Abstract: Disclosed are ceramic powder compositions that include Si, N, O, C, Mg, and/or Mn in tailored combinations of different crystalline phases for producing high temperature resistant and high strength ceramic products. In some aspects, a ceramic powder for producing high temperature-resistant and/or high mechanical strength materials comprises a silicon nitride (Si3N4) powder, comprising Si3N4 particles having a size within a range of 30 nm to 700 nm, wherein the Si3N4 powder include alpha and beta phase silicon nitride in an amount up to about 1-100% vol; and an impurity constituent intermixed with the Si3N4 powder within the ceramic powder, the impurity constituent comprising at least one of silicon (Si), nitrogen (N), oxygen (O), carbon (C), magnesium (Mg), or manganese (Mn), wherein the impurity constituent constitutes less than about 0.1% wt to 15% wt of the ceramic powder.

Abstract: The present invention is directed towards a ceramic nanocomposite comprising a nanostructured carbon component inside a ceramic host. The ceramic nanocomposite may further comprise vapor grown carbon fibers. Such nanostructured carbon materials impart both structural and thermal barrier enhancements to the ceramic host. The present invention is also directed towards a method of making these ceramic nanocomposites and for methods of using them in various applications.