Yüksek Hızlı Oksi- Yakıt Püskürtme Tekniği ile Üretilmiş MCrAlY Esaslı Kaplamaların Sıcak Korozyon Davranışı

Bu çalışmada küresel grafitli dökme demir (KGDD) altlıklar Yüksek Hızlı Oksi-Yakıt (HVOF) yöntemi ile Ni esaslı AMDRY 9624 ve Ni-Co esaslı AMDRY 9951 olmak üzere iki farklı malzeme ile kaplanmıştır. Kaplamaların mikroyapı ve faz analizleri enerji dağılımlı X-Ray spektrometreli taramalı elektron mikroskobu (SEM-EDX) ve X ışınları difraksiyonu (XRD) yöntemleri kullanılarak yapılmıştır. Bu kaplamaların, %50 V2O5 + %50 Na2SO4 korozif tuz karışımından oluşan ortamda ve üç farklı sıcaklıkta sıcak korozyon davranışları incelenmiştir. Karakterizasyon çalışmaları neticesinde dökme demir altlıklar üzerinde yaklaşık 80 µm kalınlığında yoğun, porozitesiz bir kaplama tabakası elde edildiği ve kaplama ile altlık malzeme arasında sürekli yapışma sağlandığı görülmüştür. AMDRY 9624 ile kaplanan dökme demirlerin γ ve β intermetalik fazlarını ihtiva ettiği, AMDRY 9951 ticari toz ile üretilen kaplamanın ise sadece γ fazını ihtiva ettiği tespit edilmiştir. Sıcak korozyon testleri sonrasında dökme demir altlığın korozyon tuzlarıyla reaksiyonu sonucu üç sıcaklıkta da FeVO4 korozyon ürünü oluşmuştur. Kaplama uygulaması sonrası ise 500 ºC de tuzların etkisi ile herhangi bir metal vanadat bileşiği oluşmazken, 600 ve 700 ºC sıcaklıkta çeşitli metal vanadat korozyon ürünlerinin oluşumu belirlenmiştir.

Anahtar Kelimeler:

Sıcak Korozyon, HVOF, Kaplama

Hot Corrosion Behaviour of MCrAlY Based Coatings Fabricated by High Velocity Oxy-Fuel

In this study, ductile cast irons (DCI) were coated with two different AMDRY 9624 Ni based and AMDRY 9951 Ni-Co based materials by HVOF method. Microstructure and phase analyzes of the coatings were performed to by using Scaning electron microscopy equipped with Energy-dispersive X-ray spectroscopy (SEM-EDX) and X-Ray difraction (XRD) methods. Hot corrosion behavior of DCI are investigated by using %50 V2O5 + %50 Na2SO4 salts. As a result of the characterization studies it was observed that a dense non-porous coating layer of about 80 μm thickness was obtained on the cast iron samples and continuous adhesion was provided between the coating and the substrate. It has been determined that the cast iron coated with AMDRY 9624 contains γ and β intermetallic phases and the coating produced with AMDRY 9951 commercial powder containsonly γ phase. After the hot corrosion tests, The characterization studies reveal that the reaction of the cast iron substrate with corrosive salts resulted in the formation of FeVO4 corrosion product at all three temperatures. After coating application, no metal vanadate compound was formed by the reaction of salts with the coatings at 500 ºC. The formation of various metal vanadate corrosion products at 600 and 700 ºC temperature was determined.

Keywords:

Hot corrosion, HVOF, Coating,

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