Simple carbon steel coating with Nickel base alloy 276C-Super alloy and microstructure assessment and high temperature corrosion In this study, the microscopic structure, corrosion properties and high temperature corrosion properties of 276C on-surface superalloy coating on the surface of plain carbon steel without presence and with the presence of 309AISI austenitic stainless steel middle layer were investigated. For this purpose, samples of plain carbon steel were welded in a single-layer laminate using a Tungsten-Gas Argan Arc welding (GTAW) with 276C (ERNiCrMo4) welding wire. The intermediate layer of 309AISI austenitic stainless steel filler was applied with a tungsten-gas arc welding method (plain carbon steel), and a 276C coating layer on the interlayer was coated. Cross sections of the samples were examined by optical microscope and electron microscope. X-ray diffraction (X-ray diffraction test) was used to identify the type of phases formed on the surface of the coating and the interface. Determination of dilution in samples was performed by energy spectroscopy test. Using hardness and micro-tensile test, the hardness profile of the samples was prepared. The corrosion behavior of different layers, including base metal, interlayer and coated layer by cyclic polarization test as well as electrochemical impedance spectroscopy test in one molar hydrochloric acid solution (as the acidic medium) were investigated. In the steel and AISI 309 coating on steel after failure potential (Eb), the corrosion flow density decreased with decreasing potential. A negative hysteresis loop was observed on the curve of two samples (steel and 309AISI coating on steel), which, with increasing potential and breaking the permeable layer in both samples, germination of the cavity began, but due to the resistance of the samples, the cavity In 1 M NaCl solution, with decreasing potential, the flow density decreases and the cavity buds do not start to grow (no unstable cavities) and cavities accumulate and disappear. While in the sample 276C overlay on steel after the failure potential (Eb), the corrosion current increased by decreasing the density potential. The positive hysteresis loop of this curve indicates that this sample is sensitive to corrosion of the cavity. That is, by decreasing the potential of the cavity germs, they begin to grow and become thicker, and the cavities are stable. Therefore, although the overall corrosion resistance of the 276C on the steel coating is more than the other two, this sample has a cavity corrosion sensitivity. It also compares the behavior of the 276c overlay coating and the middle layer of acetic acid stainless steel L309 in the conditions of hot corrosion test at a temperature of 750 ° C. The increase in the duration of the hot corrosion test, the amount and depth of penetration of sodium sulfate in buffered coated samples (L309) as well as the coating layer of 276C, which increased the degradation layer, increased the duration of the hot corrosion test, the number And the depth of the oxygen permeation pores increased in the laminated sample with L 309. With a further increase in the number and depth of the penetration of oxygen vapor in the layer lined with L309, this disintegrates and destroys the layer, while in the sample The 276 ° C-coated coating had no effect on the oxygen penetration pores, hence the 276 ° C overlay coating with longer life and durability It was hot in a hot corrosion test compared to the L309-coated sample.