This message was posted on behalf of Intel Corporation
In regard to your inquiry, the material of the heat spreader for the Intel® Xeon E5-2603 v3 is cooper, and it is the same material for all the processors.
On the following link you will be able to see further information about the heat spreader:
NOTE: These links are being offered for your convenience and should not be viewed as an endorsement by Intel of the content, products, or services offered there.
Any questions, please let me know.