Surface texture was prepared on the ASTM1045 steel substrate before spraying. Three texturing patterns (groove pattern, square pattern, and hexagon pattern) were acquired by laser processing to investigate the influence of texturing patterns on the adhesion strength of sprayed coatings. The Ni60 coatings were prepared on the textured surface by atmosphere plasma spraying technology. Scanning electron microscopy and laser 3D microscope were used to characterize the morphology of texturing. The adhesion strength between coating and substrate was examined by the tensile test. Image pro plus software was used to calculate the contact area ratio of the textured substrate. The results show that the texturing processed substrates by laser radiation present plain area between two dimples and the protrusion around texturing, and the contact area between coating and substrate is increased. The adhesion strength of coatings with a groove pattern, a square pattern, and a hexagon pattern is 58, 33, and 47 MPa, respectively. The adhesion strength of sprayed coatings varies with the change of the texturing pattern, and it does not only depend on the contact area ratio but also on the texturing density and the texturing microstructure.

A focused ion beam (FIB) technique was applied to cross-sectional specimen preparation to observe an interface between a plasma sprayed coating and an aluminum (Al) substrate by transmission electron microscopy (TEM). The surface of the sprayed coating film has a roughness of several tens of microns. Sputter rates for the coating film and the substrate are greatly different. The rough surface and the difference in sputter rate cause problems in making TEM specimens with smooth side walls. The top surface of the coating film was planerized by the FIB before fabricating the TEM specimen. The interfaces were investigated by TEM and energy-dispersive X-ray (EDX) analysis. The TEM observation revealed that there is a 10 nm thick amorphous layer at the interface between the coating film and substrate. The coating film consists of two kinds of sublayers with bright and dark contrast. The bright contrast sublayers were amorphous layers with thickness of 2~10 nm. The Al/Fe X-ray intensity ratio was larger in bright contrast sublayers than that in dark contrast sublayers.