Vat photopolymerization 3D printed ceramics with enhanced mechanical strength for mechanoluminescent applications

The development of ZnS/CaZnOS:Mn2+-based luminescent ceramics with enhanced mechanical and mechanoluminescent properties holds significant importance for applications in stress sensing and structural damage detection. The integration of luminescent materials with advanced manufacturing techniques has garnered attention for such applications. However, previous attempts have been limited by insufficient mechanical strength and inadequate densification. Herein, a novel approach is introduced by optimising the ceramic slurry composition with the addition of LiF as a sintering aid and employing a two-step sintering process. This method significantly enables a threefold increase in elastic modulus, compressive strength, and peak stress compared to previously reported samples. Furthermore, the mechanoluminescent behaviour of these ceramics was demonstrated through experiments that correlate luminescent intensity with applied force, enabling stress visualisation. A stress sensor and a mechanoluminescent shim for railway applications were designed, showcasing the potential of these materials in practical engineering scenarios. This work not only overcomes the limitations of existing methods but also opens new avenues for the application of ZnS/CaZnOS:Mn2+ ceramics in various fields, including structural health monitoring and smart materials. The optimised 3D printing process and enhanced mechanical properties represent a major step forward in the integration of mechanoluminescent materials with advanced manufacturing technologies.