US2082225A - Metal coating - Google Patents

Description

Patented June 1,1937

UNITED STATES PATENT OFFICE 2,082,225 METAL COATING William H. Spowers,

Tour, New York, N.

Plainfield, and Lewis S. Reid, by mesne N. J., assignors,

Jr., Maplewood, N. J., Sam Y., Thomas A. Wright.

Upper Montclair,

assignments, to

William H. Spowers, Jr., New York, N. Y. No Drawing. Application May 26, 1934, Serial Renewed October 15, 1936 4 Claims. (01. 91-702) a novel metallic coatprocess of producing pounds of phosphor-tin containing five parts of phosphorus to ninety-five parts of tin by weight. The phosphor-tin may be prepared in any conknown manner, and may be added to the and allowed to thoroughly distribute itself through the zinc, the tin serving primarily as a carrier for the phosphorus.

The coating bath, preferably maintained at 30 about 790 F. to 890 F. (preferably 800 F. to

835 F.), may then without additional finishing the bath.

The phosphorus in the bath will tend to dimin- 55 lsh at the temperatures mentioned and may be The invention has which has a high luster pensive or replenished from time to time, or continuously, by adding phosphorus to the bath to replace calculated or determined losses, to maintain the duced to about .03% at the end of four hours.

It will be seen from the foregoing that the amount of phosphorus which advantageously be extremely small, for instance portions of brilliant sheen contrasting with other relatively or somewhat dull portions of the surface. An even smaller percentage of phosphorus may produce satisfactory results for certain purposes, and the proportion of phosphorus may be increased within limits. For instance, as much as .5%, or even 1 to 2%% of phosphorus-tin may be employed, based on the zinc, but these larger amounts produce somewhat less brilliance, or duller frost, probably due to the increase in the tin. The temperature of the bath and rate of cooling of the coating appear to affect the character of the mottling and the factors should therefore be controlled, preferably though not necessarily, as mentioned.

While tin has been suggested as a carrier for the phosphorus, and is highly satisfactory for enabling the ready introduction of phosphorus into the zinc bath, the invention in its broader aspects is not limited to any particular canier or even to the use of a carrier. However, a carrier is recommended, since the addition of phosphorus directly to large amounts of zinc may tend to produce an insoluble phosphide which is not readily distributed uniformly through the zinc. As examples of other possible carriers mention is made of aluminum, zinc, lead, bismuth, antimony, copper, magnesium, and boron, although certain of these may be excessively exotherwise undesirable for certain reasons, some of which have been indicated, and others of which in the art. On the whole, tin is preferred, while aluminum appears as second choice.

K sharply The phenomena. underlying the results produced are not entirely understood, and accordingly a discussion of theories as to the action of the phosphorus will not be undertaken. Sumce it to say that through the present invention there is provided an extremely effective and simple method of producing a galvanized surface having a portions of the surface. Furthermore, a mottled surface can be produced, in which there are contrasting brilliant frosted spangles. The coating produced is considerably more ductile than the ordinary zinc coating, possibly due in part to the presence of tin. In addition a particularly firm bond is produced between the coating and the iron or other metal to which the coating is applied. 7 I

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, -of excluding any equivalents of the features shown and described, or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is: I

1. Method of galvanizing articles, which comprises maintaining a bath of molten zinc at a temperature above the melting point of zinc, incorporating in the bath an alloy of phosphorus and a carrier metal therefor in such proportions that the phosphorus constitutes from about fivethousandths of one percent to about,flve-hundredths of one percent of the zin and the carrier metal constitutes less than about one percent of the zinc, and coating said articles with said molten bath.

brilliant sheen at least over certain 2. Method of galvanizing surfaces of articles to be coated which comprises maintaining a bath of molten zinc at a temperature ing point of the zinc, incorporating in said bath an amount of phosphor tin which is less than about one percent of the bath, the phosphorus being present in amount from about five-thousandths of one percent to about five-hundredths of one percent of the bath, and applying said bath to the surfaces to be coated.

3. Method of galvanizing articles, which comprises maintaining a bath of molten zinc at a temperature above the melting point of zinc and below about 890 F., incorporating in the bath an alloy of phosphorus and a carrier metal thereforin such proportions that the phosphorus constitutes from about five-thousandths of one percent to about flve-hundredths of one percent of the zinc, and the carrier metal constitutes less than about one percent of the zinc, and coating said articles with said molten bath.

4. Method of galvanizing articles, which comprises maintaining a bath of molten zinc at a temperature above the melting point of zinc, and between about 800 F. and 835 F., incorporating in the bath an alloy of phosphorus and a carrier metal therefor in .such proportions that the phosphorus constitutes from about ,flve-thousandths of one percent to about five-hundredths of one percent of the zinc, and the carrier metal constitutes less than about one percent of the zinc, and coating said articles with said molten bath.

- WILLIAM H. SPOWERS, JR.

,SAM 'rooa.

THOMAS A. WRIGHT. LEWIS s. REID.

above the melt-