Magnesium or magnesium alloy surface autocatalytic degradation coating and preparation method thereof

A magnesium alloy, self-catalysis technology, applied in the direction of catalyst activation/preparation, chemical instruments and methods, metal material coating technology, etc., can solve the adverse effects of magnesium alloy mechanical properties, complex alloying process operation, and uncontrollable corrosion rate and other problems, to achieve the effect of obvious self-catalytic degradation, good biocompatibility and short reaction time

Active Publication Date: 2020-09-25
SHANDONG UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The operation of the alloying process is relatively complicated, the conditions are harsh, and most of the added components are in the form of impurities through metallurgical bonding, which exist in the magnesium alloy, which has an adverse effect on the mechanical properties of the magnesium alloy, and the corrosion rate is uncontrollable.

Method used

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  • Magnesium or magnesium alloy surface autocatalytic degradation coating and preparation method thereof
  • Magnesium or magnesium alloy surface autocatalytic degradation coating and preparation method thereof
  • Magnesium or magnesium alloy surface autocatalytic degradation coating and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0084] Magnesium alloy device: the material composition is Mg-3AlLi-1Zn (AZ31).

[0085] The preparation method is as follows:

[0086] The first step, the preparation of the precursor solution

[0087] Take ferrous sulfate heptahydrate and trisodium phosphate dodecahydrate respectively, add deionized water to prepare a mixed aqueous solution; among them, FeSO 4 ·7H 2 O is 100mmol / L, Na 3 PO 4 12H 2 O is 100mmol / L;

[0088] Using phosphoric acid to adjust the pH value of the above mixed solution to 3.27 to obtain a precursor solution;

[0089] The second step, pretreatment of the coated substrate

[0090] The magnesium alloy workpiece is mechanically polished to remove its surface burrs, and is sequentially washed with first water, alkali, second water, pickling and third water, and dried to obtain a magnesium alloy workpiece with a fresh surface ;

[0091] The third step is the surface coating treatment of magnesium alloy components

[0092] The ratio of the surface...

Embodiment 2

[0098] Ferrous sulfate heptahydrate and trisodium phosphate dodecahydrate are 34.4mmol / L and 100mmol / L respectively; react in a water bath at 25°C for 30min; use phosphoric acid to adjust the pH value of the above mixed solution to 3.77 to obtain a precursor solution;

[0099] All the other are the same as in Example 1. The obtained self-catalytic degradation coating on the surface of the magnesium alloy is marked as coating II.

[0100] Product testing and inspection:

[0101] The thickness of the coating is 15-20μm, the whole film layer is porous structure, the distribution of the coating is uneven, and the scattered accumulation is on the surface of the substrate.

[0102] The open circuit potential is -1.56±0.01V / SCE, which is higher than the substrate but lower than Example 1, and has a tendency to accelerate corrosion relative to the substrate; the self-corrosion current is 2.20×10 -4 A / cm 2 ~2.40×10 -4 A / cm 2 , about 1 / 3 of the current of Example 1, also has a cert...

Embodiment 3

[0104] Ferrous sulfate heptahydrate and trisodium phosphate dodecahydrate are 8.43mmol / L and 100mmol / L respectively; react in a water bath at 25°C for 30min;

[0105] Using phosphoric acid to adjust the pH value of the above mixed solution to 4.27 to obtain a precursor solution;

[0106] All the other are the same as in Example 1. The obtained self-catalytic degradation coating on the surface of the magnesium alloy is marked as coating III.

[0107] Product testing and inspection:

[0108] The thickness of the film layer is 7-8μm, relatively dense and uniform, and there are many dry river-like cracks on the surface.

[0109] The open circuit potential and current are: -1.56±0.04V / SCE, 1.04×10 -5 A / cm 2 ~1.30×10 -5 A / cm 2 It is 1 / 2 of the self-corrosion current density of the substrate. At the same time, the hydrogen evolution rate after soaking in 3.5wt.% NaCl for 78 hours was 0.08±0.01mL cm -2 h -1 . It shows that the coating III has a certain protective effect on t...

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Abstract

The invention provides a magnesium or magnesium alloy surface autocatalytic degradation coating and a preparation method thereof. Phosphate and ferrite or ferric salt are used as raw materials, a chemical conversion method is adopted to prepare a coating capable of accelerating magnesium alloy degradation on the surface of a magnesium or magnesium alloy matrix, and the obtained coating is phosphate and hydroxide of iron and ferrous iron. The composite coating is a cathode type porous coating; since the open-circuit potential is higher than that of a magnesium alloy matrix, and meanwhile, elementary iron generated by reduction of iron or ferrous ions can form galvanic corrosion with the magnesium alloy, so that the effect of accelerating corrosion of the magnesium alloy is achieved, and further, autocatalytic degradation of the magnesium alloy is realized. A new way of thinking is created in the invention. Compared with the prior art, the method disclosed by the invention has the characteristics of environment-friendly and simple process, short reaction time, low production cost, no damage to a matrix structure and mechanical properties and the like. The obtained magnesium alloy surface coating has the advantages of being porous in structure, good in biodegradability and biocompatibility and the like, and therefore the magnesium alloy surface coating can be used as a structuralmaterial and can also be used as a degradable biomedical material.

Description

technical field [0001] The invention relates to the technical field of magnesium or magnesium alloy surface coatings, in particular to a magnesium or magnesium alloy surface self-catalytic degradation coating and a preparation method thereof. Background technique [0002] Magnesium is one of the lightest metals with a density of 1.75g / cm 3 , is one of the elements with abundant resources on the earth, and its content in the earth's crust can account for about 2.7%. [0003] Magnesium alloys also have superior properties such as high specific strength, high specific stiffness, large elastic modulus, good damping, good thermal conductivity, good vibration damping, and good resistance to organic matter and alkaline solutions. In addition, magnesium alloy also has good dimensional stability, electromagnetic shielding, easy processing and recycling. Therefore, they are used as structural materials (such as automobiles, aerospace, 3C products) and functional materials (such as b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J27/185B01J37/02B01J37/10C23C26/00
CPCB01J27/1853B01J37/0217B01J37/0225B01J37/10C23C26/00
Inventor 曾荣昌殷正正曾美琪于晓彤崔蓝月李硕琦张芬邹玉红
Owner SHANDONG UNIV OF SCI & TECH
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