  Bibliographic records related to tribology research were extracted from
SCOPUS and Web of Science databases for the period of 15 years from 1998 to
2012. Macro-level scientometric indicators such as growth rate, share of
international collaborative papers, citations per paper, and share of non-cited
papers were employed. Further, the Gini coefficient and Simpson Index of
Diversity were used. Two new relative indicators : Relative International
Collaboration Rate (RICR) and Relative Growth Index (RGI) are proposed in this
study. The performance of top countries contributing more than 1000 papers
across the study period was discussed. Contributions and share of continents
and countries by income groups were examined. Further research contributions
and citation impact of selected country groups such as the Developing Eight
Countries (D8), the Association of Southeast Asian Nations (ASEAN), the Union
of South American Nations (UNASUR) and the Emerging and Growth-Leading
Economies (EAGLEs) countries were analyzed. High levels of interdisciplinarity
exist in tribology research. Inequality of distribution between countries is
highest for number of publications and citations. Asia outperforms the other
world regions and China contributes most of the papers (25%), while the United
States receives most of the citations (22%). 84% of total output was
contributed by the Asiatic region, Western Europe and North America together.
Publications from these three world regions received 88% of total citations.
Around 50% of global research output was contributed by China, the United
States and Japan.
