Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/22—Electroplating: Baths therefor from solutions of zinc

Definitions

• the invention is based on the discovery that certain organic compounds when incorporated in an alkaline pyrophosphate zinc bath in combination with various carbonyl compounds of the aldehyde and ketone types are capable of promoting the formation of excellent bright and uniformly smooth electrodeposits of zinc over a wide current density range. Moreover, the additives of this invention greatly improve the throwing power of the zinc pyrophosphate plating solution making it particularly suitable for barrel plating.
• an organic compound hereafter referred to as a carrier, selected from the group consisting of (a) his [sulfonaphthyl] methane; (b) naphthalene derivatives that contain substituents selected from the group consisting of sulfonic acids and their alkali metal salts, hydroxyl, amino, and imino radicals; (c) benzene derivatives containing the substituents selected from the group consisting of sulfonic acids and their salts with alkali metal and ammonium, alkyl and imino radicals, and (d) allyl sulfonic acid and its salts with alkali metals, when incorporated into a pyrophosphate zinc plating bath in combination with a carbonyl compound of the aldehyde and the ketone types will increase greatly the brightness and the uniformity of the zinc deposit.
• the low current density coverage of the bath also is improved, and the resultant electrodeposit of zinc shows a reduction in rough
• a preferred process for producing bright zinc deposits comprises electrodepositing zinc from an aqueous alkaline pyrophosphate solution containing at least one zinc salt in which there is dissolved from about 0.5 to about 5.0 grams per liter of a carrier selected from the group previously stated, and from about 0.025 to about 0.2 gram per liter of a carbonyl compound selected from the group consisting of aldehydes and. ketones.
• the specific carriers of this invention may be used successfully at any concentration within the broad range stated above, it is generally preferable to employ them in a concentration from about 0.9 to about 1.6 grams per liter. Also it is preferred to employ the carbonyl compound at a concentration in the range from about 0.05 to about 0.1 gram per liter. I have found that the maximum brightness of the deposit is not obtained when the concentration of the carbonyl compound is too low. A high concentration of carbonyl compound, on the other hand, decreases the low current density coverage.
• Table I sets forth examples of the carriersthat have been used successfully in the process of this invention.
• any of the carbonyl compounds of the aldehydes and ketone types which cooperate efiFectively with the carriers of this invention may be used in combination with the carriers of this invention in carrying out this process.
• the carbonyl compounds that are effective have a structural formula selected from the group consisting of wherein R is selected from the group consisting of hydrogen, alkyl, aryl and heterocyclic oxygen and sulfur radicals, and R and R" are selected from the group consisting of alkyl' and aryl radicals. Both the alkyl and the aryl radicals in R, R and R" may contain substituents such as alkoxy or hydroxy radicals.
• Table I'I sets forth the carbonyl compounds that have been used successfully in combination with the carriers of this invention.
• the other carriers of this invention combine synergistically with a carbonyl compound of the aldehyde and ketone types to provide improvements in the brightness, uniformity and the low current density coverage of the electrodcpositcd zinc.
• a carbonyl compound of the aldehyde and ketone types to provide improvements in the brightness, uniformity and the low current density coverage of the electrodcpositcd zinc.
• Example 1 6 Two grams per liter of 8 amino, 1 naphthalene sulfonic :acid were dissolved in the basic pyrophosphate solution.
• Zinc was electrodcpositcd onto a Hull panel. After the plating was completed, 0.1 gram per liter of furfural was added to the solution containing the carrier and a similar Hull panel was electrodeposited from this solution. These two plates were visually compared. It was found that the panel plated in accordance with the invention was brighter, more uniform and had better back coverage.
• Examples 17-22 Similar to Example 16 except that 6,6'-imino bis-(1 naphthol-3) sulfonic acid; 2 naphthol-6,8 disulfonic acid;
• 2,6 naphthalene-disulfonic acid 2,3- dihydroxy-6 naphthalene sulfonate (sodium salt); 1,5 dihydroxy naphthalene and 1,4 naphthalene diol were used separately as carriers in each example.
• 2,6 naphthalene-disulfonic acid 2,3- dihydroxy-6 naphthalene sulfonate (sodium salt); 1,5 dihydroxy naphthalene and 1,4 naphthalene diol were used separately as carriers in each example.
• the two panels in each example were compared visually, the one plated in accordance with the process of this invention was either brighter, more uniform or had better back coverage.
• the process for producing bright zinc deposits which comprises electroplating zinc from an aqueous alkaline pyrophosphate solution containing at least one zinc salt in which there is dissolved from about 0.5 to about 5.0 grams per liter of a carrier selected from the group consisting of (a) his [sulfonaphthyl] methane, (b) naphthalene derivates that contain substituents selected from the group consisting of sulfonic acids and their alkali metal salts, hydroxyl, amino and imino radicals, (c) benzene derivatives containing substituents selected from the group consisting of sulfonic acids and their salts with alkali metal and ammonium, alkyl and imino radicals, and (d) allyl sulfonic acid and its salts with alkali metals, and from about 0.025 to about 0.2 gram per liter of a carbonyl compound having a structural formula selected from the group consisting of wherein R is selected from the group consisting
• the process for producing bright zinc deposits which comprises electrodepositing zinc from an aqueous alkaline pyrophosphate solution containing at least one zinc salt in which there is dissolved from about 0.5 to about 5.0 grams per liter of a carrier selected from the group consisting of (a) bis [sulfonaphthyl] methane, (b) naphthalene derivatives that contain substituents selected from the group consisting of sulfonic acids and their alkali metal salts, hydroxyl, amino and imino radicals, (c) benzene derivatives containing substituents selected from the group consisting of sulfonic acids and their salts with alkali metal and ammonium, alkyl and imino radicals, and (d) allyl sulfonic acid and its salts with alkali metals, and from about 0.025 and to about 0.2 gram per liter of an aldehyde having a structural formula wherein R is selected from the group consisting of hydrogen, alkyl,
• the process for producing bright zinc deposits which comprises electrodepositing zinc from an aqueous alkaline pyrophosphate solution containing at least one zinc salt in which there is dissolved from about 0.9 to 1.6 grams per liter of a carrier selected from the proup consisting of (a) his [sulfonaphthyl] methane, (b) naphcompound having a structural formula selected from the group consisting of wherein R is selected from the group consisting of hydrogen, alkyl, aryl and heterocyclic oxygen and sulfur radicals, and R and R are selected from the group consisting of alkyl and aryl radicals.
• the process for producing bright zinc deposits which comprises electrodepositing zinc from an aqueous alkaline pyrophosphate solution .at a temperature ranging from about 40 C. to about 50 C., said solution containing 10 to 60 grams per liter of zinc which provides a pyrophosphate radical (P 0 to zinc weight ratio of 6.5 to 1 to 8.0 to 1 and a pH in the range from 10.5 to 12.0, in said solution there is dissolved from about 0.5 to about 5.0 grams per liter of a carrier selected from the group consisting of (a) his [sulfonaphthyl] methane, (b) naphthalene derivatives that contain substituents selected from the group consisting of sulfonic acids and their alkali metal salts, hydroxyl, amino, and imino radicals, (c) benzene derivatives contaninig substituents selected from the group consisting of sulfonic acids and their salts with alkali metal and ammonium, alkyl and imino radicals
• the process for producing bright zinc deposits which comprises electrodepositing zinc from an aqueous alkaline pyrophosphate solution at a temperature ranging from about 40 to. about 50 C., said solution containing 20 to 30 grams per liter of zinc which provides a pyrophosphate radical (P 0 to zinc weight ratio of 7.0 to 1 to 8.0 to 1 and a pH of about 11.0, in said solution there is dissolved from about 0.9 to about 1.6 grams per liter of a carrier selected from the group consisting of (a) his [sulfonaphthyl] methane, (b) naphthalene derivatives that contain substituents selected from the group consisting of sulfonic acids and their alkali.
• a carrier selected from the group consisting of (a) his [sulfonaphthyl] methane, (b) naphthalene derivatives that contain substituents selected from the group consisting of sulfonic acids and their alkali.
• benzene derivatives containing substituents selected from the group consisting of sulfonic acids and their salts with alkali metal and ammonium, alkyl and imino radicals,-
• allyl sulfonic acid and its salts with alkali metals and from about 0.05 to about 0.1 gram per liter of a carbonyl compound having a structural formula selected from the group consisting of gen, alkyl, aryl and heterocyclic oxygen and sulfur radicals, and R and R" are selected from the group consisting of alkyl and aryl radicals.
• the process for producing bright zinc deposits which comprises electrodeposi-ting zinc from an aqueous alkaline pyrophosphate solution at a temperature ranging from about 40 C. to about 50 C., said solution containing to 60 grams per liter of zinc which provides a pyrophosphate radical (P 0 to zinc weight ration of 6.5 to 1 to 8.0 -to 1 and a pH in the range from 10.5 to 12.0, in said solution there is dissolved from about 0.5 to about 5.0 grams per liter of his [sulfonaphthyl] methane, and from about 0.025 to about 0.2 gram per liter of an aldehyde having a structural formula wherein R is selected from the group consisting of hydrogen, alkyl, aryl and heterocyclic oxygen and sulfur radicals.
• a bright zinc plating bath comprising an aqueous alkaline pyrophospha-te solution containing about 10 to 60 grams per liter of zinc which provides a pyrophosphate radical (P 0 to zinc Weight ratio of 6.5 to 1 to 8.0 to 1 and a pH in the range from 10.5 to 12.0, about 0.5 to about 5.0 grams per liter of a carrier selected from the group consisting of (a) bis [sulfonaphthyl] methane, (-b) naphthalene derivatives that contain substituents selected from the group consisting of sulfonic acids and their alkali metal salts, hydroxyl, amino and imino radicals, (c) benzene derivatives containing substituents selected from the group consisting of sulfonic acids and their salts with alkali metal and ammonium, alkyl and imino radicals, and (d) allyl sulfonic acid and its salts with alkali metals, and from about 0.025
• a bright zinc plating bath comprising an aqueous alkaline pyrophosp'hate solution containing about 20 to 30 grams per liter of zinc which provides a pyrophosphate radical (P 0 to zinc weight ratio of from about 7.0 to 1 to 8.0 to 1, about 0.9 to 1.6 grams per liter of a carrier selected from the group consisting of (a) bis [sulfonaphthyl] methane, (b) naphthalene derivatives that contain substituents selected from the group consisting of sulfonic acids and their alkali metal salts, hydroxyl, amino, and imino radicals, (c) benzene derivatives containing substituents selected from the group consisting of sulfonic acids and their salts with alkali metal and ammonium, alkyl and imino radicals, and (d) allyl sulfonic acid and its salts with alkali metals, and about 0.05 to 0.1 gram per liter of a carbonyl compound
• a bright zinc plating bath comprising an aqueous alkaline pyrophosphate solution containing at least one zinc salt, about 0.5 to about 5.0 grams per liter of his [sulfonaphthyl] methane, and from about 0.025 to about 0.2 gram per liter of an aldehyde having a structural formula wherein R is selected from the group consisting of hydrogen, alkyl, aryl and heterocyclic oxygen and sulfur radicals.
• a bright zinc plating bath comprising an aqueous alkaline pyrophosp'hate solution containing about 10 to 60 grams per liter of zinc which provides a pyrophosphate radical (P 0 to zinc weight ratio of from about 10.5 to about 12.0, about 0.5 to 5.0 grams per liter of bis [sulfonaphthyl] methane and about 0.025 to 0.2 gram per liter of an aldehyde having a structural formula of wherein R is selected from the group consisting of hydrogen, alkyl, aryl and heterocyclic oxygen and sulfur.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electroplating And Plating Baths Therefor (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Mechanical Treatment Of Semiconductor (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

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Cited By (4)

Citations (5)

• 1963
  • 1963-10-29 US US319666A patent/US3296104A/en not_active Expired - Lifetime
• 1964
  • 1964-08-19 SE SE9992/64A patent/SE304658B/xx unknown
  • 1964-08-24 GB GB34541/64A patent/GB1083504A/en not_active Expired
  • 1964-09-28 NL NL646411274A patent/NL147793B/xx unknown
  • 1964-09-29 ES ES304489A patent/ES304489A1/es not_active Expired
  • 1964-10-10 DE DEH53997A patent/DE1294134B/de not_active Withdrawn
  • 1964-10-16 CH CH1343164A patent/CH432973A/fr unknown
  • 1964-10-19 FR FR991937A patent/FR1415033A/fr not_active Expired
  • 1964-10-19 BE BE654543D patent/BE654543A/xx unknown
  • 1964-10-29 AT AT919264A patent/AT267992B/de active

Patent Citations (5)

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