Investigation of some Intrinsic Properties of Thermal Sprayed Molybdenum Coatings for Railway Axle Applications

Abstract

Thermal sprayed Mo coatings deposited on steel support deposited by electric arc and atmospheric plasma spray were investigated. Microstructural investigation of the coatings showed that in both variants the splats formed by rapid solidification and splashing during the impact with the substrate have irregular shape, exhibit cracks and scattered debris. The measured average equivalent diameter of the splats and the calculated average diameter of the particles that generated the splats are higher for electric arc spraying. Using the measured and calculated data it was descibed the relathionship between splats diameter, splats thickness and flattening degree. Some intrinsec properties of the coatings as roughness, hardness and bond strength were measured. All these properties are influenced by the splat size. Lower size of the splats lead to reduced surface roughness, higher hardness and higher bond strength of the coatings.

A correlation between fracture toughness and cohesion strength of molybdenum thermal sprayed coatings

“…These differences can be explained by the higher temperature and velocity of sprayed particles which impact the 4 MATEC Web of Conferences 145, 02007 (2018) https://doi.org/10.1051/matecconf/201814502007 NCTAM 2017 substrate and generate a higher level of compressive residual stresses in coatings creating a stronger bond between the layers. Another factor that influences the bonding strength is the dimensions of the Mo splats, which in the case of EA-sprayed coatings are approximately 55 µm and 37 µm for APS [13] that generates a lower porosity with decreasing of the splats dimension and a higher total contact surface.…”

Molybdenum powder coating on steel substrate to study three body wear resistance

“…The Mo blend coating with bronze and Al-Si powder coating showed better hardness and resistance than the other blend coatings and its counterparts wear rate were lower. Cristian Puscasu et.al: [4] In this research thermal sprayed Mo coating were deposited on Steel support by the use of both electric and atmospheric plasma spray method and was investigated. Microstructural analysis showed that in both the methods plates formed by rapid solidification.…”