*Article* **Low Frictional MoS 2**/**WS 2**/**FineLPN Hybrid Layers on Nodular Iron**

#### **Pior Kula 1,2, Robert Pietrasik 1,2,\*, Sylwester Paw ˛eta 1,2 and Adam Rzepkowski 1,2**


Received: 1 March 2020; Accepted: 19 March 2020; Published: 21 March 2020

**Abstract:** The paper presents the new concept of low frictional hybrid composite coatings on nodular cast iron. The structure of it is multilayer and consists of MoS2 and/or WS2 nanoinclusions embedded in the iron nitrides' zone and relatively deep hard di ffusion zone. It o ffers a low friction coe fficient as well as high wear resistance of coated parts. The details of technology as well as the mechanism of layer's growth have been presented and discussed. The presented technology may be an interesting alternative for chromium-based galvanic coatings of piston rings made of nodular iron using Cr6+.

**Keywords:** nitriding; low friction; piston ring
