The Sixth International Conference on Sintering and Related Phenomena took place at the University of Notre Dame, Notre Dame, Indiana June 6-8, 1983. This conference was also the twentieth Conference on Ceramic Sciences organized yearly by a "confederation" of four institutions: North Carolina University at Raleigh, N.C., the University of California at Berkeley, CA, Alfred University at Alfred, NY and the University of Notre Dame, Notre Dame, IN. The papers presented at the last Notre Dame conference collect ed in this volume, reflect the progress in our understanding of the process of sintering achieved in the past four years. It seems that the analysis of the two particle models is finally extended to the analysis of the models of compacts. In these investigations strong emphasis is put on pore-grain boundar ies interaction which appear to be central to this problem. It is to be hoped that in the near future an adequate model of the compact will be developed which may serve as a useful basis of powder tech nology. Also, the effects of atmosphere on the sintering of ceramics after a long period of neglect, seem to attract the attention of more workers in the field."

In this volume there is set forth the text of the Pro ceedings of the Third International Conference on Sintering and Related Phenomena, which conference was held at the University of Notre Dame on June 5-7, 1972. This conference was the seventh in the series of University Conferences on Ceramic Science organized yearly by a happy "confederation" of four institutions; North Carolina State University, Raleigh, North Carolina; the University of California, Berkeley, California; Alfred University, Alfred, New York; and the University of Notre Dame, Notre Dame, Indiana. The 1972 Conference at Notre Dame was devoted to prob lems of sintering and allied phenomena. Previous gatherings at Notre Dame took place in 1954 and 1965. The proceedings of the first Notre Dame Conference were not published by reason of the conviction that a free forum similar in spirit to the Gordon Conferences should prevail. However, discus sions of the second Conference were preserved for posterity in a rather substantial volume (894 pp) published by Gordon and Breach in 1967. As the spirit of free exchange of ideas was not diminished by threat of publication of the revela tions of the second Notre Dame Conference, we deemed it just that the 1972 Proceedings be made public. Thus the present volume is a report upon progress realized in our science during the past six years.

The proceedings of the 4th International Conference on Sin tering and Related Phenomena, contained in this volume, have been broadened in scope to include the phenomena of sintering and coa lescence of catalytic materials dispersed upon refractory oxides. For it has long been recognized within the circles of chemists and chemical engineers working in the field of catalysis that one of the chief causes of the decline in heterogeneous catalytic activity and/or selectivity is, indeed sintering, or perhaps using a better term, coalescence of the supported catalytic metal and compounds thereof. Essentially catalytic deactivation by sintering is now weIl recognized as Ostwald ripening; which of course is a phenome non familiar to scientists grappling with the problem of sintering of powder compacts. The 4th Conference at Notre Dame marks the first occasion at which scientists and engineers of each discipline were assembled in the same room to exchange views on these phenome na of mutual concern. In the wake of the Conference at Notre Dame, all parties acknowledged the synergistic benefit which issued from this exchange, both at the formal and informal level. All were persuaded that signal benefits will be realized by a continuation of this collab oration in the form of future sintering conferences in which both powder metallurgists and catalytic scientists and engineers would participate.