ИСТИНА

MAX-phases attract the increasing attention due to the unique set of properties, combining metallic and ceramic ones, such as high electric and thermal conductance, elastic stiffness, easy machinability, tolerance to high-temperature corrosion and harsh environments. Thus, MAX-phases are being considered for the number of practical applications, from chemically stable electrical contacts to protective and shielding coatings and high-temperature applications. One intriguing feature is the ability to finely control the physical characteristics of the MAX-phases via the tuning of their chemical composition, for example, the doping on either M-, A- or X-site. One of the recent goals is to obtain stable magnetic MAX-phases which can be also done via the chemical doping of the existing MAX-phases with magnetic elements. The promising candidate for this purpose - (Cr1-xMnx)2AlC MAX-phase. However, the successful doping of this compound, likewise the number of other MAX-phase family representatives, suffers from two main issues. One is the poor incorporation of the dopant atoms into the MAX-phase structure; another is the dramatic worsening of the samples phase purity, accompanying the increment of the dopant concentration, especially for bulk samples. In this work two non-conventional techniques are described which can help one increase the doping level in quaternary MAX-phases, like (Cr1-xMnx)2AlC. One is the arc melting synthesis approach that is useful to obtain the samples with Mn concentrations up to 16 at.% which is half times more than it was achieved previously. The increment of the doping level appears due to the influence of the high-energetic plasma arc, causing large temperatures up to 3000°C in the melt. This technique can be also optimized to overcome the second synthesis drawback and obtain highly phase-pure samples. The second technique is the high-energy ball milling that can be applied for powder-form as-cast MAX-phases samples to further increase the doping level due to the additional incorporation of the excessing dopant in the miller.