Apparatus, and process for cold spray deposition of thermoelectric semiconductor and other polycrystalline materials and method for making polycrystalline materials for cold spray deposition

A method of making a functional material powder for use in a cold spray process, the method of making comprising:

• mechanically reducing a diameter size of particles in the functional material powder to be in an inclusive range of 0.2 μm to 40 μm, with a majority of the particles being in an inclusive range of 0.2 μm to 15 μm;
• applying the particles to a ball mill with alcohol;
• drying the particles;
• and
• storing dried particles having a diameter in the inclusive range of 0.2 μm to 40 μm, with a majority of the particles being in the inclusive range of 0.2 μm to 15 μm.

A cold-spray deposition nozzle comprising:

• a gas feed that receives a heated gas into the cold-spray deposition nozzle;
• a convergent-divergent nozzle comprising
• a convergent portion that is open at one end thereof to receive the heated gas from the gas feed and a narrower opposite end,
• a throat that receives the heated gas from the narrower opposite end of the convergent portion,
• a divergent portion that has a first end which receives the heated gas from the throat, the divergent portion tapering from the first end to a larger second end through which a mixture of the heated gas and functional material powder of particle diameter sizes in an inclusive range of 0.2 μm to 40 μm are emitted, and
• an input port that communicates with an interior of the divergent portion and through which the functional material powder is input so as to mix with the heated gas in the divergent portion prior to being emitted from the cold-spray deposition nozzle through the larger second end of the divergent portion, wherein
• the nozzle has a nozzle expansion area ratio in an inclusive range of 7 to 13,
• a diameter of the throat is 1.5 mm, and
• a diameter of the powder entrance tube diameter is 1.5 mm.