The invention discloses a method for preparing
titanium base
hydroxy apatite or
titanium oxide nano tube composite coating, comprising the following steps: the pure
titanium is taken as an
anode while a
platinum plate is taken as a
cathode; in the
dimethyl sulfoxide solution containing HF with the weight percent of 1 to 4 percent, under the
voltage of 20 to 70 V, the pure titanium and the
platinum plate are oxidized for 2 to 10 hours in the water bath with the temperature of 10 to 30 DEG C; then, a
titanium oxide nano tube array film is arranged in
aqueous solution which contains 0.1 to 0.5mol per
liter of CaC12, 0.1 to 0.5 mol per
liter of NaH2PO4 and 0.2 mol per
liter of EDTA. The PH value of the solution is adjusted by NaOH to be 4 to 6. Under the condition of the temperature of 100 to 200 DEG C and
hydrothermal reaction of 2 to 10 hours, the hydroxyapatite is induced to be crystallized and deposited on the surface of the array film of the
nano tube and a novel
hydroxyapatite coating layer which takes the array film of the
titanium oxide nano tube as a buffer layer is formed. The method is characterized by taking the array film of the
titanium oxide nano tube as the buffer layer, which reduces the
residual stress caused by mismatch of coefficient of heat expansion of the hydroxyapatite and the titanium base and enhances the binding strength of the
coating layer and the base interface.