Laser Cladding of Hydroxyapatite (HA) on to Ni-Free Stainless Steel Using a Low Power Fibre Laser
G.G. Ying, F. Yusof and M. Zakaria
The influence of laser cladding process parameters on surface morphology, chemical composition and mechanical properties of a hydroxyapatite (HA) coating on to a Ni-free F2229 stainless steel substrate have been investigated. Laser cladding experiments were conducted by melting preplaced HA powder using a low power fibre laser with varying laser power and scanning speed range of 80 to 160 W and 150 to 200 mm/s, respectively. The morphology of the laser clad HA coating shows that coating layer deteriorated when higher laser power is used and cracks propagated from small pin holes due to thermal stresses. Examination of the cross-section revealed that a transition layer consisted of a mixture of HA and F2229 stainless steel which constitute the hardness at the interface. X-ray diffraction (XRD) patterns demonstrated that the laser cladding parameters used were inadequate to change both the chemical composition and crystallinity of the HA coatings.
Keywords: Fibre laser, F2229 stainless steel, hydroxyapatite (HA), laser cladding, morphology, chemical composition, mechanical properties