Aluminum oxide modified gradient laser cladding layer and preparation method thereof

A laser cladding and gradient technology, applied in the direction of coating, metal material coating process, etc., can solve the problems of increased tissue inhomogeneity, excessive physical properties difference, galvanic corrosion of the cladding layer, etc., to promote uniform distribution , Overcome adverse effects, reduce the effect of excessive oxidation and burning loss

Active Publication Date: 2017-08-04
SHANDONG UNIV
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0007] The addition of composite materials has made some progress in the wear resistance of coatings, however, there are relatively few studies on corrosion resistance, which may be due to the large differe

Method used

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  • Aluminum oxide modified gradient laser cladding layer and preparation method thereof
  • Aluminum oxide modified gradient laser cladding layer and preparation method thereof
  • Aluminum oxide modified gradient laser cladding layer and preparation method thereof

Examples

Experimental program
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Example Embodiment

[0041] Embodiment 1 Test material and method of the present invention

[0042] 1.1.1 Base material: The base material used in this test is AZ91D cast magnesium alloy, which is most widely used in the field of magnesium alloy engineering structural materials, and was purchased from Ruihe Ribiao Metal Material Co., Ltd., Dongguan, Guangdong. Its chemical composition is shown in Table 1.

[0043] Table 1 AZ91D magnesium alloy nominal chemical composition (wt.%)

[0044]

[0045] 1.1.2 Coating material: The coating material used in the test is Ni35 self-fluxing alloy powder, the powder particle size is 140-325 mesh, and its chemical composition is shown in Table 2. Ni35 is in the form of round particles, mainly including γ-Ni, M 23 C 6 , Ni 3 B, composed of CrB. In this experiment, Ni35 powder was used to laser clad the surface of AZ91D magnesium alloy to obtain a cladding layer with excellent corrosion resistance. However, the physical properties of Ni35 and the base mate...

Example Embodiment

[0067] Example 2Ni35 cladding layer microstructure analysis

[0068] 2.1 Structural characteristics of the cladding layer:

[0069] Observation of the microstructure morphology of different areas from the bottom to the upper part of the cladding layer of the A2 sample is mainly the eutectic structure between the γ-Ni dendrites precipitated first and the Ni-Cr-B-Si elements between the dendrites. Ni35 powder is easy to form eutectic structure because it contains B, Si and other elements, and it can be seen from the phase diagram that compounds between Ni and Mg, Cr, B, Si elements are easier to form eutectic structure, so there must be a large amount of eutectic structure in the cladding layer. crystal organization. In the microstructure, a long strip-shaped single structure was observed, which is the enrichment area of ​​Mg at the bottom of the cladding layer, which is caused by the uneven distribution of heat in the molten pool, and there is a dendritic pre-precipitated phas...

Example Embodiment

[0085] Example 3 Al-Si / Ni35 cladding layer microstructure analysis

[0086] The AZ91D magnesium alloy substrate and the laser cladding Al-Si / Ni35 sample were respectively subjected to corrosion electrochemical tests, and the potentiodynamic polarization curves were measured as follows: Image 6 shown. The corrosion potential and corrosion current density of the tested samples are obtained through chi660e software fitting, as shown in Table 6. The highest corrosion potential of the cladding layer is -0.955V, which is 0.563V higher than that of the base material, and the corrosion current density is only 1 / 8 to 1 / 30 of that of the base material, indicating that the Al-Si / Ni35 cladding layer can better improve the corrosion resistance of AZ91D magnesium. Alloy surface corrosion resistance. Compared with the cladding layer only cladding Ni35, when v=200 and 300mm / min, the corrosion resistance performance is increased by 4 to 5 times. This is related to the excellent corrosion r...

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Abstract

The invention discloses an aluminum oxide modified gradient laser cladding layer and a preparation method thereof. Magnesium alloy serves as base material, Al-Si alloy powder serves as a first precoated layer, the mixed powder of nickel-based self-melting alloy powder and Al2O3 serves as a second precoated layer, and the aluminum oxide modified gradient laser cladding layer is formed through laser cladding. The corrosion potential of the Al2O3 modified gradient laser cladding layer is about -1.1 V and is similar to that of a Ni35, Al-Si/Ni35 cladding layer, the corrosion current density is large in difference and is about 1/15-1/2 that of the base material, and a good corrosion resistant effect is achieved. The aluminum oxide modified gradient laser cladding layer and the preparation method thereof can be used for surface strengthening and modification of magnesium alloy parts in the industrial field, the application range of magnesium alloy in corrosion resistant occasions is extended, and wide application prospects are achieved.

Description

technical field [0001] The present invention relates to magnesium alloy anti-corrosion coating and its preparation and application fields, in particular to Ni-based laser cladding layer on the surface of magnesium alloy and its preparation and utilization, especially to an alumina-modified gradient laser cladding layer and its preparation method. Background technique [0002] Magnesium alloy has low density, high damping strength, easy processing and forming, good thermal and electrical conductivity and electromagnetic shielding performance, and can be recycled and reused. It is known as the most promising green engineering structural material in the 21st century. Magnesium alloys have high chemical activity, and can be used in wet, CO-rich 2 , SO 2 , Cl - Corrosion is prone to occur in the environment. The impurities and alloying elements contained in magnesium alloy make it prone to galvanic corrosion, stress corrosion or fatigue corrosion during use, which limits the ...

Claims

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Application Information

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IPC IPC(8): C23C24/10C22C32/00C22C19/03
CPCC22C19/03C22C32/0026C23C24/103
Inventor 于慧君刘建利陈传忠
Owner SHANDONG UNIV
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