Abstract:
Four kinds of Al
2O
3-TiO
2 coatings with different TiO
2 contents were prepared on cast iron substrate by plasma spraying. X-ray diffraction (XRD) technique combined with the Rietveld whole pattern fitting method was used to determine the phase's content in different coatings. The effects of TiO
2 content on mechanical properties of the coatings were investigated by means of the microhardness measurement and tensile testing. The results indicate that there are a large amount of γ-Al
2O
3, α-Al
2O
3 and a small quantity of amorphous phase in Al
2O
3-3wt%TiO
2 coating; the maximum value of the amorphous content appears, and Al
2TiO
5 phase forms in Al
2O
3-13wt%TiO
2 coating. With the further increase of the TiO
2 content, the amount of the amorphous phase decreases, and Al
2TiO
5 phase's content increases in coatings. There are only α-Al
2O
3 and Al
2TiO
5 phases in the Al
2O
3-40wt%TiO
2 coating. The microhardness of the coatings decrease but the adhesion strength enhance with the increase of TiO
2 contents, this can be attributed to the formation of the Al
2TiO
5 phase.