Improvement of High Temperature Wear Resistance of AISI 316 ASS through NiCrBSiCFe Plasma Spray Coating

摘要

In this work, the microstructural description, mechanical properties and dry sliding wear features of NiCrBSiCFe plasma sprayed on AISI 316 austenitic stainless steel (ASS) substrate were examined. Defect-free metallurgically bonded coatings were obtained. Wear tests were carried out at 2 m/s sliding velocity under the load of 20N for 2000 m sliding distance at various conditions like room temperature (35°C), 150°C, 250°C and 350°C using a EN-8 medium carbon steel pin as a counterface material. The properties namely coating density, micro hardness, coefficient of friction (CoF) and wear resistance of the coating were studied. NiCrBSiCFe plasma spray coated steel substrate showed superior wear resistance properties than the uncoated steel substrate in all the temperatures. The sliding wear resistance was improved up to 4.5 times than that of the uncoated material. In wear test carried out at 350oC, the coated substrates showed relatively lesser wear than in other temperatures due to the oxide formation, which acted as a protective layer. In addition, the shallow ploughing mode of wear reduced the severity of material removal at 350°C. Using scanning electron microscope (SEM) pictures, the wear properties of the coated steel substrate were evaluated in terms of plastic deformation, material transfer and abrasion.