This study reports the influence of sputter target density, microstructure and second phase precipitation on the particle performance in W 10 wt% Ti target sputtered thin films. By controlling the sintering process, a variety of W-Ti alloy sputtering target structures were prepared. These targets were sputtered using a physical vapor deposition process. Observations of the sputtered target surfaces reveal that the brittle redeposited nodules generate in the low erosion zone and around voids in the target material. The nodules together with the precipitated tungsten in the Ti-rich phase are most likely the particle sources.