In order to understand the effect of Pb-CuI co-doping on the thermoelectric performance of Bi₂Te₃, n-type Bi₂Te₃ co-doped with x at % CuI and 1/2x at % Pb (x = 0, 0.01, 0.03, 0.05, 0.07, and 0.10) were prepared via high temperature solid state reaction and consolidated using spark plasma sintering. Electron and thermal transport properties, i.e., electrical conductivity, carrier concentration, Hall mobility, Seebeck coefficient, and thermal conductivity, of CuI-Pb co-doped Bi₂Te₃ were measured in the temperature range from 300 K to 523 K, and compared to corresponding x% of CuI-doped Bi₂Te₃ and undoped Bi₂Te₃. The addition of a small amount of Pb significantly decreased the carrier concentration, which could be attributed to the holes from Pb atoms, thus the CuI-Pb co-doped samples show a lower electrical conductivity and a higher Seebeck coefficient when compared to CuI-doped samples with similar x values. The incorporation of Pb into CuI-doped Bi₂Te₃ rarely changed the power factor because of the trade-off relationship between the electrical conductivity and the Seebeck coefficient. The total thermal conductivity(κ_tot) of co-doped samples (κ_tot ~ 1.4 W/m∙K at 300 K) is slightly lower than that of 1% CuI-doped Bi₂Te₃ (κ_tot ~ 1.5 W/m∙K at 300 K) and undoped Bi₂Te₃ (κ_tot ~ 1.6 W/m∙K at 300 K) due to the alloy scattering. The 1% CuI-Pb co-doped Bi₂Te₃ sample shows the highest ZT value of 0.96 at 370 K. All data on electrical and thermal transport properties suggest that the thermoelectric properties of Bi₂Te₃ and its operating temperature can be controlled by co-doping.

Zirconia ceramics, as a category of metal oxide ceramics, stand out due to their impressive physicochemical and mechanical properties. Recognized for being bioinert, these ceramics are non-toxic, exhibit excellent biocompatibility, and offer superior mechanical strength. Moreover, zirconia’s natural aesthetic qualities enable it to closely mimic the appearance of natural teeth, making it an optimal choice for dental restorations, such as crowns, bridges, and veneers. This review examines the complex relationship between zirconia’s microstructure, including aspects like grain size, porosity, and phase composition, and how these factors impact its translucency and mechanical durability. A specific focus is on the critical role of the tetragonal phase in zirconia, spotlighting its contribution to the material’s superior mechanical strength and esthetic qualities. The stabilization of this phase, primarily through the use of yttria, is discussed for its dual influence on enhancing both the material’s strength and esthetic properties. Challenges such as low-temperature degradation (LTD) and discoloration are highlighted, along with potential solutions like advanced surface modifications and novel manufacturing techniques. The potential of flash sintering and 3D printing to further improve zirconia’s properties is also explored.

A thermoelectric coated grain nanocomposite CuInTe₂/SnTe with eco-friendly elements was synthesized. The nanocomposite contains a coating layer of CuInTe₂ and SnO₂ at the grain boundaries of the SnTe matrix. The coating layer was synthesized using the cation exchange process considering the hard soft acid base (HSAB) concept, the solubility product, and crystal structure. The CuInTe₂ coating layer blocks the low energy carriers of the composite resulting in 40% enhancement of the Seebeck coefficient due to energy filtering. The coherent phonon scattering by the coating layer of CuInTe₂ effectively reduces the lattice thermal conductivity to almost the minimum theoretical limit. The thermoelectric figure of merit (zT) for the CuInTe₂/SnTe nanocomposite was as high as 1.68 at 823 K, which is significantly higher than that of bulk SnTe in the mid-temperature range. The average zT from 373 K to 823 K for the nanocomposite was 0.76, which is promising for utilization in industrial application.

We performed a systematic investigation of the Ti–xAu (x = 5, 10, 15, 20, and 40 wt%) alloys to assess the effect of addition of element Au on the microstructure, mechanical properties, and corrosion behavior of commercially pure titanium (cp-Ti). The phase and microstructure were characterized using X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the Ti–xAu alloys containing up to 15 wt% Au showed a hexagonal close-packed α-Ti structure, whereas the Ti–xAu alloys containing more than 20 wt% Au were mainly composed of the α-Ti phase and Ti₃Au intermetallic phase. We also investigated the effect of alloying element Au on the mechanical properties (including Vickers hardness and modulus) and corrosion behavior of Ti–xAu binary alloys. The addition of gold to Ti improved its hardness. Electrochemical results showed that the Ti–xAu alloys exhibited improved corrosion resistance than cp-Ti.

The role of metal iodides on the thermoelectric properties of Bi ₂ Te ₃ is investigated by conducting comparative studies of CuI, CsI and KI-doped Bi ₂ Te ₃ analogs. The CuI dopant is superior to CsI and KI dopants in showing a larger power factor and lower lattice thermal conductivity.