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.

Dynamic carbotermal reduction-nitridation (DCRN) is a new approach developed to produce more effective ceramic powder production than classical static system of carbothermal reduction-nitridation (CRN) method. In this new technique of DCRN, powder is produced in a moving system and production takes place at relatively lower temperatures and/or shorter times than CRN method. This study examines production of TiN powder by the DCRN method. The granules were prepared using TiO2 and carbon black powders in the stoichiometric ratio (C/TiO2=2). TiN powders of sub-micron were obtained in a graphite reactor from the prepared granules under N2 gas flow. The effects of various test parameters were investigated for TiN synthesis, such as temperatures of reaction (1350-1450°C), reaction time (0.5-3 h), N2 gas flow rate (60-120 L/h) and reactor rotation speed (2-6 rpm). The phases and microstructures of the powders were characterized by XRD, SEM and FESEM analyses.