Thermal stability and tensile properties of sol-enhanced nanostructured Ni-TiO2 composites

A highly-dispersed TiO2 nano-particles reinforced Ni-TiO2 composite was prepared by sol-enhanced composite electroplating. The microstructure, thermal stability and tensile properties of the sol-enhanced and traditional Ni-TiO2 composites were explicitly compared. TiO2 nano-particles agglomerated to large clusters of similar to 400 nm in the traditional Ni-TiO2 composite. In contrast, nano-sized TiO2 particles (similar to 15 nm) were distributed at grain boundaries in the sol-enhanced composite. The grain size, higher micro-strain (similar to 0.31%) and higher microhardness (similar to 407 HV50) of the sol-enhanced Ni-TiO2 composite were stabilized up to 250 degrees C compared to 150 degrees C of the traditional composite. The sol-enhanced Ni-TiO2 composite showed a much higher tensile strength of similar to 1050 MPa compared to similar to 610 MPa of the traditional composite. The lattice diffusion dominated at high temperatures during grain growth for the sol-enhanced composite. The distribution and location of TiO2 nano-particles played a significant role in determining the thermal stability and tensile behaviors. (C) 2011 Elsevier Ltd. All rights reserved.