In a breakthrough that could reshape the landscape of additive manufacturing and energy sector applications, researchers have developed an innovative solution to a persistent challenge in cold spraying: nozzle clogging. Led by HUANG Chunjie from the Shaanxi Key Laboratory of Friction Welding Technologies at Northwestern Polytechnical University in Xi’an, China, the study published in *Cailiao gongcheng* (which translates to *Journal of Materials Engineering*) introduces a novel approach that promises to enhance the efficiency and reliability of aluminum metal additive manufacturing.
Cold spraying, a process that involves propelling solid powder particles at high velocities to form coatings or additive structures, has long been hindered by nozzle clogging. This issue arises when aluminum powder softens and adheres to the inner walls of traditional silicon carbide (SiC) nozzles, leading to powder agglomeration and increased porosity in the final product. “The existing process results in a porosity of 0.32%, which compromises the structural integrity and performance of the coatings,” explains HUANG.
The research team addressed this problem by introducing a polybenzimidazole (PBI) polymer nozzle combined with axial center powder feeding. This combination significantly reduces particle adhesion, forming a uniform gas-solid two-phase flow that enables continuous and stable deposition. The result is a coating with a reduced porosity of just 0.16%, indicating a substantial improvement in material quality.
The implications for the energy sector are profound. Additive manufacturing techniques are increasingly being explored for producing components that can withstand extreme conditions, such as those found in power generation and renewable energy systems. “By achieving continuous spraying for 2 hours without nozzle clogging, we can now produce thicker, more robust coatings that are essential for high-performance applications,” says HUANG.
The study also highlights the potential for scaling up this technology. The team successfully deposited a 38 mm thick coating on an aluminum alloy substrate, demonstrating the process’s capability to handle larger and more complex structures. X-ray computed tomography (X-CT) analysis revealed no significant defects at the interface or within the deposit, further underscoring the reliability of the new method.
The mechanical properties of the coatings were also impressive. The in-plane tensile strength measured around 180 MPa, while the out-of-plane tensile strength was about 80 MPa, indicating significant anisotropy. This anisotropy, while a challenge, opens up new avenues for tailoring material properties to specific applications.
As the energy sector continues to demand more durable and efficient materials, this research offers a promising solution. The ability to produce high-quality, defect-free coatings and additive structures without the hindrance of nozzle clogging could revolutionize the way components are manufactured for power plants, wind turbines, and other energy infrastructure.
The study, published in *Cailiao gongcheng*, not only advances the field of additive manufacturing but also sets the stage for future innovations. “This research is just the beginning,” HUANG notes. “We are excited about the potential to further optimize the process and explore its applications in other materials and industries.”
In an industry where precision and reliability are paramount, this breakthrough could well be the catalyst for a new era of advanced manufacturing techniques, driving progress in the energy sector and beyond.