It is assumed that there is a local equilibrium of the nitrogen concentration at ��/�á� interface and at �á�/diffusion zone interface [13]. Consequently, the growth kinetics of the diffusion zone is controlled by temperature only.Figure 1.Structure of nitrided layer on iron and low-carbon steel; CN�Cnitrogen concentration, X�Cdistance from surface, inhibitor Paclitaxel �ŨCFe2,3N phase, �á�CFe4N phase.In the case of alloy and carbon steels, the sequence of phases in the compound zone evolves with nitriding time [14,15]. The subdivisions Inhibitors,Modulators,Libraries in well-defined �� and �á� sub-zones are replaced Inhibitors,Modulators,Libraries by a mixture of phases (Figure 2). On the basis of systematic studies regarding the phase constitution of the compound zone on carbon steels, it was concluded that a direct nucleation of �� phase on the diffusion zone was explained by a small solubility of carbon (<0.

2% wt.) in �á� phase in contrast to the large solubility for carbon in �� phase [16�C21].Figure 2.Example of the structure of layer nitrided on alloy steel.On the basis of the research presented in papers [22,23], it was Inhibitors,Modulators,Libraries demonstrated that owing to the construction and phase composition of the iron (carbo)nitrides zone being different than in the case of iron, as well as the structural changes occurring in this zone during the process, the quasi-equilibrium of nitrogen concentration is upset on the interfacial boundary of the diffusion zone/iron (carbo)nitrides zone. Moreover, it was demonstrated that the phase structure of the iron (carbo)nitrides zone has a significant contribution, regardless of the nitrogen potential and the temperature, to the creation of the diffusion zone, and its effective thicknesses g400, g500 and g600 in particular (Figure 3).

Figure 3.Effective thicknesses in diffusion zone.The consideration presented above makes the development of the control system and development of the control system software with regard to optimal kinetics Inhibitors,Modulators,Libraries of the layer growth more challenging.3.?Control System3.1. General ConceptThe constructed control system of the nitriding process [23] includes innovative hardware solutions and a process programming module (software) (Figure 4). The hardware, independently of the standard measuring systems of the process parameters: temperature and the composition of the nitriding atmosphere, includes the block of a process result sensor (magnetic sensor), which reacts directly in the process to the nucleation and growth of the nitrided layer.

In the programming Entinostat module, buy inhibitor in compliance with the latest world trends concerning modern control systems [24�C28], process models were integrated with the operating procedures. The process models which enable its simulations are of a particular importance: as a result, they provide the technologists with significant information concerning different variants of the realization of the process and the operating properties of the nitrided formed in such processes [26,27].