Microstructure And Properties Of AIP NiCoCrAlY(SiB) Coatings

With the development of energy industry, the gas turbines had a developmentat very fast speed. the first rotor blades of gas turbines suffered high temperatureoxidation and hot corrosion. In order to advance the using life and ensure the gastuebine run safely, besides improving the component of superalloys,the method ofspray, the design of blades,the best method is that using protect coatings, which hadthe development of diffusing coatings.Compound coatings TBCs and MCrAlYcoatings.The MCrAlY coatings deposited by AIP showed excellent oxidation -resistance and hot corrosion resistance. Furthermore, its component can be masterof the demand. up to the present the apply and research are prosperous.In this paper NiCoCrAlY(SiB) coatings deposited on DSM11.DZ125 supera-lloys by arc ion plating (AIP) were investigated systemically by XRD,SEM,TEM:the influence of bias;the different microstructure including deposited and annealedstate;the oxidation and the corrosion behavior of the coatings;the degradation ofNiCoCrAlY(SiB) coatings and the influence of substrates.The NiCoCrAlY(SiB) coatings of 40-50μm were deposited on the substratesusing an MIP-8-800 arc ion plating system.the substrate were peened in a wetatmosphere(800×800×1000mm2)and clended in acetone before deposition. thebase pressure in the chamber was below 4×10-3Pa.the dc bias change at the rangeof 0-1500V.these are the character of the method .such as the thickness of thecoatings are equality, using the vacuum ball in effect, the substrate keep lowtemperature using the water circle, the surface keep clean with high plasma density.The growth course of MCrAlY coatings deposited by AIP were researched byXRD,SEM。This was very important of excellent coatings,deposition.The resultcan not increase the acquaintance of the coatings but offer the experimentation ofdeposition excellent coatings.The results showed that the growth of the coatingswere from bombardment and mostly macroparticles(MPs).The component ofcoatings and the target had some deflection. The results showed that improving ofCo and Cr, the reducing of Al and Ni, This excursion was increased with the biasrising. The XRD diffraction peak was defleced and breaded under some bias. Thebias can affect the adhesion of the coatings, the adhesion reach the peak at 300vbias voltage, The hardness of the deposited coatings improved with the bias andreduced after annealed.The microstructure of the NiCoCrAlY coatings deposited by arc ion plating(AIP) and its initial stage oxidation mechanism were investigated by XRD, SEM,TEM and photo stimulated luminescence spectroscopy (PSLS). The results showedthat as-deposited NiCoCrAlY coatings were composed of nano-grains andpossessed apparent layered structure.After vacuum annealing, the layeredmicrostructure disappeared and the coating became much denser. The nano grainsin the coatings became much larger and twinned grains appeared. In addition, avery thin oxide scale mainly of α-Al2O3 formed on the coating surface afterannealing. In the subsequent initial oxidation stages, transient θ-Al2O3 increasedand then turned into stable α-Al2O3. The related mechanism was also discussed.The hot corrosion behavior of the NiCoCrAlY coatings deposited by arc ionplating (AIP) was investigated by SEM,EDS,TEM. From the experimental result,it can be seen that the Si-containing alumina scale on NiCoCrAlYSiB coatingisdense and continuous while scale on NiCoCrAlY coating being looseandincontinuous. So it can be concluded that the additions of Si and B can promotethe selective oxidation of the protective scale-forming element resulting in theformation of a continuous α-Al2O3 scale in the initial corrosion stage and improvethe adherence of the outer scale to the coating in the subsequent hot corrosionprocess. As a result, NiCoCrAlYSiB coating assumed better hot corrosionresistance than NiCoCrAlY coating. This is corresponding with the formerinvestigations.