Heat pipe wick structure wherein a stout sheet of perforated material
overlays a high performance wick material such as stainless steel felt
affixed to a substrate. The inventive structure provides a good flow path
for working fluid while maintaining durability and structural stability
independent of the structure (or lack of structure) associated with the
wick material. In one described embodiment, a wick of randomly laid
.about.8 micron thickness stainless steel fibers is sintered to a metal
substrate and a perforated metal overlay.