A multimaterial based on metallic copper and spinel oxide made by powder bed laser fusion: A new nanostructured material for inert anode dedicated to aluminum electrolysis

Abstract

Coherent 3D parts of cermets, made of spinel ferrite and metallic copper, are prepared in a nitrogen atmosphere by powder bed additive manufacturing of a mixture of oxide and metallic powders. The cermets obtained are constituted by the association of blocks of about 500 µm, which create between them, a relatively large porosity (# 35%). Each block is subdivided into inti mately nested wnes that are either predominantly metallic or pre dominantly oxide type. ln the metal parts, a dispersion of oxide crystals is observed, whose siz.e varies from ten nanometers to a few micrometers. A similar distribution of metal particles in the oxide zones is also demon strated. The chemical compositions of metallic and oxide phases are slightly different from those in the initial powders. Due to the high energy density of the laser, the melting temperature of the metal and oxides could be reached and therefore this could explain the chemical composition variations in the phases and the shape of oxide and metallic nanometric grains. The process used can therefore be described as powder bed fusion. These nanostructured cermets have been used as 'înert" anodes for the electrolysis of aluminum in molten cryolite. Although penalized by a high porosity, 5 mm in diameter anodes allowed to carry out an electrolysis for 4 h. Sinoe Spark Plasma Sintering can greatly reduoe their porosity, while retaining their specifi c microstructure, the implementation of additive manufacturing for producing "inert" anodes is therefore of real interest

Effect of Laser Remelting Strategy on the Forming Ability of Cemented Carbide Fabricated by Laser Powder Bed Fusion (L-PBF)

“…This result was caused by the low temperature of the liquid phase. According to Pasquet et al [ 38 ], low laser energy density might produce a low temperature of molten pools that only exceeds the melting point of Co binder materials (1457 °C) but is lower than the melting point of WC (2870 °C), which was not conducive to grain nucleation. Thus, the microstructure presented inferior characteristics.…”

Artificial Neural Network Algorithms for 3D Printing

“…Process parameters affect the 3D-printed parts’ properties [ 97 , 98 , 99 ]. A database of process–structure–property (PSP) relationships for a particular 3D printing process and materials would enable the proper selection of the parameters based on the available information in the database.…”

“…If the inputs are of different scales, the weights linked to some inputs will be updated much faster than others, which is undesirable. Hence, they are usually linearly normalized to be in the range of either [0, 1] or [−1, 1], using [ 97 , 98 , 99 ]: where r i is the particular input data, r min is the smallest input data, and r max is the largest input data, respectively. Various studies have compared ANN algorithms with conventional optimization methods such as the Taguchi method [ 53 , 100 , 101 , 102 ], polynomial regression model [ 67 , 103 , 104 ], and ANOVA [ 46 , 102 , 105 ].…”

Electrolytic Corrosion Behavior of 20 Cu-20 Ni-54 NiFe2O4-6 NiO Cermet with Interpenetrating Structure at 880 °C and 960 °C

“…The main candidate materials for inert anode are NiFe 2 O 4 -based cermet, Cu alloy, and Ni alloy [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. On 10 May 2018, Alcoa and Rio Tinto announced world’s first carbon-free aluminum smelting process, and planned for sale beginning in 2024 [ 10 ].…”