Flaky magnetic metal particles of embodiments each have a flat surface and a magnetic metal phase containing iron (Fe), cobalt (Co), and silicon (Si). An amount of Co is from 0.001 at % to 80 at % with respect to the total amount of Fe and Co. An amount of Si is from 0.001 at % to 30 at % with respect to the total amount of the magnetic metal phase. The flaky magnetic metal particles have an average thickness of from 10 nm to 100 m. An average value of the ratio of the average length in the flat surface with respect to a thickness in each of the flaky magnetic metal particles is from 5 to 10,000. The flaky magnetic metal particles have the difference in coercivity on the basis of direction within the flat surface.

Spherical particles of one or more elemental metals and elemental carbon are prepared from a precursor in the form of a metal oleate. The metal oleate precursor is dispersed in a liquid vehicle and aerosol droplets of the dispersed precursor are formed in a stream of an inert gas. The aerosol droplets are heated in the stream to decompose the oleate ligand portion of the precursor and form spherical particles that have a mesoporous nanocrystalline structure. The open mesopores of the spherical particles provide a high surface area for contact with fluids in many applications. For example, the mesopores can be infiltrated with a hydrogen absorbing material, such as magnesium hydride, in order to increase the hydrogen storage capacity of the particles.

There is provided a cuboid silver powder including silver particles having a BET specific surface area of 0.5 m.sup.2/g or less. An average aspect ratio of the cuboid silver powder is 1.2 or greater and less than 2.0 as determined by observing cross-sections of 100 or more silver particles from the silver particles. An average of a ratio represented by (Formula 1) below is 0.84 or greater. The ratio is a ratio of perimeter of one silver particle among the silver particles to perimeter of a rectangle circumscribing the one silver particle.

L/(2major axis+2minor axis) (Formula 1):

where L is the perimeter (m) of the one silver particle, and the major axis and minor axis are respectively a long side (m) and short side (m) of the rectangle of minimum area circumscribing an outline of cross-section of the one silver particle.

One aspect is a process for producing a layered body. A first powder is introduced into an interior volume to obtain a first powder layer. The interior volume has a cross-sectional width of at least 200 mm, and is bordered by a die of carbon. The first powder is a mixture comprising a first constituent powder and a further constituent powder of different chemical compositions. The first powder layer is subjected to a heat, generated by a voltage, and to a pressure to obtain the layered body. The further constituent powder has a particle size distribution D=q() of volume density q over particle size , such that D has a first local maximum at particle size .sub. with volume density q.sub., D has a second local maximum at particle size .sub. with volume density q.sub., .sub.>.sub., and q.sub./q.sub. is at least 1.