A carbon ceramic brake disc according to the present invention includes: a support body having cooling channels at the center portion; and friction layers directly attached to the top and the bottom of the support body without a bonding layer and having components different from the components of the support body, in which the support body is composed of a plurality of layers having components similar to the friction layers, gradually toward the friction layers from the cooling channels as the center. Accordingly, the support body can perform thermomechanical shock absorbing that is an original function and the friction layers and the support body can be prevented from separating while the carbon ceramic brake disc is manufactured.

This ferrite magnet has a ferrite phase having a magnetoplumbite structure, and an orthoferrite phase, and is characterized in that the composition ratios of the total of each metal element A, R, Fe and Me is represented by expression (1) A.sub.1-xR.sub.x(Fe.sub.12-yMe.sub.y).sub.z, (in expression (1), A is at least one element selected from Sr, Ba, Ca and Pb; R is at least one element selected from the rare-earth elements (including Y) and Bi, and includes at least La, and Me is Co, or Co and Zn) and in that the content (m) of the orthoferrite phase is 0<m<28.0 in mol %. The invention makes it possible to achieve a ferrite magnet with increased Br.

A ferrite composition includes main-phase particles, first sub-phase particles, second sub-phase particles, and a grain boundary. At least 10% or more of the main-phase particles contain a portion whose Zn concentrations monotonously decrease from a particle surface toward a particle central part along a length of 50 nm or more. The first sub-phase particles contain Zn.sub.2SiO.sub.4. The second sub-phase particles contain SiO.sub.2. A total area ratio of the first sub-phase particles and the second sub-phase particles is 30.5% or more.

A cathode material used in an anode and a cathode contains (Co, Fe).sub.3O.sub.4 and a perovskite type oxide that is expressed by the general formula ABO.sub.3 and includes at least one of La and Sr at the A site. A content ratio of (Co, Fe).sub.3O.sub.4 in the cathode material is at least 0.23 wt % and no more than 8.6 wt %.

A ferrite composition includes main-phase particles, first sub-phase particles, second sub-phase particles, and a grain boundary. At least 10% or more of the main-phase particles contain a portion whose Zn concentrations monotonously decrease from a particle surface toward a particle central part along a length of 50 nm or more. The first sub-phase particles contain Zn.sub.2SiO.sub.4. The second sub-phase particles contain SiO.sub.2. A total area ratio of the first sub-phase particles and the second sub-phase particles is 30.5% or more.

A cathode material used in an anode and a cathode contains (Co,Fe).sub.3O.sub.4 and a perovskite type oxide that is expressed by the general formula ABO.sub.3 and includes at least one of La and Sr at the A site. A content ratio of (Co,Fe).sub.3O.sub.4 in the cathode material is at least 0.23 wt % and no more than 8.6 wt %.

A ferrite composition is provided containing Ba, Co, and Ir and having a Z-type hexaferrite phase and a Y-type hexaferrite phase. The ferrite composition has the formula Ba.sub.3Co.sub.(2+x)Ir.sub.xFe.sub.(24-2x)O.sub.41 where x=0.05-0.20. The composition has equal or substantially equal values of permeability and permittivity while retaining low magnetic and dielectric loss factors. The composition is suitable for ultrahigh frequency applications such as high frequency and microwave antennas.

This ferrite magnet has a ferrite phase having a magnetoplumbite structure, and an orthoferrite phase, and is characterized in that the composition ratios of the total of each metal element A, R, Fe and Me is represented by expression (1) A.sub.1-xR.sub.x(Fe.sub.12-yMe.sub.y).sub.z, (in expression (1), A is at least one element selected from Sr, Ba, Ca and Pb; R is at least one element selected from the rare-earth elements (including Y) and Bi, and includes at least La, and Me is Co, or Co and Zn) and in that the content (m) of the orthoferrite phase is 0<m<28.0 in mol %. The invention makes it possible to achieve a ferrite magnet with increased Br.

A cathode material used in an anode and a cathode contains (Co,Fe).sub.3O.sub.4 and a perovskite type oxide that is expressed by the general formula ABO.sub.3 and includes at least one of La and Sr at the A site. A content ratio of (Co,Fe).sub.3O.sub.4 in the cathode material is at least 0.23 wt % and no more than 8.6 wt %.

A cathode material used in an anode and a cathode contains (Co,Fe).sub.3O.sub.4 and a perovskite type oxide that is expressed by the general formula ABO.sub.3 and includes at least one of La and Sr at the A site. A content ratio of (Co,Fe).sub.3O.sub.4 in the cathode material is at least 0.23 wt % and no more than 8.6 wt %.