An amorphous PEEK coating could be obtained on Al substrate using flame spraying process. The amorphous coatings were subjected to isothermal treatments under different temperature and holding time. Differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD) analysis were carried out to characterize the crystallization behaviour of PEEK coating under different treatment conditions. A modified cantilever beam method is used to evaluate Young’s modulus of the obtained coatings.

 

The isothermally treated coating exhibited a semi-crystalline structure. Coexistence of double crystal entities in semi-crystalline PEEK coating was deduced from DSC and WAXD measurements results. Annealing temperature and holding time under this temperature affect the morphology of the minor crystal entity which is metastable.

 

The modified cantilever beam method was a simple and effective method for evaluate the Young’s modulus of coatings. The results showed that the semi-crystalline coatings exhibit higher Young’s modulus than that of the amorphous one. Young’s modulus of PEEK coatings was correlated with coating crystallization behaviour and the obtained microstructure.