An Investigation on the Effects of Ultrasonic Peening on the Properties of CrN Nanostructured Coating by Cathodic Vapor Deposition Method

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: An Investigation on the Effects of Ultrasonic Peening on the Properties of CrN Nanostructured Coating by Cathodic Vapor Deposition Method

ارائه دهنده: Provider: Mina Masoudi

اساتید راهنما: Supervisors: Dr. Abbas Pak

اساتید مشاور: Advisory Professors: Dr. Hassan Elm Khah

اساتید ممتحن یا داور: Examining professors or referees:

زمان و تاریخ ارائه: Time and date of presentation: Year 2020

مکان ارائه: Place of presentation:

چکیده: Abstract: Nowadays, the role of nanostructured coatings in the development of technologies for application in various industries is considerable. A large percentage of industrial components are coated with ceramic, metal, and composite coatings to enhance their reliability and performance. Therefore, there are many efforts in this area to extend the service life of components in environments with poor operating conditions (including corrosive environment, high temperature oxidation and wear) by improving the coating properties of nano-coatings. The decrease in adhesion and quality of coating performance due to the high hardness and stress of most nanostructured coatings has led to the use of surface treatments before and after the process over the last decade along with the type of materials, structures and composition of coatings. Coatings to significantly improve coating properties. Meanwhile, the use of advanced manufacturing technologies such as the effects of ultrasonic surface treatment can be considered as a novel way to improve the properties of nanostructured coatings. Using ultrasonic peening, the material structure, surface roughness, mechanical properties, and residual stress levels near the surface can be changed. The results of this method can be considered as a novel surface treatment method and can be considered as a significant solution to improve the properties of nanostructured coatings including the adhesion and surface quality of coatings. the properties of CrN based nanostructured coatings. The purpose of this study was to investigate the effect of ultrasonic peening process on tool steel samples and to investigate the parameters of this process in improving the properties of CrN based nanostructured coating. The research is performed in four parts including ultrasonic peening equipment construction and surface treatment, CrN nanostructure coating by cathode arc evaporation on tool steel, in vitro evaluation of nanostructured coating properties and then analysis of results. According to the widespread use of nanostructured coatings in the automotive, airplane, oil and gas industries, medical equipment, construction, agriculture, textile, etc., the application of these results is wide-ranging. The results of this study will be useful in achieving desirable results of equipment manufacturing and service delivery. By applying ultrasonic peening operations in three ranges of amplitude 20, 25 and 30% and reviewing the results obtained from different experiments, it is possible to receive that ultrasonic peening operation by peening on the surface and plastic deformation, causing compressive residual stress on the surface of parts and The higher the amplitude of impact, the higher the compressive residual stress, so that in the sample with a amplitude of 30%, the residual stress has increased by 273%. Ultrasonic peening operation in low oscillation amplitudes has reduced the surface roughness by 38.8%, but with increasing oscillation amplitude, the roughness has increased. According to the results, it can be seen that the nanostructure coating and its low thickness did not have a significant effect on surface roughness. Surface treatment performed on the samples has caused severe deformation of the surface and the phenomenon of hardness and has increased the surface hardness by 123%. Also, with increasing oscillation amplitude in ultrasonic peening operations, the subsurface hardness increased but the depth of hardness changes remained almost constant. With increasing the hardness of the substrate by the ultrasonic peening process, the hardness of the nanocoat has also increased by 70%. According to the results of the adhesion test, the adhesion quality of the nano-coating to the substrate of the peened sample with an amplitude of 20% is optimal due to the compressive residual stress created by the ultrasonic peening operation and the improvement of the surface roughness. Other advantages of ultrasonic peening are the improvement of abrasion resistance and the relative reduction of the coefficient of friction by approximately 60% due to the increase in hardness, adhesion and reduction of surface roughness. This process also improves the corrosion behavior of the samples and the peened sample with an amplitude of 20% has optimal conditions and its corrosion resistance has improved by 32%. Key Words: Surface treatment, Ultrasonic peening, Coating, Cathodic vapor deposition, Nanostructured coatings

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