3D 打印硬质合金：光固化打印前驱体间接制备

In order to obtain 3D printed cemented carbide, this paper proposed a method based on photocuring 3D printing technology. Tungsten salt and cobalt salt were used as raw materials to print precursors by light irradiation polymerization. The precursors were sintered and densified into cemented carbide after high temperature reduction/ carbonization. In this paper, apparatuses such as rheometer, UV spectrophotometer, synchronous thermal analyzer and X-ray diffractometer, were used to study the UV rheological properties and stability of inks, the phase transformation process of precursors, and the effect of the mole ratio of tungsten salt to organic matter on the final product. Finally, 3D printed carbide parts with honeycomb structure were obtained. The results are as follows: in optimized ink, the mass ratio of water to acrylic acid is 2.5, the solubility(mass fraction) of ammonium metatungstate is less than 100%, and the amount of TPO and PEGDA is 2% of the solvent mass. In post-treatment processing, a series of reactions including decomposition, reduction and carbonization occur. Ammonium metatungstate is subsequently decomposed to tungsten oxide, reduced to pure tungsten in hydrogen atmosphere, and carbonized to W₂C and WC. As the mole ratio of tungsten salt to organic matter is lower than 0.85, the product is pure WC. Finally, the 3D printed honeycomb cemented carbide possesses complete structure and smooth surface, whose main phases are WC and Co.