News

Non-Refractory Metals and Alloys - Physical Properties of Nickel

General characteristics of non-refractory metals
Non-refractory metals commonly used in the production of electric light sources include nickel, iron, copper and aluminum. Non-refractory metals and alloys have the following common characteristics:

1. The lattice structure is not very strong. Nickel, iron, copper, aluminum, etc. all have a common cubic face-centered close-packed lattice structure; nickel also has a (c) type and iron also has a (b) type crystal structure. Their mechanical strength is not very high, they have a high degree of plasticity and good mechanical processing performance; they have a low creep limit at high temperatures, so the parts are easy to deform and the strength will decrease. They are generally used as parts with very low heat loads.

2. Low melting point. The melting points of these metals range from 658°C for aluminum to 1535°C for pure iron.

3. They are produced by smelting. Since the melting points of these metals are not very high, they are generally extracted from ores by smelting. The purity of these metals can be refined to a very high level, the price is relatively low, and these metals have some good properties, so they are widely used in electric light sources.

Physical properties of nickel
Nickel belongs to the transition metal element (Iron Group VIII) in the periodic table. It is a silvery-white metal and very hard. It has many excellent characteristics, such as good machining performance, good vacuum performance and excellent welding performance.

The melting point of nickel is 1455℃, and its conductivity is 10~11 times that of mercury. Nickel has high mechanical strength, good ductility and toughness. Nickel can also be forged, stamped, rolled and drawn in cold conditions. It can be used to make products with very precise dimensions and extremely complex shapes.

After machining, the strength of nickel increases; after annealing, the strength can be reduced, and the elongation reaches about 40~50%. The recrystallization phenomenon of nickel is very significant at around 650℃, so nickel parts can be annealed between 700~750°. Generally, the annealing temperature should not exceed 800℃, otherwise, the strength of nickel will decrease and the creep will increase. Therefore, nickel is suitable for parts with not too high heat load in electric light sources.

Nickel has poor electrical and thermal conductivity; however, it has good spot welding and brazing properties, which is very important for the production of electric light sources.

PREVIOUS：Refractory metals - titanium and zirconium NEXT：Maintenance principles of lighting equipment