Preparation of Nanometer Yttrium Oxide Dispersion Tungsten Strengthened Alloy from Ammonium Paratungstate 1/2

The key factors that determine the properties of oxide dispersion strengthening of tungsten alloy is based on the oxide particle size and particle distribution, that is to say, the smaller size of oxide particle, the better uniform the particle distribution is, and the properties of tungsten alloy will be more superior. Certain oxides, such as  La₂O₃, HfO₂, Y₂O₃, because of their high melting point, good heat stability, and small solubility in tungsten, often used as tungsten dispersion strengthening phase for graining refinement and promote the densification of the material. The nano level yttrium oxide (Y₂O₃) with the best dispersion strengthening, can obviously refine the tungsten grains, and can achieve the goal of improving the armour-piercing and self sharpening ability of tungsten alloy. Y₂O₃is a white and maybe slightly yellow powder, and it is insoluble in water and alkali, but soluble in acid. It often used as magnetic and main raw materials in microwave and military, and can also be used as additive for optical glass and ceramic materials, and a big screen TV with high brightness fluorescent powder and other imaging tube coating.



Tungsten alloy commonly producing by adding yttrium oxide powder into tungsten and tungsten carbide powder, then directly make tungsten powder by ball grounding, and then press and calcined to form it. The advantage of this method is fewer steps, easy to operating, less equipment requirements, and the production is easy to achieve. However, it has the huge disadvantages like: raw materials are easy to mixing uneven. While due to the nanosize powder of Y₂O₃is easy to agglomerate, it results in dispersed phase and grain boundary segregation of tungsten alloy grains. A new way is proposed, which is take ammonium paratungstate (APT) as raw material and the yttrium oxide as the dispersion strengthened phase to producing nanometer yttrium oxide dispersion tungsten strengthened alloy with high density and hardness.