A disc is disclosed which comprises a top layer, a middle layer, and a bottom layer. The top layer is placed proximate to a high temperature reactor and at least the outer surface of the top layer is made of a material which allows it to act as a substrate against which molten particles are impacted to microatomize the particles. The layers are positioned one above the other with a first space between the bottom surface of the top layer and the top surface of the middle layer, and a second space between the bottom surface of the middle layer and the top surface of the bottom layer. The top and bottom layers are joined together and stabilized by a peripheral wall around the circumferential edge of the top and bottom layer. The middle layer is fixedly mounted to the bottom layer. The middle layer is smaller in diameter than the diameters of the top and bottom layers so that a third space is defined between the inner surface of the peripheral wall and the circumferential edge of the middle layer. The bottom and middle layers have openings through which a cooling fluid passes to the first space to cool the top layer, and thereafter passed by centrifugal force generated by the spinning of the disc and the motion of the fluid through the third space, and exits the disc through the second space. The disc is rotatably mounted to spinning means to allow the disc to spin.