Multifunctional ZrB2-rich Zr1-xCrxBy thin films with enhanced mechanical, oxidation, and corrosion properties

Refractory transition-metal (TM) diborides have high melting points, excellent hardness, and good chemical stability. However, these properties are not sufficient for applications involving extreme environments that require mechanical strength as well oxidation corrosion resistance. Here, we study the effect of Cr addition on ZrB2-rich Zr1-xCrxBy thin films grown by hybrid high-power impulse dc magnetron co-sputtering (Cr-HiPIMS/ZrB2-DCMS) with a 100-V Cr-metal-ion synchronized bias. metal fraction, x = Cr/(Zr + Cr), is increased from 0.23 to 0.44 decreasing power PZrB2 applied DCMS ZrB2 target 4000 2000 W, while average power, pulse width, frequency HiPIMS maintained constant. In addition, y decreases 2.18 1.11 function PZrB2, result supplying growing film preferential B resputtering caused pulsed Cr-ion flux. ZrB2.18, Zr0·77Cr0·23B1.52, Zr0·71Cr0·29B1.42, Zr0·68Cr0·32B1.38 hexagonal AlB2 crystal structure columnar nanostructure, Zr0·64Cr0·36B1.30 Zr0·56Cr0·44B1.11 amorphous. All show hardness above 30 GPa. Zr0.56Cr0.44B1.11 alloys exhibit much better toughness, wear, oxidation, resistance than ZrB2.18. This combination makes ideal candidates numerous strategic applications.