This paper presents the results of the profilometric analysis of wear tracks from tribological tests of a composite material made by Diamond Metallplastic GmbH, Germany. This material has a polymer matrix reinforced with Cu, Zn, Sn particles, and various allotropic forms of SiO₂. The material belongs to Multimetall Messing category and is recommended by the manufacturer for repairing brass made parts. This composite material was tribologically tested in dry friction reciprocating conditions, in ball-on-flat configuration, using the tribotester CETR-UMT-2 (Bruker Corporation). The counterpiece was a steel ball. The tests were conducted at normal loads of 20, 30, 40 and 50N, over a distance of 100 m, at an average sliding speed of 3,50 mm/s, at room temperature and relative humidity of 40-60%. The wear tracks were examined with the help of a laser profilometer and the profilometric module of the tribotester CETR-UMT-2 (Bruker Corporation). The profilometric analysis results for the composite are compared to those obtained for brass. Comparing the wear tracks of the two materials, it can be found that the composite material has a better tribological behavior than the brass.

By relocation profilometry, a series of surface profiles can be recorded from the same track on a specimen. These techniques are used for monitoring specific particular points on the surface subjected to wear processes, in a more accurate manner as comparing to those involving average statistical information for surface. The method is providing a much more significant information about the surface, in a more efficient way, assuring that the same unworn investigated surface is studied after wear test. The studied roughness digital profiles were obtained before and after the testing of rolling/sliding line contacts, characteristic for spur gears, which has been simulated on SAE sets, with a two rollers test machine. The acquisition of the relocated profiles is performed on the same generatrix of the roller, before and after wear testing. To correlate the unworn and worn profiles, a spheroconical indentation was created on the circumferential surface of the disk, in the zone of the tested roller that remain unworn during the test. Measuring changes of the profiles by relocation techniques, two methods for wear assessment are presented: linear wear estimation by simulating the profile wearing and estimation of the volume wear.

The paper presents the researches on tribological behaviour of two materials used for parts subjected to friction, under dry sliding conditions. The composite material is a product of the company Diamant Metallplastic GmbH, Germany and the manufacturer recommend it for repairing or reconditioning worn or damaged bronze made parts. The material belongs to Multimetall category, which is a highly resistant 2-component repair system. This polymer composite material was tribologically tested in dry friction reciprocating conditions, in ball-on-flat configuration, using the tribometer UMT-2 (Bruker, former CETR). The counterpiece was a steel ball. Typical test conditions were as follows: normal loads of 20, 30, 40 and 50 N, sliding distance of 100 m, stroke length of 5mm, average sliding speed of 3,5 mm/s, room temperature and relative humidity of 50-60%. After testing, wear tracks were examined by electronic microscopy (SEM), laser profilometry and the profilometric module of the tribometer CETR-UMT-2. The results of the composite material analysis were compared with the similar ones obtained under similar test conditions for the bronze (metal material).

The paper presents some results about changes in integrity state of metal surface processed at different roughness levels subjected to fatigue plane bending tests. Experimental tests show that during fatigue process there are micro-geometrical changes related to local plastic deformations which can be evidenced by micro-hardness modifications and indentation size effect, ISE. ISE can be a quantitatively and qualitatively factor for characterize fatigue behavior of a metallic surface.

ROTRIB'16 The 13^th International Conference on Tribology September 22-24, 2016 – Galaţi, ROMANIA PROCEEDINGS EDITED BY Minodora RIPA, Professor, PhD, "Dunarea de Jos" University of Galati, ROMANIA Razvan George RIPEANU, Professor, PhD, Petroleum-Gas University of Ploiesti, ROMANIA Traian CICONE, Professor, PhD, University POLITEHNICA of Bucharest, ROMANIA Selected, peer reviewed papers from the 13^th International Conference on Tribology ROTRIB'16 FOREWORD The Conference ROTRIB'16 is the 13^th in a series of international scientific events on TRIBOLOGY organized in Romania. The general objective of this conference is to contribute and demonstrate fundamentals, applications and experiences in the field of Tribology. The conference provided an interdisciplinary forum for discussion, networking and initiating collaborations among specialists, about materials and Tribology and their application to product design and reliability. The exchange of ideas, theories, developments, innovations, improved methods and future trends was a key goal of this conference, by bringing together specialists from industry and academia, leading and young researchers, from various engineering and science fields. Papers presented at ROTRIB 2016 are included in the following topics: Friction and Wear Tribochemistry and tribocorrosion Contact Mechanics Tribology of machine elements Micro and nanotribology Tribology in manufacturing processes Lubrication Surface metrology, surface engineering, coatings Lubricants Condition monitoring These topics were discussed in sessions and two satellite symposia, VAREHD 2016 and DIPRE 2016. The official language of ROTRIB'16 for presenting and writing papers was English. We have received an excellent number of submissions out of which, after a thorough peer reviewing process, a number of 75 scientific contributions has been accepted for presentation and publication. The authors of the accepted papers have been invited to present their work in the Conference and we are pleased to welcome 110 participants from 9 countries, presenting 69 papers. The Conference program is enriched significantly by plenary presentations of renowned experts in their respective domains: Distinguished Professor. dr. Minel Braun (USA), Professor dr. Michel Fillon (France) and Emeritus Professor dr. Mircea D. Pascovici (Romania). Conference ROTRIB'16 was organized by "Dunarea de Jos" University of Galati and the Romanian Tribology Association (ART), under the aegis of the Romanian Ministry of Education and Scientific Research. The Conference was held in Galati, ROMANIA at the Natural Sciences Museum Complex, September 22 – 24, 2016. After 38 years since the first Romanian Conference on Tribology, "Tribotehnica", Galati, 1978, we organized ROTRIB'16 again in Galati, celebrating the 50^th anniversary of Tribology. Unfortunately, in this jubilee year of Tribology, Professor Peter Jost (the "father" of Tribology and President of International Tribology Council) and Professor Branko Ivkovic (former President of Serbian Tribology Association and Balkan Tribology Association) passed away. The Conference is financially supported by "Dunarea de Jos" University of Galati, the Romanian Tribology Association, the Romanian Ministry of Education and Scientific Research and our sponsors, which participated in ROTRIB'16 with company-profile presentations and/or product exhibitions. We would like to express our gratitude to the authors for submitting their work. We would like to thank to all those who have contributed, in one way or another, to the success of the Conference. We are grateful to the Scientific Committee members as well as to the external reviewers for their volunteer hard work of reading and discussing the submissions. Last but not least, we would like to thank to the members of the Organizing Committee for their technical and non-technical support. It has been a great pleasure for us to organize the Conference ROTRIB'16 and we do hope that this scientific event will stimulate future developments and innovations in the field of tribology. We also hope that all participants have had a pleasant and fruitful time in Galati, on the banks of the Danube River. Organising Committee Galati, September, 2016