Forming the locally-gradient Ni@NiTe2 domains from initial Ni inclusions embedded into thermoelectric Bi2Te3 matrix

Features of microstructure and thermoelectric properties of the cermet composites based on grained Bi2Te3 matrix with locally-gradient Ni@NiTe2 inclusions

“…Thus, features in the microstructure and thermoelectric properties of the thermoelectric cermet Bi 2 Te 3 +xNi composites with different filler Ni content, prepared by spark plasma sintering, have been found and analyzed. As was reported earlier, during SPStreatment, the initial Ni inclusions in these composites are gradually transforming into the locally-gradient Ni@NiTe 2 inclusions [13,14]. Here we report, in which manner forming these Ni@NiTe 2 inclusions allows governing the thermoelectric properties of the thermoelectric Bi 2 Te 3 matrix.…”

“…Before analyzing features of the microstructure and thermoelectric properties of the cermet Bi 2 Te 3 +xNi composites, main patterns of their formation should be considered in brief [13,14]. The starting single-phased Bi 2 Te 3 powder (hexagonal R3m structure with lattice a = 0.4354 nm and c = 3.035 nm parameters), which mainly consisted of hexagonal plates with average plate size of several hundreds of nm and width of ~100 nm, was applied to get grained matrix of the composite.…”

“…The filler inclusions are slightly distorted spherical "Ni core"-"NiTe 2 shell" (Ni@NiTe 2 ) inclusions. These inclusions were before named as locally-gradient domains [13,14]. BSE-image of one of the inclusions is shown in Fig.…”

“…In contrast to the structural cermet composites, the thermoelectric cermet composites with the metallic magnetic inclusions are functional materials, since embedding the inclusions into the matrix should primarily improve the specific thermoelectric (functional) properties of the composite. At present, the composite, consisting of the grained Bi 2 Te 3 matrix with the metallic Ni filler, can be considered as one of promising thermoelectric cermet composites with magnetic inclusions [13,14]. Matrix Bi 2 Te 3 semiconductor is usually applied as end member to prepare n-type Bi 2 Te 3-x Se x and p-type Bi 2-x Sb x Te 3 alloys for various low-temperature thermoelectric applications [15,16].…”

A Bi2Te3-Filled Nickel Foam Film with Exceptional Flexibility and Thermoelectric Performance

“…The XRD pattern of the NiFoam/Bi 2 Te 3 film prepared via the solvothermal method revealed both Ni peaks (PDF#04-0850) and Bi 2 Te 3 peaks (PDF#15-0863), indicating that Bi 2 Te 3 was in situ deposited into NiFoam ( Figure 2 a). After annealing, minor diffraction peaks of NiTe 2 (PDF#08-0004) were also found as marked by the rhombi, indicating possible formation of a NiTe 2 transition layer at the interface of Ni and Bi 2 Te 3 during annealing [ 25 ]. This was confirmed by later XPS measurement.…”