A ceramic board includes a ceramic body, a first surface, a second surface and a side surface. The ceramic body is a spinel structure. The ceramic body has a thickness. The ceramic body has a plurality of rare earth element particles. These rare earth element particles are uniformly distributed within the ceramic body. The first surface is located on one side of the ceramic body. The second surface is located on the other side of the ceramic body relative to the first surface. The first surface is parallel to the second surface. The side surface connects the first surface and the second surface. The side surface is smoothly connected to the first surface and the second surface.一種陶瓷片包含陶瓷主體、第一表面、第二表面以及側表面。陶瓷主體係為尖晶石結構。陶瓷主體具有一厚度。陶瓷主體裡具有複數個稀土元素顆粒。這些稀土元素顆粒均勻地分布於陶瓷主體之內。第一表面位於陶瓷主體的一側。第二表面位於相對於第一表面之陶瓷主體的另一側。第一表面平行第二表面。側表面連接第一表面與第二表面。側表面係圓滑地連接第一表面與第二表面。
