The powders specified herein are intended to be used with the Cold Spray process as specified in MIL-STD-3021, entitled: "Materials Deposition, Cold Spray". This standard (MIL-STD-3021) establishes the manufacturing controls for aluminum-based powders that are utilized for the 'Cold Spray' Process for repairing, coating, and the fabrication of freestanding structures, such as, Additive Manufacturing purposes. Cold Spray is a low-temperature, solid state consolidation process, whereby metal or combinations of metallic and non-metallic particles are injected into a high-velocity gas stream and are directed upon a suitable substrate where they impact and consolidate to form a coating or freestanding structure, without melting. This specification (MIL-DTL-32495) will outline the requirements for chemical composition, particle size and distribution for aluminum-based powders that are utilized by the Cold Spray Process to; (1) produce aluminum and/or aluminum alloy coatings on metallic and/or non metallic substrates including but not limited to steel, aluminum, ceramics and polymers, (2) produce deposits for dimensional restoration on metallic and/or non metallic substrates, or (3) produce near net shaped parts. The intended use for each class is as follows:

Class A: Commercially Pure (CP) Aluminum powder is intended to be used to produce sacrificial coatings with 0.5 WT % trace elements and for applications where strength is not a critical requirement.

Class B: High Purity (HP) Aluminum powder is intended to be used to produce sacrificial coatings with 0.05 WT % trace elements and for applications where strength is not a critical requirement.

Class C: Aluminum Alloy 6061 powder is intended to be used to produce coatings that have increased strength and hardness and to provide a material that is compatible with 6061 aluminum alloy substrates and for applications where increased strength and hardness are required. Cold spray 6061 aluminum materials have the capacity of achieving an ultimate tensile strength and hardness greater than or equal to 6061 wrought aluminum heat treated to the T-6 condition.

Class D: Aluminum alloy 5056 powder is intended to be used to produce coatings that have increased strength and hardness and to provide a material that is compatible with 5056 aluminum alloy substrates and for applications where increased strength and hardness are required. Cold spray 5056 aluminum materials have the capacity of achieving an ultimate tensile strength and hardness greater than or equal to 5056 wrought aluminum in the fully-worked condition.