Metal-Ceramic Composite Powders via Ball Milling and Plasma Spheroidization

The patent introduces a process control agent (PCA) as an intermediary substance during ball milling. The PCA adsorbs onto nanoparticle surfaces, providing steric stabilization that prevents agglomeration while allowing the metal matrix to maintain its spherical shape. This mediator enables uniform nanoparticle distribution without the severe plastic deformation that would otherwise irregularize the particle morphology.

The patent optimizes multiple process parameters including ball-to-powder ratio, milling speed, milling time, and PCA concentration to achieve the desired balance. By carefully controlling these parameters, the process maintains spherical particle shapes while achieving uniform nanoparticle distribution through controlled mechanical energy input that prevents both agglomeration and excessive deformation.

The process control agent serves as a mediator that enables effective nanoparticle-matrix interaction at low energy levels. The PCA creates a protective barrier around nanoparticles, preventing van der Waals attraction-driven agglomeration while allowing uniform distribution to occur during gentle mixing, thus maintaining both shape regularity and dispersion uniformity.

The process control agent provides self-service by automatically adsorbing onto nanoparticle surfaces and providing steric stabilization without requiring additional processing steps. This self-organizing behavior enables uniform nanoparticle distribution to occur naturally during mixing, eliminating the need for high-energy ball milling that would compromise particle shape.

The patent applies preliminary action by pre-coating nanoparticles with process control agent before mixing with metal powder. This preliminary surface modification ensures that nanoparticles remain well-dispersed and resistant to agglomeration throughout the subsequent gas-atomization process, maintaining uniform distribution while achieving spherical particle shapes through the rapid cooling inherent in atomization.

The process control agent acts as an intermediary that prevents direct metal-nanoparticle contact during atomization, eliminating the pushing effect by the solidification front that causes agglomeration. The PCA layer stabilizes nanoparticles against chemical segregation and physical displacement during the rapid solidification process, ensuring uniform distribution in the final spherical particles.

The patent extracts and eliminates the harmful agent-aid deposition step from the process. Instead of using external agents that contaminate the powder surface, the method relies on process control agent-assisted ball milling that achieves nanoparticle separation and uniform distribution through controlled mechanical energy input, producing clean powder surfaces without residual contamination.

The process control agent provides self-service by being inherently part of the ball milling process rather than an external additive. The PCA is consumed during milling to provide steric stabilization, and any residual PCA on particle surfaces is minimal and可控, unlike the severe contamination from agent-aid deposition methods that require additional cleaning steps.