Nickel Alloy

Nickel alloy is an alloy in which nickel is the principle component. It has following two sub categories, they are Nickel aluminium alloy and Nickel chromium alloy.

Nickel Al Alloy

The series of high strength and high temperature aluminium alloys are Hiduminium or R.R. Alloys, and it was developed by Rolls Royce before the World War II, for the use of aircrafts. Later they were manufactured and developed by High Duty Alloys Ltd. The name Hi du Minium is derived from that of High Duty Alloys. This alloy was first developed for motor racing piston and then adopted for the engine of aircraft. It was the development of earlier Y alloy, and the first of nickel containing light Al alloys. From the three main groups of high strength aluminium alloys, the nickel Al alloys has the advantage of retaining strength even at high temperatures, and making them particularly useful for pistons.

Nickel Chromium alloy

These are the alloys primarily of nickel and chromium, and are usually chosen for the behavior during high temperature, either resistance to chemical and physical erosion or to mechanical creep. It has four categories they are

Bright ray

Brightray is a nickel chromium alloy and is noted for its resistance to erosion by gas flow at high temperatures. It is used particularly on aircraft engines since 1930s. As well as it is used as a coating, it is used in wire and strip form for electrical heating elements. The original brightray was composed of 80% nickel or 20% chromium. By name Brightray S it is still in use, and can be used at temperature up to 1050°c. It has several other variants also, these includes nickel iron chromium Brightray F and Brightray C.

Chromel

Chromel is an alloy contains around 90% Nickel and 10% chromium that are used to make the positive conductors of ANSI type E (chromel-constantan) and K (chromel-alumel) thermocouples. This can be used up to 1100°c in oxidizing atmosphere.

Inconel

Inconel alloys are used in high temperatuire applications. Inconel 625, Chronin 625, Altemp 625, Haynes 625, Nickelvac 625 and Nicrofer 6020 are included in the common trade names for Inconel.

Nichrome

By mass common alloy is 80% nickel and 20% chromium. It is silvery grey in color, corrosion resistant and has a higher melting point of about 1400°c. Electric heating elements like hair dryers, electric ovens are getting widely by it because of its relatively high electrical resistivity and resistance to oxidation at high temperature. These are Nickel alloys.

Questions:

• Explain nickel chromium alloy?
• Explain Brightray?