Nickel Powders from the Carbonyl Process

Nickel Powders from the Carbonyl Process
Posted by kkkoo2kokkkoo2ko on 2021/08/25
Nickel Powders from the Carbonyl Process

    Nickel Powders from the Carbonyl Process


    Metal powder is the base materials for the production of metallic

component through the conventional powder metallurgy route or the emerging field of additive manufacturing. In

any of these process routes, the properties of the finished product depends on the character of the base powder from which it

is produced which is equally dependent on the process of production of the base powder. Therefore, there are different

methods for producing metal powders with each method offering different particle morphology and purity. These

methods include crushing (for brittle material), machining, mechanical pulverization, slotting,

electrolysis, atomization of liquid metal using water, nitrogen, argon, or a combination of these, and

reduction of metal oxides in hydrogen or using carbon. These metal oxides could be materials such as iron

ore or iron oxide generated from pickling plants, in steel strip mills. Other methods include reduction of

metal oxide with higher carbon containing, metal powder, chemical decomposition of metal carbonyls, and

electrolytic processing of cathodic deposition from molten metal salts; and in some instances, recycling (Sharma, 2011). Each

of these methods provides different particle morphology and characteristics. An illustration of typical powder shapes

produced from some of these processes is shown in Figures 1 and 2.


    New materials that can be tailored for individual applications are in constant demand. As the range of uses for powder

metallurgy, hard metals and electronic materials expands, customer requirements are causing materials companies to come up

with new products that have the necessary properties. Nickel can bring a number of benefits to these and other industries. It

can improve the mechanical and fatigue properties of alloy steels, enhance conductivity and magnetic properties of electronic

materials, act as a binder for holding together particulate materials and be used in filtration components in the form of

high porosity products. These applications rely on high purity fine nickel powders and other special nickel forms being

adapted to meet specific materials needs, for which a versatile production and processing technology is needed. The nickel

carbonyl gas process fulfils these needs.


    The Nickel Carbonyl Process


    Nickel powder can be made by a number of different

processes, including atomisation from melts or precipitation from solutions. However, these techniques tend to give

relatively large particles and can be difficult to control economically at fine particle sizes. The nickel carbonyl gas

process on the other hand tends to produce much finer particles, and with sufficient production know-how plus the latest

computerised process controls, the particles produced can be precisely controlled to very accurate shapes and tolerances.


    The nickel carbonyl gas process is used as a way of refining impure nickel. Nickel reacts with carbon monoxide to form

nickel carbonyl gas (Ni(CO)4), which can be decomposed back to nickel metal at moderate temperatures with the recovery of

carbon monoxide. Using thermal shock decomposition, fine or extra fine nickel powders can be made. Refineries in North

America and Britain can each process up to 50,000 tonnes per year of nickel in his way, producing a wide range of different

products. The use of such large volumes of carbonyl gas in the refineries allows the economic production of a range of nickel

powders. New products can also be made by using the gas stream essentially as a coating medium. These new products include

nickel coated graphite particulates, nickel coated carbon fibres and the large scale commercial production of high porosity

nickel foam. Another benefit is that the process has no real waste products, with used gas is recycled back into the main

refinery process.


    Nickel Powders for Powder Metallurgy


    The nickel powders produced for powder metallurgy applications have been developing step by step over recent decades as

customer property specifications have become ever more stringent. Today, there are no ‘standard’ products, only certain

families of powders that are based on different morphologies and subsequently fashioned for individual customer applications.

Nickel powder production can now be controlled to give the powders the right particle size, density and especially particle

shape to enhance the properties of low alloy steel powder metallurgy parts. Additions of nickel to the alloy typically range

from 1.75-5%. Nickel-enhanced alloys are increasingly being used for making pressed and sintered parts, particularly in the

automotive field.


    Powders



    Copper powder is produced by many processes including

chemical precipitation, electrolytic deposition, oxide reduction, water atomization, gas atomization, and jet

milling. Accordingly, Cu powders are commercially available in a wide range of particle shapes and sizes. Electrolytic and

chemical powders exhibit poor packing and poor rheology in molding, so they have been largely unsuccessful

for MIM (Wada, Kankawa, & Kaneko, 1997). Characteristics of examples of the other types are summarized

in Table 20.2. Representative scanning electron micrographs are given in Fig. 20.4. These powders all have similar

particle sizes but different morphologies. Typical purities reported by the manufacturers

are about 99.85 wt%; however, oxygen contents can range up to 0.76 wt%. Powders are usually shipped containing

desiccant and proper powder storage is essential to avoid oxidation between purchase and use.


    It is important to try this experiment before doing it as a demonstration, as different samples of

aluminium powder can react differently. The induction

period for some samples can be quite long. However, this is an impressive and spectacular demonstration, proving that water

can be a catalyst. It also shows that aluminium is a very reactive metal, and that its usual unreactive nature is due to the

surface oxide layer.


    The chemical properties of iodine are very similar to those of bromine and chlorine. However, its reactions are far less

vigorous. It can also act as an oxidant for a number of elements such as phosphorus, aluminium, zinc and iron, although

increased temperatures are generally required. Oxidation of finely dispersed aluminium with iodine can be initiated using

drops of water. The reaction is strongly exothermic, and the excess iodine vaporises, forming a deep violet vapour.

        Titanium powder metallurgy can produce high

performance and low cost titanium parts. Compared with those by conventional processes, high performance P/M titanium parts

have many advantages: excellent mechanical properties, near-net-shape and low cost, being easy to fabricate complex shape

parts, full dense material, no inner defect, fine and uniform microstructure, no texture, no segregation, low internal

stress, excellent stability of dimension and being easy to fabricate titanium based composite parts.

        Titanium alloys parts are ideally suited for advanced aerospace systems because of their unique combination of high

specific strength at both room temperature and moderately elevated temperature, in addition to excellent corrosion

resistance. Despite these features, use of titanium alloys in engines and airframes is limited by cost. The alloys processing

by powder metallurgy eases the obtainment of parts with complex geometry.
   
   
        The metallurgy of titanium and titanium-base alloys has been intensely investigated in the last 50 years. Titanium

has unique properties like its high strength-to-weight ratio, good resistance to many corrosive environments and can be used

over a wide range of temperatures. Typical engineering applications of titanium alloys include the manufacture of cryogenic

devices and aerospace components.

                Cosmetic boron nitrides

           
                What are these famous"white powders" that cosmetic formulators love? Why are they so addictive when

you start touching them? How can they help to improve the sensoriality, even the sensuality of a cosmetic product? Which

quality to choose for which application?

                Here are some questions that beauty technicians have been asking themselves since the appearance and

marketing of cosmetic grade boron nitride powder.

           
                But first let's talk about the cosmetic quality of boron nitride. In space, the association of BN

molecules can take two forms:

                - BN hexagonal = honeycomb slats that can stack one on top of the other.

                These two shapes have different properties, namely the hexagonal shape allows the sliding of the sheets,

which gives it a lubricating capacity. While the cubic shape is very rigid, which gives it great hardness.

           
                The BN cosmetic is hexagonal in shape and comes in the form of white powder with a very lubricating but non-

greasy touch. Moreover, it is a material which is very resistant, inert and non-toxic and does not present any danger…

neither for the consumer, nor for the formulator which must guarantee the stability of its product. It is for all these

reasons that the popularity of BN is rising to the point of replacing more and more good old talc in cosmetic formulations.

                The manufacturers of cosmetic raw materials have understood this well and present to date several ranges of

different qualities, thus bringing many cosmetic properties to the BN : - Soft and silky touch - Slippery touch improves

the spreading of the product on the skin - Light reflector for a soft focus effect - Opacity, transparency, pearly luster or

even glitter depending on the crystal form - Sebum absorber - Mattifying effect - Good compaction agent - High adhesion to

the skin for high hold or even non-transfer effect - High chemical stability, unaffected by pH

           
                These powders are thus used as well for care products as make-up products and in all types of cosmetic

formulations; emulsions, anhydrous casts, compact powders, even lotions where they bring several properties quoted.
           
           
                1.Superfine powder
           
           
                Superfine powder is not just a functional material, but

also established a solid foundation for the compounding and development of new functional material. The excellent performance

of superfine powder exsites in its surface effect and volume effect. the smaller the size of powder, the larger the ratio

between Area and volume. Because the BET (surface area) of superfine particle is large, and easy to agglomerate, so we need

to do surface treatment/modify to the powder and make it easy dispersing and maximize its performance.
           
           
                2.Surface modification of powder
           
           
                surface modification of powder is to use inorganic substance and organic substance coating the surface of

powder either by physical method or chemical process. By coating layer to the powder, the powder is recognized as composite

powder that has "core" and "shell layer". and different shell layer could improve the performance of

powder such as anti-corrosive, durability, light, thermal and chemical stability etc. by effecting its

hydrophily,hydrophobicity,hydrophily, hydrophobicity, catalytic etc.
           
           
                It is mainly applied in the production of powder metallurgy, electronic materials, friction materials, oil

bearing, electrical contact materials, conductive materials, medicine, diamond products and machinery parts. In high-tech

fields of petroleum catalysts, lubricants, conductive decorative coatings and electromagnetic shielding materials, the nano-

copper powder is also widely used.
           
           
                Processing and application technology of superfine copper powder has been a major bottleneck for development of the industry. Silty soft copper,

grinding processing difficulties, easily oxidized in moist air. Water atomization high cost, low yield, non-uniform

particles, and unstable quality. In addition, many newly developed production technology, part of the complex process, the

electrical equipment that require high investment, low production yield, high cost, wide particle distribution, environmental

pollution, energy consumption, quality instability and other issues, but also did not become a mainstream technology. Newly

developed chemical reduction method can only produce nano-copper powder, and its production process is still in the

laboratory research stage, secondary pollutants to deal with difficult due to the high cost of raw materials, low production

yield and high cost led to products for sale The high price odd enable customers difficult to accept, in particular, is not

ideal in many areas of nanoscale copper powder effect. In addition, unlike the ultra-fine copper powder metal copper, and

easily oxidized to copper oxide in the air, only the protection of nitrogen, sealed package, but also affect the large-scale

promotion and application of ultra-fine copper powder.
 


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