The high-temperature and hot corrosion behavior of Diamalloy 2002 coatings with a WC/Co–NiCrFeBSiC composite structure applied to a 316 L stainless steel surface using the atmospheric plasma spraying (APS) method was investigated. The coatings were held at 900 °C in air for 5, 25, 50, and 100 h and in a molten salt bath of Na₂SO₄ + V₂O₅ at 900 °C for 1, 3, and 5 h. SEM, EDS, and XRD analyses revealed that the oxide layer on the surface thickened with increasing temperature and corrosion duration, forming NiO, Cr₂O₃, and mixed metal oxides. These oxide phases created a protective barrier effect by limiting diffusion between the coating and the substrate. Despite a slight increase in porosity and minor WC dissolution under long-term oxidation conditions, the coatings maintained their structural integrity up to 900 °C, demonstrating significant resistance to high-temperature oxidation and molten salt corrosion. These results demonstrate that Diamalloy 2002 coatings provide an effective surface protection solution in abrasive and oxidizing high-temperature environments.

This study was conducted to evaluate the high-temperature protection performance of new hard coating systems. Woka 7202 (Cr₃C₂-NiCr) and Diamalloy 2002 (WC-NiCrFeBSiC) powders were coated onto 316L stainless steel substrates using the atmospheric plasma spraying (APS) method and subjected to isothermal oxidation (5–100 h) and hot corrosion (55% V₂O₅ + 45% Na₂SO₄, 1–5 h) tests. Although the coatings exhibited a laminar microstructure and some pores, cracks, and oxide-containing regions, they did not show any flaking or structural integrity deformations during the tests. Microstructural changes, oxide layer morphology, and the phases formed were examined in detail. The findings demonstrate that these coating systems not only provide chemical and structural stability against existing high-temperature environments, but also meet the requirements of next-generation thermal protection needs. In this regard, the study provides directly applicable information for the coating design and performance optimization for turbine blades, energy production equipment, and similar industrial components exposed to high-temperature oxidation and hot corrosion.

Inconel 718 süper alaşımı, havacılık ve uzay endüstrisinde sıcak korozyona karşı dayanıklılığıyla bilinse de düşük kaliteli yakıtların neden olduğu agresif ortamlarda ciddi yapısal hasarlara maruz kalabilmektedir. Bu çalışmada, %35 Na2SO4 + %35 V2O5 + %30 NaCl tuz karışımı, Inconel 718 altlık üzerine uygulanarak 900 °C ± 25°C sıcaklıkta 1, 3, 5 ve 24 saatlik sıcak korozyon testleri gerçekleştirilmiştir. Test öncesi ve sonrası mikroyapısal değişimler SEM, EDS, elementel haritalama ve XRD ile analiz edilmiştir. Bulgular, kısa süreli maruziyetlerde sınırlı oksitlenme görülürken, 24 saatlik sürede yüzeyde belirgin faz dönüşümleri ve yapısal bozulmaların başladığını göstermiştir. Bu sonuç, Inconel 718’in yüksek sıcaklıkta agresif tuz ortamlarına karşı dayanımının zamanla azaldığını ortaya koymaktadır.

In this study, the oxidation and hot corrosion behaviors of the manganese slag coating system were investigated. Manganese slag is a waste product generated during metal extraction and is used to reduce environmental impacts and raw material consumption. CoNiCrAlY bond coatings were produced using the high-velocity oxygen fuel (HVOF) technique, and manganese slag coatings were produced using the atmospheric plasma spraying (APS) process. The produced coatings were subjected to isothermal oxidation (5 h, 25 h, 50 h, and 100 h) and hot corrosion tests (1 h, 3 h, 5 h, and 10 h) at 600 °C. As a result of the analyses, it was determined that the coating system containing manganese slag maintained its durability at certain temperatures and times without structural degradation. The findings show that manganese slag coating system is a potential alternative for different industrial applications. This study highlights the innovative uses of waste materials in surface engineering and their performance in high temperature-based processes.