Thermogravimetric and in situ SEM characterisation of the oxidation phenomena of protective nanocomposite nitride films deposited on steel

摘要: Abstract The lifetime of TiN coatings is often limited by its poor resistance to high temperatures. For an optimized addition silicon, both mechanical and physico-chemical properties are enhanced, owing the formation a nanocomposite structure. In this study, pure Ti TiSi (80/20) targets were arc-evaporated produce hard, single-layered coatings. Magnetron sputtered SiN x films also synthesized for comparison purpose. structure was determined XRD TEM, efficiency regarding confirmed nanohardness measurements. Through thermogravimetric experiments it shown that in isothermal dynamic conditions, chemical stability inherent controls oxidation behaviour TiSiN. However, thermal cycling conditions TiSiN withstand efficiently temperature variations whereas does not. aim study understand role on film. purpose, situ approach phenomena detailed, based performed environmental scanning electron microscope (ESEM) operating controlled pressure mode up 1000 °C. ESEM, used real-time oxidative has been proved be efficient tool characterise mechanism degradation. successive steps attack throughout process as follow: first initiates at coating defects (open pores droplets), then spreads whole surface. flaking film observed microscopic scale during cooling step proves fatigue . This strong propensity cracking explained basis thermo-mechanical considerations. thus combines matrix with beneficial associated nanograins.