Also consider lifetime, what happens a year from now. Silver oxidizes and that could be the worst aging mechanism. I think the base grease is critical, that it lasts.
In the electrical industry, there is:
Sanchem electrical contact grease NO-OX-IDKOPR-SHIELD, contains colloidal copper.
For aluminum conductors, NOOXAL or NO-OX-ID-A, contains fine zinc particles which break through the Al oxide film.
When I looked at
thermal compounds they are mainly zinc oxide in silicone oil.
In the PC industry, they have very little silver, just enough to add that to the product name.
Arctic Silver 5
?% Silver
5% Boron Nitride (aka white graphite, a ceramic powder)
30-40% Zinc Oxide
5% Aluminum Oxide
Base DiPhenylamine as "Synthetic polymer" Polyol Ester
Coolermaster HTK-002-U1
30% Aluminum Oxide
20% Zinc Oxide
14% Silicon dioxide
3% Titanium Dioxide
1.2% Calcium carbonate
3% Magnesium Oxide
Base steric acid, palmitic acid
Thermal Grizzly Kryonaut
65% Aluminum Powder
25% Zinc Oxide
10% Silicones
MG Chemicals 860 Silicon Heat Transfer Compound
70% Zinc Oxide
3% Silica Powder
Base silicone oil?