Method for regulating and controlling physical phases of zinc and calcium conversion films on pure-titanium surfaces by aid of pH (potential of hydrogen) value

Abstract

The invention discloses a method for regulating and controlling physical phases of zinc and calcium conversion films on pure-titanium surfaces by the aid of a pH (potential of hydrogen) value. The method includes steps of preparing chemical conversion liquid; regulating the pH value of the chemical conversion liquid by the aid of phosphoric acid and sodium hydroxide until the pH value reaches 2.50-4.50; soaking pure-titanium samples in the chemical conversion liquid after the pure-titanium samples are subjected to acid etching and surface modification and converting the pure-titanium samples for 15-45 min to obtain the zinc and calcium conversion films on the pure-titanium surfaces. The concentration of a component Zn(H2PO4)2 2H2O in the chemical conversion liquid is 22-30 g / L, the concentration of a component Ca(NO3)2 4H2O in the chemical conversion liquid is 8-14 g / L, and the concentration of a component NaNO2 in the chemical conversion liquid is 1.5-2 g / L. The method for regulating and controlling conversion of zinc and calcium salt on the pure-titanium surfaces by means of changing the pH value of the chemical conversion liquid has the advantages that the conversion films with zinc phosphate phases [Zn3(PO4)2 4H2O] and the conversion films with zinc and calcium phosphate phases [CaZn2(PO4)2 2H2O] can be respectively obtained by the aid of the method, film layers are uniform and dense, structures and textures are patterned, preparation processes are simple, a formula for the chemical conversion liquid does not need to be changed, accordingly, resources can be saved, the structures and the physical phases of the calcium and zinc conversion films on the pure-titanium surfaces can be doubly controllably prepared, and the method has important scientific research value in the technical field of metal surface modification and important significance on expanding clinical application of titanium.

Description

technical field [0001] The invention relates to a method for regulating the phase of a zinc-calcium conversion film on the surface of pure titanium by using the pH value, and belongs to the technical field of surface modification of biomedical metal materials. Background technique [0002] It is of great scientific significance and application value to prepare a surface-modified layer with easy-to-adjust structure and composition and strong osteogenic ability on the surface of medical pure titanium for improving the long-term clinical efficacy of titanium implants. The chemical composition of calcium phosphate salt is similar to that of bone tissue, and it has good bioactivity and biocompatibility. It is often used as a bone substitute material in the medical field, and has also been widely studied for metal surface modification. However, studies have shown that pure calcium phosphate salts have little effect on stimulating bone formation and inhibiting bone resorption. The...

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Problems solved by technology

The two forms zinc salt and calcium salt conversion coatings on the surface of pure titanium respectively, but there is no mention of the preparation of conversion coatings containing zinc and calcium elements at the same time.

Other studies on the chemical conversion phase of metal surfaces are also limited to changing the conversion solution formula to determine the final film-forming phase and using the pH value to change the microscopic morphology of the film layer. For the use of pH value to regulate the film-forming phase, At present, no relevant information at home and abroad has been retrieved

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