KR20120009422A - Chrome-free coating for substrate - Google Patents

Abstract

Mixtures or alloys that do not contain chromium, preferably synthetic wires, are disclosed on the substrate to form, for example, wear and corrosion resistant coatings utilizing thermal spraying techniques. The physical properties of the coatings are particularly suitable for high temperature, erosion-corrosion environments. The resulting coatings exhibit excellent hardness, toughness and good bonding properties. The composite wire comprises a metallic sheath and an inner core, forms a coating free of chromium and comprises, by weight, an amount of 60 to 90% of the base metal, comprising at least 2% of aluminum and / or silicon; To 10% titanium, 2 to 10% silicon, and 2 to 10% boron.

Description

CHROME-FREE COATING FOR SUBSTRATE}

The present invention relates to metal-coated composites free of chromium and to thermal spray wires for making them.

It is well known in the art that it is difficult not to use CHROME in metal coatings that provide high temperature corrosion resistance. Chromium is undesirable because it is harmful to humans and the environment during the coating process.

The present invention provides a metal coated composite that does not contain chromium and a thermal spray wire for producing it.

In one embodiment of the present invention, a composite of precursor materials for forming a metal coating free of chromium is provided. In another embodiment of the invention, the precursors are provided in the form of synthetic wires. In another embodiment of the present invention, a metal coating is provided that does not contain chromium such as may be fabricated from the wire.

Generally speaking, the chromium free metal coating precursors include base metal compositions, silicon compositions, titanium compositions, and boron compositions. The base metal construct is present in an amount of at least about 54% by weight. The base metal component comprises at least one base metal selected from the group consisting of iron, nickel, cobalt, lead, zinc, copper, tin and aluminum and is always alloyed aluminum based on the mass of the coating precursor. And / or at least approximately 1% by weight of silicone. The silicon, titanium and boron constituents are present in amounts of about 1% to about 15% by weight, respectively.

According to another embodiment of the present invention, the components may be provided as a composite wire. The composite wire typically comprises a metal sheath in the range of 70% to 95% by weight and an inner core in the range of about 5% to about 30% by weight. The metal sheath preferably comprises at least about 70 wt% of base metal and at least about 2 wt% of alloyed aluminum and / or silicon, which is easily rolled up and drawn into the sheath. In one embodiment of the invention the inner core is titanium in the range of about 15% to about 30%, silicon in the range of about 15% to about 35%, boron in the range of about 20% to about 50%, and 0% to 15% Ranges of carbons, preferably all in the form of particles.

The composite wire can use a thermal spray technique to produce a metal coating free of chromium of the present invention on a substrate. The chromium free coating composite is typically in bulk by weight, from about 60% to about 90% base metal, at least about 2% aluminum, about 2% to about 10% titanium, about 2% to about 10% silicon, and about 2% to about 10% boron. The coating has high temperature wear resistance and corrosion resistance.

The coating material of the present invention has high temperature wear resistance and corrosion resistance.

1 exemplarily shows a composite wire according to an embodiment of the present invention.

In the detailed description below, any and all percentages are by weight unless otherwise specified. The present invention is described as precursors for forming a chromium-free coating, the precursors being the preferred form for employing the precursors in the form of synthetic wires, the coating being produced by the wires.

Generally speaking, chromium free metal coating precursors include base metal constructs, silicon constructs, titanium constructs, and boron constructs in the form of alloys, mixtures or composites. The base metal construct is present in an amount of at least approximately 54% by weight. The base metal construct typically comprises at least one base metal selected from the group consisting of iron, nickel, cobalt, lead, zinc, copper, tin and aluminum, and is always alloyed based on the mass of the coating precursor. At least approximately 1% by weight of aluminum and / or silicon. The silicon, titanium and boron constituents are present in amounts of about 1% to about 15% by weight, respectively.

Typically, in the coating precursor which does not contain chromium, the base metal is present in an amount of at least approximately 68% by weight, and within which at least approximately 2 weights of aluminum and / or silicon alloy constituents are based on the mass of the coating precursor. Include in amounts of%. The silicon, titanium and boron are each present in amounts of approximately 2% to 10% by weight.

Preferably, in the coating precursor without chromium, the base metal constituent is present in an amount of at least approximately 76% by weight and is selected from at least one of iron, nickel, cobalt and aluminum. The base metal construct is a mixture or alloy, preferably an alloy, and always contains at least approximately 3% by weight of aluminum, based on the mass of the coating precursor. The silicon, titanium and boron are preferably present as the inner portion of the composite wire formed from the base metal construct, preferably in an amount in the form of particles, in an amount of preferably from about 4% to about 7%.

The coating of the present invention may be formed from synthetic wires, as described herein, which is accomplished by feeding the wires through a conventional arc spraying device. Typically, the composite wire 10 comprises a metal sheath 20 in the range of 70 to 95 weight percent and an inner core 30 in the range of about 5 to about 30 weight percent. In a preferred embodiment, the composite wire comprises a metal sheath in the range of about 75 to about 85 weight percent and an inner core in the range of about 15 to about 25 weight percent.

The metal sheath preferably comprises at least about 70% by weight of the base metal, and at least about 2% by weight of alloyed aluminum and / or silicon, which can be easily rolled out and drawn into the sheath. Aluminum can also be used exclusively as the base metal. In one embodiment of the invention the inner core is titanium in the range of about 15% to about 30%, silicon in the range of about 15% to about 35%, boron in the range of about 20% to about 50%, and 0% to 15% Ranges of carbons, preferably all in the form of particles, preferably in the form of a mixture of powders. The titanium, silicon, and boron may be present as a mixture of compounds containing additional elements.

The base metal is preferably a metal or alloy of a relatively soft element, for example at least one of nickel, iron or cobalt. Nickel is preferred, and most preferably the skin includes nickel and aluminum alloys. Exemplary materials include nickel in the range of about 70 to about 98% by weight, nickel and aluminum in the range of about 2 to about 30% by weight, preferably nickel in the range of about 85 to about 98% by weight, and about 2 Alloyed aluminum and / or silicon in the range of from about 15% by weight, most preferably nickel in the range of about 90 to about 97% by weight, and aluminum in the range of about 3 to about 10% by weight.

The inner core preferably has titanium in the range of about 20% to about 30%, silicon in the range of about 20% to about 30%, boron in the range of about 30% to about 40%, and carbon in the range of 0% to about 15%. It includes. The carbon is generally in the form of carbides and may be present if necessary in the inner core, but since it is not present in the coating composite, at least by an amount to characterize it, it contributes to the coating of the present invention. It is not considered to be a material. The titanium and silicon may be provided by an appropriate amount of TiSi source, for example a TiSi source in the range of about 50 to 60%, such as TiSiFe, a source such as boron and optional carbon, for example approximately 40 To about 50% by weight of B ₄ C, such as a mixture may be provided.

The inner core may also include additional materials. The additional materials include: carbides such as tungsten carbide, titanium carbide, vanadium carbide and the like; Oxides such as aluminum oxide, zirconium oxide and the like; And borides such as nickel borides, iron borides and the like. The inner core may also comprise additional metal powders, for example aluminum, nickel, or alloy powders, or synthetic powders such as tungsten carbide nickel. As an example, the inner core may comprise about 0.1 to about 10% molybdium, about 0.1 to about 10% tungsten, about 0.1 to about 10% neodymium, and about 0.1 to about 10% carbon. . In addition, metal or metal alloy powders may include magnesium, phosphorus, vanadium, manganese, iron, cobalt, nickel, copper, zirconium, niobium, molybdium, tantalum and / or tungsten, for example For example, it may be present in the range of about 0.1 to about 10%.

In addition, the core components listed above may be alloyed into the sheath, and when so treated, the components need not be present in the inner core or may be present in reduced amounts. For example, titanium, silicon and boron may be alloyed in an amount of about 2 to about 10 weight percent based on the weight of the composite wire in the sheath. In a similar manner, the aluminum component may be present in the inner core rather than in the shell.

The particle size of the inner core in powder form affects the physical properties of the applied coating. In general, the finer the powder particles, the more homogeneous the coating, and generally the better the wear and corrosion properties. However, purchase price and manufacturing pressure will limit the lowest particle size range.

The cored wires can be made in a conventional manner by placing a mixture for forming the inner core on a strip made of the metal shell, although it does not have to be a mixture. The strip can be drawn continuously through a plurality of wire drawing devices to form a sheath wire around the inner core. The final outer diameter of the cored wire will be determined according to the application in which it is used. In most applications, the final diameter of the cored wire is in the range of about 0.8 mm to about 6.4 mm. Conventional corded wire fabrication techniques are described in US Pat. Nos. 6,156,443 (Dallaire et al.) And 6,513,728 (Hughes et al.), All of which are described herein by reference.

In addition to the synthetic wires described above, a method for forming a wear resistant and corrosion resistant coating on a substrate is also provided. This method typically provides a composite wire having a sheath formed of a metal or alloy, and an inner core formed of a powder, and using the composite wire in conjunction with a thermal spraying technique to coat the substrate and form a molten metal coating. Include. The wire of the present invention is not weldable by conventional useful techniques, and a non-welding method must be used to form the molten coating.

The resulting chromium-free coating composite of molten metal is typically in bulk by weight, from about 60 to about 90% of the base metal, at least about 2% of aluminum, about 2 to about 10% Of titanium, from about 2 to about 10% silicon, and from about 2 to about 10% boron. The base metal is preferably selected from the group comprising at least one of nickel, iron and cobalt, most preferably nickel. The coating material may, if necessary, add additional components to, for example, about 0.1 to about 10% iron, about 0.1 to about 10% molybdium, about 0.1 to about 10% tungsten, and 0 to about 10% carbons. It may include additional components selected from the group consisting of.

The coatings according to the invention are specially designed for articles subject to wear and / or corrosion. Such articles include, for example, boiler tubes, hydraulic piston rods, pump casings, rollers used in the paper and steel industry, abrasion resistant plates, journals and shafts, and turbine blades and casings.

In one application, the coatings are designed to protect boiler tubes from waste associated with erosion and corrosion and are applied to the boiler tubes using conventional arc injectors. However, it will be appreciated from the description below that the coating can be applied to the boiler tubes via another heat spray device using wires as feed material. Arc spraying methods and apparatus are well described in the prior art, see, for example, US Pat. No. 6,156,443 to Dallaire et al .; No. 5,837,326 to Dallaire et al .; And EP 0 522 438 to Zurecki et al., Which documents are incorporated herein by reference.

Experiment example

Synthetic wire was formed according to the following composition.

16 wt% Core Material:

43 wt% B ₄ C (79 wt% B, 21 wt% C)

    57 wt% TiSiFe (44 wt% T1, 44 wt% Si, 10 wt% Fe, 2 wt% remaining)

Core Composition (Based on Element)

    34 wt% B

    9 wt% C

    25 wt% Ti

    25 wt% Si

    6 wt% Fe

    1% by weight rest

84% Sheath Material

    95 wt% Ni

    5 wt% Al

Composite Wire Composition (Elements)

    79.8 wt.% Ni

    4.1 wt% Si

    4.1 wt% Al

    1.2 wt% Fe

    0.7 wt% C

    6.1 wt% B

    3.8 wt.% Ti

Claims (19)

At least about 54 wt% of at least one base metal, at least about 1 wt% aluminum, selected from the group consisting of iron, nickel, cobalt, lead, zinc, copper, tin and aluminum,
About 1 wt% to about 15 wt% silicone,
About 1 wt% to about 15 wt% titanium and
A chromium-free metal coating precursor comprising a composite consisting of about 1 wt% to about 15 wt% boron. The composition of claim 1, wherein the base metal is always at least about 2 weights, and at least about 68 weight percent of at least one base metal selected from the group consisting of iron, nickel, cobalt, lead, zinc, copper, tin and aluminum. Comprises% alloyed aluminum and / or silicon,
About 2 wt% to about 10 wt% silicone,
About 2 wt% to about 10 wt% titanium and
A chromium-free coating precursor comprising a composite consisting of about 2 wt% to about 10 wt% boron. The method of claim 1, wherein the base metal comprises at least about 76% by weight of at least one base metal selected from the group consisting of iron, nickel, cobalt, and aluminum, wherein the base metal always comprises at least about 3% by weight of alloyed aluminum. ,
About 3 wt% to about 7 wt% silicone,
About 3 wt% to about 7 wt% titanium and
A chromium-free coating precursor comprising a composite consisting of about 3 wt% to about 7 wt% boron. The chromium-free coating precursor of claim 1 comprising a composite of nickel, iron and / or cobalt alloys with aluminum, and agglomerates of silicon, titanium and boron containing particles. In an amount by weight comprising from about 70% to about 90% by weight of at least one base metal selected from the group consisting of iron, nickel, cobalt, lead, zinc, copper, tin and aluminum, always at least about 2 weight Molten chromium-free metal comprising% aluminum, about 2 wt% to about 10 wt% titanium, about 2 wt% to about 10 wt% silicon, and about 2 wt% to about 10 wt% boron Coating material composition. The method of claim 5, wherein the aluminum in the range of about 2% to about 10% by weight
Molten chromium-free metal coating composition comprising a. 7. The metal coating composition of claim 6, wherein the at least one base metal is selected from the group consisting of nickel, iron and cobalt. 8. The method of claim 7, wherein the base metal comprises nickel and the composition additionally comprises about 0.1% to about 10% by weight of iron, about 0.1% to about 10% by weight of molybdium And at least one additional constituent selected from the group consisting of about 0.1% to about 10% by weight tungsten. A synthetic wire that is essentially free of chromium for forming a wear and corrosion resistant coating on a substrate,
A metal sheath in the range of about 70 to about 95 weight percent and an inner core of the particles in the range of about 5 to about 30 weight percent,
The metallic sheath comprises at least about 70% by weight of the base metal and at least about 2% by weight of alloyed aluminum and / or silicon,
And the inner core or particles
Titanium in the range from about 15% to about 30% by weight,
Silicone in the range of about 15% to about 35% by weight,
Boron in the range from about 20% to about 50% by weight, and
A composite wire comprising carbons in the range of 0% to about 15% by weight. The composite wire of claim 9, wherein the base metal comprises at least one of nickel, iron, and cobalt. 10. The composite wire of claim 9, wherein the sheath comprises an alloy of nickel and aluminum and / or silicon. 10. The composite wire of claim 9, wherein the sheath comprises nickel in the range of about 85% to about 98% by weight and alloyed aluminum and / or silicon in the range of about 2% to about 15% by weight. . The composite wire of claim 12, wherein the sheath comprises nickel in a range from about 90% to about 97% by weight, and alloyed aluminum in a range from about 3% to about 10% by weight. The method of claim 9, wherein the inner core is
Titanium in the range from about 20% to about 30% by weight,
Silicone in the range of about 20% to about 30% by weight,
Boron in the range from about 30% to about 40% by weight, and
A composite wire comprising carbon in the range of 0% to about 15% by weight. The composite wire of claim 14, wherein the inner core comprises a TiSi source in a range from about 50% to about 60% by weight, and a mixture of B ₄ C in a range from about 40% to about 50% by weight. . 10. A composite wire according to claim 9 comprising a metallic sheath in the range of about 80 to about 90 wt% and an inner core in the range of about 10 to about 20 wt%. The method of claim 9 further comprising molybdium in the range of about 0.1% to about 10% by weight, tungsten in the range of about 0.1% to about 10% by weight, and carbon in the range of about 0.1% to about 10% by weight. Composite wire, characterized in that. 10. A method of forming a wear resistant and corrosion resistant coating on a substrate, comprising providing a composite wire according to claim 9, and forming the coating using the wire. 19. The method of claim 18, wherein forming the coating using the wire comprises thermally spraying the wire onto the substrate.

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