A method for forming an annular heat pipe wick in a controlled atmosphere includes wrapping a plurality of layers of a fine mesh screen around a mandrel to form a wick. The method also includes inserting the mandrel and the wick into a sheath, and compressing the wick between the sheath and the mandrel to form an assembly. The compressing of the wick comprises applying pressure to an exterior of the mandrel and the sheath. The method further includes diffusion bonding the assembly at a temperature sufficiently high achieving self-diffusion of the plurality of layers of the fine mesh screen used to form the wick to themselves. The method also includes cooling the diffusion bonded assembly to room temperature, and etching the mandrel and sheath from the diffusion bonded assembly, leaving the wick as a porous tube.

A heat exchanger is provided and includes parting sheets flat along a first axis and curved along a second axis perpendicular to the first axis, a fin sheet interposed between the parting sheets and corrugated along the first axis to form fins that are curved along the second axis and diffusion bonds formed along an entire length of a fin to diffusion bond the entire length of the fin to the parting sheets.

A method for manufacturing a double-wall heat-exchanger tube including an external tube and an internal tube, these tubes being metallic, cylindrical and coaxial. This method includes providing a first tube having an inside diameter d.sub.1int and an outside diameter d.sub.1ext, this first tube being intended to form the external tube, a second tube having an inside diameter d.sub.2int and an outside diameter d.sub.2ext, this second tube being intended to form the internal tube, and a cylindrical coaxial tubular leaf made from Fe.sup.0 having an inside diameter d.sub.int and an outside diameter d.sub.ext, such that 0.15 mm(d1intdext)0.25 mm, 0.15 mm(dintd2ext)0.25 mm, and 10 m(dextdint)200 m.

A manufacturing method of three dimensional heat dissipation device includes a step of manufacturing a thermally conductive casing, a step of manufacturing a preliminary three dimensional heat dissipation device and a step of manufacturing a final three dimensional heat dissipation device. The step of manufacturing a thermally conductive casing is to manufacture the thermally conductive casing with an airtight chamber. The step of manufacturing a preliminary three dimensional heat dissipation device is to install at least one round heat pipe on the thermally conductive casing to form the preliminary three dimensional heat dissipation device. The step of manufacturing a final three dimensional heat dissipation device is to fix the preliminary three dimensional heat dissipation device and shape the round heat pipe to a flat heat pipe via a shaping tool so as to form the final three dimensional heat dissipation device.