Self-propagating high temperature synthesis in two-layer (Ni + Al)/(PbO$_2$ + B + Al$_2$O$_3$ + glass) powder mixtures

The widespread use of flat electric heaters in technology and household appliances requires the search for simpler and cheaper technologies for their production. This work proposes a method for producing an electrically conductive coating (NiAl) and an electrically insulating layer (glass ceramics) in one stage - by the method of self-propagating high-temperature synthesis (SHS) in a thermally conjugated powder system (Ni + Al)/(PbO$_2$ + B + Al$_2$O$_3$ + glass). The process of propagation of the combustion wave front has been studied, the influence of layer thickness, the ratio of components in the powder mixture PbO$_2$ + B + Al$_2$O$_3$ + glass on the propagation speed and temperature of the wave front has been studied. combustion. An expansion of the wave front of the exothermic process was discovered when a mixture of PbO$_2$ + B was added to the lower layer. The addition of this mixture makes it possible to reduce the thickness of the NiAl layer and ensure the formation of a uniform dielectric coating. The phase composition and microstructure of the coating were studied. The optimal ratios of layer thicknesses and the composition of the powder mixture of layers have been established. The fundamental possibility of forming an electrically conductive and dielectric coating by the method of self-propagating high-temperature synthesis in one stage is shown.