Evaluation of Net Energy Systems

An insulative ceramic compact is composed of a fired mixture of (A) a MgAl2O4, Mg3B2O6 and/or Mg2B205 ceramic powder, and (B) a glass powder including from about 13 to 50% by weight of silicon oxide in terms of SiO2, from 8 to 60% by weight of boron oxide in terms of B2O3, about 20% by weight or less of aluminum oxide in terms of Al2O3, and from about 10 to 55% by weight of magnesium oxide in terms of MgO. The insulative ceramic compact can be obtained by firing at low temperatures of about 1000° C. or less, can be obtained by sintering with Ag or Cu, has a low dielectric constant and a high Q value, and is suitable for use in the high-frequency range.