nickel, silicon, tungsten and their alloys 3

Nickel, Silicon, Tungsten and Their Alloys

Ambrosio Ferris S. Tangco III

Profile of Elements

Profile of Elements:

Profile of Element: Silicon

1410.05°C

3279.85°C


Basic Information: Comprises 25.7% of the Earth’s crust (in terms

of weight), making it the second most common element in the crust.

Discovered in 1824 by Jons Jakob Berzelius, a Swedish chemist.

Shiny, dark gray with a tint of blue. Semi-metallic or considered a metalloid based

on its characteristics.


Silicon Extraction Extracted from quartz

mainly, which has a chemical formula of SiO2

Also extracted from other silicate minerals which all contain silicon and oxygen. They account for 90% of the mass of the Earth’s crust. Such minerals can be found on rocks such as granite and sandstone.


Quartz (Silicate Mineral)

Other Silicate Minerals


Alloys Ferrosilicon Alloy Silicocalcium or Ferro Silico Calcium Alloy Aluminum-Silicon Alloy


Ferro-silicon Alloy iron-silicon alloy that contains varying ratios of

elemental silicon and iron accounts for about 80% of the world's

production of elemental silicon Ferro-silicon is primarily used by the steel

industry


Silicocalcium Alloy calcium and iron alloy composite is an ideal

Deoxidants, desulfurization agent. Is widely used in high quality steel, low carbon

steel, stainless steel, and nickel base alloy steel, special alloys such as titanium-based alloy production

Profile of Element: Silicon Differences Between Ferro-Silicon and Silicocalcium Alloy?

The Ferro-Silicon is an alloy which is “abundantly” used in the steel casting and steel manufacturing process. Depending on the processes, it can be used as the de-oxidizing agent or as the reducing agent for the production of low carbon alloys.

Ferrosilicon is by far the “most common” addition agent. It is available in several standard grades containing from 15 to 95% Si.

Significant impurities in ferrosilicon include: Carbon (up to 0.25%, but generally less than 0.10%) Aluminum (generally 1-1.5%, but lower, 0.10%, or higher, to

2%, in certain grades). Manganese will usually be present as well, but not over 0.40%

unless specified. Phosphorus and sulfur contents are restricted to low residual

levels: in general they will not exceed 0.025 and 0.040%


Differences Between Ferro-Silicon and Silicocalcium Alloy? The Ferro Silico Calcium alloy is used in the

manufacturing of steel of higher ranks. It also has the capability to replace the Aluminum in the de-oxidation process to produce the best merit of steel and special alloy.

Calcium has a strong affinity to oxygen, making it an ideal adhesive oxygen agent or oxygen abosrber and desulfurization agent.

Calcium transforms alumina inclusions into complex Calcium aluminate compounds, that improve the castability of the steel in a continuous casting process, avoiding deposits of solid inclusions inside tundish nozzles, preventing clogging.


Similarities Between Ferro-Silicon and Silicocalcium Alloy?

Elemental silicon is added to molten cast iron as ferrosilicon or silicocalcium alloys in order to improve performance in casting thin sections, and to prevent the formation of cementite where exposed to outside air.

The presence of elemental silicon in molten iron acts as a sink for oxygen, so that the steel carbon content, which must be kept within narrow limits for each type of steel, can be more closely controlled.

Standard foundry grades of ferrosilicon specify aluminum and calcium.


Technical Specifications of Ferro Silicon

Technical Specifications of Ferro Silico Calcium


Aluminum-Silicon Alloy Often the brazing sheet has only a cladding of aluminum-

silicon alloy and the core consists of some other high melting alloy (Fe, Mn, Co, Cr, Mo, Ni).

Silicon is the main alloying element; it imparts high fluidity and low shrinkage, which result in good castability and weldability. The low thermal expansion coefficient is exploited for pistons, the high hardness of the silicon particles for wear resistance. The maximum amount of silicon in cast alloys is of the order of 22-24% Si, but alloys made by powder metallurgy may go as high as 40-50% Si. (Key To Metals)

Used mainly for casting processes.


Aluminum-Silicon Alloy Mechanical Porperties:

Alloys prepared from powders exhibit somewhat higher strengths, especially at elevated temperatures.

Increasing silicon content increases strength at the expense of ductility, but this effect is not very marked. Modification by sodium produces a limited increase of strength, but the increase of ductility is substantial, especially in sand castings.


Applications

Aluminum-Silicon Cast Ferro-Silicon and Steel with Ferro-Silicon

Silicocalcium Alloy

Rail Steel

Rail Steel Application

Questions on Silicon?

Profile of Element: Nickel

1453.05°C

2919.85°C


Basic Information: In early times, nickel-bearing materials, like niccolite,

were mixed with glass to make green glass (called kupfernickel meaning Devil’s Copper). When nickel was first extracted from niccolite, the mineral name was the source of the the element’s name, nickel.

Silvery shiny, metallic element In 1751, in the Western world, Axel Fredrik Cronstedt,

a Swedish mineralogist and chemist, discovered nickel by surprise when he attempted to extract copper from the mineral niccolite. But, in China, at 235 B.C.E., an alloy of copper, nickel, and zinc, called paitung or paktong, was used to make utensils and other metal ware.


Nickel Extraction On Earth, nickel occurs

most often in combination with sulfur and iron in pentlandite, with sulfur in millerite, with arsenic in the mineral nickeline, and with arsenic and sulfur in nickel galena. Nickel is commonly found in iron meteorites as the alloys kamacite and taenite.


Nickel Extraction The bulk of the nickel mined

comes from two types of ore deposits. The first are laterites where the principal ore minerals are nickeliferous limonite: (Fe, Ni)O(OH) and garnierite (a hydrous nickel silicate): (Ni, Mg)3Si2O5(OH)4. The second are magmatic sulfide deposits where the principal ore mineral is pentlandite: (Ni, Fe)9S8.


Properties of Nickel and its Alloys Corrosion Resistance Heat-Resistant Applications Low-Expansion Alloys Electrical Resistance Alloys Soft Magnetic Alloys Shape Memory Alloys


Corrosion Resistance Nickel-base alloys offer excellent corrosion resistance

to a wide range of corrosive media. However, as with all types of corrosion, many factors influence the rate of attack.

Heat-Resistant Applications Nickel is useful in applications wherein it is subjected

to harsh environments with high temperatures Nickel-Chromium Alloys or alloys that have more than

15% worth of Cr are used to provide both oxidation and carburization resistance at temperatures beyond 760°C.


Low Expansion Alloys Nickel was found to have a profound effect on the

thermal expansion of iron. Alloys can be designed to have a very low thermal expansion or display uniform and predictable expansion over certain temperature ranges.

Electrical Resistance Alloys Several alloy systems based on nickel or containing

high nickel contents are used in instruments and control equipment to measure and regulate electrical characteristics (resistance alloys) or are used in furnaces and appliances to generate heat (heating alloys).


Electrical Resistance Alloys Types of resistance alloys containing nickel include:

Cu-Ni alloys containing 2 to 45% Ni Ni-Cr-Al alloys containing 35 to 95% Ni Ni-Cr-Fe alloys containing 35 to 60% Ni Ni-Cr-Si alloys containing 70 to 80% Ni

Types of resistance heating alloys containing nickel include:

Ni-Cr alloys containing 65 to 80% Ni with 1.5% Si Ni-Cr-Fe alloys containing 35 to 70% Ni with 1.5% Si +

l% Nb


Soft Magnetic Alloys Two broad classes of magnetically soft materials have

been developed in the Fe-Ni system. The high-nickel alloys (about 79% Ni with 4 to 5% Mo; bal Fe) have high initial permeability and low saturation induction.

Shape Memory Alloys Metallic materials that demonstrate the ability to return

to their previously defined shape when subjected to the appropriate heating schedule.

Nickel-titanium alloys (50Ni-50Ti) are one of the few commercially important shape memory alloys.

Profile of Element: Nickel Alloys (Commercial Nickel and Nickel Alloys)

The commercial forms of nickel and nickel-base alloys are fully austenitic. They are considered mainly for their resistance to high temperature and aqueous corrosion.

Alloys Stainless Steels Copper-Nickel alloys and Nickel-Copper alloys Nickel-Chromium and Nickel-Chromium-Iron alloys Iron-Nickel-Chromium Alloys Controlled-expansion alloys Nickel-lron Low-Expansion Alloys Soft Magnetic Alloys Welding Alloys


Stainless Steels The vast majority of stainless steels contain 8-

10% of nickel. Useful as fire retardant materials since they

are able to retain their strength at higher temperatures than structural steel

An example is the 304 grade stainless steel, the most common one, that has a composition of 8% nickel, 18% chromium, and the balance or the rest being iron.


Copper-Nickel alloys and Nickel-Copper alloys Copper-Nickel alloys

Cast Copper-Nickel Alloys (Copper-Nickels, Cupro-Nickels)

Cast Copper-Nickel-Zinc Alloys (Nickel Silvers)

Nickel-Copper alloys


Copper-Nickel alloys Cast Copper-Nickel Alloys (Copper-Nickels, Cupro-

Nickels) Are copper alloys, containing 9-31% of nickel (Ni) as

the major alloying element. Cast Copper-Nickel alloys are designated with the numbers from C96000 through C96999.

Cast Copper-Nickel-Zinc Alloys (Nickel Silvers) Are copper alloys containing 12.5-25.5% of nickel (Ni)

and 2.5-21% of zinc (Zn) as the major alloying elements. Cast Copper-Nickel-Zinc alloys are designated with the numbers from C97000 through C97999.


Copper-Nickel alloys Cast Copper-Nickel and cast Copper-Nickel-

Zinc alloys have moderate mechanical strength and high ductility combined with very good corrosion resistance (particularly in sea water).

Iron, manganese and niobium are added to the cast Copper-Nickel alloys for increasing their hardness and strength.


Copper-Nickel alloys Cast Copper-Nickel Alloys (Copper-Nickels, Cupro-

Nickels) Are used for manufacturing pump bodies, bearings,

bushings, steam fittings, boat part, valves and fittings resistant to corrosion in sea water, plastic molds tooling.

Cast Copper-Nickel-Zinc Alloys (Nickel Silvers) Are used in decorative applications and for

manufacturing marine furniture, sanitary fittings, fittings for food processing, valves, pumps, window hardware, components of musical instruments.

Profile of Element: Nickel Nickel-Copper alloys (trade mark Monel)

Are nickel base alloys containing 29-33% of copper (Cu) as the major alloying element.

Alloys containing 3% of aluminum (Al) and 0.6% of titanium (Ti) as additional alloying elements (Monel K-500), are heat-treatable and may be strengthened by precipitation hardening.

These alloys have high corrosion resistance in acids and alkalis, high mechanical strength combined with good ductility and low coefficient of thermal expansion. Machinability of the alloys is poor.

They are used for manufacturing chemical processing equipment, valve stems, springs, pumps, shafts, fittings, heat exchangers, screw machine products, marine equipment. (Monel)

Have been found to possess excellent corrosion resistance in reducing chemical environments and in sea water, where they deliver excellent service in nuclear submarines and various surface vessels.


Nickel-Chromium and Nickel-Chromium-Iron alloys These alloys led the way to higher strength

and resistance to elevated temperatures. Today they also form the basis for both commercial and military power systems.

Two of the earliest developed Ni-Cr and Ni-Cr-Fe alloys were:

Alloy 600 (76Ni-15Cr-8Fe). Nimonic alloys (80Ni-20Cr + Ti/Al).


Nickel-Chromium and Nickel-Chromium-Iron alloys Some high-temperature variants include:

Alloy 601. Lower nickel (61%) content with aluminum and silicon additions for improved oxidation and nitriding resistance

Alloy X750. Aluminum and titanium additions for age hardening

Alloy 718. Titanium and niobium additions to overcome strainage cracking problems during welding and weld repair

Alloy X (48Ni-22Cr-18Fe-9Mo + W). High-temperature flat-rolled product for aerospace applications

Waspaloy (60Ni-19Cr-4Mo-3Ti-1.3Al). Proprietary alloy for jet engine applications

Profile of Element: Nickel Nickel-Chromium and Nickel-Chromium-Iron alloys

Some corrosion-resistant variants in the Ni-Cr-Fe system include:

Alloy 625. The addition of 9% Mo plus 3% Nb offers both high-temperature and wet corrosion resistance; resists pitting and crevice corrosion

Alloy G3/G30 (Ni-22Cr-19Fe-7Mo-2Cu). The increased molybdenum content in these alloys offers improved pitting and crevice corrosion resistance

Alloy C-22 (Ni-22Cr-6Fe-14Mo-4W). Superior corrosion resistance in oxidizing acid chlorides, wet chlorine, and other severe corrosive environments

Alloy C-276 (17% Mo plus 3.7W). Good seawater corrosion resistance and excellent pitting and crevice corrosion resistance

Alloy 690 (27% Cr addition). Excellent oxidation and nitric acid resistance; specified for nuclear waste disposal by the vitreous encapsulation method


Iron-Nickel-Chromium Alloys This series of alloys has also found extensive

use in the high-temperature petrochemical environments, where sulfur-containing feedstocks (naphtha and heavy oils) are cracked into component distillate parts. Not only were they resistant to chloride-ion stress-corrosion cracking, but they also offered resistance to polythionic acid cracking.

Profile of Element: Nickel Iron-Nickel-Chromium Alloys

The 800 alloy series offers excellent strength at elevated temperature (creep and stress rupture).

Some alloys of commercial importance include: Alloy 800 (Fe-32Ni-21Cr). The basic alloy in the Fe-Ni-Cr system;

resistant to oxidation and carburization at elevated temperatures Alloy 800HT. Similar to 800H with further modification to combined

titanium and aluminum levels (0.85 to 1.2%) to ensure optimum high-temperature properties

Alloy 801. Increased titanium content (0.75 to 1.5%); exceptional resistance to polythionic acid cracking

Alloy 802. High-carbon version (0.2 to 0.5%) for improved strength at high temperatures

Alloy 825 (Fe-42Ni-21.5Cr-2Cu). Stabilized with titanium addition (0.6 to 1.2%). Also contains molybdenum (3%) for pitting resistance in aqueous corrosion applications. Copper content bestows resistance to sulfuric acid

Alloy 925. Addition of titanium and aluminum to 825 composition for strengthening through age hardening


Iron-Nickel-Chromium Alloys Some corrosion variants in the Fe-Ni-Cr

system include: 20Cb3 (Fe-35Ni-20Cr-3.5Cu-2.5Mo + Nb). This

alloy was developed for the handling of sulfuric acid environments

20Mo-4 and 20Mo-6 (Fe-36Ni-23Cr-5Mo + Cu). Increased corrosion resistance in pulp and paper industry environments.


Controlled-expansion alloys include alloys in both the Fe-Ni-Cr and Fe-Ni-

Co series. Some alloys of commercial importance

include: Alloy 902 (Fe-42Ni-5Cr with 2.2 to 2.75% Ti and

0.3 to 0.8% Al). This is an alloy with a controllable thermo-elastic coefficient

Alloys 903, 907, 909 (42Fe-38Ni-13Co with varying aging elements such as niobium, titanium, and aluminum). These alloys offer high strength and low coefficient of thermal expansion.


Nickel-lron Low-Expansion Alloys This series of alloys plays a very important role in both

the lamp industry and electronics, where glass-to-metal seals in encapsulated components are highly required.

Some alloys of commercial importance include: Invar (Fe-36Ni). This alloy has the lowest thermal

expansion of any metal from ambient to 230°C (450°F)

Alloy 42 (Fe-42Ni). This alloy has the closest thermal expansion match to alumina, beryllia, and vitreous glass

Alloy 426. Additions of 6% Cr are added to this alloy for vacuum-tight sealing applications

Alloy 52 (Fe-51.5Ni). This alloy has a thermal expansion that closely matches vitreous potash-soda-lead glass.


Soft Magnetic Alloys The nickel-iron alloys also offer an interesting set of

magnetic permeability properties. Have been important in the designing of:

switchgears direct current (dc) motors generator designs.

Welding Alloys Welding products for nickel alloys have similar compositions

to the base metals, although additions of aluminum, titanium, magnesium, and other elements are made to the filler metals and welding electrodes to ensure proper de-oxidation of the molten weld pool and to overcome any hot-short cracking and malleability problems.


Applications

Turbines

Stainless Steel Appliances

Nickel Plated Musical InstrumentsNickel Shape

Memory Products

Questions on Nickel?

Profile of Element: Tungsten

3410.05°C

5499.85°C


Basic Information: Atomic symbol is W due to the German word,

“Wolfram” that was given to it. The word Tungsten comes from two Swedish words

“tung” and “sten” which mean heavy and stone respectively.

Went through three major discovery times: 1758 – was discovered by Axel Fredrik Cronstedt,

a Swedish mineralogist and chemist 1781 – Tungsten oxide was isoldated by Carl

Wilhelm Scheele, a 1783 – Tungsten was first separated from the

mineral Wolframite by Fausto and Juan Jose de Elhuyar, two Spanish chemists that were brothers

Profile of Element: Tungsten Tungsten Extraction

Tungsten occurs in: wolframite ((Fe, Mn)WO4) scheelite (CaWO4), huebnerite (MnWO4) ferberite (FeWO4).

The metal is obtained commercially by the reduction of tungsten oxide with hydrogen or carbon.

Pure tungsten is a steel-grey to tin-white metal. The pure metal has the ability to be cut with a hacksaw, may be forged, spun, drawn, and extruded. However, the impure metal is brittle and can be worked with some difficulty.


Interesting Properties Has the highest melting point of all metals Has the lowest vapor pressure of all metals Has a very high moduli of compression and elasticity At temperatures over 1650°C, it has the highest tensile

strength. Has excellent corrosion resistance and is attacked only

slightly by most mineral acids. Boiling point of tungsten is almost 5500°C (or ~5700°C for

other sources), which corresponds to the temperature of the sun’s surface.

At a density of 19.3 g/cm3, is considered as one of the heaviest metals (5th highest, behind, Re, Pt, Ir, and Os, which has the highest density at a value of 22.6 g/cm3).

Silicon: 2.336 g/cm3, Nickel: 8.908 g/cm3


Alloys Tungsten Alloys

tungsten-ThO2 tungsten-molybdenum tungsten-rhenium

Tungsten Heavy-Metal Alloys (WHAs)


Tungsten Alloys The most important applications of the pure

metallic tungsten are the production of filaments for bulb lamps, electric contacts, arch-welding electrodes, heating elements in high temperature furnaces, valves for reaction propellers used in missiles and airships, etc.

Tungsten mill products are tungsten metal products such as lighting filaments, electrical and electronic contacts, wire, rods, etc.


Tungsten-ThO2 This alloy contains a dispersed second phase

of 1 to 2% thorium. The thorium dispersion enhances thermionic electron emission, which in turn improves the starting characteristics of gas tungsten arc welding electrodes.

Increases the efficiency of electron discharge tubes and imparts creep strength to wire at temperatures above one-half the absolute melting point of tungsten.

Profile of Element: Tungsten Tungsten-Molybdenum

The alloying of molybdenum with tungsten leads to better corrosion resistance against molten zinc.

Tungsten-molybdenum alloy has a high melting point and high density for both tungsten and molybdenum own the properties of high density and high melting point.

Tungsten-molybdenum alloy can have a different proportion of tungsten and molybdenum, such as 30% tungsten and 50% tungsten.

Tungsten molybdenum alloy has following advantages compared to pure molybdenum:

higher recrystallization temperature (approx. 100 °C) better corrosion resistance against molten zinc higher strength

Tungsten molybdenum alloy has following advantages compared to pure tungsten:

better formability lower density


Tungsten-Rhenium The addition of rhenium to the tungsten

increases the ductility and shock resistance at higher temperatures encountered in thermocouple and electronic applications among others.

Uses: Tungsten / tungsten-rhenium thermocouples for

measuring the temperature in such furnaces. X-ray tubes for medical use are not only equipped

with a tungsten emitter coil, but also a static anode made of tungsten or tungsten-rhenium.


Tungsten Heavy-Metal Alloys (WHAs) A group of tungsten-based materials that contain 90-98 wt%

of tungsten. Current uses are:

Damping weights for computer disk drive heads Balancing weights for ailerons in commercial aircraft, helicopter

rotors, and for guided missiles Kinetic energy penetrators for defeating heavy armor Fragmentation warheads Radiation shielding, radio isotope containers, and collimalion

apertures for cancer therapy devices High performance lead-free shot for waterfowl hunting Gyroscope components Weight distribution adjustment in sailboats and race cars.


Applications

Tungsten Radiation Shielding

Kinetic Energy Penetrator or armor piercing shot (inner core is made of tungsten)

Tungsten-Rhenium Thermocouple

Tungsten-Molybdenum Alloy Products

Any questions you have for Tungsten?

References: http://www.eoearth.org/article/Tungsten http://www.eoearth.org/article/Nickel?topic=49557 http://www.eoearth.org/article/Silicon http://www.tungsten-alloy.com/tungsten-grades.htm http://www.tungsten-alloy.com/ http://www.keytometals.com/Article110.htm http://www.keytometals.com/Article80.htm http://www.keytometals.com/Article9.htm http://www.azom.com/article.aspx?ArticleID=2194#_Magnetic_Alloys http://en.wikipedia.org/wiki/Silicon#Alloys_2 http://www.ec21.com/offer_detail/Sell_silicocalcium--10038075.html http://hcrosscompany.com/refractory/tungsten.htm http://en.wikipedia.org/wiki/Nickel http://www.jayeshindustries.com/ferro-silico-calcium.htm http://www.jayeshindustries.com/ferro-silicon.htm http://www.tungsten.com/mtstung.html http://www.tungsten.com/tungcorr.html http://en.wikipedia.org/wiki/Tungsten http://www.azom.com/article.aspx?ArticleID=1201 http://nautilus.fis.uc.pt/st2.5/scenes-e/elem/e07430.html http://www.lenntech.com/periodic-chart-elements/density.htm http://www.tungsten-alloy.com/kinetic-energy-penetrator.htm http://www.strategic-metal.com/index.php/products/products_content/W/Tungsten%20Rhenium_%20Thermocouples http://molybdenum-alloy.com/Tungsten-Molybdenum-Alloy.html http://www.metallurgvanadium.com/siliconpage.html http://www.glbsm.com/product-information/Calcium-Silicon-Alloys.pdf http://en.wikipedia.org/wiki/Silicate_minerals http://www.azom.com/article.aspx?ArticleID=2194 http://www.substech.com/dokuwiki/doku.php?id=nickel-copper_alloys http://www.substech.com/dokuwiki/doku.php?id=cast_copper-nickel_alloys_and_nickel_silvers http://www.nickelinstitute.org/~/link.aspx?_id=2E78D186B57F4E10B6085F27D38E6E2B&_z=z

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nickel, silicon, tungsten and their alloys 3

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