. On returning to India he joined the Department of Mechanical and Industrial Engineering of the University of Roorkee. He is at present a professor and his fields of interest are material processing and machine tools. M. D. Pascovici:
(for biographic
note see Wear, 16 (1970)
Jon Pemberton: is a research student London. He is a graduate of Imperial
164).
in the Lubrication Laboratory at Imperial College, College with a mechanical engineering degree.
Geoffrey Pocock: graduated in chemistry from the University of Bristol in 1968 and was awarded a Ph. D. in 1971 for a thesis on molecular interactions in dilute gases. A one year research feiiowship in X-ray photoelectron spectroscopy at the Physical Chemistry Laboratory, Oxford, was followed by a return to Bristoi and a fellowship in the department of theoretical chemistry. Since 1973 he has worked in the tribology section of the Admiralty Materials Laboratory where he is mainly concerned with wear in oillubricated systems. G. Ramanaiah:
(for biographic
R. S. H. Richardson: E. Sacher:
note see Wear, 14 (1969)
(for biographic
(for biographic
220).
note see Wear, 28 (19743 146).
note see Wear, 32 (1975)
276).
H. S. Shan: graduated in mechanical engineering from Guru Nanak Engineering College, Ludhiana (Panjab University), in 1966. He obtained his master’s degree with honours in production engineering from the University of Roorkee in 1968 and his Ph. D. degree (mech. eng.) in 1972. Dr. Shan is at present a reader in the department of Mechanical and Industrial Engineering of the University of Roorkee. His current interests are in the field of metal machining and ergonomics. M. V. Swain: P. Swift:
(for biographic
(for biographic
note see Weor. 35 (1975)
note see Wear, 29 (1974)
204).
139).
R. M. Waghorne: studied at Imperial College, London, where he gained a B. SC. and D.I.C. in mathematical physics. Joined Fulmer Research Institute in 1960, where he has worked on a variety of research topics, including the structure of liquid metals and alloys. He is currently concerned with surface studies, mainly using X-ray photoelectron spectroscopy. J. R. White: following a B. SC. in physics (1964) and Ph. D. in chemical engineering (1968) at Imperial College, University of London, and periods at Morganite Research Ltd. and Johns Hopkins University in Baltimore, he joined the Department of Materials, Queen Mary College, University of London, in 1970 as a senior research assistant. His major research interests include electron microscopy and diffraction, and fatigue in polymers. In 1975 he was appointed as a lecturer in the Department of Metallurgy and Engineering Materials, University of Newcastle upon Tyne. W. 0. Yandetl: graduated from the University of New South Wales in 1962 in civil engineering; examined the effect of earthquake loads on stresses in earth and concrete dams at the Irrigation Commission of N.S. W. and studied scour, using hydraulic models.
200 He won a fellowship of the University of N.S.W. and obtained an M. Eng. degree in 1966 for his original practical work on the effect of cyclic loading on road making materials. While working in the Highway Schoof he designed a number of research devices including a road strength testing machine and a single-wheeled skid trailer. He anaiysed tbeoretically the stresses and friction in hysteretic materials and submitted his Ph. D. in 1970 on the effect of surface texture on skidding resistance. He is now senior lecturer and is continuing his research on road friction financed by the Australian Research Grants Commission.