Non-Ferrous Metal: Nickel & Ni Alloys

JIM ALEX ME S3 SBCE PATTORMETALLURGY

General:-• Belongs to the transition metals. • It is hard and ductile• Crystal structure - FCC• Atomic number - 28 • Atomic weight - 58.71 • Density ( ) - 8.89 • Melting point (°c) – 1455• Boiling point(°c) – 2913

Note:- Fifth most abundant element in earth

Introduction To Nickel

3/ cmg

Properties:-• Silvery shiny appearance • High toughness and ductility• Good high and low temperature strength• High oxidation resistance • Good corrosion resistance (slow rate of oxidation at room temp.)• It is Ferro-magnetic. Having FCC crystal structure.Limitations:-

• Not mixed with cheap alloying element.

•Relatively high cost.

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Applications

85% of metallic nickel used in combination with other metals alloys

1. Used in gas turbines and rocket engines

- easy to work and can be drawn into wire - resist corrosion even at high temperatures

Nickel (Ni)

gas turbines

rocket engines

2. Used for propeller shaft in boats and desalination plants- Monel: an alloy of nickel and copper- Hard, can resist the corrosion by sea water

3. Used to make stainless steel- used very widely in the home, in architecture,- in health care, in food processing and - throughout industry.

Nickel (Ni)

Monel

Stainless steel cutlery

4. Used to make Nickel-cadmium batterySmall NiCd dry cells are used for portable electronics and toys rechargeable batteryoften using cells manufactured in the same sizes as primary cells

Nickel-cadmium battery

Nickel (Ni)

5. Used in nickel-copper alloys and nickel silver

nickel-copper alloys: - improves strength and corrosion resistance - good ductility is retained - excellent resistance to marine corrosion and

biofouling Nickel silver - used in better-quality keys, making musical

instruments (e.g. cymbals, saxophones), production of coins.

- marine fittings and plumbing fixtures for its corrosion resistance, and heating

Nickel (Ni)

Nickel silver coins

There are different types of nickel and nickel alloys;

Commercially pure nickel

Nickel-copper alloys (Monels)

Nickel-chromium alloys

Nickel-base superalloys

Nickel-iron superalloys

Classification of Ni & Ni-Alloys

• High purity nickel contains 99.99% Ni.• Commercially pure nickel contains 99.5% Ni (+Co). • Microstructure consists of solid solution phase in annealed condition.

Properties:-•Good mechanical properties and retains its strength at elevated temperature. •Excellent resistance to most corrosive environment.Applications:-• Food processing equipment• Electrical & electronic parts • Caustic handling equipment.

Commercially Pure Nickel

• Ni and Cu form complete solid solution.

• Ni-Cu alloy contains 67%Ni and 33%Cu, called Monels.

Two types of Monels are found :-

1) Monel Metal:- (Metal Treated)• consists of (67% Ni + 30% Cu + small amounts of Fe, Mn, Si & C).

Properties• High strength and toughness over a range of temperature.

• Good weldability • Excellent corrosion resistance• Resistant to Sea Water, Chlorine

Nickel Copper Alloys (Monels)

Applications• Steam turbine blades (UTS-525 Mpa & Yield Strength-230 Mpa)• High temperature valves• Centrifugal pump impellors & water meter parts.

2) K-Monel:- • Consists of 66% Ni + 29% Cu + 2.57% Al +Mn + C).

Properties• wholly Non-magnetic• Al increases strength & hardness above that of monel.

ApplicationsPump shafts, springs & valve stems etc.

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1)Nichrome:-• consists of 80% Ni + 20% Cr.

Properties• high melting point• high electrical resistivity• good stability from deforming

Applications• resistance heating coils• rocket igniters• jewellery casting supports• ceramic manufacturing industry

Nickel Chromium Alloys

• High temperature heat-resistance alloys, which can retain high strengths at elevated temperatures.

There are three types of Ni-base superalloys; • Ni base, Ni- iron base and cobalt base. The alloys contain high Cr with Ti, Al to from precipitates and additions of Mo, Co, Nb, Zr, B, Fe. • Microstructures are complex.

Properties• Heat resistant and high strength at high temperature (760-980°C). •Good corrosion & oxidation resistance.

Nickel Base Superalloys

Applications• Aircrafts, space vehicles, rocket engines• Industrial gas turbines, high temp applications. • Nuclear reactors, submarines. • Steam power plants, petrochemical equipment.

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1) German Silver:-Consists of 60% Cu + 20% Ni + 20% Zn.

Properties• Hard, white & ductile• Good mechanical & corrosion resistance

Applications • silver plated cutlery•musical instruments• pipe fittings• ornamental work of cars.

Some other Nickel alloys

2) Haste alloy:-Consists of 45% Ni + 16% Cr + 15% Mo

TYPES : A,B,C,D & its variants

Properties• high wear resistance• high corrosion resistance• high stress service

Applications• Bearings• Pressure vessel linings• chemical reactor pipes

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