Electroplating, nickel

The non-ferrous alloys include the misleadingly named nickel silver (or German silver) which contains 10-30% Ni, 55-65% Cu and the rest Zn when electroplated with silver (electroplated nickel silver) it is familiar as EPNS tableware. Monel (68% Ni, 32% Cu, traces of Mn and Fe) is used in apparatus for handling corrosive materials such as F2 cupro-nickels (up to 80% Cu) are used for silver coinage Nichrome (60% Ni, 40% Cr), which has a very small temperature coefficient of electrical resistance, and Invar, which has a very small coefficient of expansion are other well-known Ni alloys. Electroplated nickel is an ideal undercoat for electroplated chromium, and smaller amounts of nickel are used as catalysts in the hydrogenation of unsaturated vegetable oils and in storage batteries such as the Ni/Fe batteries. 

Resistance to abrasion The resistance to abrasion of electroless nickel-phosphorus hardened to 600 Hy, assessed by Taber abrasion tests, has been found to be double that of electroplated nickel However, electroless nickel coatings are not suitable for applications where two electroless nickel surfaces rub together without lubrication unless the values of hardness are made to differ by over 200 Hy units. Galling of aluminium, titanium or stainless steel may be overcome by applying electroless nickel to one of the two mating surfaces. 

Nickel chloride (NiCy is used for electroplating nickel onto the surfaces of other metals and as a chemical reagent in laboratories. 

Surfaces of finely divided nickel also promote the formation of aniline. A practical route to tlie preparation of electrodes coaled with a finely divided metal involves electroplating nickel onto a cathode from a solution containing a suspension of finely divided Raney nickel (Ni 50% A1 50%) or Devarda copper alloy (Cu 50% A1 45% Zn 5%), Some alloy particles stick to the cathode surface which is then activated by leaching out the aluminium using hot aqueous sodium hydroxide... 

Nickel acetate is used as a catalyst. It also is used as a dye mordant in textiles. Other applications are in electroplating nickel and as a sealer for anodizing aluminum. 

Occupational exposure to nickel may occur by dermal contact or by inhalation of aerosols, dusts, fumes, or mists containing nickel. Dermal contact may also occur with nickel solutions, such as those used in electroplating, nickel salts, and nickel metal or alloys. Nickel-containing dust may be ingested where poor work practices exist or poor personal hygiene is practiced. A National Occupational Exposure Survey (NOES) conducted by NIOSH from 1981 to 1983 estimates that 727,240 workers are potentially exposed to some form of nickel metal, alloys, salts, or inorganic nickel compounds in the United States (NIOSH 1990). The form of nickel these workers were probably exposed to and the level of exposure for different industries and operations were reviewed by Warner (1984) and lARC (1990). 

Metal Coatings. Tellurium chlorides, as well as tellurium dioxide in hydrochloric acid solution, impart permanent and attractive black antique finish to silverware, aluminum, and brass. Anodized aluminum is colored dark gold by tellurium electro deposition. A solution containing sodium tellurate and copper ions forms a black or blue-black coating on ferrous and nonferrous metals and alloys. Addition of sodium tellurite improves the corrosion resistance of electroplated nickel. Tellurium diethyldithiocarbamate is an additive in bright copper electroplating (see Electroplating). 

For decorative purposes especially precious metal finishes frequently are applied to plastics—for example, on buttons. In one process, a layer of copper is deposited on the initial conductive film, then electroless nickel, and lastly gold is deposited by immersion. Precious metals, particularly gold, may be used as an alternative to chromium on top of the conventional thick copper and electroplated nickel system. 

In some applications (such as military equipment) a very high standard of effectiveness is required—and it can be attained by electroplating over the electroless copper to make thicker deposits. When components will be subjected to handling it may be desirable to enhance the durability of shielding by adding electroplated nickel-chromium finishes. 

Use Propionates, some of which are used as mold inhibitors in bread and fungicides in general herbicides preservative for grains and wood chips emulsifying agents solutions for electroplating nickel perfume esters artificial fruit flavors pharmaceuticals cellulose propionate plastics. 

CCRIS 1788 EINECS 231-743-0 EINECS 253-399-0 HSDB 860 Nickel chloride Nickel chloride (NiCl2) Nickel dichloride Nickel(2-r) chloride Nlckel(ll) chloride Nickelous chloride NSC 254532 Hexahydrate P791-20-0]. Electroplated nickel coatings, chemical reagent. Yellow crystals bp = 987° soluble in H2O (1 g/ml), EtOH LD (dog iv) = 4()-80 mg/kg. Ashland Atomergic Chemetals EH Atochem N. Am. Mallinckrodt Inc. Nihon Kagaku Sangyo. 

The common electronic components consist of integrated circuits (ICs), printed circuits (PCs), and connectors and contacts. IC conductors are made from aluminum alloys, often alloyed with silicon and copper. PC boards such as conductors and connectors are made of copper with solders consisting of lead-tin alloys. Contacts are made from copper covered with electroplated nickel or gold for improved corrosion resistance. 

T. Fritz, W. Mokwa, U. Schnakenberg, Material characterisation of electroplated nickel structures for microsystem technology, Electrochim. Acta 47 (2001) 55. 

In our examples of the electrolysis of NaCl, the electrodes are inert they do not react but merely serve as the surface where oxidation and reduction occur. Several practical applications of electrochemistry, however, are based on active electrodes—electrodes that participate in the electrolysis process. Electroplating, for example, uses electrolysis to deposit a thin layer of one metal on another metal to improve beauty or resistance to corrosion. Examples include electroplating nickel or chromium onto steel and electroplating a precious metal like silver onto a less expensive one. 

A FIGURE 20.26 illustrates an electrolytic cell for electroplating nickel onto a piece of steel. The anode is a strip of nickel metal, and the cathode is the steel. The electrodes are immersed in a solution of NiS04(external voltage is applied, reduction occurs at the cathode. The standard reduction potential of Ni (E°ei 0.28 V) is less negative than that of H2O (E°ed = —0.83 V), so Ni is preferentially reduced, depositing a layer of nickel metal on the steel cathode. 

Uses Electroplated nickel coatings electrodeless coating reagent (window glass) chemical reagent mfg. sympathetic ink absorbent for NFI3 in gas masks... 

Microinjection Moiding for Microfiuidics Appiications, Fig. 9 Details of micFochaimel netwmk of electroplated nickel mold insert (a) and injection molded part for agglutination assays (b) (Reprinting with permission) [18]... 

Conventional lithography. X-ray, or UV LIGA followed by electroplating nickel or nickel alloys on silicon or nickel substrates is a common technique for fabricating tools with very small and complex features [4, 11, 17]. The... 

A possible procedure for synthetic jet fabrication has been shown in Fig. 3. The first step in the fabrication process is the wet etching of the silicon wafer using KOH to form a cavity. The cavity is filled with electroplated nickel in the second step. A polyimide membrane is deposited over the silicon wafer using spin coating in the third step. The back side of the silicon substrate is etched using KOH to obtain the orifice hole. The orifice hole extends till the filled nickel inside the cavity and the nickel material are also etched away. The piezo-ceramic material is deposited on top of the membrane for actuation. In case of electrostatic-based actuation, aluminum electrode is deposited on the membrane. 

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