for Coating Small Metallic Articles with Nickel, Tin, Zinc, Gold, and similar Metals.
Year: 1899

page_text: Date of Application (in United Kingdom), 27th July, 1899
Complete Specification Left, 27th Apr., 1900-Accepted, 7th July, 1900
PROVISIONAL SPECIFICATION.
Process for Coating Small Metallic Articles with Nickel, Tin, Zinc,
Gold, and similar Metals.
ANDRÉ DARLAY, Chemist, 64, Rue Lafontaine, Paris, do hereby declare the
nature of this invention to be as follows:-
The subjoined request for a patent has for object a process enabling metallic
articles, principally those of small proportions, to be covered with a coating of any
sorts of metal, without assistance of an electrical current.
It consists in introducing the article to be covered into a bath of a certain com-
position, and to put it into contact with aluminium (or magnesium) also immersed
in the bath.
The contact of those articles with aluminium. (or magnesium) can be obtained
in different ways of which the principal ones are
1° The placing of the articles to be covered in a bath through the means of a
basket made of aluminium (or magnesium).
.
2° Immersion of the said articles in a little barrel pierced with holes and made
of aluminium (or magnesium), the barrel to roll in the bath itself.
The baths to be used are of two distinct types.
The following are examples of two specific cases; one of each type.
Type Io. The bath for nickelling belong to the first type. It is composed of
a solution of ammonium and nickel chloride, to which one adds an excess of an
alcalious phosphate or pyrophosphate, such as phosphate or pyrophosphate of
soda, and a small quantity of an alkali, such as carbonate of soda, etc.
Type II The bath for silvering belongs to the second type. It is composed
of a solution of potassium and silver cyanide, to which one adds a small quantity
of an alkali, such as soda, carbonate of soda, etc.
With baths belonging to one or other of those types, one easily obtains upon
metallic articles coatings of nickel, cobalt, zinc, tin, copper, brass, silver, gold,
ctc. by placing them simply in those baths and in contact with aluminium (or
magnesium) therein immersed.
لبيت
1 of Tul 1899

page_text: Process for Coating Small Metallic Articles with Nickel, Tin, Zinc,
Gold, and similar Metals.
I, ANDRÉ DARLAY, of 64, Rue Lafontaine, Paris, in the Republic of France,
Chemist, do hereby declare the nature of this invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
-
The advantage of superseding the use of hydroplastic baths operating by means
of an electric current for depositing metal on small metallic objects is well-known.
The following is a useful process for obtaining this result and consists in placing
the objects to be coated with metal in suitable baths and bringing them in con-
tact with aluminium or magnesium likewise immersed in the said baths.
In carrying out the invention I bring about this contact in any suitable man-
ner, preferably in one of the following ways, it being understood however that I
do not limit myself to the methods described:
1, by placing the objects in the bath in a cullender of aluminium (or of mag-
mesium);
2, by placing the objects in the bath piled up on small trays of aluminium or of
magnesium placed one above the other;
3, by placing the objects in an openwork cylinder of aluminium (or of magne-
sium) which is caused to revolve in the bath;
4, by placing the objects to be coated together with shavings, granules or other
waste cuttings of aluminium (or of magnesium) in a water-tight rotating cylin-
der or cask, containing the bath.
In practice I employ aluminium in preference to magnesium.
The baths employed are of two distinct types, as follows:-
1. A solution of a double chloride of ammonia and of the metal to be deposited,
to which is added a large excess of an alkaline phosphate (or pyro-phosphate)
and a small quantity of some alkaline body. A double chloride of sodium or of
potassium and of the metal to be deposited may be employed instead of the double
chloride with an ammoniacal base but this gives a defective result.
2. A solution of a double cyanide of potassium and of the metal to be deposited
to which is added a small quantity of an alkali (caustic soda, potash, carbonate of
soda or of potash).
:-
The following is an example of a bath of the first class:-
Nickel bath :-
Water
Double chloride of nickel and ammonia
Pyro-phosphate of sodium
Carbonate of ammonium
-
An example of a bath belonging to the second class:-
Zinc bath
Water
10 quarts.
1 pound.
4 pounds.
10 ounces.
10 quarts.

page_text: The following directions indicate the preferable course to be adopted for
obtaining various metallic coatings by this process.
Nickel. I have described above an example of a nickel bath which gives very
good results with a contact of aluminium or of magnesium.
The baths of the second type are not suitable for nickel coating.
Cobalt. The composition of the bath is similar to that given above for nickel.
Zinc or tin. Both classes of baths may be used successfully for coating with
zinc or tin. I prefer however those of the second class.
Copper. For copper coating baths of the second class are to be employed.
Brass. Baths of the second class are used. The bath. is formed of a mixture
of two solutions, viz. of a double cyanide of copper and potassium, and of a double
cyanide of zinc and potassium, to which mixture is added a small quantity of
caustic soda or of carbonate of soda.
Bronze. The same as for brass, a double cyanide of tin and potassium being
substituted for the double cyanide of zinc and potassium.
Silver. The baths to be used are of the second type.
Gilding. Both types of baths may be used but I prefer those of the second type.
Deposit of aluminium. In this case baths of the second type are to be used
but with a very simple modification reducing them to a mere alkaline solution.
Place the objects to be coated in a cullender of aluminium and immerse the whole
in a hot solution of caustic soda for instance, and the objects become coated with
aluminium.
When a magnesium contact is employed, an acid bath may be used, although
I prefer alkaline baths such as are described above.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. A process for depositing metallic coatings on metallic objects consisting in
bringing the objects to be coated in contact with metallic aluminium or with
metallic magnesium in an alkaline bath containing a salt of the metal to be
deposited substantially as set forth.
2. In a process for depositing metallic coatings on metallic objects with the
help of an aluminium or magnesium contact, the use of an alkaline bath con-
taining a salt of the metal to be deposited substantially as set forth.
3. In a process for depositing metallic coatings on metallic objects with the
help of an aluminium or magnesium contact the use of an alkaline bath con-
taining a double chloride of ammonium and of the metal to be deposited and an
alkaline phosphate or pyro-phosphate with or without the addition of ammonium
chloride substantially as set forth.
4. In a process for depositing metallic coatings on metallic objects with the
help of an aluminium. or magnesium contact the use of an alkaline bath con-
taining a double cyanide of potassium and of the metal to be deposited with the
addition of a small quantity of an alkaline salt substantially as set forth.
5. A process for depositing metallic coatings on metallic objects consisting in
bringing the objects to be coated in contact with metallic magnesium in a bath
containing a salt of the metal to be deposited substantially as set forth.
6. A process for depositing a coating of aluminium on metallic bodies con-
sisting in bringing the objects to be coated in contact with metallic aluminium
in a hot alkaline bath substantially as set forth.
Dated this 27th day of April 1900.
BOULT, WADE & KILBURN,
Agents for the Applicant.