Buyers must prioritize the chemical composition (e.g., iron, nickel, or chromium content) and particle size distribution (measured in mesh or microns), as these directly impact the flowability and weld quality. For specialized applications like thermal spraying or 3D printing, ensure the powder has high sphericity and low oxygen content to prevent porosity in the final weld. Always request a Material Test Report (MTR) or a Certificate of Analysis (COA) to verify that the batch meets your specific metallurgical requirements.