Lead-free (Ba_0.92Ca_0.08) (Ti_0.95 Zr_0.05) O₃ (BCZT) ceramics were prepared by a solid-state route (SSR) using ultra-low synthesis (700 °C/30 min and 700 °C/2 h) and sintering temperatures (from 1150 °C to 1280 °C), due to prior activation and homogenization by attrition milling of the starting high purity raw materials for 6 h before the synthesis and of the calcined powders for 3 h before the sintering. The comparison of the thermal analysis of the mixture of the starting raw materials and the same mixture after 6 h attrition milling allowed to evidence the mechanisms of activation, resulting in a significant decrease of the perovskite formation temperature (from 854 °C down to 582 °C). The secondary phases that limit the functional properties of the ceramic and their evolution with the sintering conditions were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which allowed the design of a two-step sintering method to eliminate them. A pure tetragonal BCZT perovskite phase (P4mm, c/a = 1.004) and homogeneous ceramic microstructure was obtained for synthesis at 700 °C for 2 h and sintering with the use of a two-step sintering treatment (900 °C for 3 h and 1280 °C for 6 h). The best electromechanical properties achieved were d₃₃ = 455 pC/N, k_p = 35%, Q_m = 155.

Heterostructures formed by anatase nanotitania and bidimensional semiconducting materials are expected to become the next-generation photocatalytic materials with an extended operating range and higher performances. The capability of fabricating optically transparent photocatalytic thin films is also a highly demanded technological issue, and increasing the performances of such devices would significantly impact several applications, from self-cleaning surfaces to photovoltaic systems. To improve the performances of such devices, WS₂/TiO₂ heterostructures obtained by incorporating two-dimensional transition metal dichalcogenides layers into titania mesoporous ordered thin films have been fabricated. The self-assembly process has been carefully controlled to avoid disruption of the order during film fabrication. WS₂ nanosheets of different sizes have been exfoliated by sonication and incorporated in the mesoporous films via one-pot processing. The WS₂ nanosheets result as well-dispersed within the titania anatase mesoporous film that retains a mesoporous ordered structure. An enhanced photocatalytic response due to an interparticle electron transfer effect has been observed. The structural characterization of the heterostructure has revealed a tight interplay between the matrix and nanosheets rather than a simple additive co-catalyst effect.

Due to the ever-increasing limitations of the use of lead-based materials, the manufacturing of lead-free piezoceramics with competitive piezoelectric properties and established nontoxicity is considered a priority for the scientific and industrial community. In this work, a lead-free system based on sodium potassium niobate (KNN), opportunely modified with MgNb₂O₆ (MN), was prepared through a combination of a mechanochemical activation method and air sintering, and its toxicity was evaluated. The effect of the mechanical processing on the microstructure refinement of the processed powders was established by X-ray diffraction and the average crystallite size content of the Nb₂O₅ species was evaluated. The experimental evidence was rationalized using a phenomenological model which permitted us to obtain the amount of powder processed at each collision and to optimize the activation step of the pre-calcined reagents. This influenced the final density and piezoresponse of the as-sintered pellets, which showed optimal properties compared with other KNN systems. Their toxicological potential was evaluated through exposure experiments to the pulverized KNN-based pellets, employing two widely used human and environmental cellular models. The in vitro assays proved, under the selected conditions, the absence of cytotoxicity of KNN-bases systems here studied.

A 3D-printable, ARDUINO-based multipurpose X-ray stage of compact dimensions enabling in situ electric field and temperature-dependent measurements is put into practice and tested here. It can be routinely applied in combination with a technique of structural characterization of materials. Using high-performance X-ray laboratory equipment, two investigations were conducted to illustrate the device’s performance. The lattice characteristics and microstructure evolution of piezoelectric ceramics of barium titanate, BaTiO₃ (BT), and barium calcium zirconate titanate, with compositions of (Ba_0.92Ca_0.08) (Ti_0.95Zr_0.05)O₃ (BC8TZ5), were studied as a function of the applied electric field and temperature. The X-ray stage is amenable as an off-the-shelf device for a diffraction line in a synchrotron. It provides valuable information for poling piezoceramics and subsequent optimization of their performance.

Replacement of the ubiquitous lead titanate zirconate piezoceramics is still a challenge involving sustainable materials and processes. An extended effort has been paid for the optimization of the properties of (K _0.5 Na _0.5 )NbO ₃ (KNN) lead‐free piezoceramics at the expenses of high‐energetic budget. A sustainable solid‐state processing with potential for industrial scaling (knowledge‐based, sustainable, reproducible, and cost‐effective) is still lacking. In this work, an efficient solution is proposed using the well‐known and noncontaminant attrition‐ball‐milling of the mixture of reagents for only 3 h, prior to the synthesis tests at increasing temperatures. After calcination at only 450 °C/2 h, 60 wt% KNN is achieved. Moreover, after 850 °C/2 h the calcined powder becomes a pure KNN. A second ball‐milling of powder calcined at 700850 °C gives place to populations of nanostructured particles (380–40 nm, respectively). The milled powder calcined at 700 °C is pressureless sintered in air for 2 h at 1050 and 1100 °C, leading to coarse grained ceramics. Milled powder calcined at 750 and 850 °C, sintered at the same conditions, produces fine grain homogeneous microstructures. Ceramics show an orthorhombic Amm2 pure KNN perovskite phase, as seen by x‐ray diffraction and Rietveld analysis. The piezoelectric values ( d ₃₃ = 115 pC/N, d ₃₁ = ₋ 22 pC/N, k _p = 20%, k _t = 40%) are exceptional when derived from such a straightforward solid‐state route.