WO2000005434A1

WO2000005434A1 - Method of inhibiting darkening, blackening or tarnishing of magnesium and magnesium alloys and compositions therefor

Info

Publication number: WO2000005434A1
Application number: PCT/US1999/016564
Authority: WO
Inventors: David C. Silverman; Timothy K. Hirzel
Original assignee: Solutia Inc.
Priority date: 1998-07-23
Filing date: 1999-07-21
Publication date: 2000-02-03
Also published as: AU5005799A

Abstract

There is disclosed a method of inhibiting darkening, blackening or tarnishing of magnesium and magnesium alloys comprising contacting magnesium or a magnesium alloy with a fluid composition containing a composition in an amount effective to inhibit darkening, blackening or tarnishing of the surface of the magnesium or magnesium alloy at an effective pH, and metal compositions therefor. Also disclosed are aqueous metal working fluid compositions containing the compositions of the invention.

Description

TITLE OF THE INVENTION

METHOD OF INHIBITING DARKENING, BLACKENING OR TARNISHING OF MAGNESIUM AND MAGNESIUM ALLOYS AND COMPOSITIONS THEREFOR

10

BACKGROUND OF THE INVENTION

15 This invention relates to a method of cleaning magnesium and magnesium alloys and metal cleaning compositions therefor. This invention further relates to aqueous metal working compositions containing the metal cleaning compositions of the invention.

Magnesium alloys find use in automotive applications (clutch, and

20 brake pedal support, steering column lock housings), industrial machinery (high speed applications), aerospace (weight reduction, strength, and stiffness), and commercial applications (luggage, computer housings, and ladders). Magnesium alloys are used in either the die cast or wrought form, depending on application. Magnesium as used for structural purposes but is typically alloyed with as many as five or six other

25 elements to impart desired properties. Common alloying elements are aluminum (as high as 15 wt%), zinc (as high as 6 wt%), manganese (as high as 1 wt%), zirconium (as high as 0.7 wt ), and rare earth type elements such as yttrium and rhenium.

Magnesium parts are finished by the usual steps of cleaning, chemical treatment, anodizing, electroplating and painting. One of the purposes of an

30 intermediate cleaning step is to remove blackening or tarnishing of the magnesium or magnesium alloy surface caused by the environment to which the metal was exposed. Cleaning may be mechanical or chemical. Sand blasting, gπt blasting and hydroblasting are used on sand and permanent-mold castings. Gπnding, sanding and wire brushing are other mechanical cleaning methods. Mechanical cleaning methods are undesirable, however, due to generation of dust since mixtures of fine magnesium dust and air can burn or explode if ignited. To prevent this, an approved dust collection system must be utilized. Magnesium surfaces are cleaned by acid pickling and numerous pickhng-bath compositions are available. For example, chromic acid or baths containing sulfuπc or nitπc and chromic acids are used most frequently while hydrofluoric acid is added when silica is present in the alloy.

In a recent study reported in D. Daloz, C. Rapin, P. Steinmetz, and G. Michot, Corrosion, Vol. 54, No. 6, p. 444 (1998), linear sodium mono-carboxylates were shown to inhibit corrosion of magnesium alloy AZ91HP (9 wt% aluminum. 1 wt% zinc) with a maximum in protection provided at the CIO to Cl 1 range. The use of acyl glutamate compounds is not disclosed or suggested.

It has now been surprisingly discovered that the amido acids or salts thereof of the invention are effective in cleaning, i.e. inhibiting darkening, blackening or tarnishing of, magnesium and magnesium alloy surfaces when exposed to fluids containing these compounds thereby obviating any need for any intermediate cleaning step. The metal cleaning effect is seen in aqueous compositions, particularly aqueous metal working compositions.

BRIEF SUMMARY OF THE INVENTION

It is an object of the invention to provide a method for cleaning the surface of magnesium and magnesium alloys exposed to aqueous compositions. It is a further object of the invention to provide metal cleaning compositions useful in cleaning magnesium and magnesium alloys. It is a still further object of the invention to provide aqueous metal working fluid compositions containing the metal cleaning compositions of the invention which are particularly useful in the metal working of magnesium and magnesium alloys Such a metalworking fluid could be used to circumvent an intermediate washing step of the magnesium and magnesium alloys between the metal working process and any subsequent treatment operation, e.g. coating. According to the invention, a method of cleaning the surface of magnesium and magnesium alloys is provided which compπses contacting magnesium or a magnesium alloy with a fluid composition containing a metal cleaning composition in an amount effective to clean the surface of the magnesium or magnesium alloy at an effective pH, wherein the metal cleaning composition compπses at least one amido acid or salt thereof having the formula

wherein R is an alkyl or alkenyl group having about 7 to about 21 carbon atoms, provided that R contains a linear chain of at least 7 carbon atoms; M and M' are cations independently selected from hydrogen, alkali metal or amine salts, and m and n independently represent an integer from 0 to 2.

Further according to the invention, a composition useful for cleaning magnesium and magnesium alloys is provided which compπses a concentrated solution of at least one amido acid or salt thereof having the formula

in an amount effective to clean the surface of magnesium and magnesium alloys when the composition is diluted with water and contacted with the magnesium and magnesium alloys.

Still further according to the invention, a metal working composition is provided which compπses water and a metal cleaning composition in an amount effective to clean the surface of magnesium and magnesium alloys at an effective pH, wherein the metal cleaning composition is as recited above The metal working compositions of the invention optionally contain a polyaspaπic polymer in the acid. salt or amide form thereof Such polyaspartic polymer containing metal working fluids are descπbed in U S Patents 5.401.428 which issued to Dennis J Kalota on March 28. 1995 and 5,616,544, which issued to Dennis J Kalota on Apπl 1, 1997 which are both incorporated by reference herein in their entirety

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(NOT APPLICABLE)

DETAILED DESCRIPTION OF THE INVENTION

A first embodiment of the invention relates to a method of cleaning the surface of magnesium and magnesium alloys compπsmg contacting magnesium or a magnesium alloy with a fluid composition containing a metal cleaning composition in an amount effective to clean the surface of the magnesium or magnesium alloy at an effective pH, wherein the metal cleaning composition compπses at least one amido acid or salt thereof having the formula

As used herein, "cleaning" means inhibiting formation of tarnishing, darkening or blackening of the metal surface and "to clean" means to inhibit formation of tarnishing, darkening or blackening of the metal surface In particular, formation of oxides or hydroxides on the surface ot the metal is inhibited by use of the metal cleaning composition of the invention The amido acids or salts thereof of the invention are represented by the formula

wherein R is an alkyl or alkenyl group having about 7 to about 21 carbon atoms, provided that R contains a linear chain of at least 7 carbon atoms, M and M' are cations independently selected from hydrogen, alkali metal or amine salts, and m and n independently represent an integer from 0 to 2. Suitable amine salts include water soluble cations deπved from ammonia and any amine-containing organic compound. Examples of suitable amine salts include, but are not limited to, cations represented by the formula (R')₄N⁺ wherein each R' is independently hydrogen, alkyl having 1-10 carbon atoms, ammoalkyl having 2-10 carbon atoms, or hydroxyalkyl having 2-10 carbon atoms When each of R' is hydrogen, the cation is ammonium, i.e. NH₄ ⁺. When at least one R' is other than hydrogen, (R')₄N⁺ can be a pπmary, secondary or tertiary ammonium, or a quaternary ammonium. Preferably, the amine salt is tnethanolammonium or ammonium Preferably, m is 0 and n is 1 or 2, and at least one of M and M' is other than hydrogen More preferably, m is 0 and n is 2. When at least one of M and M' is other than hydrogen, it is preferably an alkali metal or tπhydroxyalkylammomum, and more preferably sodium, potassium or tnethanolammonium. The number of carbon atoms in R is preferably about 8 to about 17 carbon atoms, and more preferably about 9 to about 17 carbon atoms

Examples of the amido acids or salts thereof include, but are not limited to, N-cocoyl-L-glutamic acid, sodium N-cocoyl-L-glutamate, tnethanolammonium N-cocoyl-L-glutamate, tnethanolammonium N-lauroyl-L- glutamate, sodium N-lauroyl-L-glutamate, N-stearoyl-L-glutamic acid, sodium N- stearoyl-L-glutamate, N-cocoyl-L-aspartic acid, sodium N-cocoyl-L-aspartate, tnethanolammonium N-cocoyl-L-aspartate, tnethanolammonium N-lauroyl-L- aspartate, sodium N-lauroyl-L-aspartate, N-stearoyl-L-aspartic acid and sodium N- stearoyl-L-aspartate The currently preferred amido acids or salts thereof are N- cocoyl-L-glutamic acid, N-lauroyl-L-glutamic acid, and the salts thereof

The metal cleaning composition of the invention can be diluted with a diluent, preferably water, to prepare the fluid composition used in contact with the magnesium or magnesium allovs Upon dilution of the metal cleaning composition , the amido acid or salt thereof is present in the resultant fluid composition in an amount effective to clean the magnesium and magnesium alloys. The effective amount of the metal cleaning composition may depend on the number of carbon atoms and amount of branching in the R group of the amido acid or salt thereof, and will be readily apparent to one skilled in the art based on the teachings of the instant invention Generally, the amido acid or salt thereof is present in the dilute fluid composition at a level of at least 0.05 wt. %. The upper level of amido acid or salt thereof is readily determined by one skilled in the art and is that amount which is soluble in the fluid composition, i.e. diluted metal cleaning composition. Preferably, the amido acid or salt thereof is present in the fluid composition at a level in the range of about 0.075 wt. % to about 10 wt. %, and more preferably 0.1 wt. % to about 2 wt. %.

As used herein, the effective pH of the fluid composition is that pH in which cleaning of the magnesium or magnesium alloys is achieved. The preferred pH range of the fluid composition is about 7 to about 9.5.

The metal cleaning compositions of the invention are useful in cleaning magnesium and magnesium alloys. Magnesium is known to be intentionally alloyed with as many as five or six other elements to impart desired properties. Magnesium alloys can contain about 10 to 15 elements other than magnesium. Common alloying elements are aluminum (as high as 15 wt%), zinc (as high as 6 wt%), manganese (as high as 1 wt%), zirconium ( as high as 0.7 wt%), and rare earth type elements such as yttπum and rhenium. Cast and wrought aluminum may be employed in this invention. A second embodiment of the invention relates to a composition useful for cleaning magnesium and magnesium alloys compπsing a concentrated solution of at least one amido acid or salt thereof having the formula

in an amount effective to clean magnesium and magnesium alloys when said composition is diluted with water and contacted with the magnesium and magnesium alloys, wherein R is an alkyl or alkenyl group having about 7 to about 21 carbon atoms, provided that R contains a linear chain of at least 7 carbon atoms. M and M' are cations independently selected from hydrogen, alkali metal or amine salts, and m and n independently represent an integer from 0 to 2. Generally, the amount of amido acid or salt thereof present in the concentrated solution is at least about 0.75 wt. %. The upper level of amido acid or salt thereof is readily determined by one skilled in the art and is that amount which is soluble in the concentrated solution composition. It is well known in the art that other additives such as coupling agents, hydrotropes and emulsifiers, e g polyalkylene glycols and denvatives thereof or short chain fatty acids, can be used to increase the solubilities in aqueous solutions. Such additives can be used in the concentrated solution composition of the invention to increase the solubility of the amido acids or salts thereof. Preferably, the amount of amido acid or salt thereof present in the concentrated solution is about 1.1 wt. % to about 30 wt. %. When the concentrated solution is diluted, such as with water, the concentration of amido acid or salt thereof is as disclosed above for use in the first embodiment of the invention

The third embodiment of the invention is a metal working composition compπsing water and a metal cleaning composition in an amount effective to clean magnesium and magnesium alloys at an effective pH, wherein said metal cleaning composition compnses at least one amido acid or salt thereof having the formula

wherein R is an alkyl or alkenyl group having about 7 to about 21 carbon atoms, provided that R contains a linear chain of at least 7 carbon atoms; M and M' are cations independently selected from hydrogen, alkali metal or amine salts, and m and n independently represent an integer from 0 to 2

Generally, the amido acid or salt thereof is present in the metal working composition at a level of at least 0 05 wt. % The upper level of amido acid or salt thereof is readilv determined bv one skilled in the art and is that amount which is soluble in the metal working composition Preferably, the amido acid or salt thereof is present in the metal working composition at a level in the range of about 0.075 wt. 7o to about 10 wt. %, and more preferably about 0 1 wt % to about 2 wt. %.

The metal working composition of the invention optionally contains a polyaspartic polymer in the acid, salt or amide form thereof A typical concentration of the polyaspartic polymer in a fluid concentrate is in the range of from about 0.5 wt. % to about 70 wt. %, preferably about 3 wt. % to about 50 wt. %, of the metal working composition. Polyaspartic polymers for use in the invention include those descπbed in U.S. 5,616,544, supra, which is incorporated herein in its entirety by reference.

The metal working compositions of the invention are useful in vanous metal working operations including, but not limited to, cutting, threading, bending, gnnd g, broaching, tapping, planing, gear shaping, reaming, deep hole dπlling/gundrilling, drilling, bonng, hobbing, milling, turning, sawing and shaping of vaπous ferrous and non-ferrous metals. The metal working compositions of the invention are useful in the vanous metal working operations noted above with any number of types of metals. In particular, they are useful in working ferrous metals such as iron, steel (carbon steel and low alloy carbon steel), and stainless steel. Non- ferrous metals which can be worked with metal working compositions of this invention are titanium, zirconium, copper, brass, nickel, cobalt, magnesium, aluminum and alloys thereof. Particularly preferred non-ferrous metals are magnesium, aluminum and alloys thereof Such metals are safely worked with lubπcity supplied by the aqueous metal working fluids of this invention.

One or more vaπous additives may be employed in the metal working compositions of the invention to enhance or contπbute properties which enable broader function or better performance with respect to the use of the compositions in metal working applications. The types of additives include corrosion inhibitors, oxidation inhibitors, antifoam agents, biocides. emulsification agents, viscosity modifiers, coupling agents, lubncants, residue modifiers, pH buffers, wetting agents. and antiwear and antifriction agents

Lubncants may be of several kinds, including simple, hydrodynamic. boundary, and extreme pressure lubncants A particularly useful class of lubncants are the polycarboxylic acids or salts thereof having two or more carboxylic acid groups Examples of applicable polycarboxylic acid or salts thereof include, but are not limited to, butanetetracarboxylic acid, succinic acid, oxalic acid, malonic acid, glutanc acid, adipic acid, propanetncarboxyhc acid, hexanetπcarboxyhc acid, maleic acid, fumanc acid, citnc acid, the salts thereof and the like. The preferred polycarboxylic acids are butanetetracarboxylic acid and salts thereof and succinic acid and salts thereof

After reading this specification, one skilled in the art of metalworking fluid formulation will be able to identify a number of additives for imparting hydrodynamic or boundary lubπcity , including but not limited to long- chain alkyl carboxylic acids, salts, esters or amides thereof, polyalkylene glycols, and polyalkylene glycol denvatives of long-chain alkyl alcohols, acids or amines, mixtures thereof and the like

Corrosion inhibitors for a vaπety of metals can be employed in the metal working compositions of the invention Examples of corrosion inhibitors include, but are not limited to, alkanolamines, aryltnazoles, 3-ammo-l,2,4-tnazole, and the like

The metal working compositions of the invention preferably compnse at least one of an aryltnazole having the formula

or 3-amιno-l 2 4-tπazole. wherein Y is an alkyl group having 1 to about 6 carbon atoms or -COO M^"*" . M" is hydrogen or an alkali metal, and p is an integer from 0 to 4 Preferably, M" is hydrogen, p is 0 or 1 and Y is methyl, ethyl or butyl

The aryltπazole or 3-amιno-l,2,4-tnazole can be used in conjunction with the required amido acid or salt thereof to impart synergistic corrosion inhibition properties with respect to ferrous metals When utilized in the metal working compositions of the invention, the aryl tπazole or 3-amιno-l,2,4-tnazole compound is present in an amount (when used in conjunction with the amido acids or salts thereof of the invention) effective to inhibit corrosion of ferrous metals; preferably present in an amount of at least about 0 04 wt % of the metal working composition; and more preferably present in an amount of about 0.05 wt. % to about 0 75 wt. %.

The aryltπazoles of the invention are represented by the formula

wherein Y is an alkyl group having 1 to about 6 carbon atoms or -COO M⁺ , M" is hydrogen or an alkali metal, and p is an integer from 0 to 4. Preferably, M" is hydrogen, p is 0 or 1 and Y is methyl, ethyl or butyl.

Examples of the aryltnazoles include, but are not limited to, benzotπazole, tolyltnazole, 5-ethylbenzotπazole and 5-butylbenzotnazole. The currently preferred aryltπazoles are benzotnazole and tolyltnazole

The alkanolamine compounds also function as a pH stabilizer and a residue enhancer (i.e. prevention of formation of a hard residue on drying) and include, but are not limited to. tπethanolamine, l,3-Bιs[tπs(hydroxymethyl)- methylamιno]propane, and the like

Biocides that can be used in the metal working compositions of the invention include those conventional biocides that are known in the art. Examples of biocides include, but are not limited to, l,2-benzιsothιazohn-3-one known as Proxel, poly(oxy- 1 ,2-ethanedιyl(dιmethvhmιno)- 1 ,2-ethanedιyl(dιmeth vhmino)- 1 ,2- ethanediyl dichlonde) known as Busan 77, 2-Methyl-4-ιsothiazolin-3-one. 2-n-Octyl- 4-isothιazohn-3-one, mixtures thereof and the like.

EXAMPLES

Example 1 Example 1 shows corrosion results on magnesium for several solutions of amido acids or salts thereof, specifically N-acyl glutamates, in water. The solutions were formed by dissolving a given amount of the monosodium salt of a specific N-acyl glutamic acid in deionized water, assisted by the simultaneous adjustment of the solution pH to a specific value ranging from 7.0 to 9.5 with triethanol amine. The particular N-acyl glutamic acid monosodium salt used, the quantity added, and the final pH are given in Table 1.

The procedure is: The specified amount of the given substance was weighed out and placed in a 400 mL beaker. Approximately 170 g of water was added, and the amount recorded. The pH of the stined suspension was adjusted with triethanolamine (TEA), and the amount which was added was recorded. Deionized water was then added until the total mass of the solution was 200.0 g.

The corrosion coupons were magnesium AZ31B, with a surface finish of 120 gnt. The coupons were suspended in glass jars using glass string that had been burned to remove any resins. Rubber stoppers were placed on the jars. The exposures lasted about 1 14 hours and were at room temperature. Longer term exposure resulted in some easily removed blackening or darkening. Table 1

The results in this table indicate the metal cleaning ability of the cocoyl and lauroyl compounds. Stearoyl compounds at low concentration enabled the surface to remain free of any blackening. At high concentrations, the stearoyl glutamate was less effective. The N-(2-ethyl)hexanoyl glutamate did not prevent blackening. In all cases, there was a small corrosion rate of between 0 5 and 1. mil per year. The instances of blackening under the stnng are believed to be caused by shielding of the metal surface from the bulk fluid by the stnng. As a result, the fluid within this occluded cell is less effective than the bulk fluid.

Example 2 Comparative Example To deionized water was added either tπethanolamine (TEA) or sodium hydroxide to create solutions with pH values of 8.5 and 9.5. Table 2 shows the pH and the substance used for pH adjustment for each of the four examples. Corrosion tests were performed in accordance with the procedure descπbed in Example 1 In all cases, blackening of the magnesium was found, such blackening being present under the glass stnng and on the exposed surface. In this case, solution 15 showed a weight gam and solutions 16 through 18 showed virtually no change in weight. The blackening was probably through formation of a thick oxide which either caused a weight gain or offset any weight loss normally found with magnesium corrosion in such solutions. Table 2

Companng the results of Tables 1 and 2 demonstrate that the presence of the amido acids or salts thereof of the invention inhibit blackening of the magnesium coupons.

Example 3 This example shows the effect on blackening of magnesium of metalworking solutions made from concentrate formulations containing N-acyl glutamates. Solution 19 is a formulation wherein N-cocoyl glutamate is the sole glutamate denvative present. Solution 20 is a formulation wherein N-stearoyl glutamate is the sole glutamate denvative present. Solutions 21 through 26 are formulations otherwise identical to solutions 19 and 20 of this example, except that they contain vanous mixtures of N-cocoyl glutamate and N-stearoyl glutamate having weight ratios of cocoyfstearoyl varying from 3.2 to 3.38.

Solutions 19 through 22, 25 and 26 were formulated using N-cocoyl glutamic acid and N-stearoyl glutamic acid Solutions 23 and 24 were formulated using mono-tnethanolammonium N-cocoyl glutamate and monosodium N-stearoyl glutamate The amounts of tnethanolamine added in these two examples were reduced by an amount equivalent on a molar basis to the amount of countenon (both tnethanolammonium and sodium ion) introduced with the mono-salts They were generally prepared as follows: the tnethanolamine, most of the deionized water, the Ethox 90-R-4 (polyoxyalkylene ethylene diamine. CAS number 26316-40-5 available from Ethox Chemicals, LLC) and the Surfynol® SE (registered trademark of Air Products and Chemicals, Inc.; active ingredient (<80%) is 2,4,7,9 tetramethyl-5-decyne-4.7-dιol, CAS number 126-86-3) were combined and heated to ca. 50 degrees centigrade. To the warm liquid, the N-acyl glutamates, butane tetracarboxy c acid, and benzotπazole were added and dissolved. Upon complete dissolution of the solids, the solution was cooled to ambient temperature (20-30 degrees centigrade), and the Proxel® MW200 (registered tradename of Zeneca Inc.; active ingredient is 1,2 benzιsothιazolιn-3-one at 19.7%, the balance inert ingredients) and the balance of the deionized water were added. Finally, the Foam- Ban MS-625 (a product of Ultra Additives Inc. containing two polyoxyalkylene polymers, water, an organosiloxane polymer (trade secret 1119950000-5005P), and a siloxane glycol copolymer) was added. The specific proportions of matenals in the concentrates are given in weight-percent in Table 3, below. Note that the monotnethanolammonium N-cocoyl glutamate is reported on a 100% actives basis.

These concentrate solutions were then diluted with water for the subsequent corrosion testing The dilution ratio was 1 part by volume of concentrate to 14 parts by volume of water The corrosion expenment was conducted as follows. Magnesium

AZ31B coupons with a 120 gπt surface finish were suspended in jars so that the vapor/liquid interface intersected with about the midpoint of the corrosion coupon. This arrangement enabled two observations, corrosion at the interface and corrosion below the interface. The two environments can be different Corrosion at the interface can be far worse than under full immersion conditions because of higher levels of oxygen and decreased levels of active compounds in the solution in that region. Both sets of results are reported but the metal cleaning attπbute is reflected in the full immersion observation Table 3

Sample No. 19 20 21 22 23 24 25 26

Component

N-Cocoyl glutamic acid 9.00% 0.00% 4.50% 2.25% 0.00% 0.00% 0.90% 0.45%

N-Stearoyl glutamic acid 0.00% 6.00% 3.00% 4.50% 0.00% 0.00% 5.40% 5.70%

N-cocoyl glutamic acid, mono TEA salt 0.00% 0.00% 0.00% 0.00% 6.54% 3.27% 0.00% 0.00% ) 0 N-Stearoyl glutamic acid, monosodium salt 0.00% 0.00% 0.00% 0.00% 3.16% 4.74% 0.00% 0.00% ) Triethanolamine (TEA) 27.18% 27.18% 27.18% 27.18% 24.06% 24.54% 27.18% 27.18%

1,2,3,4-Butane tetracarboxyhc acid 0.91% 0.91% 0.91% 0.91% 0.91% 0.91% 0.91 % 0.91%

Benzotriazole 0.75% 0.75% 0.75% 0.75% 0.75% 0.75% 0.75% 0.75%,

D.I. water 44.10% 47.10% 45.60% 46.35% 31.27% 40.10% 46.80% 46.95%

Ethox 90-R-4 (polyalkylene glycol) 15.00% 15.00% 15.00% 15.00% 15.00% 15.00% 15.00'!{, 1 5.00%

Surfynol SE (alkynediol) 1.50% 1.50% 1.50% 1.50% 1.50% 1.50% 1 .50% 1 .50%.

Proxel MW200 (solution) 1.26% 1.26% 1.26% 1.26% 1.26% 1.26% 1.26% 1 .26% > Ultra Additives' Foam-Ban MS-625 0.30% 0.30% 0.30% 0.30% 0.30% 0.30% 0.30% 0.30%

Surface Appearance:

Fully Immersed Surface No Black- ] Mo BlackNo No No BlackBlackBlackened over < ening Black- BlackBlackened ened ening surface ening ening ening over over surface surface

Interface Dark line Darken-ed Dark line Dark line Dark Dark Dark Dark line line line line line

Thus, it is apparent that there has been provided, in accordance with the instant intervention, a composition and method of use that fully satisfies the objects and advantages set forth herein above While the invention has been descnbed with respect to vanous specific examples and embodiments thereof, it is understood that the invention is not limited thereto and many alternatives, modifications and vanations will be apparent to those skilled in the art in light of the foregoing descnption. Accordingly, it is intended to embrace all such alternatives, modifications and vanations as fall within the spint and broad scope of the invention.

Claims

CLAIM OR CLAIMSTHAT WHICH IS CLAIMED IS:

1. A method of cleaning the surface of magnesium and magnesium alloys comp╧Çsing: contacting magnesium or a magnesium alloy with a fluid composition containing a metal cleaning composition in an amount effective to clean the surface of said magnesium or magnesium alloy at an effective pH, wherein the metal cleaning composition compnses at least one amido acid or salt thereof having the formula

2. The method of claim 1 wherein said amido acid or salt thereof is present in said fluid composition in an amount of at least 0.05 wt. %.

3. The method of claim 2 wherein said amido acid or salt thereof is present in said fluid composition in a range of about 0.075 wt. % to about 10 wt. %.

4. The method of claim 1 wherein R is an alkyl or alkenyl group having about 8 to about 17 carbon atoms.

5. The method of claim 4 wherein m is 0 and n is 1 or 2.

6. The method of claim 5 wherein M and M' are independently hydrogen, alkali metal or t╧Çhydroxyalkylammonium

7. The method of claim 6 wherein at least one of M and M' is sodium, potassium or tnethanolammonium.

8. The method of claim 1 wherein the pH is in the range of about 7 to about 9.5.

9. The method of claim 1 wherein said magnesium alloy is a cast magnesium alloy.

10. The method of claim 1 wherein said megnesium alloy is a wrought magnesium alloy.

11. A composition useful for cleaning magnesium and magnesium alloys compnsing a concentrated solution of at least one amido acid or salt thereof having the formula

in an amount effective to clean magnesium and magnesium alloys when said composition is diluted with water and contacted with said magnesium and magnesium alloys, wherein R is an alkyl or alkenyl group having about 7 to about 21 carbon atoms, provided that R contains a linear chain of at least 7 carbon atoms; M and M' are cations independently selected from hydrogen, alkali metal or amine salts, and m and n independently represent an integer from 0 to 2

12. The composition of claim 1 1 wherein the amido acid and salts thereot are present in an amount of at least 0.75 wt. %

13. The composition of claim 12 wherein the said amido acid or salt thereof is present in a range of about 1.1 wt. % to about 30 wt. %.

14. The composition of claim 11 wherein R is an alkyl or alkenyl group having about 8 to about 17 carbon atoms.

15. The composition of claim 14 wherein m is 0 and n is 1 or 2.

16. The composition of claim 15 wherein M and M' are independently hydrogen, alkali metal or t╧Ç(hydroxyalkyl)ammon╬╣um.

17. The composition of claim 16 wherein at least one of M and M' is sodium, potassium or tnethanolammonium.

18. The composition of claim 11 further comp╧Çsing water in an amount wherein said amido acid or salt thereof is present in an amount of at least 0.05 wt. %.

19. The composition of claim 18 wherein said amido acid or salt thereof is present in a range of about 0.075 wt. % to about 10 wt. %.

20. A metal working composition compnsing water and a metal cleaning composition in an amount effective to clean magnesium and magnesium alloys at an effective pH, wherein said metal cleaning composition compnses at least one amido acid or salt thereof having the formula

21. The composition of claim 20 wherein the amido acid and salts thereof are present in an amount of at least 0 05 wt %.

22. The composition of claim 21 wherein the said amido acid or salt thereof is present in a range of about 0.075 wt. % to about 10 wt. %.

23. The composition of claim 20 wherein R is an alkyl or alkenyl group having about 8 to about 17 carbon atoms

24 The composition of claim 23 wherein m is 0 and n is 1 or 2

25. The composition of claim 24 wherein M and M' are independently hydrogen, alkali metal or tn(hydroxyalkyl)ammon╬╣um.

26. The composition of claim 25 wherein at least one of M and M' is sodium, potassium or tnethanolammonium

27 The composition of claim 20 further comp╧Çsing an alkanolamine

28. The composition of claim 27 wherein said alkanolamine is selected from tnethanolamme.

29. The composition of claim 27 further comp╧Çsing a biocide.

30. The composition of claim 29 wherein said biocide is selected from l,2-benz╬╣soth╬╣azol╬╣n-3-one, poly(oxy-l,2-ethaned╬╣yl(d╬╣methyhm╬╣no)-l,2- ethaned╬╣yl(d╬╣methyl╬╣m╬╣no)- 1 ,2-ethaned╬╣yl dichlonde) 2-Methyl-4-╬╣soth╬╣azohn-3-one, 2-n-Octyl-4-╬╣soth╬╣azol╬╣n-3-one, and mixtures thereof.

51. The composition of claim 29 further compnsmg a polycarboxylic acid.

32. The composition of claim 31 wherein said polycarboxylic acid is selected from butanetetracarboxylic acid and salts thereof, succinic acid and salts thereof, and mixtures thereof.

33. The composition of claim 31 further comp╧Çsing at least one of an aryltnazole having the formula

or 3-am╬╣no-l,2,4-tnazole, wherein Y is an alkyl group having 1 to about 6 carbon atoms or -COO M⁺ , M" is hydrogen or an alkali metal, and p is an integer from 0 to 4; wherein said aryltnazole or 3-am╬╣no-l,2,4-t╧Çazole is present in an amount such that the combination of said aryltnazole or 3-am╬╣no-l,2,4-tnazole with said amido acid or salt thereof is effective to inhibit ferrous metal corrosion

34. The composition of claim 20 further comp╧Çsing a polyaspartic polymer in the acid, salt or amide form thereof wherein the concentration of said polymer is in the range of from about 0 5 wt. % to about 70 wt 7c of said composition.

35. The composition of claim 20 wherein the pH is in the range of about 7 to about 9.5.

36. A metal working composition compnsing:

(a) water,

(b) a metal cleaning composition in an amount effective to clean magnesium and magnesium alloys at an effective pH, wherein said metal cleaning composition compnses at least one amido acid or salt thereof having the formula

wherein R is an alkyl or alkenyl group having about 7 to about 21 carbon atoms, provided that R contains a linear chain of at least 7 carbon atoms; M and M' are cations independently selected from hydrogen, alkali metal or amine salts, and m and n independently represent an integer from 0 to 2,

(c) at least one of an aryltriazole having the formula

or 3-am╬╣no-l,2,4-t╧Çazole; wherein Y is an alkyl group having 1 to about 6 carbon atoms or -COO^"M⁺ , M" is hydrogen or an alkali metal, and p is an integer from 0 to 4; wherein said aryltnazole or 3-amino-l,2,4-t╧Çazole is present in an amount such that the combination of said aryltriazole or 3-am╬╣no-l,2,4-t╧Çazole with said amido acid or salt thereof is effective to inhibit ferrous metal corrosion, (d) an alkanolamine, and (e) a biocide.

37. The composition of claim 36 further compnsing. (0 a polycarboxylic acid.

38. A method of metal working magnesium or magnesium alloys thereof using the metal working composition of claim 20.