Niobium silicide-based alloys are a promising new high temperature material to replace nickel-based superalloys for use in turbofan jet engines to improve efficiency. In order to overcome the poor oxidation resistance of Niobium silicide-based alloys, boron and germanium are added to the alloy system. These elements are intended to reduce oxide formation and improve oxide adherence. As both boron and germanium can be substituted into SiO₂  for Si, the formation of an amorphous B-Ge-Si-O layer is a possible route to acceptable oxidation resistance.

Three alloys are investigated with varying boron and germanium contents KZ5: Nb-18Si-24Ti-5Cr-5Al, JW1: Nb-18Si-24Ti-5Cr-5Al-5Ge-5B, JW2: Nb-18Si-24Ti-5Cr-5Al-5Ge-10B (at. %). This study demonstrates the improved oxidation resistance of boron and germanium containing alloys and the changes in microstructure and phase compositions are characterised.