"Pressure-free slurry high energy absorption steel foam sintering technology" is based on the principle of powder metallurgy, creating a new application and research field for the defense technology industry. This technology can be used to prepare high melting point and lightweight steel foam. In addition to controlling porosity and pore size, it can also produce large-scale structures. The compressive strength of the foamed steel is more than ten times higher than that of the foamed aluminum, and it can be used on the defense bulletproof structure to absorb 60% to 70% of the kinetic energy of the target penetrator."Pressure-free high energy absorption slurry steel foam sintering technology" breaks through the traditional low-melting aluminum foam manufacturing process, and can produce porous steel foam mainly made of high-melting iron-based materials. This technology can control the porosity and pore size, and break through the limitation of the traditional powder metallurgy method that only small specimen can be made. It can complete the production of large-sized steel foam, and its compressive strength is dozens of times higher than that of aluminum foam. The anti-ballistic structure can absorb 60-70% of the kinetic energy of the armor-piercing projectile.Steel foam has the characteristics of compression resistance, sound insulation and energy absorption that are not comparable to low-melting foam aluminum. Compared with aluminum foam, steel foam can work for a long time at 300°C, and can also work in a high temperature environment of 700°C. Therefore, it can be popularized in bulletproof structures such as armored vehicles, armed helicopters, bulletproof vests and helmets, and can meet the ever-changing needs of vehicles, aviation, navigation and construction.