| Based on the weak-bonding property between Al2O3 and LaPO4, machinable LaPO4/Al2O3 composites were designed and investigated, including reparation of LaPO4/Al2O3, sintering of composites system, thermal properties and structures of materials. The experimental results indicated that the toughness and thermal property was improved by the introduction of LaPO4.The study of LaPO4 illustrated that LaPO4 could be successfully sintered above 1500℃. Its bending intensity was about 150 Mpa. There were layered structures in the LaPO4.The layered structures of layered structures was the key ingredient of improving the mechanical and thermal properties of LaPO4/Al2O3 composites.The study emphasized on the"machinable"action and thermal propertity of LaPO4/Al2O3 composites, which was related to special structure of the weak bonding of layered LaPO4 and the weak interface between LaPO4 and Al2O3. The mechanism was the uniform distributing of weak interfaces in the network structure of strong interfaces formed by Al2O3 grains. The margin of indentation visibly collapsed and the crack propagation of indentation showed discontinuity, entirely different from those without LaPO4. LaPO4/Al2O3 composites showed a better resistance to thermal shocks than Al2O3 especially when the thermal shock temperature was above 400℃.
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