Abstract: Provided is a new board with a sufficient adhesion strength between an insulating layer and a metal layer. A board of the embodiment is a board including an insulating layer and a metal layer. The insulating layer contains a resin containing an insulating filler. The metal layer is disposed on a surface of the insulating layer. The resin is present partially between at least a part of the insulating filler present in the surface of the insulating layer and a metal constituting the metal layer. In an interface between the insulating layer and the metal layer, a depth of the metal present at a deepest portion in the insulating layer is 1.2 µm or less based on the resin or the insulating filler present in an outermost surface of the insulating layer.

Abstract: According to the present invention, a fluorescent powder composed mainly of an acicular or fibrous zinc oxide single crystal with an aspect ratio of 5 or higher is produced by the following steps: a step of producing a raw material solution selected from the group consisting of a raw material solution (A) that is an alkali solution containing zing ions, a raw material solution (B) that is a solution containing zinc ions and ions of dopant element, and a mixed solution of the raw material solution (A) and the raw material solution (B); and a hydrothermal reaction step wherein a hydrothermal reaction of the mixed solution is carried out in a hermetically sealed vessel at a subcritical or supercritical temperature and at a subcritical or supercritical pressure. A zinc oxide single crystal powder can be produced at low cost without the need for a pulverization step or a similar step and high-density orientation can be realized by such crystal powder.

Abstract: According to the present invention, a fluorescent powder composed mainly of an acicular or fibrous zinc oxide single crystal with an aspect ratio of 5 or higher is produced by the following steps: a step of producing a raw material solution selected from the group consisting of a raw material solution (A) that is an alkali solution containing zing ions, a raw material solution (B) that is a solution containing zinc ions and ions of dopant element, and a mixed solution of the raw material solution (A) and the raw material solution (B); and a hydrothermal reaction step wherein a hydrothermal reaction of the mixed solution is carried out in a hermetically sealed vessel at a subcritical or supercritical temperature and at a subcritical or supercritical pressure. A zinc oxide single crystal powder can be produced at low cost without the need for a pulverization step or a similar step and high-density orientation can be realized by such crystal powder.