US3761302A - Reducing re evaporation of vacuum vapor deposited coatings - Google Patents
Reducing re evaporation of vacuum vapor deposited coatings Download PDFInfo
- Publication number
- US3761302A US3761302A US00166585A US3761302DA US3761302A US 3761302 A US3761302 A US 3761302A US 00166585 A US00166585 A US 00166585A US 3761302D A US3761302D A US 3761302DA US 3761302 A US3761302 A US 3761302A
- Authority
- US
- United States
- Prior art keywords
- coating
- metal
- zinc
- substrate
- vapor pressure
- 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
Links
- 238000000576 coating method Methods 0.000 title abstract description 84
- 238000001704 evaporation Methods 0.000 title description 14
- 230000008020 evaporation Effects 0.000 title description 3
- 239000011248 coating agent Substances 0.000 abstract description 78
- 229910052751 metal Inorganic materials 0.000 abstract description 78
- 239000002184 metal Substances 0.000 abstract description 78
- 150000002739 metals Chemical class 0.000 abstract description 12
- 239000000126 substance Substances 0.000 abstract description 3
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 41
- 229910052725 zinc Inorganic materials 0.000 description 41
- 239000011701 zinc Substances 0.000 description 41
- 239000000758 substrate Substances 0.000 description 34
- 238000000034 method Methods 0.000 description 15
- 239000002344 surface layer Substances 0.000 description 9
- 238000009833 condensation Methods 0.000 description 7
- 230000005494 condensation Effects 0.000 description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 229910000831 Steel Inorganic materials 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical group [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 4
- 229910052793 cadmium Inorganic materials 0.000 description 4
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 238000007740 vapor deposition Methods 0.000 description 3
- 238000005019 vapor deposition process Methods 0.000 description 3
- 230000008021 deposition Effects 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000011787 zinc oxide Substances 0.000 description 2
- 241000282337 Nasua nasua Species 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000005028 tinplate Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Images
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
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
Definitions
- This invention relates to a process of coating a substrate with a coating metal by vacuum vapor deposition. It is more particularly concerned with a process for coating a high vapor pressure coating metal.
- the thickness of the coating metal remaining on the substrate at equilibrium conditions is dependent upon the relative thickness of coating metal and substrate and their relative heat conductivities. Under the near adiabatic conditions existing in the evacuated coating chamber, heat losses are minimized and the heat supplied to the substrate by coating metal condensation is distributed throughout the coating and substrate in accordance with the known laws of heat fiow.
- Re-evaporation is the factor limiting the thickness of United States Patent 0 ice vacuum vapor deposited coatings of a number of metals in addition to zinc. Each of these metals, in common with zinc, has a vapor pressure at its melting point greater than the vapor pressure in the coating chamber. We include these metals under the designation high vapor pressure metals. The more useful metals in this group in addition to zinc are cadmium, chromium, magnesium and nickel.
- the factor limiting vacuum vapor coating with a metal such as aluminum or tin which has at its melting point a vapor pressure less than the vapor pressure in the coating chamber is its melting point.
- the oxide of a metal has a vapor pressure appreciably lower than the metal itself, so that an oxidizing gas is a suitable surface modifying agent.
- oxides of zinc, cadmium, chromium, magnesium, and nickel are representative of suitable surface modifying agents.
- FIG. 1 of the attached drawing Steel strip 1, the substrate here, is unwound from an uncoiling reel 2, passed through an evacuated chamber 4, and recoiled on coiling reel 3.
- chamber 4 In chamber 4 is a crucible 5 heated by an electrical resistance heater 6.
- Crucible 5 is positioned below the path of travel of the strip 1.
- Crucible 5 contains molten coating metal 7, for example, zinc, which evaporates in the evacuated chamber 4 into metal vapor 8. This vapor condenses on the colder strip 1 as it passes over crucible 5.
- Adjacent crucible 5 inside chamber 4 is a pipe 9 from which an oxidizing gas such as air is directed onto the surface of the condensed coating metal. At its condensation temperature, that metal reacts very rapidly with air or other oxidizing gas to form an oxide of the metal over its surface.
- the coating metal is zinc
- the second metal is preferably aluminum or tin.
- FIG. 2 of the attached drawing in which elements like those in FIG. 1 have the same reference characters.
- Evacuated chamber 4 in FIG. 2 is not provided with the pipe 9 of FIG. I, but in its place has a second crucible 10 positioned adjacent crucible 5 and downstream therefrom, below the path of travel of the strip 1.
- Crucible is heated by electric resistance heater 11.
- Crucible 10 contains a second molten metal 12 which is maintained at its evaporation temperature and evaporates into vapor 13.
- the strip 1 after passing over crucible 5 and being coated with the condensed coating metal 7 evaporated therefrom passes immediately over crucible 10 and the second metal 12 evaporated therefrom condenses on the surface of the first coating metal 7. If second coating metal 12 is selected to have a lower vapor pressure than first coating metal 7, the re-evaporation of the vapor deposited coating within chamber 4 is correspondingly reduced.
- the coating chamber is continuously pumped to a pressure between 1 and 4X10- mm. of Hg.
- the substrate in the form of steel strip is passed into the coating chamber and over a crucible in which zinc is heated and vaporized.
- the crucible temperature is raised until the vapor pressure of the zinc immediately over the crucible reaches values between 0.2 and 3.0 mm. of Hg.
- This high pressure region is confined to the immediate vicinity of the crucible.
- the vaporized zinc condenses on the substrate and its condensation releases heat which raises the substrate temperature to values which may exceed 500 F.
- a zinc vapor pressure of 0.2 mm. of Hg corresponds to a zinc temperature in excess of 800 F.
- a top coating of a metal or a metal oxide which has a vapor pressure lower than that of zinc is provided on the zinc coated substrate immediately after the latter has passed over the vapor source.
- This top coating is selected so that it does not re-evaporate in the coating chamber at the highest temperature reached by the strip and the coating metal thereon, and it thus puts an end to coating metal re-evaporation.
- the coated strip leaving the coating chamber has a thicker coating of zinc under the top coat than it would have had if the top coating had not been applied.
- the method of vacuum vapor coating a metal substrate with a coating metal comprising passing the metal substrate through an evacuated chamber over a source of coating metal vapor, said coating metal having a vapor pressure at its melting point greater than the vapor pressure of the evacuated chamber, adjusting the rate of evaporation of the coating metal so as to increase its vapor pressure immediately over the source above the pressure of the evacuated chamber, thereby to increase the rate of condensation of the coating metal on the substrate and the temperature of the coating metal on the substrate to a temperature above that at which the vapor pressure of the coating metal equals the pressure in the evacuated chamber, passing the coated substrate away from the source into a region of the evacuated chamber of pressure lower than the vapor pressure of the coating metal on the substrate, where the coating metal would commence to re-evaporate from the substrate if permitted to do so, and in that region providing on the surface of the coating metal a surface layer of a substance selected from the group consisting of metals and metal oxides which have vapor pressures lower than the vapor pressure of the coating metal, the
- the coating metal is selected from the group consisting of zinc, cadmium, chromium, magnesium, and nickel and the surface layer is selected from the group consisting of zinc oxide, cadmium, oxide, chromium oxide, magnesium oxide, and nickel oxide.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physical Vapour Deposition (AREA)
Abstract
Description
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US16658571A | 1971-07-21 | 1971-07-21 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3761302A true US3761302A (en) | 1973-09-25 |
Family
ID=22603928
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00166585A Expired - Lifetime US3761302A (en) | 1971-07-21 | 1971-07-21 | Reducing re evaporation of vacuum vapor deposited coatings |
Country Status (1)
Country | Link |
---|---|
US (1) | US3761302A (en) |
-
1971
- 1971-07-21 US US00166585A patent/US3761302A/en not_active Expired - Lifetime
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: JONES & LAUGHLIN STEEL, INCORPORATED Free format text: MERGER;ASSIGNORS:JONES & LAUGHLIN STEEL CORPORATION, A CORP. OF PA.;YOUNGTOWN SHEET & TUBE COMPANY, A CORP. OF OH. (MERGED INTO);NEW J&L STEEL CORPRATION, A CORP. OF DE., (CHANGED TO);REEL/FRAME:004510/0801 Effective date: 19851018 |
|
AS | Assignment |
Owner name: LTV STEEL COMPANY, INC., Free format text: MERGER AND CHANGE OF NAME EFFECTIVE DECEMBER 19, 1984, (NEW JERSEY);ASSIGNORS:JONES & LAUGHLIN STEEL, INCORPORATED, A DE. CORP. (INTO);REPUBLIC STEEL CORPORATION, A NJ CORP. (CHANGEDTO);REEL/FRAME:004736/0443 Effective date: 19850612 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED FILE - (OLD CASE ADDED FOR FILE TRACKING PURPOSES) |