US1075583A - Molten bath and means for coating iron articles therewith. - Google Patents

Description

nu saunas a caution.

. HERMAN J. LOHMANN, 0F J'EES'EYfiI-TY, NEW 3ESEY,"ASSiG- N0B TO THE LOEMANN COMPANY A GQBPORAIHQN"OF :NEW YGRK.

MOLTEN BATH AND MEANS FOR 00 Specification oIJettersBatent.

ATING IRON ARTICLES THEREWITH.

Patented Oct. 114, 11913.

No Drawing. Application filed February 1, 1911, Serial No. 605,944. Renewed August 21, 1913. Serial No. 786,009.

To all whom it may concern:

Be it known that I, HERMAN J LOHMANN, a citizen of the United States, residing at 90 Monticello avenue, Jersey City, county of Hudson, and State of New Jersey, have invented certain new and useful Improvements in Molten Baths and Means for Coating Iron Articles Therewith, fully described and represented in. the following specification.

The object of the present invention is to produce a homogeneous molten bath of lead and zinc for coatingiron articles by immersion therein.

It is well known that lead has the property of resisting corrosive vapors and mineral acids which zinc is quite incapable of resisting, but zinc has heretofore been used almost exclusively as a metal coating for iron articles, because in a molten state thelead could not be kept in a homogeneous mixture therewith.

Heretofore, when lead and zinc have been mixed in a molten bath, the zinc has floated upon the surface and iron articles dipped therein were coated solely with the zmc, as the contact of the zinc first with the articles serves to cover them and protect them from the adhesion of the lead. This result followed from the much greater specific gravity of the lead which ordinarily pr vents the two metals from mixing in a melting pot.

I have discovered that the occasional placing in the melting pot of a small amount of mercury will maintain a homogeneous mixture of the lead and zinc, and that iron articles dipped in such a bath become coated with the mixed metals in the desired proportions. The mercury produces such effects if used in the proportion of less than onetenth of one per cent. of the weight of the bath, and its effect is. doubtless 'due to the great difiusibility of the mercury in such a molten bath and its property of amalgamating with the fluid metals and attracting or cementing them together so as to overcome the influence of gravity. This effect is produced in spite of the fact that the mercury is volatile and gradually dissipated from the bath.

' The mercury vaporizes below the melting temperature of lead and is gradually evaporated from the bath, and the amountthus lost must be-replaced at intervals by supplying an additional charge of the mercury in suflicie'nt proportion to maintain the homogeneity of the bath, which amount is readily ascertained by experiment in -.operating with a given bath. The molten bath of lead and zinc may thus be kept in a homogeneous mixture for an indefinite. length of time so. as to operate commercially during the whole of a working day in coating iron articles by immersion therein.

I find that lead and zinc. may be mixed in any desired proportions, and the mixture kept homogeneous while in a molten state by the means described, that is, the lead and zinc may be mixed in equal parts or either may be in excess of the other, the mixture being kept perfectly homogeneous by the small admixture of mercury from time to time as may be found needful.

The effects produced by the mercury are the same if other met-a1 be added to the mixture, as the lead and zinc possess the same relative weights whether or not any additional metal be added to the molten bath, and the effect of gravity upon the lead and zinc are equally overcome by the presence of the mercury if another metal be present in the alloy.

I have discovered that a very small proportion of mercury suffices to make a molten bat-h homogeneous which comprises metals of such diverse specific gravity as lead or zinc, and the addition of a greater amount of mercury is therefore unnecessary; but it is obviously immaterial if a larger proportion of mercury be used.

I am aware that alloys oflead, zinc and mercury have been made in sheets for sheathing vessels and for various manufacturing purposes, but my invention does not furnish any alloy for manufacturing purposes, but isbased upon the discovery that a molten bath of lead andzinc can be kept indefinitely in a homogeneous mixture by a slight addition of mercury.

What I claim and desire to secure by Let- In testimony whereof I have hereunto set t-ers Patent is: my hand in the presence of tWo subscribing 1o vThe process'of maintaining in a homo- Witnesses. geneous condition for an indefinite length of 5 time,'a bat-h comprising lead and zinc in a HERMAN LOHMANB molten condition, which processconsists in Witnesses:

' adding a small proportion of mercury to J. H. MOODY,

the bath, substantially 21s herein described. THOMAS S. CRANE.