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A Study of Calcium Phosphate Bioceramics Coating Deposited by Wet Chemical Reaction

Author: ZhangChunYan
Tutor: GaoJiaCheng
School: Chongqing University
Course: Materials Science
Keywords: chemical deposition titanium alloys hydroxyapatite biocerimic coating
CLC: TG174.4
Type: Master's thesis
Year: 2002
Downloads: 165
Quote: 2
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Abstract

Biomaterials not only have important social effect in bettering the people’s living quality,improving their health and saving their lifes but also become the new growth point in economic and scientific-technological areas.At present,the plasma-spray process is widely applyed to prepare HA biocremic coatings on Ti-bassed alloys’ surface which are used as repairing and implanting materials for hard human tissues. But this method need prepare costly HA powder before spary and amorphous phase and impurities are readily to appear in coatings layer,which will affect the coatings’ bioactivity.In this thesis,a method to prepare calcuium-phosphate bioceramics coatings on Ti6A14V by wet chemistry of imitate organism has been adapted. Through changing the alkali-treating condition and the deposite parameter,followed by observe the coatings’chemical composition,phase and morphology,we studied the metallic active mechanism,set the optimal parameter of the deposition and probed into the mechanism of the reaction and deposition.The experiment was performed by etching the samples with a mixture of HCL and H,SO4 followed by soaking in highly concentrated NaOH solution for 5 h,then incubating the samples in Na2HPO4 solution for 10 h and in saturated Ca(OH)2 solution for 5 h,at last immersing the samples in a fast calcification solution (PCS) to deposited the calcium phosphate (Ca-P) coatings on Ti6A14V(TC4) automatically.After a series of experiments related to pre-treatment parameters,we found that the best netted surface was created on the condition of 10 N NaOH aging under 100C. The FT-IR result show there was -OH in the sample surface after alkali treated. Using a pre-calcification (pre-Ca) procedure prior to immersion in PCS can accelerate the deposition and the coating was more even than unpretreated samples. By thermodynamic equations and X- ray analysis,it can be determined that the apatite phase of coating is hydroxy apatite.The thesis also discussed the coatings surface morphology. During the coating growth,coatings morphology changed from thin to thick,the coatings grew in two layer,the layer inside was fine and close which will inhance the bonding intensity and the layer outside was 100se which will benfit the growth of bone.Compared with other method,the coatings prepared by wet chemistry had even surface,high crystallo-degree and the main apatite phase of coating is hydroxyapatite which is also the main chemical composition of human bone.

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