As a traditional processing method, powder metallurgy has the advantages of low cost and simple process in the process of preparing porous metal, but the sintering time is short, it is difficult to control the solidification rate and the size of porosity, so it is difficult to prepare the porous structure with uniform pore size and porosity and it is difficult to obtain the porous metal parts with complex shapes. In recent years, with the continuous development of additive manufacturing technology, there are more and more new attempts of porous medical metal implants. Compared with traditional powder metallurgy processing methods, additive manufacturing is more accurate for the manufacture of products with porous shapes and hollow structures. Reduces production costs (mouldless manufacturing) and speeds time to market for high-value components; Additive manufacturing process, greatly reduce material waste, small pollution; Flexible manufacturing, high degree of customization. The main metals used in additive manufacturing of porous implants are titanium alloy, cobalt-chromium alloy, and tantalum metal. Titanium alloy as a relatively mature material is mainly used in the manufacture of acetabulum cup, porous stent and other implant products. Tantalum metal can be used to make porous bionic bone trabecular scaffolders. According to news reports, in 2021, the Orthopedics Department of Hospital used tantalum 3D printed long segmental artificial vertebra for the first time in the world to reconstruct the defect after the resection of the whole malignant tumor of the spine.
Tantalum 3D printed long segment artificial vertebral body, additive manufacturing titanium porous implant. Although the use of metal niobium or titanium niobium alloy in the 3D printing of porous implants is still relatively rare, with the development of additive manufacturing technology and equipment, in-depth research on the mechanism in the manufacturing process, as well as the continuous decline of metal niobium cost and other factors, the application of additive manufacturing of porous niobium metal implants will gradually develop. The excellent mechanical properties and cellular activities of niobium can be fully developed.
Because of its excellent biocompatibility and corrosion resistance, niobium has been applied in many medical segments, as a supplement to pure titanium or a substitute for toxic elements in titanium alloy, in order to improve the mechanical and chemical properties of biological materials and improve biocompatibility. As a new kind of porous medical metal implant material, it has a strong development potential and application value.
