Electronic module for a piece of vehicle-borne aeronautic equipment and a piece of aeronautic equipment for an aeronautic vehicle

1. An electronics module for onboard aviation equipment designed to operate at a maximum temperature of about +225° C., the module including a ceramic hybrid circuit covered in a protective coating of poly-p-xylylene, the circuit comprising at least a first conductive element and a second conductive element, the first element including at least a first metal different from a second metal of the second element and being electrically and mechanically connected to the second conductive element by a connection in such a manner as to oppose diffusion of the first metal into the second metal, and the first element including a third metal for co-operating with the second metal at the connection to form a metallurgical barrier opposing migration of the first metal to the second metal, the second element being a track of silver covered in a coating superposing in succession nickel, palladium, and gold, or a coating superposing in succession nickel and gold.

2. The module according to claim 1 , wherein the first element is a palladium-doped gold wire welded on the second element.

3. The module according to claim 1 , wherein the first element is a copper wire wire bonded on the second element.

4. The module according to claim 1 , wherein the coating has a total thickness that is less than or equal to about 15 μm.

5. The module according to claim 1 , wherein the hybrid circuit includes an aluminum core supporting superposed conductive layers having portions that are connected together by plated-through holes.

6. The aircraft equipment including an electronics module according to claim 1 .

7. The use of an electronics module in onboard aviation equipment that is subjected to temperature variations lying in the range appropriately −60° C. to +225° C., the module including a ceramic hybrid circuit covered in a poly-p-xylylene protective coating, the circuit comprising at least a first conductive element and a second conductive element, the first conductive element including at least a first metal different from a second metal of the second element and being electrically and mechanically connected to the second conductive element via a connection in such a manner as to oppose diffusion of the first metal into the second metal, and the first element including a third metal to co-operate with the second metal at the connection to form a metallurgical barrier opposing migration of the first metal to the second metal.

8. The use according to claim 7 , wherein the metals are selected to have atomic weights that are sufficiently high and/or electronegativity coefficients that are sufficiently close to limit diffusion of one of the metals into the other.

9. The use according to claim 7 , wherein the first element is a palladium-doped gold wire wire bonded on the second element.

10. The use according to claim 7 , wherein the first element is a copper wire bonded on the second element.

11. The use according to claim 7 , wherein the second element is an aluminum-doped pad.

12. The use according to claim 7 , wherein the second element is a silver track covered in a coating comprising superposing in succession nickel, palladium, and gold, or a coating comprising superposing in succession nickel and gold.

13. The use according to claim 7 , wherein the second element is a palladium-doped gold track.

14. The use according to claim 13 , wherein the palladium content is at least 1%.

15. The use according to claim 7 , wherein the first metal is alloyed gold and the second element is solder comprising either a majority of lead, tin, and silver, or else a majority of lead, indium, and silver.

16. The use according to claim 15 , wherein the first element is a silver track covered in a coating comprising superposing in succession nickel, palladium, and gold, or a superposing coating comprising in succession nickel and gold.

17. The use according to claim 7 , wherein the coating has a total thickness that is less than or equal to about 15 μm.

18. The use according to claim 7 , wherein the hybrid circuit includes an aluminum core supporting superposed conductive layers having portions connected together via plated-through holes.