Effect of powder size on corrosion resistance of TiBw/TA15 composite with mesh structure

To investigate the impact of matrix powder particle size on the corrosion resistance of mesh-reinforced TiBw/TA15 composites, spherical TA15 titanium powders of varying sizes (approximately 60 μm, 140 μm, and 190 μm) were utilized to prepare 5 vol% TiBw/TA15 composites with distinct mesh structures. The corrosion resistance of the composites with a network structure had been studied for the first time. The research results indicated that the corrosion resistance of the composites improved as the size of TA15 powder particles increases. Specifically, the composites with an average TA15 powder particle size of around 190 μm exhibited the best corrosion resistance, with the lowest self-corrosion current (0.029 μA cm⁻²), highest polarization resistance (44230 kΩ cm²), and minimal pitting corrosion. Conversely, the composites with an average TA15 powder particle size of about 60 μm exhibited the poorest corrosion resistance. This was because, as the particle size of TA15 powder increases, the composites exhibited a lower grain boundary density and a smaller specific surface area, resulting in an increased local concentration of TiBw. The network structure of the composites became more cohesive, further impeding the movement of free electrons, which leaded to a reduced self-corrosion current. Consequently, composites with larger TA15 powder particle sizes demonstrated improved corrosion resistance.