JPH0347999A - Support metal having improved surface mor- phology - Google Patents

Abstract

A metal surface is now described having enhanced adhesion of subsequently applied coatings. The substrate metal of the article, such as a valve metal as represented by titanium, is provided with a highly desirable surface characteristic for subsequent coating application. This can be initiated by selection of a metal of desirable metallurgy and heat history, including prior heat treatment to provide surface grain boundaries which may be most readily etched. In subsequent etching operation, the surface is made to exhibit well defined, three dimensional grains with deep grain boundaries. Subsequently applied coatings, by penetrating into the etched intergranular valleys, are desirably locked onto the metal substrate surface and provide enhanced lifetime even in rugged commercial environments.

Description

DETAILED DESCRIPTION OF THE INVENTION 2. BACKGROUND OF THE INVENTION The adhesion of coatings applied directly to the surface of a support metal is particularly important when the coated metal is used in harsh industrial environments. Careful attention is usually paid to surface preparation and pretreatment operations prior to coating. In particular, achieving a clean surface is a priority during such treatment or pretreatment operations.

A typical example of a coating applied directly to a base metal is an electrocatalytic coating, which often contains noble metals of the platinum group, and is applied directly onto a metal such as valve metal. In this area of technology of electrocatalytic coatings applied to base metals, the metal is simply cleaned to give a very smooth surface.

U.S. Patent No. 4.797.182. Treatment with fluorine compounds provides a smooth surface. U.S. Patent No. 3,864.
No. 163. Cleaning may include chemical degreasing, electrolytic degreasing, or treatment with oxidizing acids. US Patent No. 3
, No. 864, 163.

Cleaning can be followed by mechanical roughening to prepare the surface for coating. U.S. Patent No. 3.778307.

If the mechanical treatment is sandblasting, this can be followed by etching. U.S. Patent Nos. 3 and 8
No. 78,083. Alternatively, a rough surface for coating can be prepared by pickling with a non-oxidizing acid. U.S. Patent No. 3,864,163. Such pickling can be followed by degreasing. U.S. Reissued Patent No. 28,820. By pickling, titanium is reduced to approximately 3.8 to 5.1 tt m (
It is easily etched to a surface roughness of 150-200 microinches). ``Titanium Hayfield as a support for electrodes.

P, C, S,), IMI Re5search and
Development Report.

If there is a pre-existing coating on the support metal, the metal can be treated to remove the coating.

For electrocatalytic coatings, this type of treatment uses a melt containing a basic substance in the presence of an oxidant or oxygen. This is followed by pickling to restore the original surface for coating.

U.S. Patent No. 3.573.100. Alternatively, when using a molten alkali metal hydroxide containing an alkali metal hydride, it is preferable to perform a hot mineral acid treatment subsequently. U.S. Patent No. 3,706,600. It has also been proposed to prepare the surface without stripping off the old coating. U.S. Patent No. 3.684.543. More recently, this method has been improved by activating the old coating before applying the new coating. U.S. Patent No. 4,446°245.

Another method for adhering the new coating to the support, which has been found to be useful in applying electrocatalytic coatings to valve metal, is to form a porous oxide layer on the base metal. It is something to do.

However, it is difficult to provide long-life coated metal articles useful in today's commercial oxygen generating anodes employed in extremely harsh commercial environments, such as electroplating, electrotin plating, electroforming or electrowinning. I found out something. That is, this is a continuous operation. May involve harsh conditions including potential surface damage. It would be highly desirable to provide a coating 5 metal-based support that could be used as an electrode in such operations and exhibit long-term stable operation while retaining excellent film adhesion. It would also be highly desirable to provide electrodes of this type not only from fresh metal, but also from recoated metal.

SUMMARY OF THE INVENTION A metal surface has been discovered that provides an excellent adherent coating with excellent coating adhesion. This coated metal-based support has a very desirable long life, even in extremely harsh industrial environments. For electrocatalytic coatings, the present invention provides support metal grains that give lower effective current densities and are stabilized in a state favorable for passivation.
ins).

- In one aspect, the present invention provides a metal article with a surface compatible with improved coating adhesion, wherein the surface retains a desirable surface grain size without being subjected to the deleterious effects of an abrasive treatment; deep grain B
The surface is etched, including the etching of impurities located at the grain boundaries of the metal surface, and this intergranular etching results in an average surface roughness of at least about 6.5 mm as measured by a profilometer. 4 μm (2
50 microinches) and average surface peak count of at least about 167 cm (40/inch) - profilometer - threshold upper limit of about 10.2 μm (400 microinches) and profilometer - threshold upper limit of about 7.6 #m (
300 microinches) for the given article.

In another aspect, the present invention provides a method for preparing an impure valve metal surface for improving coating adhesion thereon, including at least a substantially continuous interparticle obtuse network - an impurity containing impurity on the surface of the metal. for a period sufficient to provide 1. surface annealing at elevated temperatures;
The resulting annealed surface is cooled; and the surface is intergranularly etched with a strong acid or caustic etchant at elevated temperatures; The aim is to maintain a state of being free from negative effects.

In yet another aspect, °ζ is a metal article having a surface suitable for improving adhesion of a coating (=J), wherein the surface has an average surface roughness of at least about 6.4 μm (250 μm) as measured by a profilometer. microinch) and average surface peak number of at least about 16/cm (40
/inch) - is intended for articles having a dark value of 1 relative to the lower and upper dark limits listed above. This surface most preferably has a maximum peak to maximum valley distance of at least about 25
．． 4 μm (1,000 microinches) and an average peak height of at least about 25.4 μm (1,000 microinches).

Continuous electrogalvanizing (e.g.
Even in harsh commercial operations, including electrogalvanizing, electroplating, electroforming or electrowinning, this type of electrode has a highly desirable service life. This type of metal also provides an effective low current density as an electrode, which helps to extend the life of the electrode when used in the above-mentioned applications or as an electrode for water or seawater, for example.

DESCRIPTION OF PREFERRED EMBODIMENTS The metal of the support is broadly considered to be any coatable metal. For a particular electrocatalytic coating, the support metal may be, for example, nickel or manganese (but most often valve metals, including titanium, tantalum, aluminum, zirconium, and niobium). and of particular importance with respect to effectiveness is titanium.Besides the commonly available metallic elements themselves, metals suitable as supports include alloys and metal mixtures; for example, titanium is combined with nickel, cobalt, iron, It can also be alloyed with manganese or copper.More specifically grade 5 titanium is 6
．． up to 75% aluminum and up to 4.5% vanadium, grade 6 up to 6% aluminum and 3% tin, grade 7 up to 0.25% palladium; Grade 10 contains up to 10-13% molybdenum and 4.5-
It will contain up to 7.5% by weight of zirconium, etc.

By metallic elements, alloys and metallic mixtures are meant, in particular, metals in the state in which they are normally obtained, ie containing small amounts of impurities. Therefore, for a particular metal, such as titanium, various grades of the metal can be obtained, including those in which the other components are alloys or alloys plus impurities. In the case of titanium, iron is a common impurity. Its maximum concentration is 0.2% by weight for grades 1 and 11
It can be expected to range from 0.5% for grades 4 and 6.

Other impurities found throughout various grades of titanium include nitrogen, carbon, hydrogen and oxygen.

Since the β-titanium located at the titanium grain boundaries is susceptible to etching, the β-titanium is considered an impurity in the grain for the purposes of this discussion. Therefore, the etching of impurities discussed herein may also include etching of certain phases of the metal itself. The very specific metal titanium of beta-titanium may contain beta-titanium stabilizers, some of which are present in very small amounts as impurities, including vanadium, niobium, tantalum, molybdenum, ruthenium, Includes zirconium, tin, hafnium and mixtures thereof. The grades of titanium are described in more detail in the standard specification relating to titanium detailed in STM R265-7.

Regardless of the metal chosen and the mode of subsequent metal surface treatment, it is advantageous for the support metal to have a clean surface. This can be achieved by any treatment method employed to obtain a clean metal surface, although mechanical cleaning is generally minimized and preferably avoided unless required to remove old coatings. . It is therefore advantageous to employ conventional chemical or electrolytic fat cleaning methods or other chemical cleaning operations.

If an old coating is present on the metal surface, this will need to be addressed before recoating. If the final product is to be used with an electrocatalytic coating, for example as an oxygen generating electrode, it is preferable to remove the old coating for maximum performance. Chemical means for removing coatings are well known in the art of this invention relating to electrochemically active coatings on valve metals. For example, as taught in U.S. Pat. No. 3,513,100, applying a melt of an essentially basic material followed by an initial pickling process properly restores the metal surface. There will be. Alternatively, as described in US Pat. No. 3,706,600, it is also useful to treat with a melt of an alkali metal hydroxide containing an alkali metal hydride followed by treatment with a mineral acid.

Once a cleaned surface, or preferably a prepared and cleaned surface, is obtained, in the practice of the present invention, etching G is used to roughen the surface, especially when applying an electrocatalytic coating to valve metal. Gaining is considered. In the etching concept of the present invention, it is important to aggressively etch the metal surface to present deep grain boundaries that provide well-exposed three-dimensional grains. It is preferable that impurities located at these grain boundaries be etched by this operation. Convenience h. Processing metals containing etchable grain boundary impurities to ensure proper “metallicity”
However, in addition to or in conjunction with the roughness achieved by etching, other roughening methods are also considered, such as valve metal or valve metal oxide-valve metal suboxide. (suhoxid
Roughness can also be obtained by spraying one or more of e) onto the metal surface. The details of how these properties were measured using a profilometer will be described below. When selecting an etching method to obtain surface roughness, an important aspect of the present invention is to enhance the metal impurities at the grain boundaries. Accompany. It is advantageous to do this at an early stage of the entire metal preparation process. One method of this enhancement that is considered is to induce or introduce one or more impurities to the metal into the grain boundaries. For example, in the most typical metal titanium, this metal impurity includes iron, nitrogen, carbon, hydrogen, oxygen and β.
Contains titanium. While possible impurity introduction methods include surface precipitation, e.g. vapor deposition, followed by heat treatment for diffusion of surface impurities, a method of particular consideration for impurity enhancement is to subject the titanium metal to a hydrogen-containing treatment. This is accomplished in part by exposing the metal to a hydrogen atmosphere at elevated temperatures. Alternatively, hydrogen treatment can be carried out electrochemically using the metal as a cathode in a suitable electrolyte that generates hydrogen.

Another aspect of the present invention involving etching, according to which grain boundary impurities can be enhanced, involves the heat treatment history of the metal. For example, to prepare metals such as (-tan) for etching, it is very useful to condition the metal, e.g. by annealing, to diffuse impurities into the grain boundaries.
1. Properly annealing the titanium. Then, the concentration of iron impurities in the grains will increase. If a suitable preparation method includes annealing 1, and the metal is grade 1 titanium, the titanium can be annealed at a temperature of at least about 500° C. for at least about 15 minutes. For efficiency of operation, higher annealing temperatures, e.g.
~800°C is advantageous. Annealing times at these higher temperatures will generally be on the order of 15 minutes to 4 hours. or short-term high temperature annealing, e.g. 800
℃ for several minutes, for example 5 to 10 minutes, and then quenched or slowly cooled for several hours (generally 10 to 20 hours) at a very low temperature (200 to 400'(': is common). Suitable conditions include annealing in air or under vacuum or with an inert gas, such as argon.The annealed metal can then be cooled to The grain boundaries are stabilized to a state suitable for etching. Stabilization can be accomplished by controlled or rapid cooling of the metal, or by other conventional methods of cooling metals, including quenching. H. Metals stabilized in this way are referred to as metals with a desirable thermal history. From the etching perspective of the present invention, in order to increase the adhesion of the film, it is necessary to use an appropriate amount of steam. S2, which combines a metal surface with grain boundary metallicity and advantageous grain size, is desirable.

Again, referring to titanium as an example and L7, at least a substantial amount of the grains have a grain size of about 3 to about 7'! is advantageous. The grain size (grain 5tze) described in , °2,'2 is /IsTM I'! 1
This is based on the display shown in No. 12-84. A 1,000 tan grain size less than about 3,000 produces a high proportion of broad grains and J
This impairs the advantageous film adhesion. Preferably, for titanium, the grains will have a grain size of about 4 to about 6, as grain sizes greater than about 7 are undesirable for optimal three-dimensional grain structure development.

The above operations, such as cleaning, or coating removal and cleaning, and 6. Dual purpose zuzugi and drying process,
and 'After impurity enhancement for any subsequent grain boundary etching, the metal surface is in a condition suitable for subsequent operations. If this is an etching, then this is an aggressive etching
This is done using an etching solution with sufficient activity to cause C grain boundary attack.

- Etching liquid and L acid solution are available. These are hydrochloric acid, sulfuric acid, perchloric acid, nitric acid, silicic acid, tartaric acid and phosphoric acid; and mixtures thereof, such as aqua regia. Other gill-thinning agents that may be used include caustic
? Included are alkali-based etching agents, such as a combination potassium hydroxide/hydrogen peroxide solution, or a potassium hydroxide melt containing potassium nitrate. For operational efficiency. Etching solutions are strong or concentrated solutions, such as hydrochloric acid
The solution in the container, which is advantageously a 8-22% solution by weight, is etched at an elevated temperature, e.g. , or more, 11 being held in continuous flow is advantageous.

Etching. The etched metal surface is subjected to a grinding and drying process to prepare the surface for overlaying.

1. Relates to the method adopted to achieve the desired surface roughness. If 'c <, l, -, no matter whether plasma melting η・1 or interparticle etching is used, the average surface roughness (Ra) of the metal surface is at least about 6.41 t m.
I'! 50 microinch) and an average surface peak number (Nr) of at least about 16/CTrl (40/inch)
There is a need for two things. Surface peak numbers are generally measured at a lower threshold of about 1.6 pm (300 microinches) and a lower threshold of about 111-211-27 microinches. Average surface roughness approximately 6.4 tt
Surfaces less than 250 microinches are undesirably difficult to obtain the required substantially enhanced coating adhesion, as are surfaces less than 16/c+n (AO/intertaft) in average surface peak number. It will be smooth. Advantageously, the surface is about 6.4 μm (250 microinches) or more, such as about 19.1-38.1 μm (7
It has an average surface roughness on the order of 50 to 1500 microinches) and contains no low spots below about 5.1 micrometers (200 microinches). Advantageously, in the best conditions to avoid surface smoothness, the surface is about 5.3-5.6 μm (
Contains no spots as low as 210-220 microinches. The surface is approximately 7.6-12.7 μl11 (approximately 30
It is preferred to have an average surface roughness of from 0 to about 500 microinches. Advantageously, the surface has an average peak count of at least about 24/cm (60/in), although this may range up to 51/[phase] (130/in) or more, with an average of about 31 to about 47/in. (about 80 to about 120/inch) is preferred. Furthermore, the surface has an average distance between the largest peak and the largest valley (Rz) of at least about 25.4 μm (1,
000 microinches) and the maximum peak height (Rm
) advantageously exhibit at least about 25.4 μm (1,000 phycroinches). All of the above surface properties were measured using a profilometer. More desirably the coating surface has an Rm value of at least about 3.
8.1 to about 88.9 μm (about 1,500 to about 3,50
0 microinch) and a maximum valley characteristic of at least about 38.1 to about 88.9 μl11 (about 1,500 to about 3
500 microinches).

A typical example of an electrochemically active coating that is subsequently applied to an etched metal surface is platinum or other platinum group metal.
ζ or they are represented by active oxide coatings such as platinum group metal oxides, magnetite, ferrite, cobalt spinel, or mixed metal oxide coatings.

These coatings were generally developed for use as anode coatings in the electrochemical industry. These may be aqueous or solvent-based, for example using alcoholic solvents. Suitable coatings of this type are commonly found in U.S. Pat. No. 3,265,52
6.3,632,498.3,711,385 and 4
, 528,084. Mixed metal oxide coatings often contain at least one valve metal oxide, as well as platinum, valadiram, rhodium,
Contains oxides of platinum group metals, including iridium and ruthenium, or on their own and in mixtures with other metals. In addition to those listed below, the coating may further include manganese dioxide, lead dioxide, platinate coatings such as MxPt3.
(where M is an alkali metal and X is generally targeted to be about 0.5), nickel-nickel oxide, and nickel decalanthanide oxide.

The coating is applied to the metal by any convenient method for applying a liquid coating composition to a support metal.

These methods include dip spin and dip drain methods, brushing, roller coating, and spray coating, such as electrostatic spraying. Furthermore, a combination method of spraying, such as an immersion drain method with spraying, is also used. For the above coating compositions to obtain electrochemically active coatings, a modified dip-drain operation is very effective. After performing any of the coating methods described in Section F, upon removal from the liquid coating composition, the coated metal surface may be simply dip-drained or subjected to other post-coating treatments, such as forced air drying.

Typical curing conditions for electrocatalytic coatings include about 300 to about 60
A curing temperature of 0°C is included. Curing times range from just a few minutes to over an hour for each coating layer, with longer curing times required after several coatings have been applied, for example. However, the hardening process overlaps with the annealing conditions of elevated temperatures and prolonged exposure to these elevated temperatures.
Generally avoided due to economics of operation. General The curing method used may be any method that can be employed to cure a coating on a metal support. For example, oven curing may be utilized, including conveyor ovens.

Additionally, infrared curing methods are also useful. A very economical curing method uses oven curing, and the curing temperature used for electrocatalytic coatings will be from about 450 to about 550<0>C. At this temperature, curing time is only a few minutes; for example, in most cases about 3 to 10 minutes will be used for each layer of coating applied.

The following examples illustrate embodiments of the invention and are also comparative. However, the embodiments of the present invention should not be construed as limiting the invention.

Example 1 Dimensions approximately 5.1. CTII x 15.2cm x 1.
A titanium plate was used that was 2 in. x 6 in. This titanium sheet therefore contained up to 0.20% iron impurities.

The plates, which were fresh grade T titanium plates, were degreased in tetrachloroethylene vapor, rinsed with deionized water, and air dried. This was then etched for about 1 hour by immersing it in a 20% by weight aqueous hydrochloric acid solution heated to 95 TJ. After removal from the hot hydrochloric acid, the plates were rinsed again with deionized water and air dried. Due to this etching number, the plate has a surface area of 500 to 6
A weight loss of 0.00 g occurred.

This loss is determined by weighing the plate sample before and after etching and then calculating the loss per hole by direct calculation based on the large biplanar surface area of the plate.

The surface roughness of the sample plate on both wide sides was then examined in this test under a stereomicroscope at various magnifications from 40x to 60x. It was observed that the plate surface had clear three-dimensional grain boundary etching.

The etched surface was then subjected to surface profilometer measurements using a Hommel Model T 1000 C instrument manufactured by Hommel Werck. Plate surface profilometer measurements are average values calculated from eight separate measurements taken by running the instrument in random directions over a large plane of the plate. As a result, the surface roughness (Ra) is approximately 10, Op rn (393 microinches), the number of peaks (Nr) is approximately 34/cm (86/inch), and the average distance between the maximum peak and maximum valley (Rz) is approximately 53.4 μm. (2104 microinches). The number of peaks was measured within a lower threshold of about 300 microinches and an upper threshold of 400 microinches.

Comparative Example 1 A titanium plate sample of unalloyed grade I titanium, but from a different hatch than the plate sample of Example 1, was etched under the same conditions as Example 1. Visually, the etched surface of the titanium plate sample obtained was observed using the method of Example 1 and was found to contain no obvious grain boundary etching. Subsequent profilometer measurements made in the manner of Example 1 averaged approximately 4.0 μm (157 microinches) (Ra), approximately 12/cm (31/in> (Nr)), and approximately 23.6 μm (931 microinches). inch) (Rz). This plate sample was not a comparative sample due to the absence of distinct grains as determined visually and the absence of distinct three-dimensional grain boundary etching as determined by profilometer. Ta.

Example 2 A second sample from the same batch of unalloyed titanium used for the plate sample of Comparative Example 1 was subjected to an annealing operation. In this operation, the sample is placed in an oven and the temperature is 70°C.
The oven was heated until it reached 0°C. This temperature was then held for 15 minutes, cooled to 450°C and held for 30 minutes. The oven temperature was then cooled to approximately 200° C. over a period of 1.5 hours while the sample was kept in the oven. The sample was then removed to cool to room temperature.

The resulting test sample was then boiled in 18% HC.
It was etched for one hour in 1 hour and then dried as described in Example 1. Upon visual inspection using the method of Example 1, the etched sample plate was found to contain highly desirable three-dimensional grain boundary etching. This was confirmed by profilometer measurements, which yielded average values of approximately 10.1 μm (398 microinches) (Ra), approximately 30/cm' (76/inch) (Nr), and approximately 51, F1 μm (20
40 microinches) (Rz) was obtained.

Example 3 A grade 1 titanium plate sample prepared by the method of Example 1 and containing a highly desirable three-dimensional well-defined grain boundary etch similar to that described in Example 1 was subjected to electroplating of titanium oxide and iridium oxide. A chemically active coating was applied with an acidic aqueous solution of chloride salts. The coating is U.S. Patent No. 4,
It was applied and baked in the manner described in Example I of No. 797,1.82.

5 The obtained sample was mixed with 285 g of sodium sulfate/1. and sulfuric acid mag screw? The electrolyte solution is a mixture of 60g/ff. I tested this as a node. The test chamber was maintained at 65°C and the current density was 15 to 8/rT? was operated on. Habo-Weekly T4 knee electrolysis was briefly interrupted 1-7? The coated titanium plate anode was removed from the electrolyte, rinsed in deionized water, air dried, and then cooled to ambient temperature.

Then, each time a piece of the adhesive pressure-sensitive tape was pressed firmly against the coating 1- by hand, the tape was quickly pulled from the plate and removed from the surface. After 3000 hours of operation, including approximately 18 tape tests, one coated annot still showed excellent coating adhesion to the underlying titanium-based support. Ta.

Comparative Example 2 A 1f~tan sample coated with a pre-coated electrochemically active film was prepared. I plasted it with Lumi+ powder and removed the previous coating. After polishing method 1', it was determined by X-ray fluorescence that the coating at the tip had been removed.

Remove polishing residue 1. Then, the obtained sample prolate was etched in the composition of Example 1 by the force method of Example 10. Example 1L The visual inspection described below,
It was observed that the desired grain boundary etching was not demonstrated. Furthermore, under profilometer measurement (the average value obtained was approximately 3.571 m (L37 microinches) (Ra
) approx. 5/cml: 12/in 1,000) (Nr) and approx. 21. I II m (841 microinches) (R2
) There is F.

It was recognized that

Nevertheless, samples of J- were coated with the electrocatalytic coating of Example 3 by the method described in Example 3. Used as a notebook.

After 91 hours of operation, samples were removed and the coatings were tested for adhesion using the tape test method of Example 3. 1-,',
After only 91 hours of testing, the tape peeled off most of the coating, exposing the underlying support, and further testing was discontinued.

(3 other people)

Claims (59)

[Claims] 1. A metal article with a surface compatible with improved coating adhesion, wherein the surface possesses a desirable surface grain size without being subjected to the deleterious effects of abrasive treatments, and where the surface is three-dimensionally crystalline with deep grain boundaries. the surface is etched including etching of impurities located at the grain boundaries of the metal surface, and this interparticle etching results in an average surface roughness of at least about 6.4 μm as measured by a profilometer.
(250 microinches) and average surface peak number of at least about 16/cm (40/inch) - profilometer threshold upper limit of about 10.2 μm (400 microinches)
and profilometer threshold lower limit approximately 7.6 μm (30
Articles given - based on 0 microinches). 2. The metals of the article are titanium, tantalum, niobium, aluminum, zirconium, manganese and nickel;
The article of claim 1 selected from the group consisting of alloys and intermetallic mixtures. 3. 3. The article of claim 2, wherein the metal is unalloyed titanium. 4. The article of claim 1, wherein the metal article comprises an oxygen generating anode. 5. 2. The article of claim 1, wherein the metal article comprises an electrode other than an oxygen generating anode. 6. 2. The article of claim 1, wherein the metal surface comprises at least substantially all grains having a grain size of about 3 to about 7. 7. 4. The article of claim 3, wherein the titanium surface includes interparticle impurities selected from the group consisting of iron, nitrogen, carbon, hydrogen, beta-titanium, beta-phase stabilizers, and mixtures thereof before etching. 8. Etching attacks at least a substantially continuous interparticle impurity network. The article according to claim 1. 9. 2. The article of claim 1, wherein the etching is an interparticle etching with elevated temperature strong acid or strong caustic. 10. 10. The article of claim 9, wherein the elevated temperature etching is performed using an aqueous etching solution maintained at an elevated temperature of at least about 80<0>C. 11. the strong acid is selected from the group consisting of hydrochloric acid, sulfuric acid, perchloric acid, oxalic acid and phosphoric acid and mixtures thereof;
The article according to claim 9. 12. Strong caustic alkali is potassium hydroxide/hydrogen peroxide,
and a potassium hydroxide/potassium nitrate mixture. 13. The surface has an average surface roughness of at least about 6.4 μm (250 microinches) as measured by a profilometer.
2. The article of claim 1, wherein the article has no low spots of less than about 200 microinches. 14. The surface has an average surface peak number measured by a profilometer of at least 24/cm (60/inch) based on an upper threshold of about 400 microinches (10.2 μm) and a lower threshold of about 300 microinches (7.6 μm). , the article of claim 1. 15. The surface has an average distance of at least about 25.4 μm between the maximum peak and maximum valley measured by a profilometer.
1,000 microinches). 16. The surface has an average distance of about 38.1 to about 88.9 μm between the maximum peak and maximum valley measured by a profilometer.
2. The article of claim 1, having a diameter of about 1,500 to about 3,500 microinches. 17. 2. The article of claim 1, wherein the surface has an average peak height of at least about 1,000 microinches as measured by a profilometer. 18. The surface has an average peak height of at least about 38.1 to about 88.9 μm (about 1.5 μm) as measured by a profilometer.
00 to about 3,500 microinches). 19. The article is annealed at an elevated temperature for a period sufficient to provide at least a substantially continuous interparticle impurity network including impurities at the surface of the interparticle network prior to etching. and is allowed to cool in a controlled manner after annealing at this elevated temperature.
The article according to claim 1. 20. The metal is unalloyed titanium annealed in one or more of air, vacuum, or an inert gas, and the temperature reached during the annealing is at least about 500 m
20. The article of claim 19, wherein the temperature is <0>C. 21. Claim 19, wherein the controlled cooling includes quenching.
Articles listed in . 22. 20. The article of claim 19, wherein the titanium is annealed for at least 15 minutes. 23. 2. The article of claim 1, wherein the surface is coated. 24. 24. The article of claim 23, wherein the coated surface has an electrochemically active surface coating comprising a platinum group metal or metal oxide or mixtures thereof. 25. 25. The article of claim 24, wherein the electrochemically active surface coating contains at least one oxide selected from the group consisting of platinum group metal oxides, magnetite, ferrite, and cobalt spinel. 26. 25. The article of claim 24, wherein the electrochemically active surface coating contains a mixed crystal material of at least one valve metal oxide and at least one platinum group metal oxide. 27. 24. The article of claim 23, wherein the coated surface has a coating containing one or more of manganese dioxide, lead dioxide, platinate, nickel-nickel oxide, and nickel plus lanthanide oxides. 28. The article of claim 1, wherein the article is an anode in an electrogalvanizing bath. 29. In a method of conditioning a surface of an impure metal to improve film adhesion on the surface; the resulting annealed surface is cooled; and the surface is interparticle etched with a strong acid or strong caustic etchant at elevated temperature; a method comprising: maintaining said surface at least substantially free from the deleterious effects of mechanical surface treatments. 30. 30. The method of claim 29, wherein the metal is titanium and the annealing is carried out in one or more of air, vacuum, or an inert gas at a temperature reached during annealing of at least about 500<0>C. 31. 30. The method of claim 29, wherein cooling comprises quenching. 32. Claim 2, wherein the etching attacks at least a substantially continuous interparticle network of diffused impurities.
9. 33. 30. The method of claim 29, wherein the surface is coated after etching. 34. a surface adapted to improve coating adhesion, the surface having an average surface roughness of at least about 6.4 μm (250 microinches) and an average surface peak number of at least about 16 cm (40 microinches) as measured by a profilometer; -Profilometer threshold lower limit approximately 7.6 μm (3
00 microinches) and a profilometer threshold upper limit of 10.2 μm (400 microinches). 35. The surface has an average surface roughness of at least about 6.4 μm (250 microinches) as measured by a profilometer.
35. The article of claim 34, having no low spots of less than about 200 microinches. 36. The surface has an average surface peak number of at least about 24/cm (60/inch) as measured by a profilometer, based on an upper threshold of about 10.2 μm (400 microinch) and a lower threshold of about 7.6 μm (300 microinch). 35. The article of claim 34, comprising: 37. The surface has an average distance of at least about 25.4 μm between the maximum peak and maximum valley measured by a profilometer.
35. The article of claim 34, having a diameter of 1000 microinches). 38. The surface has an average distance between the maximum peak and maximum valley measured by a profilometer of at least about 38.1 to about 8.
35. The article of claim 34, having a diameter of about 1,500 to about 3,500 microinches. 39. 35. The article of claim 34, wherein the surface has an average peak height of at least about 1,000 microinches as measured by a profilometer. 40. The surface has an average peak height of at least about 38.1 to about 88.9 μm (1,50 μm) as measured by a profilometer.
0 to about 3,500 microinches).
Article described in 4. 41. 35. The article of claim 34, wherein the surface is at least substantially free from the deleterious effects of mechanical treatment. 42. 35. The article of claim 34, wherein the surface comprises at least substantially all grains having a grain size of about 3 to about 7. 43. 35. The article of claim 34, wherein the metal is a valve metal. 44. 35. The article of claim 34, wherein the surface has a surface roughness provided by three-dimensional grains with deep grain boundaries. 45. 35. The article of claim 34, wherein the metal of the article is selected from the group consisting of titanium, tantalum, niobium, aluminum, zirconium, manganese and nickel metals, alloys and intermetallic mixtures. 46. 44. The article of claim 43, wherein the valve metal is unalloyed titanium. 47. 47. The article of claim 46, wherein the drub metal is unalloyed titanium annealed in one or more of air, vacuum, or an inert gas at temperatures reached during annealing of at least about 500<0>C. 48. 35. The article of claim 34, wherein the article is an anode for an electrogalvanizing bath. 49. In a method of preparing the surface of a coated metal for coating, the coated metal surface is treated with a melt containing a basic substance for the removal of the coating; the metal surface is separated from the melt, and this cooling and removing melt residue therefrom; for a period sufficient to provide at least substantially continuous interparticle network diffusion of surface impurities to the metal;
subjecting the surface to an elevated temperature annealing; cooling the resulting annealed surface; and interparticle etching the surface with a strong acid or strong caustic etchant at an elevated temperature; the surface remains at least substantially free from the deleterious effects of mechanical surface treatments. 50. The bath containing the dissolved metal species to be deposited has an average surface roughness of at least about 6.4 μm (250 microinches) and an average surface peak number of at least about 16/cm (4 μm).
0/inch) - both measured by a profilometer, the peak number is about 7.
6μm (300 microinches) and profilometer threshold upper limit approximately 10.2μm (400 microinches)
A method of electrodepositing metals onto a support by electrolysis using an anode having as its working surface an electrochemically active surface coating on the support metal having a reference to . 51. 51. A method according to claim 50 for electrogalvanizing a metallic support from a zinc-containing bath. 52. 51. A method according to claim 50 for electroplating a metallic support from a tin-containing bath. 53. In order to electrolyze the dissolved species contained in the tank bath,
In the bath in which the anode is immersed; an average surface roughness of at least about 6.4 μm (250 microinches);
and an average surface peak number of at least about 16/cm (40
/inch) - both measured by a profilometer, the peak number is approximately 7.6 mm below the profilometer threshold.
μm (300 microinches) and a profilometer threshold upper limit of about 10.2 μm (400 microinches) on a support metal having an electrochemically active surface coating as its working surface. Tank. 54. The surface has an average surface roughness of at least about 6.4 μm (250 microinches) as measured by a profilometer.
54. The vessel of claim 53, having no low spots of less than about 200 microinches. 55. The surface has an average surface peak count as measured by a profilometer of at least about 24/cm (60/inch) based on an upper threshold of about 400 microinches and a lower threshold of about 300 microinches. 54. The tank of claim 53, comprising: 56. The surface has an average distance of at least about 25.4 μm between the maximum peak and maximum valley measured by a profilometer.
54. The tank of claim 53, having a diameter of 1,000 microinches). 57. The surface has an average distance of about 38.1 to about 88.9 μm between the maximum peak and maximum valley measured by a profilometer.
(1,500 to about 3,500 microinches). 58. 54. The vessel of claim 53, wherein the surface has an average peak height of at least about 1,000 microinches as measured by a profilometer. 59. The surface has an average peak height of at least about 38.1 to about 88.9 μm (about 1.5 μm) as measured by a profilometer.
54. The tank of claim 53, having a diameter of 0.00 to about 3,500 microinches.