Preparation, microstructure, and properties of tungsten alloys reinforced by ZrO2 particles

Tungsten alloys reinforced by in-situ tetragonal zirconia (W-ZrO2) were developed via the azeotropic distillation method combined with the powder metallurgy method. The microstructure and abrasive wear properties were studied. The in-situ ZrO2 particles in the tungsten matrix were obtained by the decomposition of zirconium nitrate after liquid-liquid incorporation of (NH4)(6)H2W12O40 and Zr(NO3)(4) aqueous solution. The ZrO2 particles were distributed evenly in the tungsten matrix, which refined tungsten powders and the grains of tungsten alloys significantly. The density and Vickers hardness of the tungsten alloys decreased with increasing ZrO2 mass fraction. However, the wear resistance increased firstly and then decreased with increasing ZrO2 mass fraction. The optimal amount of ZrO2 for improving wear property is 3%, with the wear resistance of W-3% ZrO2 improving by approximately 20%-40% compared with that of pure tungsten. The proper amount of ZrO2 particles can efficiently prevent microcutting to protect the tungsten matrix, thereby enhancing the wear resistance of tungsten alloys. (C) 2017 Elsevier Ltd. All rights reserved.