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Nickel based superalloy, Inconel 718, is one of the main candidates for high temperature applications such as air craft, land base and marine turbines. This technical paper deals with high temperature erosion behaviour and its mechanism of Al 2 O 3 -40TiO 2 (A40T) coating on Inconel 718 alloy. Al 2 O 3 -40TiO 2 coatings through plasma spray method were made on Inconel 718. The erosion behaviour of the A40T coating was studied using hot air jet erosion experiments at 800uC with varying parameters like angle of impingement and erodent velocity. Characterisation of the samples was carried out using SEM images, and mechanisms of erosion are discussed. Images (SEM) reveal that the A40T coating exhibit ductile and brittle behaviour by ploughing and network cracking with grain chipping at 45u angle of impingement, while at 90u, it is brittle behaviour by network cracking and grain ejection. This investigation concludes that A40T coating on IN718 provides good erosion resistance at elevated temperatures.

This paper deals with high temperature dry sliding wear behaviour and its mechanism of carbonitrided AISI 8620 steel. The sliding wear behaviour of the carbonitrided AISI 8620 steel was investigated using a pin on disc equipment at 1008C with varying parameters like normal load and sliding velocity. The scanning electron microscopy features of the worn samples reveal that abrasion with shallow and narrower wear track is the dominant wear mechanism of carbonitrided AISI 8620 at 50 N, while at 150 N, plastic deformation is caused by high friction sliding, delamination, spalling, pitting and deep grooving. The analysis of wear track was performed using high resolution universal tribometer.

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IN718 is a Nickel-based superalloy, widely used in high-temperature applications such as aircraft, and landbased and marine turbines. This technical paper deals with high-temperature erosion behavior and its mechanism of IN718. The erosion mechanism of the IN718 was studied using hot air jet erosion experiments at 800°C with varying parameters such as angle of impingement and erodent velocity. Characterization of the eroded samples was done using SEM micrographs and high-resolution universal tribometer to determine the erosion mechanisms. SEM micrographs of eroded samples reveal that lip formation, cutting, and ploughing are the dominant erosion mechanisms for IN718 at 45°angle of impingement, while at 90°, it is lip extrusion followed by flattening of lip and detachment of platelet. These mechanisms eventually retard the particle impact velocity, thus enhancing erosion resistance.