US2039326A - Pen - Google Patents

Description

Patented May 5, 1936 UNITED STATES PIN Hiram Stanhope Lnkena,

lignor to 0. Howard Hunt Pen Camden, N. 1., a corporation of New Jersey No Drawing. Applicati Serial No.

on January :0, 1084, 707.5

9 Claims. (01. RO-l) This invention relates to the manufacture of tarnish and corrosion proof metallic articles and is specially concerned with an improved pen point, and the manufacture thereof.

One of the principal objects of the invention is the provision of a pen composed of a metal on the surface of which a non-metallic film normally forms, and having a gold plate electrolytically deposited thereon. As will appear more fully herebelow, this article is very advantageous in a number of respects, for example, by improving wearing and writing qualities as well as appearance, while, at the same time, providing a pen which is substantially tarnish proof. The nature of the invention and the manner in which the objects are accomplished will appear to best advantage after a consideration of prior developments in this field.

Heretofore, some gold plated pens have been employed, especially in the relatively inexpensive fountain pens or in the common type of desk pen holder. These prior developments, however, were subject to a number of serious disadvantages, chief among which was the tendency to tarnishing and corrosion. The prior pens were made from brass or some copper alloy or carbon steel and then electroplated in accordance with well known processes for electrodeposition of gold on such metals. It has been found that gold plated pens of this prior type (probably due to the porosity of the plating) are subject to almost as rapid and serious tarnishing and corrosion, from acid ingredients in ink and other conditions of use, as similar pens without the gold plating. Thus the advantages of a gold surface on the pen, such as smoothness of ink flow and writing, as well as appearance, have not been attained heretofore. In addition, no great improvement or advantage in avoiding tarnishing or the like, was secured,

I have found that the tendency to corrosion may be eliminated by employing an alloy which is normally rendered substantially stainless by virtue of the formation of a non-metallic, usually an oxide film on the surface thereof and forming the pens from this alloy in the manner referred to hereinafter. Preferably, I use a chromiumnickel alloy steel which is rendered stainless by the formation of a chrome oxide film on the surface thereof. However, satisfactory plating of a metal of this type having a non-metallic film on the surface thereof cannot be effectively performed since a direct bonding of the plate and the metal cannot be secured if a film is introduced therebetween. In accordance with the preferred practice of this invention, a direct bondingoftheplatetothebasemetalisobtained by removing the non-metallic film (the chrome oxide film in the case of chromiumnlckel steels) and by preventing reformation of 5 the film, after removal thereof, until and during the plating operation. Note also that the plating is effected in a special manner in, accordance with this invention as fully brought out hereelow.

I have found that even though the oxide film has been eliminated and replaced, so to speak, by the gold plate, the resulting article is one which is not subject to tarnishing or corrosion. Thus, even though the very thing which is usu- 15 ally considered to provide the protection for a metal of the type in question has been removed, the pens are not subject to the difiiculties heretofore encormtered. In this way, substantially all of the advantages of the gold type of pen 20 point are secured, the pen will not corrode on tarnish and, in addition, the expense of the article is very materially reduced as compared with pens of the solid gold type.

The following comments will bring out the manner in which the objects are attained in accordance with the present invention.

As already indicated, I prefer to employ a chromium-nickel alloy steel. This alloy may suitably contain about 18% chrome, about 8% nickel, about 2%% molybdenum, and the balance iron, except for small amounts of impurities which are sometimes present although not in quantities sufficient to materially affect the characteristics of the alloy. The presence of molybdenum is not essential and it may therefore be omitted, al though I have found that an alloy containing the ingredients in substantially the proportions'indicated is preferable for the reason that, with the presence of molybdenum, a molybdenum oxide 40 is also formed on the surface of the alloy, this being of advantage for reasons mentioned below.

The pen is first formed from the alloy referred to and preferably completely finished, after which I proceed as follows:

I subject the pens to the action of a bath containing some acid, preferably hydrochloric, in sufficient concentration to remove the chrome oxide from the alloy. This bath may contain from about 25% to about hydrochloric acid. .30

Subsequent'to this treatment, which destroys the chrome oxide film, I preferably rinse the pens in a dilute acid wash. By way of example, this wash may contain from about 10% to about 15% hydrochloric acid. Subsequent to the washing,

the pens troplatins are transferred very quickly to an elecbath, and it is to be noted that the rapidity of transfer is important for the reason that the relatively low strength of the hydrochloric acid wash is only sufilcient to prevent the reformation of the oxide film for a relatively short period of time. Further with reference to the foregoing point, the hydrochloric acid rinse or wash is relatively low in concentration, since the gold plating cannot be as efilciently and effectively performed with a high concentration in the wash.

In general, the gold plating procedure is similar in a number of respects to that employed in gold plating other metals, the pens constituting the cathode in the electroplating bath. While I employ a bath of the acid type, in accordance with this invention the acidity of the bath is reduced. Stated'in another way, this invention contemplates the electrodeposltion .of the gold in a bath which is characterized by a low hydrogen ion concentration. Thus it might be said that the bath approaches "neutrality", although it should be understood that some leeway is'permissible, and I therefore prefer to define the bath as one having a relatively low hydrogen ion concentration. It should further be understood, however, that the acidity of the bath is very materially reduced as compared with that of the more usual type of acid bath. lbr this purpose I may use some alkali such as sodium cyanide or sodium hydroxide, this material being added to a bath which is generally of the acid type and the amount thereof being sufiicient to give the low hydrogen ion concentration desired.

As a still more specific example of a bath which I may employ, 1 pint of concentrated hydrochloric acid, 8 ounces of sodium cyanide, and ounce of sodium gold cyanide, may be added to each gallon of water. This bath has the low hydrogen ion concentration desired.

In connection with the foregoing it should be pointed out that the continual introduction of pens into the plating bath increases the acidity of the bath, so that from time to time I prefer to add additional alkali in amounts suflicient to substantially maintain the relatively low hydrogen ion concentration. As a guide in determinin whether additional alkali is necessary, the brilliance of the precipitate may be observed. When the precipitate noticeably loses its brilliance, additional alkali should be added.

After this gold plating step, the pens may be removed from the bath and the film of chrome oxide, of course, will be used in this condition, although I prefer to add a second gold plate in one of the common types of alkaline baths, such as a cyanide .bath.

By way of example, a suitable alkaline bath may contain about /2 ounce sodium gold cyanide and about 2 /2 ounces sodium cyanide per gallon of water. a

In summary, therefore, it will be seen that in accordance with the present invention the pens are treated with acid to remove the non-metallic or oxide film, and thereafter the plating is accomplished by electrodeposition in a novel type of electroplating bath and in a manner which prevents reformation of any film until a direct bonding of the plate to the metal is secured. When a direct bonding is obtained, of course, the film cannot reform. be noted that, in accordance with the preferred practice, the oxide or non-metallic film is removed by a strong acid solution and the pens not reform. The pens may In summarizing it should also are then washed in a dilute acid solution before the first plating operation is carried out. Attention is directed to the fact that the method herein disclosed is described and claimed in my copending application Serial No. 21,190, filed May 13, 1935.

While all of the reasons why the foregoing procedure is effective for the purposes here involved, including the prevention of tarnishing or corrosion, may not be fully understood, I have found in actual practice that even though the nonmetallic film (such as the chrome oxide film formed on the surface .of a chromium-nickel alloy steel which normally is the protection which renders this alloy corrosion proof) has been removed and replaced by a gold plate, the final product is one which is not subject to tarnishing or corrosion. It might seen that since the protective film is removed and replaced by a plate which is well known to be porous, the final product would be subject to difficulties similar to those encountered with prior gold plated pens, as mentioned above. Possibly the reason why my improved pen resists tarnishing or corrosion through the gold plate is because the oxide film reforms in the pores of the plating. In any event, my improved article, as a matter of fact, is not subject to noticeable corrosion under the normal conditions of use.

With regard to the inclusion of molybdenum in the alloy, it is pointed out that some inks contain free hydrochloric acid which, of course, attacks a chrome oxide film, although it does not attack molybdenum oxide, at least in the concentration in which this acid appears from time to time in commercial inks. I have found, however, that the presence of molybdenum oxide (at least in the quantity produced by a relatively small percentage of molybdenum such as suggested hereinbefore) does not impair the direct and effective bonding of the gold plate and the alloy. Thus in the event of wear of the pen to such an extent as to expose the alloy, the hydrochloric acid which is present in some inks will not affect the pens to any appreciable extent. Similarly, it may be that the presence of molybdenum oxide in the pores of the plating may also prevent tarnishing of the metal through the plating, even though hydrochloric acid may be present in the ink used.

The numerous objects of the invention will be apparent to those skilled in the art, although it might be mentioned that durability of the plating and resistance to tarnishing and corrosion are the most outstanding advantages.

In connection with the appended claims, the term chromium alloy steel is not to be understood as excluding the presence of other alloying ingredients, such for instance as nickel or molyb-- denum or other elements which may be employed without departing from the spirit of the invention.

I claim:-

1. As an article of manufacture, a pen point comprising a base composed of a chromium alloy steel on the surface of which a non-tarnishing corrosion-resistant film normally forms, the pen having an adherent electrolytically-deposited gold plate thereon.

2. As an article of manufacture, a pen point comprising a base composed of a chromium alloy steel on the surface of which a non-tarnishing corrosion-resistant film normally forms, the pen having an adherent gold plate electrolytically deposited on said base.

3. As an article of manufacture, a pen point comprising a base composed of a chromium alloy steel on the surface of which a non-tarnishing corrosion-resistant film normally forms, the pen having an electrolytically-deposited gold plate directly bonded to the metal of the base.

4. As an article of manufacture, a pen point comprising a base composed of a metal or metal alloy on the surface of which a non-tarnishing corrosion-resistant film normally forms, the pen having a plurality of layers of electrolytically-deposited plates thereon, the outermost layer of which is composed of gold.

5. As an article of manufacture, a pen point comprising a base composed of a metal or metal alloy on the surface \of which a non-tarnishing corrosion-resistant film normally forms, the pen having a plurality of layers of adherent acidresistant platings electrolytically deposited on said base, at least the outermost layer of plating being sold.

6. As an article of manufacture, a pen point comprising a base composed of a metal or metal alloy on the surface of which a non-tarnishing corrosion-resistant film normally forms, the pen having a plurality of layers of electrolyticallydeposited plates thereon, the innermost layer of which is directly bonded to the metal of said base and the outermost layer of which is gold.

7. As an article of manufacture, a pen point comprising a base composed of a chromiumnickel-molybdenum alloy steel, the pen having an adherent electrolytically-deposited gold plate thereon.

8. As an article of manufacture, a pen point comprising a base composed of a chromiumnickel-molybdenum alloy steel, the pen having an adherent gold plate electrolytically deposited on said base.

9. As an article of manufacture, a pen point comprising a base composed of a chromiumnickel-molybdenum alloy steel, the pen having an adherent electrolytically-deposited gold plate directly bonded to the metal of said base.

HIRAM S. LUICENS.