*Article* **Preparation and Properties of Mo Coating on H13 Steel by Electro Spark Deposition Process**

**Wenquan Wang <sup>1</sup> , Ming Du <sup>1</sup> , Xinge Zhang 1,\*, Chengqun Luan <sup>1</sup> and Yingtao Tian <sup>2</sup>**


**Abstract:** H13 steel is often damaged by wear, erosion, and thermal fatigue. It is one of the essential methods to improve the service life of H13 steel by preparing a coating on it. Due to the advantages of high melting point, good wear, and corrosion resistance of Mo, Mo coating was fabricated on H13 steel by electro spark deposition (ESD) process in this study. The influences of the depositing parameters (deposition power, discharge frequency, and specific deposition time) on the roughness of the coating, thickness, and properties were investigated in detail. The optimized depositing parameters were obtained by comparing roughness, thickness, and crack performance of the coating. The results show that the cross-section of the coating mainly consisted of strengthening zone and transition zone. Metallurgical bonding was formed between the coating and substrate. The Mo coating mainly consisted of Fe9.7Mo0.3, Fe-Cr, FeMo, and Fe2Mo cemented carbide phases, and an amorphous phase. The Mo coating had better microhardness, wear, and corrosion resistance than substrate, which could significantly improve the service life of the H13 steel.

**Keywords:** electro spark deposition (ESD); Mo coating; H13 steel; microhardness; wear resistance; corrosion resistance
