Fabrication and Properties of Mg-Based Phosphate Ceramics

Calcined MgO is a requirement for forming practical Mg-based ceramics, while boric acid addition is not essential in several systems such as formation of MgKP04-6H20, unless the mixing and pumping times of the slurry need to be extended for several hours. We will be discussing various Mg-based ceramics that have been developed using these methods. 

One common characteristic of these ceramics is that a significant amount of MgO is unreacted and left behind in the final product. Thus, in addition to the phases given in Table 9.1, one finds a large amount of MgO, and to a small extent, brucite [Mg(OH)2] in the ceramic. 

Reaction between even well calcined MgO and H3PO4 solution is highly exothermic, and only small-size ceramics can be formed by this reaction. Rapid reaction gives a soluble Mg(H2P04)2 product, but the same reaction in the presence of boric acid slows down, and 

Mg-Phosphate Ceramics Produced by Using Acid or Acid Phosphates. 

Equation Starting pH Reaction Number (size) Product Reference 

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