Microstructural dependence of the thermal and mechanical properties of monazite LnPO4 (Ln = La to Gd)

Abstract In this work are given some thermal and mechanical properties of monazite, related to the microstructure. This compound is a poor thermal conductive ( λ −1  K −1 ), with a thermal expansion in between 9 and 10 × 10 −6  K −1 according to the considered crystallographic direction, and a relatively high specific heat ( C p  ≈ 110 J mol −1  K −1 ). Mechanical properties of monazite are characteristic of a brittle behavior: bending strength is of about 100 MPa and fracture toughness is close to 1 MPa m 1/2 . Porosity plays a large role on both thermal and mechanical properties pointing out the importance of controlling the whole elaboration process.