Article and method

A method of providing an article having a set of directional channels, including a first directional channel, therein, the method comprising:

• preparing a mixture including particles comprising a first material and a first binding agent;
• providing an article precursor by surrounding a pattern comprising a second material with the mixture;
• heating the article precursor thereby coalescing the particles to provide the article;
• and
• removing the pattern by reacting the second material to form a gaseous product, thereby providing the set of directional channels in the article, wherein the set of directional channels corresponds with the removed pattern;
• wherein the heating comprises heating the article precursor in the presence of oxygen at a first temperature for a first period, wherein removing the pattern is by reacting the second material and/or combusting the second material to form the gaseous product;
• and
• wherein the heating comprises heating the article precursor in the presence of oxygen at a second temperature for a second period, thereby oxidizing the particles to provide oxidized particles, wherein coalescing the particles comprises coalescing the oxidized particles;
• and
• wherein the method further comprises heating the oxidized particles in an absence of oxygen and/or in a reactant or in a vacuum at a third temperature for a third period, thereby reducing the oxidized particles to provide the article having the set of directional channels therein.