**4. Conclusions**

The NiCr–TiB2–ZrB2 composite coatings were successfully fabricated on the SUS304 surface using high-energy ball milling and air plasma spraying technology. The microstructure and mechanical properties of the NiCr–TiB2–ZrB2 coatings with various TiB2 and ZrB2 contents were investigated. The following results can be highlighted:


**Author Contributions:** Investigation, N.Z.; Conceptualization and Supervision, N.N.Z.; SEM (scanning electron microscope) Analysis, S.G.; XRD (X-ray diffraction) Analysis, S.L.; Data Reduction, G.Z.; Writing–Original Draft, N.Z; Writing–Review & Editing, Y.Z.

**Funding:** This research was funded by the Natural Science Foundation of Liaoning Province (201602553) and Chinese National Natural Science Foundation (51301112).

**Acknowledgments:** Thanks to Yingdong Qu for giving help on the wearing surface observation.

**Conflicts of Interest:** The authors declare no conflict of interest.
