Raw material powder of self-repairing wear-resistant coating and preparation method of coating

Abstract

The invention discloses self-repairing wear-resistant coating raw material powder and a preparation method of a coating. The method comprises the following steps: 1, carrying out spray granulation on Mo and AlPO4 powder to obtain Mo-AlPO4 powder; 2, the Mo-AlPO4 powder and the AT40 powder are subjected to ball milling, and raw material powder is obtained; the preparation method of the coating comprises the following steps: 1, pretreating the substrate; 2, preheating a substrate and preparing a coating; and 3, hole sealing, polishing and grinding. According to the method, the AlPO4 powder is coated with the Mo powder with the high melting point, so that the AlPO4 powder is not decomposed and damaged at the thermal spraying high temperature and is uniformly distributed in the coating; the raw material powder releases AlPO4 in the process that Mo on the shell is corroded, the AlPO4 reacts with Al2O3 and corrosive liquid to generate Al (PO3) 3 to seal pores, the self-repairing effect is achieved, meanwhile, Mo serves as a bonding phase to improve the bonding strength between coatings and cooperatively improve the wear resistance and corrosion resistance of the coatings, and the coating is suitable for the field of engineering parts.

Description

Technical Field

[0001] The invention belongs to the technical field of plasma spraying, and in particular relates to a preparation method of a raw material powder of a self-repairing wear-resistant coating and a coating. Background Art

[0002] As the core equipment of the underground working face of coal mines, the hydraulic support columns, jacks and other components are severely rusted and worn on the surface due to the harsh environment underground, which reduces their performance, seriously affects their service life and causes significant economic losses. Although electroplating hard chrome, laser cladding and other technologies are used for protection at this stage, the effect is not good. Therefore, there is an urgent need for a highly corrosion-resistant and wear-resistant coating to extend the service life of the columns. As the most representative technology in surface treatment engineering, thermal spraying is very suitable for applications related to improving the corrosion resistance and wear resistance of parts. At present, the preparation of high-performance corrosion-resistant and wear-resistant coatings by thermal spraying is restricted by the process principles, resulting in the inability to eliminate pores. How to reduce the porosity of the coating is the key to solving the problem of corrosion performance when thermal spraying technology is applied in underground coal environments or even in the general public.

[0003] AlPO4 is a commonly used thermal spray sealing agent material. It can not only fill the surface pores, but also react with Al2O3 to further hinder the corrosion. Therefore, by coating the surface of AlPO4 micro-nano particles, the coating can be released as a "repair factor" during the later erosion process to fill the pores. However, how to make AlPO4 not be destroyed at high temperature and evenly distributed in the coating is the difficulty in preparing thermal spray self-repairing coatings.

[0004] As coal continues to play a dominant role as an energy source, the demand for extending the service life of hydraulic supports in coal mine comprehensive mining equipment is increasing, and the demand for high-performance corrosion-resistant and wear-resistant coatings is also increasing. Therefore, it is of great significance to seek a corrosion-resistant and wear-resistant coating that can also meet the self-repair function. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing a raw material powder and a coating of a self-repairing wear-resistant coating in view of the deficiencies of the above-mentioned prior art. The method uses high-melting-point Mo powder to coat AlPO4 powder and then mixes it with AT40 powder by ball milling to prepare the raw material powder, so that the AlPO4 powder is not decomposed and destroyed under the high temperature of the subsequent thermal spraying process and is evenly distributed in the coating, thus solving the problem that AlPO4 is easily destroyed under the high temperature of thermal spraying and is difficult to be evenly distributed in the coating.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing raw material powder of self-repairing wear-resistant coating, characterized in that the method comprises the following steps:

[0007] Step 1, spray granulating Mo powder and AlPO4 powder to obtain Mo-AlPO4 powder;

[0008] Step 2: The Mo-AlPO4 powder obtained in step 1 is mixed with the AT40 powder by ball milling to obtain a raw material powder.

[0009] The above-mentioned method for preparing raw material powder of self-repairing wear-resistant coating is characterized in that the mass proportion of Mo powder in the Mo powder and AlPO4 powder in step 1 is 90% to 91%. By controlling the mass proportion of Mo powder, the coating effect of Mo powder on AlPO4 powder is ensured, and at the same time, the bonding effect of Mo powder as a bonding relative coating and substrate during thermal spraying is ensured.

[0010] Generally, the particle size of the Mo-AlPO4 powder in step 1 of the present invention is 15 μm to 45 μm, and the particle size of the AT40 powder in step 2 is 15 μm to 45 μm.

[0011] The above-mentioned method for preparing raw material powder of self-repairing wear-resistant coating is characterized in that the mass ratio of Mo-AlPO4 powder to AT40 powder in step 2 is 10% to 15%. By limiting the mass ratio of Mo-AlPO4 powder, the wear-resistant effect of the coating prepared by the raw material powder is guaranteed.

[0012] At the same time, the present invention also discloses a method for preparing a self-repairing wear-resistant coating using the raw material powder prepared by the above method, characterized in that the method comprises the following steps:

[0013] Step 1: Pre-treat the substrate by sandblasting and degassing;

[0014] Step 2: preheating the substrate after sandblasting and degassing pretreatment in step 1 by using a plasma spraying process, and preparing a coating by using raw material powder;

[0015] Step three: perform surface sealing treatment and polishing on the coating prepared in step two to obtain a self-repairing wear-resistant coating on the substrate.

[0016] The above method is characterized in that the parameters of the plasma spraying process in step 2 are: spraying voltage 40V~50V, spraying current 700A~800A, main gas flow rate 80SCFH~100SCFH, scanning speed 700mm / s, pass spacing 1.5mm, spraying distance 100mm, auxiliary gas flow rate 3SCFH, and carrier gas flow rate 12SCFH.

[0017] Typically, in step three of the present invention, a sealing treatment solution, aluminum phosphate suspension, is used for surface sealing treatment, and the aluminum phosphate suspension is prepared by mixing aluminum hydroxide and orthophosphoric acid with a mass concentration of 85% in a mass ratio of 1:4.2, adding 20% ​​by mass of deionized water to dilute and stirring and heating to a suspension.

[0018] Generally, the process of surface sealing treatment in step three of the present invention is: placing the substrate with coating in step two into the sealing treatment solution and ultrasonically immersing it at 50°C for 30 minutes, then standing at room temperature for 12 hours, and then curing at 100°C, 200°C, and 250°C for 2 hours in sequence.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The present invention uses high-melting-point Mo powder to coat AlPO4 powder and then mixes it with AT40 powder by ball milling to prepare raw material powder, so that the AlPO4 powder is not decomposed and destroyed under the high temperature of the subsequent thermal spraying process, ensuring the sealing effect of AlPO4 in filling the pores on the surface of the coating, and the AlPO4 powder is evenly distributed in the AT40 powder, and then evenly distributed in the coating prepared by thermal spraying.

[0021] 2. The present invention uses high-melting-point Mo powder to coat AlPO4 powder to avoid its high-temperature decomposition, and the undecomposed AlPO4 powder is uniformly present in the thermal spray coating, avoiding the problem of insufficient immersion depth of the traditional sealing layer. In the process of corrosion of the outer layer Mo, AlPO4 is released, and with the help of the corrosive liquid, it reacts with Al2O3 in the thermal spray coating component AT40 to generate Al(PO3)3 to close the pores, further hindering the corrosion, improving the corrosion resistance of the coating, and achieving a self-repairing effect. It is suitable for the corrosion resistance of engineering components.

[0022] 3. The high melting point Mo powder coated on the outside of the AlPO4 powder of the present invention exists as a bonding phase in the thermal spray coating, which improves the bonding strength between the coating and the substrate, and both Mo and its oxide have corrosion resistance, which is beneficial to improving the wear and corrosion resistance of the coating.

[0023] 4. The self-repairing and wear-resistant coating prepared by thermal spraying in the present invention has excellent self-repairing and wear-resistant properties, prolongs the service life of the coating, ensures that the substrate is suitable for underground coal mining environment, and has great promotion value.

[0024] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the preparation process of the raw material powder and the self-repairing wear-resistant coating of the present invention.

[0026] Figure 2 Polarization curves of the self-repairing wear-resistant coating prepared in Example 1 of the present invention and the traditional AT40 coating before and after sealing.

[0027] Figure 3 This is a cross-sectional morphology of the self-repairing wear-resistant coating prepared in Example 2 of the present invention.

[0028] Figure 4 This is the XRD diagram of the self-repairing wear-resistant coating prepared in Example 2 of the present invention before and after surface sealing treatment. DETAILED DESCRIPTION

[0029] Example 1

[0030] like Figure 1 As shown, the raw material powder preparation method of this embodiment includes the following steps:

[0031] Step 1: spray granulate Mo powder and AlPO4 powder to obtain Mo-AlPO4 powder with a particle size of 15 μm to 45 μm; the mass proportion of Mo powder in the Mo powder and AlPO4 powder is 90%;

[0032] Step 2: ball-mill the Mo-AlPO4 powder obtained in step 1 and AT40 powder with a particle size of 15 μm to 45 μm to obtain a raw material powder; the mass proportion of the Mo-AlPO4 powder in the Mo-AlPO4 powder and the AT40 powder is 10%.

[0033] The method for preparing a self-repairing wear-resistant coating using raw material powder in this embodiment comprises the following steps:

[0034] Step 1: Pre-treat the substrate by sandblasting and degassing;

[0035] Step 2: preheat the substrate after sandblasting and degassing pretreatment in step 1 by plasma spraying process, and prepare the coating by raw material powder; the parameters of the plasma spraying process are: spraying voltage 40V, spraying current 700A, main gas flow rate 80SCFH, scanning speed 700mm / s, pass spacing 1.5mm, spraying distance 100mm, auxiliary gas flow rate 3SCFH, carrier gas flow rate 12SCFH;

[0036] Step three, use a sealing treatment solution, aluminum phosphate suspension, to perform surface sealing treatment and polishing on the coating prepared in step two to obtain a self-repairing wear-resistant coating on the substrate; the aluminum phosphate suspension is prepared by mixing aluminum hydroxide and 85% orthophosphoric acid in a mass ratio of 1:4.2, adding 20% ​​deionized water by mass to dilute and stir and heat to a suspension; the surface sealing process is as follows: placing the substrate with the coating in the sealing treatment solution, ultrasonically immersing it at 50°C for 30 minutes, then standing at room temperature for 12 hours, and then curing it at 100°C, 200°C, and 250°C for 2 hours.

[0037] After testing, the self-repairing wear-resistant coating obtained on the substrate in this embodiment has a larger passivation area, and the self-corrosion current density after sealing is 4.35×10 -8 A.cm -2 , which is 2 orders of magnitude higher than the traditional corrosion-resistant coating (6.10×10 -6 A.cm -2 ).

[0038] Figure 2 The polarization curves of the self-repairing wear-resistant coating prepared in this embodiment and the traditional AT40 coating before and after sealing, wherein AT40 represents the traditional AT40 coating prepared by plasma spraying process using AT40 powder, ST-AT40 represents the traditional AT40 coating after sealing, MA-AT40 represents the coating prepared by plasma spraying process in step 2 of this embodiment, and ST-MA-AT40 represents the MA-AT40 coating after sealing. Figure 2 It can be seen that compared with the traditional AT40 coating, the self-repairing wear-resistant coating prepared in this embodiment has a larger passivation area, and the self-corrosion current density after sealing is 4.35×10 -8 A.cm -2 , which is 2 orders of magnitude higher than the traditional corrosion-resistant coating (6.10×10 -6 A.cm -2 ), has stronger corrosion resistance.

[0039] Example 2

[0040] like Figure 1 As shown, the raw material powder preparation method of this embodiment includes the following steps:

[0041] Step 1: spray granulate Mo powder and AlPO4 powder to obtain Mo-AlPO4 powder with a particle size of 15 μm to 45 μm; the mass proportion of Mo powder in the Mo powder and AlPO4 powder is 91%;

[0042] Step 2: ball-mill the Mo-AlPO4 powder obtained in step 1 and AT40 powder with a particle size of 15 μm to 45 μm to obtain a raw material powder; the mass proportion of the Mo-AlPO4 powder in the Mo-AlPO4 powder and the AT40 powder is 15%.

[0043] The method for preparing a self-repairing wear-resistant coating using raw material powder in this embodiment comprises the following steps:

[0044] Step 1: Pre-treat the substrate by sandblasting and degassing;

[0045] Step 2: preheating the substrate after sandblasting and degassing pretreatment in step 1 by plasma spraying process, and preparing coating by raw material powder; the parameters of the plasma spraying process are: spraying voltage 50V, spraying current 800A, main gas flow rate 100SCFH, scanning speed 700mm / s, pass spacing 1.5mm, spraying distance 100mm, auxiliary gas flow rate 3SCFH, carrier gas flow rate 12SCFH;

[0046] Step three, use a sealing treatment solution, aluminum phosphate suspension, to perform surface sealing treatment and polishing on the coating prepared in step two to obtain a self-repairing wear-resistant coating on the substrate; the aluminum phosphate suspension is prepared by mixing aluminum hydroxide and 85% orthophosphoric acid in a mass ratio of 1:4.2, adding 20% ​​deionized water by mass to dilute and stir and heat to a suspension; the surface sealing process is as follows: placing the substrate with the coating in the sealing treatment solution, ultrasonically immersing it at 50°C for 30 minutes, then standing at room temperature for 12 hours, and then curing it at 100°C, 200°C, and 250°C for 2 hours.

[0047] Figure 3 This is a cross-sectional morphology of the self-repairing wear-resistant coating prepared in this embodiment. Figure 3 It can be seen that in the cross-sectional morphology of the self-repairing wear-resistant coating obtained on the substrate in this embodiment, Al(PO3)3 exists and fills the pores, and the coating has a self-repairing function.

[0048] Figure 4 The XRD patterns of the self-repairing wear-resistant coating prepared in this embodiment before and after the surface sealing treatment, where MA-AT40 represents the coating prepared by the plasma spraying process in step 2 of this embodiment, and ST-MA-AT40 represents the MA-AT40 coating after sealing. Figure 4 It can be seen that compared with the large amount of AlPO4 sealing agent existing on the surface after sealing, the self-healing coating before sealing has only a very small amount of AlPO4, and the powder coating and coating preparation effects are excellent.

[0049] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing raw material powder of self-repairing wear-resistant coating, characterized in that: The method comprises the following steps: Step 1, spray granulating Mo powder and AlPO4 powder to obtain Mo-AlPO4 powder; Step 2: The Mo-AlPO4 powder obtained in step 1 is mixed with the AT40 powder by ball milling to obtain a raw material powder.

2. The method for preparing raw material powder of self-repairing wear-resistant coating according to claim 1, characterized in that: The mass proportion of Mo powder in the Mo powder and AlPO4 powder in step 1 is 90% to 91%.

3. The method for preparing raw material powder of self-repairing wear-resistant coating according to claim 1, characterized in that: The mass ratio of the Mo-AlPO4 powder to the AT40 powder in step 2 is 10% to 15%.

4. A method for preparing a self-repairing wear-resistant coating using a raw material powder prepared by the method according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: Step 1: Pre-treat the substrate by sandblasting and degassing; Step 2: preheating the substrate after sandblasting and degassing pretreatment in step 1 by using a plasma spraying process, and preparing a coating by using raw material powder; Step three: perform surface sealing treatment and polishing on the coating prepared in step two to obtain a self-repairing wear-resistant coating on the substrate.

5. The method according to claim 4, characterized in that The parameters of the plasma spraying process described in step 2 are: spraying voltage 40V~50V, spraying current 700A~800A, main gas flow 80SCFH~100SCFH, scanning speed 700mm / s, pass spacing 1.5mm, spraying distance 100mm, auxiliary gas flow 3SCFH, and carrier gas flow 12SCFH.

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