Three-dimensional porous tungsten via DLP 3D printing from transparent ink

Abstract

Tungsten, an essential refractory metal material, has the characteristics of high melting and boiling points, high hardness, low expansion coefficient, and low vapor pressure. An indirect strategy to print three-dimensional (3D) refractory metal materials via digital light processing (DLP) followed by a post-treatment process was proposed. To analyze this strategy, a transparent ink with tungsten salts was developed, printed into a 3D precursor via DLP, and subsequently transited into 3D porous tungsten. The ultraviolet rheological properties and stability of the ink, transition process from the precursor to a 3D article, and the properties of the obtained 3D porous tungsten were investigated. This ink was preferable for DLP 3D printing, possessing consistency, stability and favorable absorbance at the wavelength of 385 nm. With increasing temperature, the weight of the tungsten salt in the 3D precursor decreased by 8.97% and was transited to tungsten oxide below 460 ℃, reduced to pure nano-sized tungsten at approximately 700 ℃, and finally sintered into porous articles. The organics initially contributed to polymerization during printing as well as reduction as a carbon reducer after pyrolysis. The pore size distribution of porous tungsten is nonlinear or multimodal, depending on the final sintering temperature. At 1200 ℃, two distinct peaks are observed in the pore distribution curves of the products. At 1400 ℃, the small pore as a whole decreases from approximately 100 to 1000 nm. Correspondingly, the relative density of the samples increased with temperature.

3D-printed epifluidic electronic skin for machine learning–powered multimodal health surveillance

“…S1, and table S1) (23,24). A phase elimination strategy, which involves the selective removal of the sacrificial component in the ink (25)(26)(27)(28), was used to transform as-printed 3D filaments into porous architectures to enhance the performance. This technology enables low-cost customizable prototyping of sustainable and wearable multifunctional physiochemical sensing systems via a simple process, ideally suitable for remote healthcare surveillance (fig.…”

High‐Resolution Patterning of Organic–Inorganic Photoresins for Tungsten and Tungsten Carbide Microstructures

“…Recently, it was reported that digital light processing (DLP) was utilized to structure tungsten oxidebased catalysts, tungsten, and a tungsten nickel alloy. [47][48][49] In the former two applications, an ammonium metatungstate containing aqueous ink was structured, then dried for 3-4 days at room temperature, and subsequently thermally reduced to tungsten oxide and porous tungsten, respectively. [47,48] The resulting tungsten oxide was successfully utilized as a catalyst for the hydrogenation of alkynes and nitrobenzenes, whereas the resulting porous tungsten reached feature sizes of around 700 μm.…”

“…[47][48][49] In the former two applications, an ammonium metatungstate containing aqueous ink was structured, then dried for 3-4 days at room temperature, and subsequently thermally reduced to tungsten oxide and porous tungsten, respectively. [47,48] The resulting tungsten oxide was successfully utilized as a catalyst for the hydrogenation of alkynes and nitrobenzenes, whereas the resulting porous tungsten reached feature sizes of around 700 μm. [47,48] In the latter, 3D-architected hydrogels were manufactured as scaffolds by DLP.…”

“…[47,48] The resulting tungsten oxide was successfully utilized as a catalyst for the hydrogenation of alkynes and nitrobenzenes, whereas the resulting porous tungsten reached feature sizes of around 700 μm. [47,48] In the latter, 3D-architected hydrogels were manufactured as scaffolds by DLP. The scaffolds were then infused with the metal precursor solutions (tungsten and nickel), calcinated, and reduced to metal replicas of the initial scaffold with feature sizes of 100-150 μm.…”

Assessing the wear degradation of tungsten in acidic solutions using a lubricated tribocorrosion model

“…Tungsten is a refractory metal that presents high strength and hardness, good thermal and electrical conductivity, high melting point and low thermal expansion coefficient, and good corrosion resistance. [1][2][3][4][5][6][7] Owing to these prominent properties, tungsten finds its application in many areas, such as integrated circuits, gun bullet and nuclear facility materials, fusion devices, and photoelectric materials. [4][5][6][7] In addition, due to the clear improvement of the strength, wear and corrosion resistance, tungsten is a commonly used alloying element, and tungsten carbide has been selected as a good reinforcing phase for various alloys used in aerospace and tooling industries.…”