US1975375A - Alloy - Google Patents

Description

- 45 series antimony Patented Oct. 2. 1934 v UNITED STATES PATENT/OFFICE Austria, asslgnor to American Magnesium 'Metals Corporation, Pittsburgh, Pa., a corporation of Delaware No Drawing.

application November 18,

1932, Serial No. 643,297. Divided and this application August 22, 1933, Serial No. 688,319. In Austria February 19, 1932 36mins.-

This application is a division of my prior application Serial No. 643,297, filed November 18, 1932.

The present improved 'alloyis one in which magnesium is the predominant element, the primary object being ,to develop an alloy that will possess the characteristic low specific gravity which isiobtained bythe use of magnesium in excess of a0 per centwhile such alloy-will be characterized by higher resistance to corrosion and at the same time will have a higher strength than theknown alloys of this kind. The known alloys in use containing gene more than 85% magnesium and as principal is additional ingredient aluminum or zinc or both of these ingredients, other constituents being present in relatively small amounts, do not exhibit a suflicient resistance to corrosion by water or even by damp air, and cannot be used at all 2 when in continuous contact with sea-water. Various attempts have been made to render the surfaces of these metals more resistant by applying coatings, but such attempts failed since corrosion often takes place to an increased extent when the superficial protective layer is damaged. The object of the invention is attained by the, addition of further additional metals to the alloys, namely antimonv or bismuth or both of these metals amounting in general to not less than 0,05% and not more than 2% of the total.

' The most diverse alloys of the kind referred to containing antimony or bismuth have proved distinctly superior, when exposed to the action of a 3% solution of common salt, to alloys of the same kind which do not contain antimony or bismuth; whilst the alloys containing antimony or bismuth showed an almost unaltered airface, the samples devoid of antimony or bismuth were strongly corroded on carrying out the compara- 40 tive tests.

In general exceed the upperlimit of 2%.

From their position in the and bismuth are more valuable than magnesium, and moreover do not form a solid solution with the latter; the assumption therefore would rather have been that the addi-f.

tion of these metals to the irnown alloys of magnesium would involve decreasing their resistance tocorrosion. 1 The magnesium-base alloys developed by the presentinvention show also a considerable increase in strength. without the elongation de- "I creasing. As the alloys of the kind the lower limit of efiiciency is givenby additions of 0,05%, and it is preferable not to a hitherto in use (electron, Dow-metal) have a comparatively small strength, this constitutes a further advance of considerable importance, the more so as the specific gravity of the alloys is scarcely increased to any perceptible extent by the small amount of the added metals.

Furthermore, the alloys according to the invention show in comparison with similarly com-.

posed known electron alloys an increase of the permanent impact strength by 50% The alloys may be used as cast alloys or mechanically worked alloys and may be improved by thermal treatments. y

A satisfactory formula for an alloy according to my invention, in which zinc is the principal additional ingredient isas follows, viz:

Magnesium 945%, zinc 43%, antimony 1%;

Magnesium 962%, zinc 35%, bismuth 0,3%.

what I claim is:--

1. A low specific gravity magnesium-base alloy containing from about 80% to 98.9 percent of magnesium, and zinc in an amount between about 1 to about 20%, and subject to corrosion, this alloy being rendered more resistant against corrosion by the addition of at least one metal of the group consisting of antimony and bismuth in an amount from 0,05 to 2%.

2. A low specific gravity magnesium-base alloy consisting of from about 86% to 98,8% of magnesium, from about 1 to 10% ofzinc, and from about 0,05 to 2% of at least one metal of the group consisting of antimony and bismuth.

3. A low specific gravity magnesium-base alloy consisting of from about 86 iii-98.8% of magnesium, from about 1 to about 10% of zinc, and antimony and bismuth in a combined amount of from about 0,05 to 2%.

i I GEORG- SCHICH'I'EL.