Method for preparing strontium-doped calcium phosphate coating on surface of magnesium alloy through one-step hydrothermal method

[0027] Example 1

[0028] Process the AZ31 magnesium alloy into a block of 10mm×10mm×2mm, and use 600 # , 1200 # , 2000 # Polished with SiC sandpaper, then ultrasonically cleaned in acetone, deionized water, and absolute ethanol for 10 minutes, and dried with hot air. Prepare 150 mL of 3 mol/L NaOH deionized aqueous solution. Soak the polished magnesium alloy in NaOH solution at 60°C for 3 hours, then rinse the magnesium alloy sample with deionized water and dry it. With Ca(NO 3 ) 2 Prepare Ca for Ca source 2+ Aqueous solution, as Na 2 HPO 4 Preparation of PO for P source 4 3- Aqueous solution, with Sr(NO 3 ) 2 Preparation of Sr for Sr source 2+ aqueous solution. Then Sr 2+ and PO 4 3- The aqueous solution was added dropwise with Ca 2+ In the aqueous solution, finally the pH value of the mixed solution was adjusted to 6 with 20 M dilute hydrochloric acid, and stirred by magnetic force for 2 h. Among them, Ca in the mixed solution 2+ The concentration is 6mmol/L, Sr 2+ The concentration is 0.6mmol/L, PO4 3- The concentration is 2mmol/L. Measure 40mL of the mixed solution as the conversion coating solution. Put the coating conversion solution in the reaction kettle, soak the magnesium alloy sample after the alkali treatment in the coating solution, place the reaction kettle in the oven, keep it at 100°C for 3 hours, and cool it to room temperature with the oven, and the magnesium The alloy samples were taken out, rinsed with deionized water, and dried. The surface morphologies of the prepared conversion coatings and deposits are as follows figure 1 As shown, the coating consists of flower-like cluster structures and sheet-like structures. The prepared coated magnesium alloy was inlaid in the resin powder, pressed and polished, and then the cross-section test was carried out. The cross-sectional morphology of the coating was as follows: figure 2 As shown, the thickness of the strontium-doped calcium-phosphorus coating is 2 μm. In the in vitro immersion test, deposited hydroxyapatite appeared on day 1. AC impedance spectroscopy of strontium-doped calcium-phosphorous coating coated magnesium alloy and magnesium alloy die in simulated body fluid image 3 As shown, the AC impedance of magnesium alloy coated with strontium-doped calcium-phosphorus coating is 14000ohm cm 2.

[0029] Example 2

[0030] Process the AZ91 magnesium alloy into a block of 10mm×10mm×2mm, and use 600 # , 2000 # Polished with SiC sandpaper, then ultrasonically cleaned in acetone, deionized water, and ethanol for 6 minutes, and dried with hot air. Prepare 150 mL of 2 mol/L NaOH deionized aqueous solution. Soak the polished magnesium alloy in NaOH solution at 70°C for 2 hours, then rinse the magnesium alloy sample with deionized water and dry it. with CaCl 2 Prepare Ca for Ca source 2+ Aqueous solution, as NaH 2 PO 4 Preparation of PO for P source 4 3- Aqueous solution, with Sr(NO 3 ) 2 Preparation of Sr for Sr source 2+ aqueous solution. Then Sr 2+ and PO 4 3- Aqueous solution was added dropwise to Ca 2+ In the aqueous solution, the pH value of the mixed solution was finally adjusted to 5.5 with 15M dilute nitric acid, and magnetically stirred for 1.5 h. Among them, Ca in the mixed solution 2+ The concentration is 5.5mmol/L, Sr 2+ The concentration is 0.4mmol/L, PO 4 3- The concentration is 1.5mmol/L. Weigh 35mL of the mixed solution as the conversion coating solution. Put the coating conversion solution in the reaction kettle, soak the magnesium alloy sample after the alkali treatment in the coating solution, place the reaction kettle in the oven, keep it at 110°C for 2 hours, and cool it to room temperature with the oven, and the magnesium The alloy samples were taken out, rinsed with deionized water, and dried. The surface morphology of the as-prepared conversion coatings and deposits consisted of flower-like cluster structures and sheet-like structures. In the in vitro immersion test, deposition of hydroxyapatite occurred on day 2. The thickness of the coating was 2 μm. The AC impedance of the magnesium alloy sample coated with strontium-doped calcium-phosphorus coating is 8000ohm·cm 2.

[0031] Example 3

[0032] AZ61 is used as the magnesium alloy matrix, followed by 600 # , 1200 # , 1500 # Polished with SiC sandpaper, then ultrasonically cleaned in acetone, deionized water, and ethanol for 8 minutes, and dried with hot air. Prepare 150 mL of 2 mol/L NaOH deionized aqueous solution. Soak the polished magnesium alloy in NaOH solution at 80°C for 1 hour, then rinse the magnesium alloy sample with deionized water and dry it. With Ca(CH 3 COO) 2 Prepare Ca for Ca source 2+ Aqueous solution, as NaH 2 PO 4 Preparation of PO for P source 4 3- Aqueous solution, with Sr(NO 3 ) 2 Preparation of Sr for Sr source 2+ aqueous solution. Then PO 4 3- The aqueous solution was added dropwise with Ca 2+ In the aqueous solution, the pH value of the mixed solution was finally adjusted to 6 with 5M acetic acid, and magnetically stirred for 1.5 h. Among them, Ca in the mixed solution 2+ The concentration is 5mmol/L, Sr 2+ The concentration is 0.2mmol/L, PO 4 3- The concentration is 1.5mmol/L. Measure 35mL of the mixed solution as the conversion coating solution. Put the coating conversion solution in the reaction kettle, soak the magnesium alloy sample after the alkali treatment in the coating solution, place the reaction kettle in the oven, keep it at 110°C for 1 hour, and cool it to room temperature with the oven, and the magnesium The alloy samples were taken out, rinsed with deionized water, and dried. The surface morphology of the as-prepared conversion coatings and deposits consisted of flower-like cluster structures and sheet-like structures. In the in vitro immersion test, deposition of hydroxyapatite occurred on day 2. The thickness of the coating was 1.5 μm. The AC impedance of the magnesium alloy sample coated with strontium-doped calcium-phosphorus coating is 8500ohm·cm 2.