KR101585446B1 - Slurry Composition and Method For Manufacturing Spray Coating Powder Using the Same - Google Patents

Abstract

The present invention relates to a slurry composition and a method for preparing a powder for spray coating using the slurry composition, and more particularly to a powder for coating comprising Fe powder and SiC or BN powder; A dispersing agent for dispersing the coating powders to each other; A binder for providing a bonding force between the powders for coating; Defoamers to remove air bubbles; And a dispersion solvent for preventing oxidation of the metal; The present invention relates to a slurry composition having improved friction reducing and abrasion resistance by setting optimal spray coating conditions for the powder, and a method for producing a powder for spray coating using the slurry composition.

Description

Technical Field [0001] The present invention relates to a slurry composition,

The present invention relates to a spray coating powder, and more particularly, to a slurry composition for a new spray coating powder capable of simultaneously improving friction reduction and abrasion resistance when spray coating is applied to a cylinder liner, and a method for producing a powder for spray coating using the same will be.

Spray coating is a cold coating technology that can be applied without thermal deformation to the base material. It is a cold coating technique that transports the coating material in the form of powder, wire or rod into a flame, electric arc, or plasma flame, Is a surface treatment technology for forming.

These spray coatings can be coated without any limitation on the material, size and shape of the base material such as paper, wood, stone, PVC, glass, concrete, etc., and there is no thermal deformation of the base material during coating. And is widely used because of its various advantages such as long thickness, easy control of coating thickness, and very fast coating speed.

In the case of automobile cylinder liners, it is important to contribute to the improvement of the fuel efficiency and durability of the engine by implementing the friction reduction between the cylinder liner and the piston moving system such as the piston ring and the skirt and the improvement of the abrasion resistance simultaneously.

Accordingly, the present inventors have completed a new slurry composition made of metal, ceramics and the like, a method for producing a powder for spray coating and a spray coating method for spray coating on a cylinder liner and the like.

It is an object of the present invention to provide a spray coating improved in friction reduction and wear resistance by preparing Fe-SiC or Fe-BN mixed powder for spray coating and setting optimal spray coating conditions for the powder thus prepared.

In order to achieve the above object, the present invention provides a slurry composition comprising: a powder for coating comprising Fe powder and SiC or BN powder; A dispersing agent for dispersing the coating powders to each other; A binder for providing a bonding force between the powders for coating; Defoamers to remove air bubbles; And a dispersion solvent for preventing oxidation of the metal; And a control unit.

The volume ratio of the Fe powder and the SiC or BN powder is preferably 60 to 80:20 to 40.

The coating powder is composed of Fe powder and SiC powder, and the volume ratio is preferably 80:20.

The dispersion solvent may be ethanol, and the volume ratio of the ethanol and the coating powder may be 70-90: 10-30.

The binder is preferably an emulsion type PVB (polyvinyl chloride) using ethanol.

Wherein the dispersant, the binder, the defoaming agent, and the dispersion solvent are nonaqueous.

According to another aspect of the present invention, there is provided a method for preparing a powder for spray coating, comprising the steps of: preparing the slurry composition; Aging the slurry composition; Drying the aged slurry composition to produce spherical granules; And heat-treating the spherical granules to produce a powder; . ≪ / RTI >

In this case, the step of preparing the spherical granules is preferably spray drying. In the step of preparing the powder, the spherical granules are put into a vacuum sintering furnace to prevent oxidation of the metal, .

The effect of the present invention having the above-described configuration can be applied to an automobile cylinder liner or the like, so that friction with the piston moving system can be reduced and the fuel consumption can be improved.

Further, it is excellent in wear resistance and can contribute to improvement of durability of a coating object.

In addition, the coating efficiency can be improved by using the existing coating process as it is.

FIGS. 1A and 1B are photographs of powders in which the Fe powder and the SiC powder are applied in a volume ratio of 60:40 in the step 1- (2).
FIGS. 2A and 2B are photographs of powders in which Fe powder and SiC powder are applied at a volume ratio of 80:20.
FIGS. 3A and 3B are photographs of a powder in which Fe powder and H-BN powder were applied at a volume ratio of 80:20.
FIGS. 4A and 4B are photographs showing coating structures applied with APS spray coating by applying Fe powder and SiC powder at a volume ratio of 8: 2. FIG.
5A and 5B are photographs showing a coating structure in which Fe powder and SiC powder are applied at a volume ratio of 8: 2 and HVOF spray coating is performed.
FIG. 6 is a graph showing a result of performing a friction test.
7 is a graph showing a result of a scuffing test.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In general, the process sequence for preparing the powder for spray coating consists of combining the slurry composition, milling, aging, spray drying, heat treatment and classification.

At the time of slurry composition combination, consideration is given to whether or not there is reaction between additives, whether viscosity can be controlled, whether the amount of additive suitable for spherical granules is derived, whether viscosity is suitable for spray drying, the uniform distribution of different powders, In consideration of physical properties such as particle size, viscosity, RPM and amount of powder, suitability of spray drying temperature, existence of hollow phase, binder burning phenomenon, etc., and heat treatment, selection of vacuum or inert atmosphere, Set the temperature considering the effect.

The present invention, in one aspect, relates to a slurry composition for making a spray coating powder. It is possible to improve the coating efficiency and to apply the existing coating process as it is by preparing the precursor powder in which SiC or BN powder is mixed with the Fe powder base.

Specifically, the slurry composition according to the present invention comprises a powder for coating consisting of Fe powder and SiC or BN powder; A dispersing agent for dispersing the coating powders to each other; A binder for providing a bonding force between the powders for coating; Defoamers to remove air bubbles; And a dispersion solvent for preventing oxidation of the metal; And a control unit.

In this case, it is preferable that the volume ratio of the Fe powder and the SiC or BN powder is 60 to 80:20 to 40 in consideration of the friction coefficient and the SO scuffing property.

In order to prevent the oxidation of metal, ethanol, which is a non-aqueous solvent, can be used as a dispersion solvent, and dispersants, defoaming agents and binders as additives are also used for non-aqueous systems.

The volume ratio of the ethanol and the coating powder is preferably 70 to 90: 10 to 30, and the binder is an emulsion type PVB (Poly Vinyl Burly) using ethanol.

In another aspect, the present invention relates to a method for producing a powder for spray coating.

Specifically, there is provided a method for producing a slurry composition, comprising the steps of: Aging the slurry composition; Drying the aged slurry composition to produce spherical granules; And heat-treating the spherical granules to produce a powder; And a control unit.

At this time, it is preferable to use spray drying as the step of producing the spherical granules, but it is more preferable to use an explosion-proof spray dryer because ethane is used as a dispersion solvent.

In addition, in the step of preparing the powder, it is preferable that the spherical granules are put into a vacuum sintering furnace and heat treatment is performed while nitrogen gas is introduced to prevent oxidation of the metal. Through this heat treatment, the bonding force between the particles is strengthened and the strength of the granules is formed and the additives are degreased.

The powder prepared by the above method can be spray-coated using a plasma spray process (APS).

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these examples are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

1. Preparation of slurry composition

(1) A 2 L polyethylene bottle was charged with a stainless steel Φ 3 mm ball into the bottle by 1 L volume.

(2) Fe powder and SiC powder were weighed to be 1 kg at a volume ratio of 60:40, and then injected into the bottle.

(3) Ethanol as a dispersion solvent was titrated so that the volume ratio of ethanol and powder was 80:20, and then injected into the bottle.

(4) The dispersant was weighed in an amount of 0.1 to 0.2% by weight based on the weight of the powder and injected into the bottle.

(5) The dispersion was homogenized by using a ball mill for 20 hours and the dispersant was adsorbed on the powder.

(6) PVB (Poly Vinyl Buryral) as a binder was weighed in an amount of 0.5% by weight based on the weight of the powder and injected into the bottle. At this time, it is preferable that the binder is put in an emulsion form using ethanol.

(7) The antifoaming agent was weighed in an amount of 0.05 to 0.1% by weight based on the weight of the powder and injected into the bottle.

(8) The binder was adsorbed on the particle surface using a ball mill for 2 hours.

(9) The ball milled slurry was filtered to remove aggregated particles.

(10) Aging was performed for 1 hour to remove bubbles from the filtered slurry and stabilize the slurry.

2. Powder preparation for spray coating

(1) The above aged slurry composition was pumped into a spray dryer. A rotary atomizer or two fluid type can be used as the spray dryer type, but an explosion-proof spray dryer of the rotary atomizer type is used in this embodiment.

(2) Spray drying conditions were atomizer rpm 10,000-150,000, spherical granules were prepared by spray drying while maintaining the inlet temperature at 120 ° C, the feed rate 10L / hr, and the outlet temperature 80 ° C.

(3) The spray-dried spherical granules were put into a vacuum sintering furnace.

(4) The inside of the vacuum sintering furnace was vacuum-treated by a pump and heat treatment was carried out at a temperature raising rate of 2 ° C./min, a temperature of 1,000 to 1,200 ° C., a dwelling time of 4 hours, and a descending rate of 2 ° C./min.

(5) The heat-treated powder was classified using a vibrating body.

3. Coating powder composition change

In the step 1- (2), the Fe powder and the SiC powder were weighed at a volume ratio of 60:40, the Fe powder and the H-BN powder were mixed at a volume ratio of 80:20, and then the process was repeated.

Examples of the processes for spray coating the spray coating powder prepared as described above include atmospheric plasma spraying (APS), high velocity flame spraying (HVOF), and the like.

Tables 1 and 2 below are tables showing the conditions of the two spray coating processes and the process results of each particle.

Condition APS Condition HVOF Powder size (μm) 45 ~ 106 Powder size (μm) 53 or less Input gas (positive / negative pressure) Ar: 120 / 4.8
He: 0 / 4.6 Amount of fuel 5 Voltage (V) 109 Oxygen amount 1500 Current (A) 405 Gun distance (mm) 380 Gun distance (mm) 130

Coating material
(Volume ratio) Coating method Coating base material Pre-treatment of base material Coating thickness Remarks Fe: SiC
= 60: 40 APS SCM415 Sandblast 300μm HVOF SCM415 Sandblast 300μm Not Coating Fe: SiC
= 80: 20 APS SCM415 Sandblast 300μm HVOF SCM415 Sandblast 300μm Fe: BN
= 80: 20 APS SCM415 Sandblast 300μm HVOF SCM415 Sandblast 300μm

FIGS. 1A and 1B are powder photographs of Fe powder and SiC powder in a volume ratio of 60:40 in the step 1- (2), FIGS. 2A and 2B are photographs of Fe powder and SiC powder at a volume ratio of 80:20 And FIGS. 3A and 3B are photographs of a powder in which the Fe powder and the H-BN powder are applied at a volume ratio of 80:20. As shown in the figure, it can be seen that the powder for spray coating produced by the present invention in powder size is more suitable for APS than HVOF.

FIGS. 4A and 4B are photographs showing a coating structure in which Fe powder and SiC powder were applied at a volume ratio of 8: 2, and APS spray coating was applied. FIGS. 5A and 5B show the results of HVOF spraying Fig. 6 is a photograph showing the coated structure subjected to the coating.

 As shown in the figure, when APS spray coating was performed, many pores were observed in comparison with the HVOF coating, and it was confirmed that the melting trace of SiC particles and SiC were relatively spherical (Crushed type in the case of HVOF).

FIG. 6 is a graph showing a result of performing a friction test, and FIG. 7 is a graph showing a result of a scuffing test.

(Friction test: 100 to 250 N, 5 Hz, normal temperature, touch contact; scuffing test: 100 to 400 N, 5 Hz, 150 캜, surface contact)

As shown, when the Fe to SiC volume ratio was 8: 2 and the APS method was applied, the friction coefficient was the lowest and the best scuff resistance was obtained.

While the present invention has been described with reference to exemplary embodiments and drawings, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And variations are possible. Accordingly, it is intended that the scope of the invention be defined by the claims appended hereto, and that all equivalent or equivalent variations thereof fall within the scope of the present invention.

Claims (10)

A powder for coating consisting of Fe powder and SiC or BN powder;
A dispersing agent for dispersing the coating powders to each other;
A binder for providing a bonding force between the powders for coating;
Defoamers to remove air bubbles; And
And a dispersion solvent for preventing oxidation of the metal,
Wherein the Fe powder and the SiC or BN powder have a volume ratio of 70 to 80: 20 to 30, respectively.
delete The method according to claim 1,
Wherein the coating powder comprises Fe powder and SiC powder and has a volume ratio of 80:20.
The method according to claim 1,
Wherein the dispersion solvent is ethanol.
5. The method of claim 4,
Wherein the volume ratio of the ethanol and the coating powder is 70-90: 10-30.
6. The method of claim 5,
Wherein the binder is an emulsion type PVB (Poly Vinyl Buryral) using ethanol.
The method according to claim 1,
Wherein the dispersant, the binder, the defoaming agent, and the dispersion solvent are nonaqueous.
8. A method of making a slurry composition, comprising: preparing a slurry composition of any one of claims 1 and 3 to 7;
Aging the slurry composition;
Drying the aged slurry composition to produce spherical granules; And
Heat-treating the spherical granules to produce a powder; ≪ RTI ID = 0.0 > 1, < / RTI >
9. The method of claim 8,
Wherein the step of preparing the spherical granules comprises spray drying.
10. The method of claim 9,
Wherein the step of preparing the powder comprises the step of placing the spherical granules in a vacuum sintering furnace to prevent oxidation of the metal, and then heat-treating the mixture while injecting nitrogen gas.

Images