US3041227A - Chemical polishing composition and method for aluminum metals - Google Patents
Chemical polishing composition and method for aluminum metals Download PDFInfo
- Publication number
- US3041227A US3041227A US761955A US76195558A US3041227A US 3041227 A US3041227 A US 3041227A US 761955 A US761955 A US 761955A US 76195558 A US76195558 A US 76195558A US 3041227 A US3041227 A US 3041227A
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- US
- United States
- Prior art keywords
- acid
- aluminum
- chemical polishing
- bath
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 229910052782 aluminium Inorganic materials 0.000 title claims description 21
- 238000005498 polishing Methods 0.000 title claims description 21
- 239000000126 substance Substances 0.000 title claims description 20
- 239000000203 mixture Substances 0.000 title claims description 13
- 238000000034 method Methods 0.000 title claims description 5
- -1 aluminum metals Chemical class 0.000 title description 5
- 229910052751 metal Inorganic materials 0.000 title description 5
- 239000002184 metal Substances 0.000 title description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 31
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 19
- 235000011007 phosphoric acid Nutrition 0.000 claims description 16
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical class OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 claims description 11
- 229910000838 Al alloy Inorganic materials 0.000 claims description 10
- 150000007933 aliphatic carboxylic acids Chemical class 0.000 claims description 7
- DTQVDTLACAAQTR-UHFFFAOYSA-N Trifluoroacetic acid Chemical compound OC(=O)C(F)(F)F DTQVDTLACAAQTR-UHFFFAOYSA-N 0.000 description 17
- 150000001875 compounds Chemical class 0.000 description 12
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 6
- 229910017604 nitric acid Inorganic materials 0.000 description 6
- 239000005711 Benzoic acid Substances 0.000 description 5
- 239000002253 acid Substances 0.000 description 5
- 235000010233 benzoic acid Nutrition 0.000 description 5
- 239000003795 chemical substances by application Substances 0.000 description 5
- 238000007598 dipping method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000000654 additive Substances 0.000 description 4
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- ILRRQNADMUWWFW-UHFFFAOYSA-K aluminium phosphate Chemical compound O1[Al]2OP1(=O)O2 ILRRQNADMUWWFW-UHFFFAOYSA-K 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 239000004094 surface-active agent Substances 0.000 description 3
- QEWYKACRFQMRMB-UHFFFAOYSA-N fluoroacetic acid Chemical compound OC(=O)CF QEWYKACRFQMRMB-UHFFFAOYSA-N 0.000 description 2
- 239000003517 fume Substances 0.000 description 2
- 230000009931 harmful effect Effects 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 150000002823 nitrates Chemical class 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- NSTREUWFTAOOKS-UHFFFAOYSA-N 2-fluorobenzoic acid Chemical compound OC(=O)C1=CC=CC=C1F NSTREUWFTAOOKS-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 150000008065 acid anhydrides Chemical class 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F3/00—Brightening metals by chemical means
- C23F3/02—Light metals
- C23F3/03—Light metals with acidic solutions
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- ing And Chemical Polishing (AREA)
- Chemical Treatment Of Metals (AREA)
Description
tax-ro United States Patent 3,041,227 CHEMICAL POLISHING COMPOSITION AND METHOD FOR ALUMINUM METALS John F. Jumer, Elmhurst, 11]. No Drawing. Filed Sept. 19, 1958, Ser. No. 761,955 12 Claims. (Cl. 156-21) My invention relates to the chemical polishing of metals and particularly to nonferrous metals such as aluminum.
In the past several years a number of bright dipping or chemical polishing bath compositions have been proposed and used in various localities throughout the United States. A number of these have been widely accepted due to their relatively low cost and ease of proper operation. Of these baths which have been accepted, those based on the use of phosphoric acid have been the most successful, particularly when they could properly be classed as chemical polishing rather than bright dipping baths. Chemical polishing is considered preferable to bright dipping since the former produces a surface leveling action, attacking the microscopic surface projections preferentially to the valleys, while a bright dipping bath tends to act uniformly over the surface and produces little or no leveling action.
Substantially all of the chemical polishing or bright dipping baths occasionally produce irregularly polished or pitted surfaces particularly on articles of aluminum or aluminum alloy. It has been noted that this unsatisfactory surface condition occurs when the gaseous film forming at the interface of the metal and bath is relatively thick or irregular and when the size of the bubbles discharged from the film are either irregular or large as contrasted to small and uniform in size. Another characteristic of the film usually indicative of unsatisfactory action is the formation of a more or less static fihn in which the bubbles formed tend to hang to the work surface rather than being promptly released. Control of the film characteristics however has proven particularly diflicult and has in some instances demanded complete revision of equipment and bath composition.
One of the principal objects of my invention is a chemical polishing bath for aluminum which contains an acid stable surface active agent capable of controlling the thickness, mobility and uniformity of the gaseous film which forms around the object being treated as well as insuring liberation of many small uniformly sized bubbles thereby yielding consistently a bright uniformly polished aluminum surface practically free from pits or unpolished areas.
Other objects include the provision of additive agents for chemical polishing baths for aluminum which permit a reduction in the bath temperature, which increase the tolerance of the bath toward undesirable compounds such as aluminum phosphate, which do not yield excessive quantities of fumes, which are relatively inexpensive and which are sufficiently nontoxic to permit handling without special precautions.
Other objects as well as the many advantages of my invention will be disclosed in the following detailed description of my invention.
Essentially, m ntion involves the addition to a bath consistingg rincipally of orthophosihorrc aci'g' E1 small quantity 0 a. uorma e sur ace active acid stable m acidic media and preferably a fiuorinated aliptggtic car oxy c aci en use in quantities varying from Mt to approximately 1 percent by weight, these compounds exert a uniform surface tension effect across the entire work surface which apparently aids materially in maintaining the desired film characteristics and in insuring substantially uniform activity on the exposed surface of the article being treated.
URUOO UEl'lElibC More specifically, a satisfactory bath for the chemical polishing of aluminum may be prepared by adding to 100 ccs. of commercial orthophosphoric acid (75%), about 6 grams Of gr ll-1mm and 1.5 grams of sodium 5 sulfate. To this I add about of 1 percent by volume trifluoroacetic acid (CF OOH). The temperature of the resulting bath may be maintained at 180 to 210 F. and the article immersed for from 5 to 180 seconds. It is of course not essential that 75 percent orthophosphoric l0 acid be employed since the 85 percent grade is also suitable as are similar compounds prepared from acid anhydrides.
Another suitable bath may be prepared by utilizing 94 percent by volume orthophosphoric acid mixed with 15 6 percent by volume nitric acid. In this instance the orthophosphoric acid should be of the commercial 85 percent grade and the nitric acid of the 36 Baum grade. To this bath, as in the previous example, I add from $5 0 of 1 percent to 1 percent by volume of a fiuorinated aliphatic carboxylic acid, such as trifluoroacetic acid.
For general use, trifluoroacetic acid is the best of the commonly available fiuorinated hydrocarbon agents for use as an additive in phosphoric acid baths intended for use in chemically polishing aluminum. Its boiling point (72.4 C.) is somewhat below the usual operating temperature of the bath which allows gradual evaporation and loss of the agent during normal bath utilization. As this loss is occurring, other bath components such as the nitrates are also being lost or rendered inelfective. Thus, when necessary the bath may be refreshed or restored to a satisfactory operating condition by adding predetermined quantities of the necessary materials such as trifiuoroacetic acid and nitrates at the same time without danger of unintentionally exceeding the optimum concentrations. This is considered desirable because the chemical determination of trifluoroacetic acid and its equivalent compounds is not a simple operation and excessive quantities can prove harmful.
Although trifluoroacetic acid constitutes a preferred material, not only because of its physical characteristics but also because of its relatively low cost and availability, there are nevertheless related compounds which yield satisfactory results when used in the quantities indicated and which have characteristics of particular use under certain circumstances. Monofluoroacetic acid (CH FCOOH) for example has a relative y g oiling W). Solubility of this compound in aqueous phosphoric acid is so limited that excessive concentrations cannot be created. Thus, this compound is quite useful in baths utilizing high operating temperatures even thoigh its activity is somewhat less than trifiuoroacetic ac:
Difluoroaeetic acid (CHFgCOOH) also has a relatively o g pom ut this compound has a solubility in aqueous phosphoric acid which makes possible the creation of an undesirable overconcentration of the compound in all but the very highest temperature baths. Thus, the use of this compound would be indicated either where the temperature of the bath exceeds about 140 C. or where the bath is periodically replaced in its entirety without the use of additives.
Orthofluoro benzoic acid constitutes an example of J the several uonnate cyc c car y c act s w 1c may beemoe. iyo .2 part for 100 parts of water and a melting point of 122 C. Although such compounds may be utilized, the fiuorinated aliphatic acids are preferred for general utilization.
The addition of these surface active agents such as trifluoroacetic acid to phosphoric acid aluminum polishing baths produces a number of desirable effects. In their presence the gaseous film which forms at the work CAHlYl I l IL surface becomes substantially uniform both in thickness and in density. The bubbles which form the film are more nearly uniform in size and are quite small. In
addition they are promptly released, forming what may be termed a highly mobile uniform film. Uniform brightly polished aluminum surfaces can be obtained with considerably less care than has heretofore been necessary. In addition, the presence of even the minimum amount of agent in the bath permits a reduction in the temperature of the bath, usually on the order of 10 F., without any apparent harmful effect on the quality of the work. This reduction in temperature is highly desirable since it reduces the rate at which fumes and vapors are generated and prolongs the life of the bath. Similarly, concentrations of deleterious compounds, such as aluminum phosphate, may be permitted to exceed the usual limits before taking steps to reduce concentration. It has also been noted that the amount of bath solution lost by drag-out is somewhat reduced.
From the foregoing it will be apparent that the use of the fiuorinated hydrocarbon additive agent is beneficial from many aspects. Over and above the marked improvement in finish and the reduction of rejected work pieces, the lower bath temperatures, the reduction in drag-out and the increased tolerance of the bath to aluminum phosphate effect economies of operation which more than offset the increased cost of the addition of fiuorinated hydrocarbon.
I claim:
1. A composition for the chemical polishing of aluminum and aluminum alloys consisting essentially of a solution of orthophosphoric acid having a concentration of H P not less than about 75 by weight and containing from about 0.001% to about 1.0% by weight of a member selected from the group consisting of a fiuorinated lower aliphatic carboxylic acid and a fiuorinated benzoic acid.
2. A composition for the chemical polishing of aluminum and aluminum alloys consisting essentially of a solution of orthophosphoric acid having a concentration of H PO not less than about 75% by weight and containing from about 0.001% to about 1.0% by weight of a fiuorinated acetic acid.
3. A composition for the chemical polishing of aluminum and aluminum alloys consisting essentially of a solution of orthophosphoric acid having a concentration of H PO not less than about 75 by weight and containing from about 0.001% to about 1.0% of trifluoroacetic acid, by weight.
tration of H PO not less than about 75% by weight and 4 containing from about 0.001% to about 1.0% by weight of a member selected from the group consisting of a fiuorinated lower aliphatic carboxylic acid and a fiuorinated benzoic acid.
8. A method for the chemical polishing of aluminum and aluminum alloys which comprises applying to the surface thereof at a temperature between about 180 F. and about 210 F. a composition consisting essentially of a solution of orthophosphoric acid having a concentration of H PO not less than about by weight and containing from about 0.001% to about 1.0% by weight of trifluoroacetic acid, for a period between about 5 and 180 seconds.
9. A composition for the chemical polishing of aluminum and aluminum alloys consisting essentially of a solution of orthophosphoric acid having a concentration of H PO not less than about 75 by weight and containing a minor proportion of nitric acid and from about 0.001% to about 1.0% by weight of a fiuorinated acetic acid.
10. A method for the chemical polishing of aluminum and aluminum alloys which comprises applying to the surface thereof at a temperature between about 180 F. and about 210 F. a composition consisting essentially of a solution of orthophosphoric acid having a concentration of H PO not less than about 75 by weight and containing a minor proportion of nitric acid and from about 0.001% to about 1.0% by weight of a member selected from the group consisting of a fiuorinated lower aliphatic carboxylic acid and fiuorinated benzoic acid.
11. A composition for the chemical polishing of aluminum and aluminum alloys consisting essentially of a solution of orthophosphoric, acid having a concentration of H PO not less than about 75 by weight and containing a minor proportion of nitric acid and from the group consisting of a fiuorinated lower aliphatic carboxylic acid and a fiuorinated benzoic acid.
12. A composition for the chemical polishing of aluminum and aluminum alloys consisting primarily of orthophosphoric acid, a minor quantity of nitric acid, water and from about 0.001% to about 1.0% by weight of a memlber selected from a group consisting of a fiuorinated aliphatic carboxylic acid and a fiuorinated benzoic acid dissolved therein.
References Cited in the file of this patent UNITED STATES PATENTS 1,525,606 Gravel] Feb. 10, 1925 2,257,960 Humphrey et a1 Oct. 7, 1941 2,516,685 Douty et al. July 25, 1950 2,652,360 Bond et al. Sept. 15, 1953 2,692,189 Bo-Shin Ro Oct. 19, 1954 2,729,551 Cohn Jan. 3, 1956 2,788,362 Bamhart et al. Apr. 9, 1957 OTHER REFERENCES Harris: Trend in Aluminum Cleaning, pp. 28-32, Aluminum and Magnesium Magazine, April 1945.
Schwartz et al.: Surface Active Agents and Detergents; vol. II; copyright I an. 23, 1958, by Interscience Publishers, Inc. New York; pp. -152.
Claims (1)
- 7. A METHOD FOR THE CHEMICAL POLISHING OF ALUMINUM AND ALUMINUM ALLOYS WHICH COMPRISES APPLYING TO THE SURFACE THEREOF AT A TEMPERATURE BETWEEN ABOUT 180*F. AND ABOUT 210*F. A COMPOSITION CONSISTING ESSENTIALLY OF A SOLUTION OF ORTHOPHOSPHORIC ACID HAVING A CONCENTRATION OF H3PO4 NOT LESS THAN ABOUT 75% BY WEIGHT AND CONTAINING FROM ABOUT 0.001% TO ABOUT 1.0% BY WEIGHT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF A FLUORINATED LOWER ALIPHATIC CARBOXYLIC ACID AND FLUORINATED BENZOIC ACID.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US761955A US3041227A (en) | 1958-09-19 | 1958-09-19 | Chemical polishing composition and method for aluminum metals |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US761955A US3041227A (en) | 1958-09-19 | 1958-09-19 | Chemical polishing composition and method for aluminum metals |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3041227A true US3041227A (en) | 1962-06-26 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US761955A Expired - Lifetime US3041227A (en) | 1958-09-19 | 1958-09-19 | Chemical polishing composition and method for aluminum metals |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US3041227A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3607398A (en) * | 1969-06-18 | 1971-09-21 | Avco Corp | Chemical stripping process |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1525606A (en) * | 1923-10-11 | 1925-02-10 | James H Gravell | Composition of matter and process for preparing metal for painting |
| US2257960A (en) * | 1939-01-12 | 1941-10-07 | William M Humphrey | Cleaning aluminum surfaces |
| US2516685A (en) * | 1944-04-19 | 1950-07-25 | American Chem Paint Co | Process of preparing iron and aluminum surfaces to receive organic coatings and solution therefor |
| US2652360A (en) * | 1951-05-10 | 1953-09-15 | Pure Oil Co | Acidizing siliceous earth formations |
| US2692189A (en) * | 1952-04-15 | 1954-10-19 | Khe Beng Chiong | Chemical polishing solution and method |
| US2729551A (en) * | 1954-01-18 | 1956-01-03 | Samuel L Cohn | Surface treatment of aluminum and its alloys |
| US2788362A (en) * | 1955-05-18 | 1957-04-09 | Kellogg M W Co | Perchlorofluoronitriles and methods for their preparation |
-
1958
- 1958-09-19 US US761955A patent/US3041227A/en not_active Expired - Lifetime
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1525606A (en) * | 1923-10-11 | 1925-02-10 | James H Gravell | Composition of matter and process for preparing metal for painting |
| US2257960A (en) * | 1939-01-12 | 1941-10-07 | William M Humphrey | Cleaning aluminum surfaces |
| US2516685A (en) * | 1944-04-19 | 1950-07-25 | American Chem Paint Co | Process of preparing iron and aluminum surfaces to receive organic coatings and solution therefor |
| US2652360A (en) * | 1951-05-10 | 1953-09-15 | Pure Oil Co | Acidizing siliceous earth formations |
| US2692189A (en) * | 1952-04-15 | 1954-10-19 | Khe Beng Chiong | Chemical polishing solution and method |
| US2729551A (en) * | 1954-01-18 | 1956-01-03 | Samuel L Cohn | Surface treatment of aluminum and its alloys |
| US2788362A (en) * | 1955-05-18 | 1957-04-09 | Kellogg M W Co | Perchlorofluoronitriles and methods for their preparation |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3607398A (en) * | 1969-06-18 | 1971-09-21 | Avco Corp | Chemical stripping process |
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