The Preparation And Oxidation Resistance Mechanism Of TiAlSiN Composite Coatings

In this paper, TiAlSiN nano composite coatings were prepared on carbide substrates surface by cathodic arc ion plating. At the same time, TiN and TiAIN coatings were prepared for comparation. The adhesion strength of coating-substrate were measured by scratch method, and the mechanical properties such as thickness, hardness and friction coefficient were measured. The oxidation behavior and oxidation resistance of the coating were analyzed by high temperature oxidation experiment. The influence of Al and Si content on the coatings was analyzed. At the same time, the effect of high temperature on the TiAlSiN nano composite coating during high speed cutting was studied by using the field cutting experiment to study the oxidation wear and failure of the three kinds of coated cutter and the uncoated milling cutter in the milling process. The main conclusions are as follows:(1) TiAlSiN composite coatings were deposited on YG-10 cemented carbide substrates surface by cathodic arc ion plating. The composite deposite is very dense,uniform and good appearance. The micro hardness of TiAlSiN composite coating is 3800HV0.05, the thickness is moderate to 3.45?m,the friction coefficient is 0.3, and the bonding strength is 42N (maximum critical load value), which is up to HF-1 of the industrial application standard by comparison with TiN and TiAIN coating.(2) TiAlSiN coating was prepared by heat treatment at high temperature of 400?,600? 800? and 1000?, made a comparison with TiN, TiAIN coatings. The maximum oxidation temperature of TiN is 600?, the surface had a large number of white spots peeling phenomenon, the formation of TiO2 oxide did not have the protective effect, the coating was easy to fail; TiAIN coatings' maximum oxidation temperature is up to 800 ?, the failure form is differ from TiN coatings, its high temperature formation of Al2O3 oxide dense, which can hinder the substrate from further oxidized,the higher the temperature, the more severe the surface cracks intensified, the coating showed more stress concentration damage; TiAlSiN antioxidant performance revealed best, oxides color were changed during the coating oxidation process,formed a variety of Al2O3,SiO2,TiO2 and other oxides. After 1000? treatment, the base had serious deformation, from which coating became to take off.(3) According to the field cutting processing experiment, the cutting performance of the TiAlSiN coating from high speed was evaluated at the cutting speed, the wear bandwidth and the wear rate of tools. TiAlSiN coatings showed the most stable and the longest processing time , and the average wear value of the TiAlSiN coating was 0.1 895, lower than TiN, TiAIN coating tools. When added Al, Si content, it improved the tool wear resistance and red hardness greatly, slow down high temperature wear of the tool in the high-speed cutting process.