US2498485A - Method of tinning a steel shell bearing - Google Patents
Method of tinning a steel shell bearing Download PDFInfo
- Publication number
- US2498485A US2498485A US688965A US68896546A US2498485A US 2498485 A US2498485 A US 2498485A US 688965 A US688965 A US 688965A US 68896546 A US68896546 A US 68896546A US 2498485 A US2498485 A US 2498485A
- Authority
- US
- United States
- Prior art keywords
- tinning
- article
- tin
- bath
- polysiloxane
- 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
- 238000000034 method Methods 0.000 title description 9
- 229910000831 Steel Inorganic materials 0.000 title description 4
- 239000010959 steel Substances 0.000 title description 4
- -1 polysiloxane Polymers 0.000 description 44
- 229920001296 polysiloxane Polymers 0.000 description 37
- 229920005989 resin Polymers 0.000 description 36
- 239000011347 resin Substances 0.000 description 36
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 21
- 229910052718 tin Inorganic materials 0.000 description 21
- 239000011135 tin Substances 0.000 description 21
- 239000004115 Sodium Silicate Substances 0.000 description 13
- 229910052911 sodium silicate Inorganic materials 0.000 description 13
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 13
- 238000007747 plating Methods 0.000 description 11
- 238000000576 coating method Methods 0.000 description 10
- 230000000873 masking effect Effects 0.000 description 10
- 239000011248 coating agent Substances 0.000 description 9
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 8
- 238000005554 pickling Methods 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
- 239000002253 acid Substances 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 7
- 238000005524 ceramic coating Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 238000007598 dipping method Methods 0.000 description 3
- 230000004907 flux Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 125000001183 hydrocarbyl group Chemical group 0.000 description 3
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 3
- 229920001187 thermosetting polymer Polymers 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- 239000005028 tinplate Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 235000005074 zinc chloride Nutrition 0.000 description 2
- 239000011592 zinc chloride Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-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
- 229910001128 Sn alloy Inorganic materials 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 229910052910 alkali metal silicate Inorganic materials 0.000 description 1
- 229920000180 alkyd Polymers 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000007859 condensation product Substances 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 235000011167 hydrochloric acid Nutrition 0.000 description 1
- 239000011344 liquid material Substances 0.000 description 1
- 239000012768 molten material Substances 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 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
- 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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/08—Tin or alloys based thereon
-
- 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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
-
- 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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/06—Sliding surface mainly made of metal
- F16C33/14—Special methods of manufacture; Running-in
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/02—Sliding-contact bearings for exclusively rotary movement for radial load only
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2204/00—Metallic materials; Alloys
- F16C2204/30—Alloys based on one of tin, lead, antimony, bismuth, indium, e.g. materials for providing sliding surfaces
- F16C2204/34—Alloys based on tin
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/06—Sliding surface mainly made of metal
- F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
- F16C33/122—Multilayer structures of sleeves, washers or liners
- F16C33/125—Details of bearing layers, i.e. the lining
Definitions
- This invention is concerned with a method of partially tinning metallic articles. More particularly, the invention is concerned With a method of partially tinning a metallic article which comprises shielding the portion of the article desired to be kept free of the tin plating with an organosubstituted polysiloxane resin, and thereafter dipping the shielded article in the tinning bath.
- One method comprises coating the portion of the article desired to be protected from the tinning bath with an alkali silicate, more specifically sodium silicate, prior to the plating operation.
- an alkali silicate more specifically sodium silicate
- sodium silicate is also disadvantageous because of the poor acid and moisture resistance of the sodium silicate. After masking the metallic article with the sodium silicate, a length of time may often elapse before the article is actually tinned. During this period the sodium silicate, because of its extreme hygroscopicity, tends to absorb moisture unless extreme precautions are taken. When later the article is dipped in the tinning bath, sputtering caused by the moisture contained in the sodium silicate results in flaking away of pieces of the film, thereby exposing unprotected portions of the article which it is desired to keep free from tinning.
- Ceramic coatings have also been employed as masking materials for preventing the deposition of tin plate on portions of an article desired to be tinned by dipping in a tinning bath.
- the use of ceramic coatings as shielding materials also presents many difficulties. In order to get a sufliciently protective coating, it is necessary to put a thick coating on the article desired to be masked. If the dimensions of the article are to be kept within close tolerances, the use of thick masking coatings is obviously a disadvantage.
- the ceramic coatings are often quite porous, thereby permitting absorption of such liquid materials as, for example, pickling solutions, fiuxing solutions, etc, usually employed in the preparation of the article for dipping in the tinning bath.
- ceramic coatings as masking media are susceptible to the same objection as regards their moisture pick-up and their brittleness as was pointed out above in connection with the same defect inherent in the properties of sodium silicate.
- an organo-substituted polysiloxane resin for brevity hereinafter referred to as the polysiloxane resin
- the polysiloxane resin is employed as the masking material for the metallic article.
- These polysiloxane resins more particularly, hydrocarbon-substituted polysiloxane resins, have outstanding heat-resistance and heat-stability at elevated temperatures. At temperatures encountered in the tinning baths (from about 300 to 500 C.
- the polysiloxane resins are admirably suited for the stated purpose, since they are able to withstand the elevated temperatures for the short periods of time within which any part of the shielded portion of the metallic article may happen to be immersed in the molten tinning bath.
- the polysiloxane resins have excellent moistureand acidresistance which renders them unaffected by any moisture medium or by the pickling baths ordinarily employed for that purpose. Due to the flexibility which can be obtained with the polysiloxane resins, there is not as great a danger 3 that the resinous coating will chip from the coated article under the extreme temperature changes, thereby to contaminate the tinning bath.
- tinning bath or other expressions using the term tinning is intended to include within its meaning molten metal baths wherein at least a preponderant amount of the molten materials comprises tin.
- materials that may be used in such baths are tin or alloys of tin which melt at a temperature of the order of 300 to 500 C.
- alloys corresponding to the above description are (in addition to pure tin) alloys comprising tin and lead, alloys comprising tin and antimony, alloys comprising tin and cadmium, alloys comprising tin and copper, alloys comprising tin and zinc, alloys comprising tin and aluminum, etc.
- organo-substituted polysiloxane resins e. g., hydrocarbon-substituted polysiloxane resins
- hydrocarbon-substituted polysiloxane resins containing an average of from about 0.5 to less than 2 hydrocarbon groups per silicon atom.
- High temperature-resistant thermoplastic polysiloxane resins are usually obtained when the polysiloxane resin contains an average of from about 1.5 or 1.6 to less than 2,
- hydrocarbongroups e. g., methyl
- thermoplastic polysiloxane resins ethyl, phenyl, or total methyl and phenyl radicals, etc.
- I may also employ the usual heat-hardenable or potentially thermosetting hydrocarbonsubstituted polysiloxane resins, e. g., polysiloxane resins containing an average of from about 0.5 to 1.3 or 1.4 hydrocarbon groups (e. g., methyl, ethyl, phenyl, or total methyl and phenyl radicals, etc.) per silicon atom.
- hydrocarbon groups e. g., methyl, ethyl, phenyl, or total methyl and phenyl radicals, etc.
- hydrocarbon-substituted polysiloxane resins employed in this invention may be further modified by the admixture with them of thermosetting resins such as phenolic, urea and melaminealdehyde' condensation products, unsaturated alkyd resins, etc.
- the portion of the article desired to be protected from 1 the tinning plate may be dipped in, sprayed, coated or brushedwith the particular polysiloxane resin (or a solution of the polysiloxane resin) employed as the masking medium.
- the shielded article is then preferably heated at an elevated temperature of the order of 150 to 300 C. for approximately 10 to 30 minutes. The temperatures and times of heating are not critical.
- the main object in these steps is to drive off any solvent which may be present and to advance the polysiloxane resin to a more advanced state of cure.
- This heat-treatment willordinarily convert heat-convertible pol-ysiloxane resins to the substantially infusible and insoluble state, thus increasing their heat-resistance at more elevated temperatures.
- Example A steel shell bearing was coated on the outside by brushing on a hydrocarbon-substituted polysiloxane resin containing an average of about 1.7 total methyl and phenyl radicals per silicon atom (dissolved in toluene to about '70 per cent solids). The coated bearing was then heated in a 150 C. oven for about 20 minutes to advance the resin to the substantially infusible and insoluble state. The bearing was then placed in a muriatic acid pickling bath for about 1 minute and thereafter in a flux (a bath used to prepare the article for the tin plating operation) comprising zinc chloride dissolved in Water.
- a flux a bath used to prepare the article for the tin plating operation
- the bearing was immersed in a tinning bath containing pure molten tin for a few seconds (temperature of the bath was about 400 C.). After exposure to air for a short time, it was observed that the hearing was satisfactorily coated with the tin plate on th inside and that no tin at all adhered to the surface of the bearing which had previously been coated withthe .polysiloxane resin. Neither the pickling solution, nor the flux solution, nor the tinning bath had perceptibly affected the polysiloxane coating on the outside of the bearing. This result followed 'even though the thickness of the polysiloxane coating was less than 0.002 inch thick.
- this invention is not intended to be restricted to the particular polysiloxane resin nor tinning bath employed in the above example, nor to the specific article masked and tinned.
- Other polysiloxane resins of the type previously described, including methyl-, ethyl-, propyl-, phenyl-, benzyl-, tolyltotal methyland phenyl-, etc; substituted polysiloxane resins may also be employed.
- This invention is especially applicable in the masking and tin plating of bearings, boxes, sheets of metal, i. 'e., metal to which tin plating Will adhere, decorative tinning, etc.
- the polysiloxane resin may easily be removed from the plated object by abrasion or by various chemical means. However, by virtue of the fact that the polysiloxane resin can be present in such a thin layer (and still act as an effective masking agent), the polysiloxane coating may be allowed to remain on the metallic article. i
- the method of partially tinning a steel shell bearing which comprises (1) applying to the outside of the bearing a thin coating of a methyl and phenyl-substituted polysiloxane containing an average of about 1.7 total methyl and phenyl groups per silicon atom, (2) heating the coated bearing at a temperature of about 150 C. to advance the resinous coating to the infusible and insoluble state, (3) placing the bearing in an acid pickling bath and then in a flux bath comprising water and zinc chloride, and (4) clipping the treated bearing in a molten tinning bath maintained at a temperature of around 400 C. to obtain an article tinned. on the inside and completely free of tin on the outside.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- General Engineering & Computer Science (AREA)
- Coating With Molten Metal (AREA)
Description
Patented Feb. 21, 1950 METHOD OF TINNING A STEEL SHELL BEARING John H. Clawson, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York No Drawing. Application August 7, 1946, Serial No. 688,965
1 Claim.
This invention is concerned with a method of partially tinning metallic articles. More particularly, the invention is concerned With a method of partially tinning a metallic article which comprises shielding the portion of the article desired to be kept free of the tin plating with an organosubstituted polysiloxane resin, and thereafter dipping the shielded article in the tinning bath.
Several methods have been employed to mask a portion of a metallic article intended to be tinplated so as to prevent that portion of the article from being plated when the article is later dipped in the tin plating bath. One method comprises coating the portion of the article desired to be protected from the tinning bath with an alkali silicate, more specifically sodium silicate, prior to the plating operation. However, there are several disadvantages which accompany the use of sodium silicate as the masking (or rejecting) medium for the metallic article. Since the temperature of the tinning bath may be from about 300 to 500 C. or higher, depending, e. g., on the exact constitution of the bath, it often happens that when any portion of the sodium silicate becomes immersed in the bath, small pieces of the sodium silicate will chip oif and fall into the tinning bath thereby contaminating it. This is especially true because of the brittleness and poor coeflicient of expansion of sodium silicate which, when applied as a coating on a metallic article having a greater coefficient of expansion, causes the sodium silicate to chip away when the metal is caused to expand by any extreme temperature change as is usually the case when a cold metal is dipped in a hot tinning bath.
The use of sodium silicate is also disadvantageous because of the poor acid and moisture resistance of the sodium silicate. After masking the metallic article with the sodium silicate, a length of time may often elapse before the article is actually tinned. During this period the sodium silicate, because of its extreme hygroscopicity, tends to absorb moisture unless extreme precautions are taken. When later the article is dipped in the tinning bath, sputtering caused by the moisture contained in the sodium silicate results in flaking away of pieces of the film, thereby exposing unprotected portions of the article which it is desired to keep free from tinning.
It is often necessary, and usually desirable, to immerse the metallic article in an acid pickling solution prior to the tinning operation, especially if any length of time has elapsed after a previous pickling operation. Such an acid treatment yields a clean surface on which the tin can be Ill-) plated. Sodium silicate, because of its poor resistance to acids, especially to dilute acid solutions, would obviously be at a disadvantage if it were necessary to dip the entire sodium silicatecoated metallic article into the acid pickling solution prior to the actual tinning operation.
Ceramic coatings have also been employed as masking materials for preventing the deposition of tin plate on portions of an article desired to be tinned by dipping in a tinning bath. However, the use of ceramic coatings as shielding materials also presents many difficulties. In order to get a sufliciently protective coating, it is necessary to put a thick coating on the article desired to be masked. If the dimensions of the article are to be kept within close tolerances, the use of thick masking coatings is obviously a disadvantage. In addition, the ceramic coatings are often quite porous, thereby permitting absorption of such liquid materials as, for example, pickling solutions, fiuxing solutions, etc, usually employed in the preparation of the article for dipping in the tinning bath. On occasion, because of the porosity of the ceramic coating, minute portions of the tinning bath have found their way onto those portions of the article desired to be kept free of the tin plating. Moreover, ceramic coatings as masking media are susceptible to the same objection as regards their moisture pick-up and their brittleness as was pointed out above in connection with the same defect inherent in the properties of sodium silicate.
I have now discovered that the above-discussed defects can be satisfactorily obviated if an organo-substituted polysiloxane resin (for brevity hereinafter referred to as the polysiloxane resin) is employed as the masking material for the metallic article. These polysiloxane resins, more particularly, hydrocarbon-substituted polysiloxane resins, have outstanding heat-resistance and heat-stability at elevated temperatures. At temperatures encountered in the tinning baths (from about 300 to 500 C. or more), the polysiloxane resins are admirably suited for the stated purpose, since they are able to withstand the elevated temperatures for the short periods of time within which any part of the shielded portion of the metallic article may happen to be immersed in the molten tinning bath. In addition, the polysiloxane resins have excellent moistureand acidresistance which renders them unaffected by any moisture medium or by the pickling baths ordinarily employed for that purpose. Due to the flexibility which can be obtained with the polysiloxane resins, there is not as great a danger 3 that the resinous coating will chip from the coated article under the extreme temperature changes, thereby to contaminate the tinning bath.
The term tinning bath or other expressions using the term tinning is intended to include within its meaning molten metal baths wherein at least a preponderant amount of the molten materials comprises tin. Examples of materials that may be used in such baths are tin or alloys of tin which melt at a temperature of the order of 300 to 500 C. Examples of alloys corresponding to the above description are (in addition to pure tin) alloys comprising tin and lead, alloys comprising tin and antimony, alloys comprising tin and cadmium, alloys comprising tin and copper, alloys comprising tin and zinc, alloys comprising tin and aluminum, etc.
Various organo-substituted polysiloxane resins, e. g., hydrocarbon-substituted polysiloxane resins, may be employed in the practice of my invention. These include hydrocarbon-substituted polysiloxane resins containing an average of from about 0.5 to less than 2 hydrocarbon groups per silicon atom. High temperature-resistant thermoplastic polysiloxane resins are usually obtained when the polysiloxane resin contains an average of from about 1.5 or 1.6 to less than 2,
-e. g., 1.6 to 1.9, hydrocarbongroups (e. g., methyl,
ethyl, phenyl, or total methyl and phenyl radicals, etc.) per silicon atom. It will of course be understood by those skilled in the art that i it is possible, by the application of sufficient heat, to convert so-called thermoplastic polysiloxane resins to a state whereby their characteristics and properties resemble those of heat-converted or thermoset polysiloxane resins.
In addition to the aforementioned polysiloxane resins, I may also employ the usual heat-hardenable or potentially thermosetting hydrocarbonsubstituted polysiloxane resins, e. g., polysiloxane resins containing an average of from about 0.5 to 1.3 or 1.4 hydrocarbon groups (e. g., methyl, ethyl, phenyl, or total methyl and phenyl radicals, etc.) per silicon atom. I prefer to employ as the shielding or masking medium a hydrocarbon-substituted polysiloxane resin containing an average of from about 1.0 to 1.8 hydrocarbon groups per silicon atom. More specific directions for the preparation of the aforementioned hydrocarbon-substituted polysiloxane resins may be found in Rochow U. S. Patents 2,258,218 to 2,258,222, assigned to the same assignee as the present invention. It will also be apparent that the hydrocarbon-substituted polysiloxane resins employed in this invention may be further modified by the admixture with them of thermosetting resins such as phenolic, urea and melaminealdehyde' condensation products, unsaturated alkyd resins, etc.
Various methods well known in the art may be e employed to practice my invention. The portion of the article desired to be protected from 1 the tinning plate may be dipped in, sprayed, coated or brushedwith the particular polysiloxane resin (or a solution of the polysiloxane resin) employed as the masking medium. The shielded article is then preferably heated at an elevated temperature of the order of 150 to 300 C. for approximately 10 to 30 minutes. The temperatures and times of heating are not critical.
The main object in these steps is to drive off any solvent which may be present and to advance the polysiloxane resin to a more advanced state of cure. This heat-treatment willordinarily convert heat-convertible pol-ysiloxane resins to the substantially infusible and insoluble state, thus increasing their heat-resistance at more elevated temperatures.
It is customary to dip the masked article, prior to the plating step, in an acid picklin solution. The article may then be dipped for a short time in fiuxing solutions usually employed immediately preceding the tin-plating step. The shielded article is thereafter dipped in the specific type of molten tinning bath employed for the occasion in accordance with methods now well known in the art.
Inorder that those skilled in the art may better understand how the present invention may be practiced, the following example is given by Way of illustration and not by way of limitation.
Example A steel shell bearing was coated on the outside by brushing on a hydrocarbon-substituted polysiloxane resin containing an average of about 1.7 total methyl and phenyl radicals per silicon atom (dissolved in toluene to about '70 per cent solids). The coated bearing was then heated in a 150 C. oven for about 20 minutes to advance the resin to the substantially infusible and insoluble state. The bearing was then placed in a muriatic acid pickling bath for about 1 minute and thereafter in a flux (a bath used to prepare the article for the tin plating operation) comprising zinc chloride dissolved in Water. The bearing was immersed in a tinning bath containing pure molten tin for a few seconds (temperature of the bath was about 400 C.). After exposure to air for a short time, it was observed that the hearing was satisfactorily coated with the tin plate on th inside and that no tin at all adhered to the surface of the bearing which had previously been coated withthe .polysiloxane resin. Neither the pickling solution, nor the flux solution, nor the tinning bath had perceptibly affected the polysiloxane coating on the outside of the bearing. This result followed 'even though the thickness of the polysiloxane coating was less than 0.002 inch thick.
The use of a methyl-substituted polysiloxane resin containing an average of about 1.5 methyl groups per silicon atom in place of the methyland phenol-substituted polysiloxane resin employed in the above example afforded the same protection against plating by the tin.
It is to be understood that this invention is not intended to be restricted to the particular polysiloxane resin nor tinning bath employed in the above example, nor to the specific article masked and tinned. Other polysiloxane resins of the type previously described, including methyl-, ethyl-, propyl-, phenyl-, benzyl-, tolyltotal methyland phenyl-, etc; substituted polysiloxane resins may also be employed. This invention is especially applicable in the masking and tin plating of bearings, boxes, sheets of metal, i. 'e., metal to which tin plating Will adhere, decorative tinning, etc. After the tin plating operation, the polysiloxane resin may easily be removed from the plated object by abrasion or by various chemical means. However, by virtue of the fact that the polysiloxane resin can be present in such a thin layer (and still act as an effective masking agent), the polysiloxane coating may be allowed to remain on the metallic article. i
What I claim as new and desire to secure by Letters Patent of the United States is:
The method of partially tinning a steel shell bearing which comprises (1) applying to the outside of the bearing a thin coating of a methyl and phenyl-substituted polysiloxane containing an average of about 1.7 total methyl and phenyl groups per silicon atom, (2) heating the coated bearing at a temperature of about 150 C. to advance the resinous coating to the infusible and insoluble state, (3) placing the bearing in an acid pickling bath and then in a flux bath comprising water and zinc chloride, and (4) clipping the treated bearing in a molten tinning bath maintained at a temperature of around 400 C. to obtain an article tinned. on the inside and completely free of tin on the outside.
JOHN H. CLAWSON.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US688965A US2498485A (en) | 1946-08-07 | 1946-08-07 | Method of tinning a steel shell bearing |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US688965A US2498485A (en) | 1946-08-07 | 1946-08-07 | Method of tinning a steel shell bearing |
Publications (1)
Publication Number | Publication Date |
---|---|
US2498485A true US2498485A (en) | 1950-02-21 |
Family
ID=24766521
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US688965A Expired - Lifetime US2498485A (en) | 1946-08-07 | 1946-08-07 | Method of tinning a steel shell bearing |
Country Status (1)
Country | Link |
---|---|
US (1) | US2498485A (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2742382A (en) * | 1953-03-09 | 1956-04-17 | Boeing Co | Method of annealing with a silicone oxidation scale prohibitor |
US2752274A (en) * | 1953-11-12 | 1956-06-26 | Westinghouse Electric Corp | Method of bright heat-treating metals |
US2814731A (en) * | 1954-09-20 | 1957-11-26 | Honeywell Regulator Co | Measuring apparatus |
US2897588A (en) * | 1955-12-12 | 1959-08-04 | Gen Steel Wares Ltd | Selected area galvanizing method |
US2996340A (en) * | 1956-06-26 | 1961-08-15 | Macks Elmer Fred | Fluid dynamic bearing and method of making same |
US2999771A (en) * | 1958-04-17 | 1961-09-12 | Norman I Gaynes | Chrome plating and anodizing stopoff composition |
US3177085A (en) * | 1960-07-27 | 1965-04-06 | Nalco Chemical Co | Silica sol-masking in galvanizing process |
US3181963A (en) * | 1960-11-08 | 1965-05-04 | Wheeling Steel Corp | Alkali metal borate masking in galvanizing process |
US3935346A (en) * | 1973-03-12 | 1976-01-27 | Owens-Illinois, Inc. | Coated plastic substrates for coating compositions |
US3958045A (en) * | 1971-12-09 | 1976-05-18 | Coleman Charles M | Method of making an automatic volume control pipet |
US4047977A (en) * | 1972-05-04 | 1977-09-13 | Nippon Steel Corporation | Method of continuous galvanizing steel strip on partial or one side |
US4110095A (en) * | 1975-03-27 | 1978-08-29 | Owens-Illinois, Inc. | Manufacture of glass wherein hot metal molds are provided with a solid film lubricant layer |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US158790A (en) * | 1875-01-19 | Improvement in tin lining metallic pipes | ||
US1741204A (en) * | 1926-11-01 | 1929-12-31 | Bohn Aluminium & Brass Corp | Method of tinning bearing shells and the like |
US2258218A (en) * | 1939-08-01 | 1941-10-07 | Gen Electric | Methyl silicones and related products |
US2258220A (en) * | 1940-04-27 | 1941-10-07 | Gen Electric | Resinous materials and insulated conductors and other products utilizing the same |
US2258222A (en) * | 1940-04-27 | 1941-10-07 | Gen Electric | Methyl aryl silicones and insulated conductors and other products utilizing the same |
US2258221A (en) * | 1940-04-27 | 1941-10-07 | Gen Electric | Aroxy silicones and insulated conductors and other products utilizing the same |
-
1946
- 1946-08-07 US US688965A patent/US2498485A/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US158790A (en) * | 1875-01-19 | Improvement in tin lining metallic pipes | ||
US1741204A (en) * | 1926-11-01 | 1929-12-31 | Bohn Aluminium & Brass Corp | Method of tinning bearing shells and the like |
US2258218A (en) * | 1939-08-01 | 1941-10-07 | Gen Electric | Methyl silicones and related products |
US2258220A (en) * | 1940-04-27 | 1941-10-07 | Gen Electric | Resinous materials and insulated conductors and other products utilizing the same |
US2258222A (en) * | 1940-04-27 | 1941-10-07 | Gen Electric | Methyl aryl silicones and insulated conductors and other products utilizing the same |
US2258221A (en) * | 1940-04-27 | 1941-10-07 | Gen Electric | Aroxy silicones and insulated conductors and other products utilizing the same |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2742382A (en) * | 1953-03-09 | 1956-04-17 | Boeing Co | Method of annealing with a silicone oxidation scale prohibitor |
US2752274A (en) * | 1953-11-12 | 1956-06-26 | Westinghouse Electric Corp | Method of bright heat-treating metals |
US2814731A (en) * | 1954-09-20 | 1957-11-26 | Honeywell Regulator Co | Measuring apparatus |
US2897588A (en) * | 1955-12-12 | 1959-08-04 | Gen Steel Wares Ltd | Selected area galvanizing method |
US2996340A (en) * | 1956-06-26 | 1961-08-15 | Macks Elmer Fred | Fluid dynamic bearing and method of making same |
US2999771A (en) * | 1958-04-17 | 1961-09-12 | Norman I Gaynes | Chrome plating and anodizing stopoff composition |
US3177085A (en) * | 1960-07-27 | 1965-04-06 | Nalco Chemical Co | Silica sol-masking in galvanizing process |
US3181963A (en) * | 1960-11-08 | 1965-05-04 | Wheeling Steel Corp | Alkali metal borate masking in galvanizing process |
US3958045A (en) * | 1971-12-09 | 1976-05-18 | Coleman Charles M | Method of making an automatic volume control pipet |
US4047977A (en) * | 1972-05-04 | 1977-09-13 | Nippon Steel Corporation | Method of continuous galvanizing steel strip on partial or one side |
US3935346A (en) * | 1973-03-12 | 1976-01-27 | Owens-Illinois, Inc. | Coated plastic substrates for coating compositions |
US4110095A (en) * | 1975-03-27 | 1978-08-29 | Owens-Illinois, Inc. | Manufacture of glass wherein hot metal molds are provided with a solid film lubricant layer |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2498485A (en) | Method of tinning a steel shell bearing | |
US2408116A (en) | Selenium coated elements and method of making them | |
EP0125352B1 (en) | Zincating aluminium | |
US2544139A (en) | Process for enameling aluminumrich alloys | |
US3498824A (en) | Primer for silicone rubber adhesion | |
US2367978A (en) | Nitriding hardening treatment | |
JPH0649173B2 (en) | Heavy anticorrosion treatment method for metal articles | |
JPH0213898B2 (en) | ||
US2421719A (en) | Vitreous enamelled article | |
US2381778A (en) | Process of producing protected metal articles | |
US3498823A (en) | Electroless tin plating on electroless nickel | |
US3158495A (en) | Solid lubricant coatings and coating compositions | |
US4047977A (en) | Method of continuous galvanizing steel strip on partial or one side | |
US2176066A (en) | Tin-coated object | |
US3089780A (en) | Method and composition for shielding steel from molten coating metal | |
US2465228A (en) | Liquid treatment of contact surfaces for copper oxide rectifiers | |
US1456274A (en) | Process of rendering metal nonoxidizable and the metal | |
US2878189A (en) | Method of de-oxidizing metal surfaces | |
JPS5825468A (en) | Dipping member for molten metal bath | |
US3617345A (en) | Method of manufacturing aluminum coated ferrous base articles | |
US1832979A (en) | Method of cleaning metals | |
US3700485A (en) | Vacuum vapor deposited zinc coatings | |
US3022201A (en) | Method of coating a body with titanium and related metals | |
US547381A (en) | Robert mcknight | |
US3136656A (en) | Ferrous metal |