Kusinova N.G., Mashtakova K.H., Ahmadiyarova Z.C., Sertaeva Z.O.
1) Objective: To carry out a bright nickel plating products under laboratory conditions. We used a copper plate and cut out the shape of her bear.
2) Summary: Nickel plating – a process of electroplating or chemical deposition of the nickel layer thickness of from 1 micron to 100 microns. Nickel plating is one of the most common electroplating processes. From conventional electrolytes in the absence of special additives nickel matte coatings obtained. To give them a shine to resort to very expensive and time-consuming operations – polishing cloth circles. When polishing is irretrievably lost about 20% of electrodeposited nickel and becomes impossible to implement the process of applying the multilayer coatings (Cu-Ni-Cr) in the circuit units. For this reason, the issue of producing brilliant nickel (and copper) coating directly from the bath is given a lot of attention.
Electrolytes for shiny nickel, in addition to the main components – nickel sulfate, boric acid and chlorides must contain special additives (brighteners), which radically changed electrocrystallization nickel process, allowing it to get into great layers of sufficient thickness over the surface of shiny and matte. Input brighteners give the best effect at high current densities, in connection with which the main components are also entered in increased concentration, namely the nickel content is adjusted to 75-100 g/l of chlorides at least 14 g/l, and in some cases up to 68 g/l.
Boric acid is to be administered in an amount not less than 38 g/l. Under such conditions, light tan prevented in areas of high current density. The high concentration of boric acid favors the production of plastic and good adhesion of coatings. Numerous brighteners, often patented, can be divided into two classes differ significantly in their chemical composition and their effect on the course of the process. Brighteners 1st class let you receive the shiny coating on the polished surface, but they cannot provide a high gloss. Compounds of this class maybe introduced into the electrolyte in a relatively high concentration; they do not adversely affect the ductility of the coating and its adhesive strength to the substrate. Second class brighteners are introduced in small concentrations; they are responsible for getting brilliant, but very intense rainfall and fragile. Brighteners of the second class are effective when used in combination with the first class brighteners.
3) Effect on quality of electrolytic sludge mode and the current efficiency. On the properties of nickel coatings is strongly influenced baths mode:
– Composition;
– Temperature;
– The pH;
– Current density;
– Impurities.
All nickel electrolytes are divided into the following main groups:
– Sulfate (nickel Watts);
– Sulphate;
– Ftorboratny;
– Chloride;
– Hydrogen silicofluoride.
In practice the first two most often used.
4) The benefits of brilliant nickel compared with a matt:
1. Eliminates the time-consuming mechanical polishing operation.
2. Reduced nickel consumption, as by mechanical polishing on the corners, edges and edges.
3. Reducing the number of process steps and conditions are created for the automation of the entire production cycle.
4. Deposition process is intensified by the use of higher current densities.
The main disadvantages compared shiny coatings with matte are strong hydrogenation, the presence of internal pressure and a large amount of impurities, which deteriorate the mechanical properties.
5) Reagents and Equipment:
– nickel sulfate 6-water (NiSO4 * 6H2O);
– nickel chloride 7-water (NiCl2 * 7H2O);
– boric acid (H3BO3);
– ELPELYT SALT X NEX;
– ELPELYT GS-7 CARRIER H;
– ELPELYT GS-7 BRIGHTENER HL;
– ELPELYT GS-7 BRIGHTENER ST;
– NON PITTER 62A;
– copper electrode;
– glass 500 ml;
– distilled water;
– mount (end sleeves);
– copper plate;
– two wires;
– power supply;
– electrolytic cell;
– tripod.
6) Options:
– Temperature (60C0);
– Time (15 min);
– Current density (4 A/dm2);
– Electrolyte (solution).
7) Progress of work:
1. Prepare the electrolyte, i.e., solution. Take in beaker:
ü NiSO4 * 6H2O – 140 g;
ü NiCl2 * 7H2O – 25 g;
ü H3BO3 – 20 g;
ü ELPELYT SALT X NEX – 1,0 g;
ü ELPELYT GS-7 CARRIER H – 1,0 ml;
ü ELPELYT GS-7 BRIGHTENER HL – 0,2 ml;
ü ELPELYT GS-7 BRIGHTENER ST – 0,5 ml;
ü NON PITTER 62A – 1,5 ml, and dilute with distilled water to 500ml.
Solution was heated and stirred to completely dissolve the precipitate.
