US2974021A - Process and composition for chemically treating titanium and its alloys - Google Patents

Process and composition for chemically treating titanium and its alloys Download PDF

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US2974021A
US2974021A US639121A US63912157A US2974021A US 2974021 A US2974021 A US 2974021A US 639121 A US639121 A US 639121A US 63912157 A US63912157 A US 63912157A US 2974021 A US2974021 A US 2974021A
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parts
reagent
specimen
alloys
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Borowik Albert
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    • 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
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/10—Etching compositions
    • C23F1/14—Aqueous compositions
    • C23F1/16—Acidic compositions
    • C23F1/26—Acidic compositions for etching refractory metals
    • 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
    • C23F3/04—Heavy metals
    • C23F3/06—Heavy metals with acidic solutions

Definitions

  • This invention relates to a material and process for the chemical polishing and etching of titanium and its alloys for metallographic examination and has for an object to provide a suitable reagent and process for this purpose.
  • An examination of the true microstructure of a metal specimen has been said to be the prime function of chemical as distinguished from electroyltic polishing.
  • the specimen may have been mechanically polished beforehand to obtain good light-reflective surface.
  • Chemical etching dissolves more metal at grain boundaries than from the surface of the grains in order to provide better grain delineation.
  • Titanium and its solid solution alloys have been diflicult to polish mechanically because the metal is quickly work-hardened yet at the same time it has a tendency to flow and hide the true grain structure in a manner sowewhat analogous to the way in which a plastic will be deformed and hide a subsurface layer. Hand-polishing of such metal has been done but such is tedious for titanium and its alloys for the reason mentioned.
  • a reagent which is peculiarly suited to give good results with metallographic specimen of titanium and its alloys.
  • the reasons therefor are unknown and the discovery of such has been empirical.
  • That one reagent includes 10 cc. of 48% GP. hydrofluoric acid with 10 cc. of 69.3% of commercial nitric acid, 60 cc. of U.S.P. 3% hydrogen peroxide, and 30 cc. of distilled water.
  • a better reagent composition has been found to result from the addition to the foregoing of 150 cc. of commercial glycerol having a specific gravity of 1.249.
  • the best reagent for titanium metals and alloys is when 300 cc. of commercial ethylene glycol is added to the first mentioned combination of ingredients. In that first combination, plus or minus 5% by volume of each acid, the hydrogen peroxide and the distilled water constitute approximate limits for each of those components.
  • the time of immersion may vary depending upon the results desired, from to 60 seconds.
  • the Work is then rinsed and dried. Having the polishing and etching bath at a slightly elevated temperature but not over about 200 F. will reduce the immersion time.
  • the functions of the various ingredients is not certain.
  • the hydrofluoric acid is possibly the principal acid for attack upon the metal.
  • the nitric acid and the hydrogen peroxide both cooperate in an oxidizing reaction.
  • the distilled water serves as both a diluent and as a carrier or vehicle in producing a uniformly distributed polishing action.
  • the ethylene glycol is believed to function as a carrier to insure uniformity in distribution of the polishing and etching action. The same may be said of the glycerol.
  • a metallographic reagent for chemical polishing and simultaneously preferentially etching metallographic specimen of titanium and its alloys in solid solution whereby they are made ready for microscopic metallographic examination said reagent consisting essentially of 10 parts by volume of 48% GP. hydrofluoric acgl, 10 parts by volume of commercial 69.3% nitric acid, 60 parts by volume of U.S.P. 3% hydrogen peroxide and 30 parts by volume of distilled water.
  • a chemical polishing reagent according to claim 1 having also at least and not more than 300 parts by volume of one from a group consisting of ethylene glycol and glycerol.
  • a chemical polishing reagent according to claim 2 containing 150 parts by volume of glycerol.
  • a chemical polishing reagent according to claim 2 containing 300 parts by volume of ethylene glycol.
  • a process for preparing a specimen of titanium solid solution alloys for metallographic examination by reflected light from a specimen into a microscope which comprises chemically polishing said specimen to enhance reflectivity of light rays incident upon a surface of the specimen into a microscope, and simultaneously etching said surface of said specimen for delineation of grain boundaries during said polishing by reacting grain boundaries in said surface to the action of a reagent at a temperature of not over about 200 F. for not more than about one minute depending on the temperature of the reagent, and terminating said reaction by separating said surface from said reagent, when said reagent consists essentially of 10 parts by volume of 48% GP. hydrofluoric acid, 60 parts by volume of U.S.P. 3% hydrogen peroxide, 10 parts by volume of commercial 69.3% nitric acid, and 30 parts by volume of distilled water.
  • a process according to claim 5 which includes in said reagent at least about 150 parts by volume and not more than about 300 parts by volume of one member of a group consisting of glycerol and ethylene glycol.

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  • 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)
  • Sampling And Sample Adjustment (AREA)

Description

United States Patent PROCESS AND COMPOSITION FOR CHEMICALLY TREATING TITANIUM AND ITS ALLOYS Albert Borowik, Bridgeport, Pa., assignor to the United States of America as represented by the Secretary of the Army No Drawing. Filed Feb. 8, 1957, Ser. No. 639,121
8 Claims. (Cl. 41-42) (Granted under Title 35, U.S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.
This invention relates to a material and process for the chemical polishing and etching of titanium and its alloys for metallographic examination and has for an object to provide a suitable reagent and process for this purpose.
An examination of the true microstructure of a metal specimen has been said to be the prime function of chemical as distinguished from electroyltic polishing. The specimen may have been mechanically polished beforehand to obtain good light-reflective surface. Chemical etching dissolves more metal at grain boundaries than from the surface of the grains in order to provide better grain delineation.
Titanium and its solid solution alloys have been diflicult to polish mechanically because the metal is quickly work-hardened yet at the same time it has a tendency to flow and hide the true grain structure in a manner sowewhat analogous to the way in which a plastic will be deformed and hide a subsurface layer. Hand-polishing of such metal has been done but such is tedious for titanium and its alloys for the reason mentioned.
According to this invention a reagent has been discovered which is peculiarly suited to give good results with metallographic specimen of titanium and its alloys. The reasons therefor are unknown and the discovery of such has been empirical. Specifically, only one reagent formed from a number of old ingredients has been found satisfactory for the intended purpose. That one reagent includes 10 cc. of 48% GP. hydrofluoric acid with 10 cc. of 69.3% of commercial nitric acid, 60 cc. of U.S.P. 3% hydrogen peroxide, and 30 cc. of distilled water. A better reagent composition has been found to result from the addition to the foregoing of 150 cc. of commercial glycerol having a specific gravity of 1.249. The best reagent for titanium metals and alloys is when 300 cc. of commercial ethylene glycol is added to the first mentioned combination of ingredients. In that first combination, plus or minus 5% by volume of each acid, the hydrogen peroxide and the distilled water constitute approximate limits for each of those components.
The time of immersion may vary depending upon the results desired, from to 60 seconds. The Work is then rinsed and dried. Having the polishing and etching bath at a slightly elevated temperature but not over about 200 F. will reduce the immersion time.
The functions of the various ingredients is not certain. The hydrofluoric acid is possibly the principal acid for attack upon the metal. The nitric acid and the hydrogen peroxide both cooperate in an oxidizing reaction. The distilled water serves as both a diluent and as a carrier or vehicle in producing a uniformly distributed polishing action. The ethylene glycol is believed to function as a carrier to insure uniformity in distribution of the polishing and etching action. The same may be said of the glycerol. Whatever the actions of these ingredients, it should be emphasized that their cooperative action results in the most satisfactory results with titanium solid solution alloys.
ice
Among the advantages of this invention may be mentioned the provision of a polished light reflecting surface of titanium alloys at the same time a revealing etched surface is provided whereby the previous difliculties with mechanical polishing of this metal have been eliminated.
I claim:
1. A metallographic reagent for chemical polishing and simultaneously preferentially etching metallographic specimen of titanium and its alloys in solid solution whereby they are made ready for microscopic metallographic examination, said reagent consisting essentially of 10 parts by volume of 48% GP. hydrofluoric acgl, 10 parts by volume of commercial 69.3% nitric acid, 60 parts by volume of U.S.P. 3% hydrogen peroxide and 30 parts by volume of distilled water.
2. A chemical polishing reagent according to claim 1 having also at least and not more than 300 parts by volume of one from a group consisting of ethylene glycol and glycerol.
3. A chemical polishing reagent according to claim 2 containing 150 parts by volume of glycerol.
4. A chemical polishing reagent according to claim 2 containing 300 parts by volume of ethylene glycol.
5. A process for preparing a specimen of titanium solid solution alloys for metallographic examination by reflected light from a specimen into a microscope which comprises chemically polishing said specimen to enhance reflectivity of light rays incident upon a surface of the specimen into a microscope, and simultaneously etching said surface of said specimen for delineation of grain boundaries during said polishing by reacting grain boundaries in said surface to the action of a reagent at a temperature of not over about 200 F. for not more than about one minute depending on the temperature of the reagent, and terminating said reaction by separating said surface from said reagent, when said reagent consists essentially of 10 parts by volume of 48% GP. hydrofluoric acid, 60 parts by volume of U.S.P. 3% hydrogen peroxide, 10 parts by volume of commercial 69.3% nitric acid, and 30 parts by volume of distilled water.
6. A process according to claim 5 which includes in said reagent at least about 150 parts by volume and not more than about 300 parts by volume of one member of a group consisting of glycerol and ethylene glycol.
7. A process according to claim 5 in which said reagent includes about 150 parts by volume of glycerol.
8. A process according to claim 5 in which said reagent includes about 300 parts by volume of ethylene glycol.
References Cited in the tile of this patent UNITED STATES PATENTS 2,542,727 Theuerer Feb. 20, 1951 2,606,960 Little Aug. 12, 1952 2,687,345 Murray Aug. 24, 1954 2,711,364 Beach June 21, 1955 2,724,667 MacPherson Nov. 22, 1955 2,734,837 Hands Feb. 14, 1956 2,828,192 Langfield Mar. 25, 1958 2,876,144 Bomberger Mar. 3, 1959 FOREIGN PATENTS 753,158 Great Britain July 18, 1956 789,625 Great Britain Ian. 22, 1958 OTHER REFERENCES New Etches for Germanium, by Ellis and Wolsky,
from the Journal of Applied Physics, vol. 24, 1953; pages 1411 and 1412.
Lflhi'simati

Claims (2)

1. A METALLOGRAPHIC REAGENT FOR CHEMICAL POLISHING AND SIMULTANEOUSLY PREFERENTIALLY ETCHING METALLOGRAPHIC SPECIMEN OF TITANIUM AND ITS ALLOYS IN SOLID SOLUTION WHEREBY THEY ARE MADE READY FOR MICROSCOPIC METALLOGRAPHIC EXAMINATION, SAID REAGENT CONSISTING ESSENTIALLY OF 10 PARTS BY VOLUME OF 48% C.P. HYDROFLUORIC ACID, 10 PARTS BY VOLUME OF COMMERCIAL 69.3% NITRIC ACID, 60 PARTS BY VOLUME OF U.S.P. 3% HYDROGEN PEROXIDE AND 30 PARTS BY VOLUME OF DISTILLED WATER.
5. A PROCESS FOR PREPARING A SPECIMEN OF TITANIUM SOLID SOLUTION ALLOYS FOR METALLOGRAPHIC EXAMINATION BY REFLECTED LIGHT FROM A SPECIMEN INTO A MICROSCOPE WHICH COMPRISES CHEMICALLY POLISHING SAID SPECIMEN TO ENHANCE REFLECTIVITY OF LIGHT RAYS INCIDENT UPON A SURFACE OF THE SPECIMEN INTO A MICROSCOPE, AND SIMULTANEOUSLY ETCHING SAID SURFACE OF SAID SPECIMEN FOR DELINEATION OF GRAIN BOUNDARIES DURING SAID POLISHING BY REACTING GRAIN BOUNDARIES IN SAID SURFACE TO THE ACTION OF A REAGENT AT A TEMPERATURE OF NOT OVER ABOUT 200* F. FOR NOT MORE THAN ABOUT ONE MINUTE DEPENDING ON THE TEMPERATURE OF THE REAGENT, AND TERMINATING SAID REACTION BY SEPARATING SAID SURFACE FROM SAID REAGENT, WHEN SAID REAGENT CONSISTS ESSENTIALLY OF 10 PARTS BY VOLUME OF 48% C.P. HYDROFLUORIC ACID, 60 PARTS BY VOLUME OF U.S.P. 3% HYDROGEN PEROXIDE, 10 PARTS BY VOLUME OF COMMERCIAL 69.3% NITRIC ACID, AND 30 PARTS BY VOLUME OF DISTILLED WATER.
US639121A 1957-02-08 1957-02-08 Process and composition for chemically treating titanium and its alloys Expired - Lifetime US2974021A (en)

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3992235A (en) * 1975-05-21 1976-11-16 Bell Telephone Laboratories, Incorporated Etching of thin layers of reactive metals
US4220706A (en) * 1978-05-10 1980-09-02 Rca Corporation Etchant solution containing HF-HnO3 -H2 SO4 -H2 O2
DE4127085A1 (en) * 1991-08-16 1993-02-18 Lorenz Stoeger Pneumatic screwdriver for higher torque and screws at closer centres - has feed cylinder parallel to main cylinder and adjusting screw for setting height of screwdriver relative to workpiece
US5248386A (en) * 1991-02-08 1993-09-28 Aluminum Company Of America Milling solution and method
US20060157542A1 (en) * 2003-07-11 2006-07-20 Joachim Rosler Method for machining a workpiece made from a titanium-based alloy
US20060231948A1 (en) * 2005-04-13 2006-10-19 Stats Chippac Ltd. Integrated circuit system for bonding
EP1793016A1 (en) * 2005-12-01 2007-06-06 Elpochem AG Polishing and deburring composition for workpieces of carbon steel and method of chemical polishing and deburring
WO2008098593A1 (en) * 2007-02-15 2008-08-21 Basf Se Titanium etchant composition
US9481934B2 (en) 2012-05-09 2016-11-01 Mitsubishi Heavy Industries Aero Engines, Ltd. Method of removing work-affected layer
RU2610601C1 (en) * 2015-11-06 2017-02-14 Акционерное общество "Научно-исследовательский институт полимерных материалов" Method for treatment of waste water produced in manufacture of solid propellant components

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2542727A (en) * 1949-12-29 1951-02-20 Bell Telephone Labor Inc Etching processes and solutions
US2606960A (en) * 1949-06-01 1952-08-12 Bell Telephone Labor Inc Semiconductor translating device
US2687345A (en) * 1950-11-22 1954-08-24 Printing Dev Inc Etching composition for lithographic plates
US2711364A (en) * 1953-12-31 1955-06-21 John G Beach Polishing metals and composition therefor
US2724667A (en) * 1955-01-14 1955-11-22 Wayne Foundry & Stamping Co Process of removing scale from titanium
US2734837A (en) * 1953-10-03 1956-02-14 Surface treatment of titanium or
GB753158A (en) * 1953-03-25 1956-07-18 Standard Telephones Cables Ltd Method of etching germanium or silicon
GB789625A (en) * 1955-09-13 1958-01-22 Ericsson Telephones Ltd Improvements in and relating to the manufacture of germanium
US2828192A (en) * 1954-10-04 1958-03-25 Turco Products Inc Method for etching metals
US2876144A (en) * 1956-02-24 1959-03-03 Crucible Steel Co America Metal pickling solutions and methods

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2606960A (en) * 1949-06-01 1952-08-12 Bell Telephone Labor Inc Semiconductor translating device
US2542727A (en) * 1949-12-29 1951-02-20 Bell Telephone Labor Inc Etching processes and solutions
US2687345A (en) * 1950-11-22 1954-08-24 Printing Dev Inc Etching composition for lithographic plates
GB753158A (en) * 1953-03-25 1956-07-18 Standard Telephones Cables Ltd Method of etching germanium or silicon
US2734837A (en) * 1953-10-03 1956-02-14 Surface treatment of titanium or
US2711364A (en) * 1953-12-31 1955-06-21 John G Beach Polishing metals and composition therefor
US2828192A (en) * 1954-10-04 1958-03-25 Turco Products Inc Method for etching metals
US2724667A (en) * 1955-01-14 1955-11-22 Wayne Foundry & Stamping Co Process of removing scale from titanium
GB789625A (en) * 1955-09-13 1958-01-22 Ericsson Telephones Ltd Improvements in and relating to the manufacture of germanium
US2876144A (en) * 1956-02-24 1959-03-03 Crucible Steel Co America Metal pickling solutions and methods

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3992235A (en) * 1975-05-21 1976-11-16 Bell Telephone Laboratories, Incorporated Etching of thin layers of reactive metals
US4220706A (en) * 1978-05-10 1980-09-02 Rca Corporation Etchant solution containing HF-HnO3 -H2 SO4 -H2 O2
US5248386A (en) * 1991-02-08 1993-09-28 Aluminum Company Of America Milling solution and method
DE4127085A1 (en) * 1991-08-16 1993-02-18 Lorenz Stoeger Pneumatic screwdriver for higher torque and screws at closer centres - has feed cylinder parallel to main cylinder and adjusting screw for setting height of screwdriver relative to workpiece
US20060157542A1 (en) * 2003-07-11 2006-07-20 Joachim Rosler Method for machining a workpiece made from a titanium-based alloy
US20060231948A1 (en) * 2005-04-13 2006-10-19 Stats Chippac Ltd. Integrated circuit system for bonding
US7381634B2 (en) * 2005-04-13 2008-06-03 Stats Chippac Ltd. Integrated circuit system for bonding
EP1793016A1 (en) * 2005-12-01 2007-06-06 Elpochem AG Polishing and deburring composition for workpieces of carbon steel and method of chemical polishing and deburring
WO2008098593A1 (en) * 2007-02-15 2008-08-21 Basf Se Titanium etchant composition
US9481934B2 (en) 2012-05-09 2016-11-01 Mitsubishi Heavy Industries Aero Engines, Ltd. Method of removing work-affected layer
RU2610601C1 (en) * 2015-11-06 2017-02-14 Акционерное общество "Научно-исследовательский институт полимерных материалов" Method for treatment of waste water produced in manufacture of solid propellant components

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