3D Printing of Transparent Spinel Ceramics with Transmittance Approaching the Theoretical Limit

Abstract

3D printing of transparent ceramics has attracted great attention recently but faces the challenges of low transparency and low printing resolution. Herein, magnesium aluminate spinel transparent ceramics with transmittance reaching 97% of the theoretical limit are successfully fabricated using a stereolithography‐based 3D printing method assisted by hot isostatic pressing and the critical factors governing the transparency are revealed. Various transparent spinel lenses and microlattices are printed at a high resolution of ≈100–200 µm. The 3D printed spinel lens demonstrates fairly good optical imaging ability, and the printed spinel diamond microlattices as a transparent photocatalyst support for TiO2 significantly enhance its photocatalytic efficiency compared with its opaque counterparts. Compared with other 3D printed transparent materials such as silica glass or organic polymers, the printed spinel ceramics have the advantages of broad optical window, high hardness, excellent high‐temperature stability, and chemical resistance and therefore, have great potential to be used in various optical lenses/windows and photocatalyst supports for application in harsh environments.

Injection Molding of Magnesium Aluminate Spinel Nanocomposites for High‐Throughput Manufacturing of Transparent Ceramics

“…The theoretical maximum transmission T max was calculated from the refractive index n using following equation. [ 16 , 43 ] …”

“…The transparent MAS ceramic shows a high transmission close to the theoretical maximum with up to 84 % transmission at 1000 nm (theoretical maximum at 1000 nm = 87.3 %) similar to previous reports on transparent MAS ceramics. [ 16 , 17 , 28 , 33 , 37 , 38 ] A slight absorption can be observed in the upper NIR region reducing the transmission by 10% at most. This absorption may be caused by Fe 2+ impurities, probably due to non‐hardened steels employed in the injection molding process.…”

A review on the ceramic additive manufacturing technologies and availability of equipment and materials

“…ZrO 2 [276][277][278][279][280][281][282][283][284][285][286][287] [296] Heat exchanger/dissipation Al 2 O 3 [170], AlN [297][298][299] Tool with optimized design (inner cooling structure) Al 2 O 3 [180], cemented carbide [300] Optical application (lens, armored/ sensor window, etc.) Al 2 O 3 [301], MgAl 2 O 4 spinel [302], SiC [303], Nd-doped YAG [304], Yb-doped YAG [305] Antenna Al 2 O 3 +glass [306], Ba 1-x Sr x Zn 2 Si 2 O 7 [307], MgTiO 3 +CaTiO 3 [308] Nuclear fusion Li 2 TiO 3 [309], Li 2 SiO 3 [310] Table VIII waste. Thus, machines that work with a small amount of material (60 mL) [316] and studies about recycling raw materials [286,354] have emerged.…”

Selectively Metalizable Low-Temperature Cofired Ceramic for Three-Dimensional Electronics via Hybrid Additive Manufacturing

“…To meet this challenge, it is essential to investigate HAM technologies based on robust ceramic materials for customizing heavy-duty electronics. Although various AM processes, such as SLA, two-photon printing (TPP), FDM, Jetting, , etc., are capable of dealing with ceramics, only a few studies focused on AM ceramic electronics. For instance, Hirao et al developed multimaterial inkjet 3D printing technology that was able to print ceramic ink, copper ink, and support material ink alternately for building a ceramic circuity board .…”