BE95-1231 Preparation of AgSnO2 Contact Material by Reactive Milling
The objective of the project is to develop a new process for manufacturing of silver Ag-SnO2 metal matrix composites. These silver matrix oxide reinforced composites are used as the essential parts in the electrical contactors. The number of electrical contacts present throughout the world is estimated at 6500 Millions, which represent more than 500tons of silver matrix composites. 90% of the contactors use AgCdO elements.

In order to meet the project objective the partners intend to develop the reactive milling process, a variant of mechanical alloying. The preliminary work has shown that the use of the reactive milling leads to an essential improvement of the functional properties of the concerned material: The erosion rate of the material is divided by a factor 3 to 10 while exposed to electric arc. The importance of such an improvement can be understood when compared to the 20% or 30% percent improvement obtained applying other presently known methods.

The project implies:
- development of reactive milling technique
- development of high energy, non polluting attritor

The consortium comprises:
- CLAL, French leader in precious metal transformation and electrical contact manufacturing- project co-ordinator;
- SRM/CEA the reactive milling process inventor (FR);
- ZOZ Gmbh - German SME specialised in high energy mills manufacturing an its usual academic partner Siegen University (D);
- Inasmet Spanish research institute which will be in charge of development of coating for improved rnill;
- final user of electrical contacts, Swedish consortium ABB manufacturing electrical contactors;

The improvement of electrical properties of Ag-SnO2 is supposed to be the decisive factor in the replacement of toxic Ag-CdO which has been postulated and permanently delayed since 10 years. The very moderate estimation shows that the realisation of objectives of the present project would generate the increase of the European companies turnover of 2S millions of ECU per year.