High-corrosion-resistance normal-temperature curing coating for hub bearing and preparation method of high-corrosion-resistance normal-temperature curing coating

Abstract

The invention discloses a high-corrosion-resistance normal-temperature curing coating for a hub bearing and a preparation method of the high-corrosion-resistance normal-temperature curing coating. The high-corrosion-resistance normal-temperature curing coating comprises the following raw material components in parts by weight: 12-15 parts of zinc powder; 8-10 parts of aluminum powder; 1.5 to 2.5 parts of sodium benzoate; 2.5-5 parts of a sodium silicate solution; 2.5-5 parts of sodium nitrate; 0.5 to 1.5 parts of potassium hydroxide; 0.5 to 1.5 parts of ammonium bifluoride; and 60-65 parts of butanol. Butanol is used as a dispersing agent and a solvent, and inorganic components such as zinc powder, aluminum powder and a sodium silicate solution are mixed to obtain the coating which can be quickly attached and cured on the metal surface indoors or outdoors at normal temperature because the sodium silicate component cannot react with zinc and aluminum to generate chemical bonds and can also react with iron elements on the metal surface to generate chemical bonds; and under the cooperation of components such as ammonium bifluoride, the circulating corrosion performance is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface treatment of automobile parts and relates to a room temperature curing coating, and specifically to a highly corrosion-resistant room temperature curing coating and a preparation method thereof, which is applied to the corrosion protection of wheel hub bearing surfaces (and can also be applied to the surfaces of other automobile parts such as brake discs, bolts and springs). Background Art

[0002] Dacromet (DACROMET, also known as DACROMET, Dacromet, and Dikron) is named zinc-chromium coating in China. It is a new type of anti-corrosion coating with zinc powder, aluminum powder, chromic acid and deionized water as the main components. Dacromet is a new type of surface treatment technology. Compared with the traditional electroplating process, Dacromet is a "green electroplating"; its advantages are as follows: (1) Super corrosion resistance: The thickness of the Dacromet film layer is only 4-8μm, but its anti-rust effect is more than 7-10 times that of traditional electrogalvanizing, hot-dip galvanizing or paint coating. (2) No hydrogen embrittlement: Dacromet's treatment process determines that Dacromet has no hydrogen embrittlement phenomenon; (3) High heat resistance: Dacromet can resist high temperature corrosion, and the heat resistance temperature can reach more than 300℃; (4) Good bonding and re-coating performance: Dacromet coating has good bonding with the metal substrate and has strong adhesion with other additional coatings. The treated parts are easy to spray and color, and the bonding strength with organic coatings even exceeds that of phosphating films. However, the above-mentioned Dacromet needs to be cured at about 300°C, which greatly limits its use and requires the use of special equipment for thermal curing.

[0003] The Chinese invention patent with application number 20091002617971 discloses a water-based composite flaky zinc-aluminum heavy anticorrosion coating and its preparation method. The coating is a two-component coating, which is prepared by mixing two components, an organic-inorganic composite modified base material and a pigment, in a certain weight ratio. The components of the organic-inorganic composite base material are silica sol, potassium hydroxide, silicone-acrylic emulsion, pigment dispersant, film-forming aid, defoaming agent, and the rest is deionized water or distilled water; the components of the pigment are flaky zinc powder; flaky aluminum powder. The weight ratio of the organic-inorganic composite base material to the pigment is 5:1-2. The water-based composite flaky zinc-aluminum heavy anticorrosion coating does not contain chromium, can be self-cured at room temperature, has the beneficial effects of being green and environmentally friendly, low energy consumption, and can prepare thin and highly corrosion-resistant coatings, but its anti-cyclic corrosion performance still has room for improvement. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a high corrosion-resistant room-temperature curing coating for a wheel hub bearing.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a high corrosion-resistant room temperature curing coating for a wheel hub bearing, which comprises the following raw material components in parts by weight:

[0006]

[0007] Optimally, it also includes:

[0008] 1.5 to 2.5 parts of brightener.

[0009] Furthermore, it also includes:

[0010] 0.5-1.5 parts of sodium metabisulfite.

[0011] Furthermore, the brightener is a mixture of one or more selected from HAS-805, A28, A29, SN and JX-105.

[0012] Optimally, the zinc powder is flaky zinc powder with a mesh size of 350 to 450.

[0013] Optimally, the aluminum powder is flaky aluminum powder with a mesh size of 450 to 550.

[0014] Another object of the present invention is to provide a method for preparing the above-mentioned high corrosion-resistant room temperature curing coating for wheel hub bearings, comprising the following steps:

[0015] Add the formulated amount of zinc powder and aluminum powder to the formulated amount of butanol in sequence, and stir to disperse evenly; then add the formulated amount of sodium benzoate, sodium silicate solution and sodium nitrate, and stir evenly; then add the formulated amount of potassium hydroxide and ammonium bifluoride, and stir evenly.

[0016] Optimally, the brightener and / or the sodium pyrosulfite in a prescribed amount are also added and stirred evenly.

[0017] The high corrosion-resistant room-temperature curing coating for wheel hub bearings of the present invention uses butanol as a dispersant and solvent, and is mixed with inorganic components such as zinc powder, aluminum powder, and sodium silicate solution to achieve rapid adhesion and curing on a metal surface at room temperature indoors or outdoors. This is because the sodium silicate component can react with zinc and aluminum to form chemical bonds, but can also react with iron elements on the metal surface to form chemical bonds; and with the cooperation of components such as ammonium bifluoride, the cyclic corrosion performance is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a comparison chart of the use of high corrosion-resistant room temperature curing coatings for wheel hub bearings.

[0019] Figure 2 This is a cyclic corrosion test diagram of the high corrosion-resistant room temperature curing coating for the wheel hub bearing in Example 1. DETAILED DESCRIPTION

[0020] The high corrosion-resistant room-temperature curing coating for wheel hub bearings of the present invention comprises the following raw material components in parts by weight: 12-15 parts of zinc powder; 8-10 parts of aluminum powder; 1.5-2.5 parts of sodium benzoate; 2.5-5 parts of sodium silicate solution; 2.5-5 parts of sodium nitrate; 0.5-1.5 parts of potassium hydroxide; 0.5-1.5 parts of ammonium hydrogen fluoride; and 60-65 parts of butanol. Butanol is used as a dispersant and solvent, and inorganic components such as zinc powder, aluminum powder, and sodium silicate solution are mixed to obtain rapid adhesion and curing on the metal surface at room temperature indoors or outdoors. This is because the sodium silicate component can react with zinc and aluminum to form chemical bonds, and can also react with the iron element on the metal surface to form chemical bonds; and with the cooperation of components such as ammonium hydrogen fluoride, the cyclic corrosion performance is improved.

[0021] It also includes: 1.5-2.5 parts of brightener; the brightener is a mixture of one or more selected from HAS-805, A28, A29, SN and JX-105; to improve the brightening effect of the coating after curing. It also includes: 0.5-1.5 parts of sodium pyrosulfite to prevent oxidation of zinc powder and aluminum powder. The zinc powder is 350-450 mesh flaky zinc powder, and the aluminum powder is 450-550 mesh flaky aluminum powder, to ensure the covering effect of the coating, block corrosion factors and achieve local micro-battery corrosion protection.

[0022] The method for preparing the high corrosion-resistant room temperature curing coating for the wheel hub bearing comprises the following steps: adding the zinc powder and the aluminum powder in the formula amount to the butanol in sequence, stirring to disperse evenly; then adding the sodium benzoate, sodium silicate solution and sodium nitrate in the formula amount, stirring evenly; then adding the potassium hydroxide and ammonium bifluoride in the formula amount, stirring evenly. Preferably, the brightener and / or the sodium pyrosulfite in the formula amount are also added and stirred evenly.

[0023] The preferred embodiments of the present invention will be described in detail below.

[0024] Examples 1-3, Comparative Examples 1-2

[0025] Examples 1-3 and Comparative Examples 1-2 respectively provide a high corrosion-resistant room-temperature curing coating for a wheel hub bearing, and the raw material composition thereof is shown in Table 1 (the unit in the table is kg).

[0026] Table 1 Composition ratio of high corrosion resistant room temperature curing coating for wheel hub bearing in Examples 1-3 and Comparative Examples 1-2

[0027]

[0028]

[0029] Note: The zinc powder is commercially available 400-mesh flake zinc powder purchased from Yunnan Hongjing Kechuang Zinc Industry; the aluminum powder is commercially available 500-mesh flake aluminum powder, brand YB-224, purchased from Advanced Institute (Shenzhen) Technology Co., Ltd.; the sodium silicate solution is brand Vetec, purchased from Merck; the brightener is HAS-805.

[0030] The preparation method of the high corrosion-resistant room temperature curing coating for the above-mentioned wheel hub bearing is as follows: add the formulated amount of zinc powder and aluminum powder to the formulated amount of butanol in sequence, and stir to disperse evenly; then add the formulated amount of sodium benzoate, sodium silicate solution and sodium nitrate, and stir evenly; then add the formulated amount of potassium hydroxide and ammonium bifluoride, and stir evenly; also add the formulated amount of brightener and sodium metabisulfite, and stir evenly.

[0031] The coatings in Examples 1-3 and Comparative Examples 1-2 were sprayed on the surfaces of deoiled commercial wheel hub bearings (5 from the same batch), and cured at room temperature for 30 minutes to form a 10 μm thick coating, followed by a salt spray test and a cyclic corrosion test (tested according to SAEJ2334-2016). The salt spray resistance of the products using the coatings in Examples 1-3 and Comparative Examples 1-2 reached 1400h, 1300h, 1250h, 216h and NG (not satisfied), respectively; the number of cycles in the cyclic corrosion test was 15 times, 10 times, 5 times, NG (not satisfied), and NG (not satisfied), respectively (see some data) Figure 1 and Figure 2 ).

[0032] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A high corrosion resistant room temperature curing coating for a wheel hub bearing, characterized in that: It includes the following raw material components in parts by weight:

2. The high corrosion resistant room temperature curing coating for wheel hub bearing according to claim 1, characterized in that: It also includes: 1.5 to 2.5 parts of brightener.

3. The high corrosion resistant room temperature curing coating for wheel hub bearing according to claim 1 or 2, characterized in that: It also includes: 0.5-1.5 parts of sodium metabisulfite.

4. The high corrosion resistant room temperature curing coating for wheel hub bearing according to claim 2, characterized in that: The brightener is a mixture of one or more selected from HAS-805, A28, A29, SN and JX-105.

5. The high corrosion resistant room temperature curing coating for wheel hub bearing according to claim 1, characterized in that: The zinc powder is flaky zinc powder with a mesh size of 350 to 450.

6. The high corrosion resistant room temperature curing coating for wheel hub bearing according to claim 1, characterized in that: The aluminum powder is flaky aluminum powder with a mesh size of 450 to 550.

7. The method for preparing the high corrosion resistant room temperature curing coating for wheel hub bearings according to any one of claims 1 to 6, characterized in that: The following steps are involved: Add the formulated amount of zinc powder and aluminum powder to the formulated amount of butanol in sequence, and stir to disperse evenly; then add the formulated amount of sodium benzoate, sodium silicate solution and sodium nitrate, and stir evenly; then add the formulated amount of potassium hydroxide and ammonium bifluoride, and stir evenly.

8. The method for preparing the high corrosion-resistant room temperature curing coating for wheel hub bearing according to claim 7, characterized in that: Also add the brightener and / or the sodium pyrosulfite in the formula amount and stir evenly.

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