Hot Corrosion Resistance of ZrO2-5%CaO Thermal Barrier Coating (TBC) System

Abstract

Thermal barrier coatings (TBCs) provide thermal and corrosive protection to metallic substrate materials under high temperature conditions. TBC systems applied to hot part components of workpieces are exposed to oxidation and hot corrosion damage. Hot corrosion, in particular, causes destructive damage earlier than oxidation. In this study, NiCoCrAlY powders were sprayed on 316L stainless steel substrate material using High Velocity Oxygen Fuel (HVOF) technique. Calcia-stabilized zirconia (ZrO2-5% CaO, CSZ) was deposited as a top coating material by the atmospheric plasma spray technique (APS) on the substrate with the bond coat. The produced TBC system was subjected to 25 hours cyclic hot corrosion tests with a mixture of 50% V2O5- 50% Na2SO4 at 900 °C. At the end of the hot corrosion tests, as a result of the reaction of CaO with hot corrosion salts, phase transformation has occurred in the top coating. It has been found that the molten corrosion salts penetrate through the top coating, but have not yet seriously damaged the coating under these test conditions.

Keywords

• Hot corrosion; Thermal barrier coating (TBC); CaO-ZrO2; V2O5; Molten salt.

ZrO2-5%CaO TERMAL BARİYER KAPLAMA (TBC) SİSTEMİNİN SICAK KOROZYON DİRENCİ

Abstract

Termal bariyer kaplamalar (TBCs), yüksek sıcaklık koşullarında metalik altlık malzemeleri termal ve korozif koruma sağlamaktadır. TBC sistemleri, iş parçalarının sıcak bölüm komponentlerinde oksidasyon ve sıcak korozyon hasarlara maruz kalmaktadır. Özellikle sıcak korozyon, oksidasyona nazaran daha erken yıpratıcı hasarlara neden olmaktadır. Bu çalışmada, NiCoCrAlY tozları, yüksek hız oksi yakıt (HVOF) tekniği kullanılarak 316L paslanmaz çelik altlık malzeme üzerine püskürtülmüştür. Kalsiya ile stabilize zirkonya (ZrO2-5% CaO, CSZ), bağ kaplaması üretilmiş altlıklar üzerine üst kaplama malzemesi olarak atmosferik plazma sprey tekniği (APS) ile biriktirilmiştir. Üretilen TBC sistemi, 900 ° C' de % 50 V2O5-50 Na2SO4 karışımı ile 25 saatlik çevrimli sıcak korozyon testlerine tabi tutulmuştur. Sıcak korozyon testlerinin sonunda TBC sistemlerinde korozyon etkisi ve faz analizi stereo mikroskop, taramalı elektron mikroskobu (SEM), SEM - Enerji Dağılımlı X-Ray (EDX), SEM Haritalama ve XRD analizi kullanılarak incelenmiştir.

Keywords

• Sıcak korozyon,Termal bariyer kaplama,CaO-ZrO2,V2O5,Ergimiş tuz

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