Crystals

Low-dimensional lead-free metal halide perovskites have demonstrated excellent performance in indirect X-ray detectors; however, the imaging resolution remains limited due to the lack of effective scintillation waveguiding. In this work, array-structured scintillation screens were fabricated using anodic aluminum oxide (AAO) templates via a spatial confinement–assisted in situ growth strategy. The resulting directional optical confinement effect significantly enhances the scintillation performance of the screen. The fabricated Cs₃Cu₂Br_1.25I_3.75-AAO scintillator arrays achieve a spatial resolution of 14.10 lp/mm and a minimum detectable dose rate of 243 nGy/s under X-ray irradiation. In addition, the scintillator arrays exhibit excellent radiation stability, providing a reliable and cost-effective solution for high-resolution array-based X-ray imaging.

This study investigates how laser power–scan speed combinations influence densification, surface quality, and mechanical performance of Ti-6Al-4V parts fabricated by Powder Bed Fusion–Laser Beam/Metal (PBF-LB/M) on a DMG MORI LASERTEC 30 SLM (2nd generation) system. A parametric matrix was explored by varying laser power (150–400 W) and scan speed (0.9–1.4 m·s⁻¹) at constant layer thickness and hatch spacing, deliberately omitting contour exposure to isolate core scan effects. A stable processing window was identified (250–300 W; 0.9–1.0 m·s⁻¹) corresponding to ~50–60 J·mm⁻³ volumetric energy density (VED) achieved at 99.5% with residual porosity of 0.1–0.3%. In this regime, as-built roughness measured Ra = 4–6 µm on top surfaces and Ra = 15–17 µm on side surfaces. Mechanical testing in the as-built showed ultimate tensile strength (UTS) = 1150–1180 MPa and offset yield strength (YS_0.2) = 955–994 MPa, with elongation up to 6.7%. Hardness increased from 220 HV to 360 HV as densification improved. Notably, similar VED values derived from distinct power–speed combinations resulted in divergent outcomes, confirming that VED alone does not uniquely predict quality. Comparative benchmarks from the literature data highlight the performance achieved. The resulting process–property map provides a practical reference for parameter optimization, reproducibility evaluation, and transferability across platforms.

Stainless-steel nitride thin films were deposited onto silicon substrates at different temperatures ranging from 150 to 600 °C using reactive magnetron sputtering. The influence of substrate temperature on nitrogen incorporation, surface roughness, microstructure, and mechanical properties was systematically investigated. X-ray photoelectron spectroscopy (XPS) analysis showed that the nitrogen content increased with substrate temperature, reaching a maximum value of 34 wt.% at 350 °C, while at higher substrate temperatures (450–600 °C), the nitrogen content decreased. X-ray diffraction analysis revealed that the coating structure strongly depends on the substrate temperature. At temperatures above 450 °C, the films comprise a multiphase structure consisting of CrN, bcc-Fe, and Ni. In contrast, films deposited below 450 °C are dominated by the S-phase, corresponding to a nitrogen-supersaturated fcc structure. Scanning electron microscopy (SEM) analyses confirmed microstructural evolution with substrate temperature, showing fine, compact grains at lower temperatures and coarser structures at higher temperatures. Surface roughness measured by a profilometer exhibited a minimum at 350 °C. The mechanical performance of the films was evaluated using micro-Knoop hardness measurements, together with the calculated elastic strain indicator (H/E) and resistance to the plastic deformation parameter (H³/E²). The results showed that hardness and these mechanical indicators reached their maximum values at a substrate temperature of 350 °C. These findings provide valuable insight into the deposition–structure–property relationships of stainless-steel nitride thin films for wear-resistant and protective coating applications.