In this study, kinetic examinations on boronized AISI 304 Stainless Steel samples were described. Samples were boronized in indirect heated fluidized bed furnace consists of Ekabor 1? boronizing agent at 1123, 1223 and 1323 K for 1,2 and 4 hours. Morphologically and typically examinations of borides formed on the surface of steel samples were studied by optical microscope, scanning electron microscope (SEM) and X-Ray diffraction (XRD). Boride layer thickness formed on the steel X5CrNi 18-10 ranges from 12 to 176 ?m. The hardness of the boride layer formed on the steel X5CrNi 18-10 varied between 1709 and 2119 Hv0,1. Layer growth kinetics were analyzed by measuring the extent of penetration of FeB and Fe2B sublayers as a function of boronizing time and temperature. The kinetics of the reaction has been determined with K=Ko exp (-Q/RT) equation. Activation energy (Q) of boronized steel X5CrNi 18-10 was determined as 244 kj/mol.

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In this study, kinetic examinations on boronized X45NiCrMo4 (DIN 1.2767) and 90MnCrV8 (DIN 1.2842) steel samples are described. Samples were boronized in indirect heated fluidized bed furnace at 1123 K, 1223 K, and 1323 K for 1 h, 2 h, and 4 h. Morphologically and typically examinations of borides formed on the surface of the steel samples were studied by optical microscope, scanning electron microscope (SEM), and X-ray diffraction (XRD). Boride layer thickness formed on the steel X45NiCrMo4 ranges from 45 μm to 382 μm and for the material 90MnCrV8 ranges from 33 μm to 471 μm. The hardness of the boride layer formed on the steel X45NiCrMo4 varied between 1713 HV0.1 and 2111 HV0.1 and for the steel 90MnCrV8 between 1716 HV0.1 and 2761 HV0.1. Layer growth kinetics were analyzed by measuring the extent of penetration of FeB and Fe2B sublayers as a function of boronizing time and temperature. The kinetics of the reaction has been determined with K = Ko exp (-Q/RT) equation. Activation energy (Q) of the borided steel X45NiCrMo4 was determined as 156 kJ/mol and that of the steel 90MnCrV8 was determined as 179 kJ/mol.

S teels with martensitic microstructure (low carbon) and high creep resistance can be used at high temperatures for a long period of time. One of the potential applications of these materials is thermal and nuclear power plants. Over the years, the demand on the service temperature level in these plants have increased. As a result, studies on the development of new steel-based materials with enhanced creep and corrosion resistance have soared. The graph shown in Fig. 1 shows the need for service temperatures and pressures depending on years. Steels with 9-12% Cr content have been started to be used in these applications since 1950s. These steels