Surface modification of NiTi/PZT heterostructure thin films using various protective layers for potential MEMS applications

► Protective layers (AlN, CrN and TiCrN) of approximate thickness (~ 200 nm) were used. ► Surface, mechanical and corrosion properties of NiTi/PZT/TiOx films were improved. ► Protective layers did not deteriorate the characteristic properties of the constituent films. ► Surface modified NiTi/PZT/TiOx exhibits higher hardness and better wear resistance. ► The CrTiN coated NiTi/PZT/TiOx heterostructure showed the best corrosion resistance.