Non-Metalic Materials selection Presented By

NON METALLIC MATERIALS Contents1) Types of materials.2) Selection of materials and its criteria.3) Non-metallic Materials definition.4) Various types of non metalic materials. 1) ceramics 2) polymers 3) composites 5) References 6) conclusion.

TYPES OF MATERIALS

Properties of metal and non-metals

SELECTION OF MATERIALS Selection of material for the machine component is one of the most

important steps in the process of machine design. The following factor should be considered while selecting the material

Availability- The material should be readily available in the market ,in large enough quantity to meet the requirement

Cost- For every application, there is limiting cost beyond which the designer cannot go. It is likely that the cost of material might be low, but the processing may involve costly machine operation.

Mechanical properties- The important mechanical properties of materials from the considerations of design are Strength, rigidity, toughness, resilience, frictional properties , wear resistance, creep characteristics, corrosion resistance, hardness etc.

These properties are measured in terms of following quantities

NON METALLIC MATERIAL Non-metallic Materials - Materials that do not

have the properties of, or do not contain, metal and that are able to combine with hydrogen to form stable compounds, acids, acidic oxides, and anions.

Non-metal

Ceramics Organic polymers Composite

But Why Non-Metals Materials ?Corrosion Resistance Products molded in non metal are more weather resistant

than fabricated metal products. Non-metals will not corrode and can be designed to

accommodate many climatic conditions. Special additives may be added to the plastic resin to combat failure due to high exposure to UV.

Chemical Resistance Since Non-metals is impervious to many chemical

compounds, plastic is an ideal material for a wide variety of solution tanks.

Solar Non-metals has expertise in manufacturing solution tanks for the agricultural, paper, medical and turf industries.

Strength Non-metals parts may be designed to be impact and dent resistant. Parts can be reinforced with core - through and kiss-offs for added

strength.Economical Non-metals is lighter weight for better fuel economy and cheaper to

manufacture than metal parts. One of the great features of rotational molding is the ability to

convert large numbers of assembled components into a single functional plastic part. This not only eliminates assembly time and cost, but can also result in a more functional part with better economics.

Aesthetics Since colour is part of the molded piece, no secondary painting

operations are necessary. The result: a uniform, maintenance free and cost effective colour for your part.

Graphics can be made to your specifications and molded into the part, which protects the graphic from ever coming off.

Ceramics- The word ceramic is described from Greek, Keramos through the

group of materials now so described includes glass, products, cements, and plasters, some abrasive and cutting tool materials, building materials such as bricks, tiles and drain pipes, various electrical insulation materials etc.

The term ceramics is applied to a range of inorganic materials of widely varying uses. generally these materials these materials are non metallic and in most cases have been treated at a high temperature at some stage during manufacture.

Ceramics materials can be classified conveniently into four main groups-

1) Amorphous ceramics. 2) crystalline ceramics. 3) Bonded ceramics . 4) cements.

Types of ceramics

Amorphous Ceramics- These are substances referred to generally as “glasses” . They

include those such as obsidian which occurs naturally and glasses used for the manufacturing of bottles, windows, and lenses.

Crystalline Ceramics- These may be single phase materials like magnesium oxide or

aluminium oxide or various mixtures of materials such as these. In addition some carbides and nitrides belongs to this groups.

Bonded Ceramics- Materials in which individual crystals are bonded together by a

glassy matrix as in large number of products derived from day.

Cements- cements a number of these arte crystalline but some may contain

both crystalline and amorphous.

Properties of ceramic materials

1) Optical properties- many types of glasses have been used for the production of windows and optical lenses. A number of special glasses have also been employed for selective transmission or absorption of particular wavelength such as infrared and ultraviolet.

2) Thermal properties- ceramics posses favourable properties at high temperature and under oxidation conditions.

3) Electrical conductivity- Although many ceramics are insulators of them of course conduct electricity quite well at room temperature and constitute a very special class of semi-conductors.

e.g.)porcelain, steatite, forsterite, and alumina etc.4) Mechanical properties- a) Non-ductile stress concentration has little or no effect on

compressive strength.

b) The compressive strength several times more than the tensile strength.

c) Temp rigidity is high.d) The ceramic materials posses ionic and covalent bonds which

impact high modulus of elasticity etc.e) Below recrystallisation temperature, non-crystalline ceramics are

fully brittle.f) In case of alloy consisting of two or metal, each phase many have

appreciable difference of coefficient of thermal expansion which generate stress. This stress may then cause the metal to fail.

Application of ceramic materials-1) Ceramic materials are used in electrical and electronics

industry because of their high electrical resistivity , dielectrical strength and magnetic properties suitable for applications such as magnets for speakers.

2) The capability of ceramics to maintain their strength and stiffness at elevated temperatures makes them very attractive for high temperature applications.

3) High resistance to wear makes them suitable for applications such as cylinder liners, bushings, seals, and bearing.

4) Internal combustion engines are only about 30% efficient, but with the use of ceramic components their operating performance can be improved by at least 30%

5) Ceramic materials have been used successfully especially in gasoline and diesel engine components and as rotors, are silicon nitride, silicon carbide, and partially stabilised zircon.

6) High speed components for machine tools. 7) Ceramics are also used to coat metal which may be done to

reduce wear, prevent corrosion and a thermal barrier.8) Silicon-nitride ceramics are also used as ball bearing and

rollers. because of their strength and inertness.

Examples of ceramics materials

Until the 1950s, the most important ceramic materials were (1) pottery, bricks and tiles,

(2) cements and

(3) glass. A composite material of ceramic and metal is known

as cermet.

1. Barium titanate (often mixed with strontium titanate) displays ferroelectricity, meaning that its mechanical, electrical, and thermal responses are coupled to one another and also history-dependent. It is widely used in electromechanicaltransducers, ceramic capacitors, and data storage elements. Grain boundary conditions can create PTC effects in heating elements.

Bismuth strontium calcium copper oxide, a high-temperature superconductor

Boron nitride is structurally isoelectronic to carbon and takes on similar physical forms: a graphite-like one used as a lubricant, and a diamond-like one used as an abrasive.

Earthenware used for domestic ware such as plates and mugs.

Ferrite is used in the magnetic cores of electrical transformers and magnetic core memory.

Lead zirconate titanate (PZT) was developed at the United States National Bureau of Standards in 1954. PZT is used as an ultrasonic transducer, as its piezoelectric properties greatly exceed those of Rochelle salt.

Magnesium diboride (MgB2) is an unconventional superconductor.

Porcelain is used for a wide range of household and industrial products.

Sialon (Silicon Aluminium Oxynitride) has high strength; resistance to thermal shock, chemical and wear resistance, and low density. These ceramics are used in non-ferrous molten metal handling, weld pins and the chemical industry.

Silicon carbide (SiC) is used as a susceptor in microwave furnaces, a commonly used abrasive, and as a refractory material.

Silicon nitride (Si3N4) is used as an abrasive powder. Steatite (magnesium silicates) is used as an 

electrical insulator. Titanium carbide Used in space shuttle re-entry shields and

scratchproof watches. Uranium oxide (UO2), used as fuel in nuclear reactors.

Yttrium barium copper oxide (YBa2Cu3O7-x), another high temperature superconductor.

Zinc oxide (ZnO), which is a semiconductor, and used in the construction of varistors.

Zirconium dioxide (zirconia), which in pure form undergoes many phase changes between room temperature and practical sintering temperatures, can be chemically "stabilized" in several different forms. Its high oxygen ion conductivity recommends it for use in fuel cells and automotive oxygen sensors. In another variant, metastable structures can impart transformation toughening for mechanical applications; most ceramic knife blades are made of this material.

Partially stabilised zirconia (PSZ) is much less brittle than other ceramics and is used for metal forming tools, valves and liners, abrasive slurries, kitchen knives and bearings subject to severe abrasion

Day to Day life uses

Polymers Polymers means many units (poly=many, mer=units) is

composed of a large number of repetitive called monomers or simple molecules.

Thus a polymers is made up of thousands of monomers joined chemically together to form a large molecules.

It has been observed that each molecule of polymer is either a long chain or a network of repetitive units or monomers.

Classification of polymers – 1) Thermoplastic polymers. 2) Thermosetting polymers.

A) Thermoplastic polymers-1) Thermoplastic polymers are the polymers which become soft

and deformable when heated, which is characteristic of linear polymeric molecules.

2) Thermoplastic materials are similar to metals that again ductility a high temperatures. It has been noted that, as with metal, the ductility of thermoplastics polymers is reduced by cooling.

3) These polymers are noted in engineering polymers, which retain good strength and stiffness up to 150-175 degree Celsius.

4) Although polymers can not, in general, be expected to duplicate fully the mechanical behaviour of traditional metal alloy, a major effort is made to produce some polymers with sufficient strength and stiffness to be serious candidates for structural applications once dominated by metal.

5) It has been estimated that industry has developed more than half a million engineering polymers part design part design specifying nylon.

B) Thermosetting polymers-1) Thermosetting polymers are the polymers which are the

opposite of thermoplastics. They become hard and rigid when heating.

2) Common thermo-setting polymers which is subdivided into two categories, thermosetting and elastomers. In this case, thermosets refers to materials that share with the engineering polymers.

3) Significant strength and stiffness so as to be common Metal substitutes. However , thermosets have the disadvantages of not being recyclable and in general, having less variable techniques.

4) In addition to the many applications found. Such as films foams and coatings. The adhesive serves to join the surfaces of two solids by secondary faces similar to those between molecular chain in thermoplastics.

mechanical properties of polymers

Materials Specific gravity

Tensile strength

Compressive strength

polyamide 1.04-1.14 70 50-90Low density polythene

0.92-0.94 7-20 -

acetal 1.41-1.42 55-70 -polyurethane 1.21-1.26 35-60 25-80Teflon 2.14-2.20 10-25 10-12

C) Synthetic Rubbers Synthetic rubbers or elastomers are manufactured from raw materials

such as coke, limestone, petroleum, natural gas, salt, alcohol, ammonia, coal tar etc.

We can say that the processing of synthetic rubbers involved approximately the same steps as that of natural rubber. moreover, some of the properties of the synthetic rubbers are better than those of natural rubbers.

Example, some synthetic rubbers are more resistant to sunlight than the natural rubbers. Similarly , some synthetic rubbers have greater solvent resistance and other have greater elasticity than that of natural rubber.

Some important synthetic rubbers are- 1)silicon rubbers 2)polyurethane rubbers 3)nitrite rubbers 4)butadiene rubbers 5)butyl rubbers 6)polychloroprenes

etc.

Properties of engineering polymers The following are the properties of engineering polymers- 1) Polymers have good corrosion resistance.2) Low density3) Low co-efficient of friction.4) Temperature resistance.5) Poor tensile strength. 6) Good mouldability.7) Modulus of elasticity.8) Light weight.9) Polymers are good thermal and electrical insulators.10) Good resistance to chemicals.11) High coefficient of thermal expansion.

Application of polymers

1) Several inorganic materials have structure composed of building blocks connected in chain and network configurations.

2) The rear quarter panel on this sports car was a pioneering application of an engineering polymers in a traditional structural metal application.

3) In automotive industry engineering polymers are used.4) Consumer and industrial products made of polymers include

food and beverage containers, packing, housewares, textiles, medical devices foam, paints, safety, shields and toys.

5) Relative humidity is a design consideration for the use of nylons.

Applications of Polymers

Day to Day uses of Polymers

3) Composite materials Composite materials comprising two or more different

materials bonded together having combined properties of constituents are called as composites.

In its simplest form composites consists of two independent and dissimilar materials.

The common example of composites used in everyday life are plywood, vehicle tyres etc. plywood is the composites of thin sheets of wood with grains of alternate sheets perpendicular to each other and bonded together by a polymer in between them.

Classification of composite materials

Properties of composite materials1) The properties such as strength resistance to heat or some other

properties of composite materials are better than the properties of the individual materials from which they are made.

2) The specific strength is sometimes referred to as the strength to weight ratio.

3) Composite materials have stiffness, toughness, creep resistance.

4) Properties like density and heat capacity depend on the amount of each phase and are independent of microstructure.

5) Properties like elastic modulus, thermal and electrical conductivities depends upon geometry of the constituents as well as to their volume fraction.

composite materials Carbon- carbon fiber, alternatively graphite fiber. Carbon fiber is a

material consisting of fibers about 5-10µm in diameter and composed mostly of carbon atom.

• Glass- fiber glass also called glass reinforce plastic. Glass fiber

Reinforced plastic is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass.

Aramid- Aramid fiber a class of heat resistant and strong synthetic

fibers. They are used in aerospace and military application.

Application of composite materials

1) Composite materials to be used in certain application like space vehicles.

2) Aircrafts.3) Rockets.4) High pressure vessels.5) Building construction.6) Aerospace.7) Fuel efficient automobiles.

Application of composite materials1) Automotive Industry

In the automotive industry, the physical properties of long glass fibre thermoplastic composites and (SMC) sheet moulding compound make these materials ideal for a wide range of components where form and structure are required. Examples are:

Wheel tubs Under body noise shields Seat frames Battery trays Load floors Body panels Under engine covers Reinforcement beams

2) Building and Construction

In building and construction industries, the insulation properties of SMC and Bulk moulding compound (BMC) have definite advantages over traditional materials, for such uses as:

Roof tiles Shower bases Computer access flooring systems Exterior door panels

SMC and BMC provide a relatively higher degree of design freedom than traditional materials, without surrendering structural properties. These compounds are non-slip, will resist water absorption and provide good electrical, fire-retardant and corrosion-resistance properties—making them a favourite right across the building sector.

3) Food Processing

The food processing sector employs SMC because of its bio-inert properties, which make it ideal for:

1) Starch trays2) Storage and container systems

Food-grade approved, SMC can replace polymers and timber, resulting in longer life and subsequently lower lifecycle costs. While traditional materials tend to chip, break or jam in process machinery, SMC products last longer and are operational unaffected.

4) Electrical, Electronic and Telecommunications Applications

In electrical, electronic and telecommunications applications, both Bulk moulding compound (BMC) and SMC are ideal for high-volume production. These compounds often take the place of MDF and phenolic laminates for:

Enclosures Switchgear components Circuit boards Busbar support insulators Antenna ‘radomes’ or shrouds Insulating panels

Inherently good electrical and fire-retardant properties, strength, corrosion-resistance and low water absorption characteristics make these compounds ideal for use in these applications. Their compression moulding manufacturing processes also allow the production of small complex shapes in high volumes.

Day to Day uses of composite

References1) Bhandari, V. B. “Machine Design data book,” Tata McGraw Hill

Publication Co. Ltd.

2) “Material Science & Metallurgy For Engineers”, Dr. V.D. Kodgire & S. V. Kodgire,Everest Publication.

3) “Engineering Metallurgy”, Higgins R. A., Viva books Pvt. Ltd., 2004.

4) “Material Science & Engg.” Raghvan V., Prentice Hall of India , New Delhi. 2003.