Refractory metal heat exchangers with embedded sensors and related methods

A method of forming a heat exchanger, the method comprising:

• additively manufacturing a shapeholder comprising elongated bodies that correspond to fluid passageways to be defined within a body;
• additively manufacturing one or more sensors on the elongated bodies of the shapeholder;
• forming a material of the body around the elongated bodies of the shapeholder;
• sintering the material of the body around the elongated bodies of the shapeholder and the one or more sensors;
• and
• removing the shapeholder from the body, leaving the one or more sensors embedded at an inner surface of the fluid passageways.

A shapeholder for use in forming a heat exchanger with one or more sensors embedded within fluid passageways of the heat exchanger, the shapeholder comprising:

• elongated bodies configured in a negative pattern corresponding to the fluid passageways of the heat exchanger;
• a ceramic capsule disposed on an outer surface of one or more of the elongated bodies;
• and
• a sensor disposed within the ceramic capsule,
• wherein the elongated bodies comprise a first material that is reactive to a chemical solution and wherein the ceramic capsule comprises a second material that is resistant to the chemical solution.