Recent questions tagged chemistry-of-engineering-materials

Description : Explain composition of stainless steel.

Last Answer : Chemical composition of Stainless steel: Min 12 % chromium 12 to 30 % Cr 4 to 25 % Ni Stainless steel 316: Cr = 16 - 18 %, Ni = 10-14 % , Mo= 2-3 %, C= 0.08 %, Mn = 2 % , Si= 1%, Stainless steel ... 18 % Tungsten (W) 4 % Cr 1 % vanadium 0.7 % carbon Small amount of Si , S , P ,Mn , Fe.

Description : Write about the corrosion of metals by water, steam and soil in detail. 

Last Answer : Corrosion (i)by water: physical configuration of the system hardness of water, salts, chlorides, and dissolved gases such as oxygen, carbon dioxide, and sulphur dioxide. Presence of suspended ... is more corrosion is less. If dissolved salts more, conductivity is more and corrosion is more.

Description : Write down any two purposes of alloy steel. Explain any one method of preparation of alloy. 

Last Answer : Purpose of alloy steel  1. To improve corrosion resistance 2. To enhance wear resistance 3. To improve toughness 4. To enhance tensile strength 5. To improve grain size Method of preparation ... and then they are mixed together by application of heat and pressure to obtain the final product. 

Description : Explain different engineering properties of silicon carbide. Also discuss its uses.

Last Answer : Silicon carbide: Properties: Density = 3.2 g/cu.cm M.P = 2800 deg C Hardness = 9 Mohs Modulus of elasticity = 6.5 High wear resistance Excellent ... bulletproof vests Bearings Semiconductors wafer processing equipment Light emitting diode Cutting tools and burner nozzles.

Description : Classify the following materials as metals and non-metals : Hydrogen, Sulphur, Selenium, Manganese, Calcium, Platinum, Gold, Silica, Polyester, Wood, Glass, Iron 

Last Answer : Metals: calcium , manganese, platinum, gold , iron Non- metals: hydrogen, Sulphur, silica, polyester, wood, glass, selenium

Description : Differentiate between metal and non-metal.  

Last Answer : Metals Non-metals While metals are good conductors of electricity and heat non-metals are poor conductors of electricity and heat metals are ductile Non metals are not ductile ... are malleable  Non metals are brittle Metals are opaque  Non metals are transparent

Description : Describe the procedure to estimate the density of any liquid.

Last Answer : Density of liquid:  Density of liquid can be determined using specific gravity bottle. Procedure: First determine the weight of the density bottle(w1) when it's empty. Then fill it with the liquid ... the mass of the liquid divided by its volume density = m/v.  = (w2-w1)/ volume

Description : Explain requirement of thermal insulation to chemical process equipment with example. 

Last Answer : Requirement of Thermal insulation: 1. Thermal insulation is the reduction of heat transfer. 2. Thermal insulation is used to prevent excessive heat loss. 3. It is used to minimize the ... . 4. In refrigeration, refrigerator consists of a heat pump and a thermally insulated compartment. 

Description : Describe the classification of steel.

Last Answer : Classification of steels: 1. Based on carbon Low carbon steel (0 %) : it is cheap, it has good tensile strength, ductility, it is malleable. Used for structural section Medium carbon steel ... ) 2. Based on de-oxidation practice: Killed steel Semi killed steel Rimmed steels Capped steels

Description : Write down the factors determining the choice of material to avoid corrosion. 

Last Answer : Factors determining the choice of material to avoid corrosion: 1. Resistance to corrosion in given environment 2. Operating condition such as temperature, pressure and flow rate. 3. Mechanical ... cost, replacement cost 7. Expected life 8. Material selection based on sound economic analysis.

Description : Differentiate ceramic substances based on properties.  

Last Answer : Classification of ceramics: 1.Glasses: Glasses Ceramic glasses 2.Natural ceramics: Bones Rocks and minerals 3.Traditional ceramics: White wares Structural clay products ...  Dense SiC Nitride ceramics: silicon nitride  Silicon aluminium oxynitride  Aluminium nitride

Description : Explain the mechanism of corrosion. 

Last Answer : Dry corrosion Mechanism: When a metal is exposed to air it gets oxidized by loosing its valence electrons & reduction of oxygen take place M+n/4 (o^2) => M^n+ + O^2- At point of ... when the environment is alkaline / basic or neutral, and contains more oxygen, OH- ions will be given out.

Description : Write on ductility and malleability of material. 

Last Answer : Ductility Ductility is the ability of a material to deform plastically without fracture under tensile load. Because of this property , materials can be drawn out into fine wire without fracture ... Gold and silver are highly malleable. Malleable metals usually bend and twist in various shapes.

Description : Explain chemical reactivity of iron with acid. 

Last Answer : Chemical reactivity of iron with acid. Definition -Chemical reactivity is the ability of a material to combine with other materials such as water , air , acids , steam etc. (i) Iron (mild Steel) ... with hydrochloric acid producing ferric chloride and hydrogen gas. 2Fe + 6HCl -----> 2FeCl3 + 3H2

Description : Describe thermal stability and thermal expansion of material. 

Last Answer : Thermal Expansion : Thermal expansion is the increase in the volume of a material a the temperature is increased. It is usually expressed as a fractional change in dimensions of ... material will not be destroyed/degraded/decomposed by heat under high operating temperatures of the application.

Description : Discuss thermochemistry of chemical reactions. 

Last Answer : Thermochemistry of chemical reactions. Thermochemistry is the study of the heat energy associated with chemical reactions and/or physical transformations. A reaction may release or absorb ... favorable or unfavorable. Endothermic reactions absorb heat, while exothermic reactions release heat.

Description : List the types of iron.

Last Answer : The types of iron are : 1) Pig iron 2) Wrought iron 3) Cast iron 4) Pure iron (butte iron)

Description : Define polymerisation reaction. 

Last Answer : Polymerisation reaction:  (i) The process by which the monomer molecules are linked to form a large molecular weight polymer molecule is called polymerization. Or (ii) Any process in which relatively small molecules called monomers combine chemically to produce a very large chainlike molecule.

Description : List the uses of ceramic in chemical industry. 

Last Answer : Ceramics are used for following engineering applications: 1. Cutting io and dies 2. Molten metal filters 3. Bearings 4. Sealing rings 5. Bushes 6. Fuel injection components 7. Spark ... Filters 30. Rotors and gears 31. Electrode materials 32. Precise instrument parts 33. Grinding media

Description : Describe dielectric strength of material.  

Last Answer : Dielectric strength of material: Dielectric strength is the ability of a dielectric material of specified thickness to withstand at high voltage without breaking down. It is a measure of the strength of ... strength can withstand at high voltage. It is expressed in the unit of kV/cm.

Description : Define yield stress.

Last Answer : Yield stress: (i) The yield strength or yield stress is defined as the stress at which a material begins to deform plastically Or (ii) stress is the amount of force/energy that is being exerted on a material object divided by its cross-sectional area.

Description : Define biomaterials.

Last Answer : Biomaterials: (i) A biomaterial is any material that has been engineered to interact with biological systems for a medical purpose (a therapeutic or a diagnostic) Or (ii) ... use for therapeutic , prosthetic and diagnostic applications without affecting the living organism and its components.

Description : List out the types of crystal structure.  

Last Answer : Types of crystal structures. (i) Atomic atructure (ii) Nano sturucture (iii) Microsturcture (iv) Macrostructure

Description : Explain the mechanism of wet corrosion in details.

Last Answer : Mechanism of wet corrosion: wet corrosion of metals occurs through electron transfer, involving two processes, oxidation and reduction. The metal, where electrons are lost, is called the anode the reaction that ... evolution type of wet corrosion 2. Oxygen absorption type of wet corrosion :

Description : Differentiate between addition and condensation polymerization process.

Last Answer : Differentiate between addition and condensation polymerization: Addition polymerization Condensation polymerization Produces by addition of monomers Produces by condensation of monomers Monomers must have ... multiple of monomers e.g. Polypropylene e.g. Bakelite

Description : Describe the procedure to calculate the density of air.

Last Answer : Procedure to calculate the density of air: Measure the mass of the empty balloon. a) Calculate mass of air in the inflated balloon in kg. b) Calculate the volume of the inflated balloon in m3. ... and relative humidity. The density of dry air can be calculated using the ideal gas law,

Description : Explain the effects of following chemical elements on iron. 1) Chromium 2) Nickel 3) Silicon.

Last Answer : Effect on Iron:  1) chromium: Cr increases the hardenability of steel while there is a minimal effect on the ductility. Cr is normally added to steel for increasing oxidation resistance, and ... form of graphite results in a softer iron, reduces shrinkage, lowers strength, and decreases density.

Description : Describe different thermal properties of an engineering material.

Last Answer : Thermal properties of Engg. Materials: 1.Temperature: Temperature is the degree to measure hotness and coldness. Temperature is a physical quantity expressing hot and cold. 2.Thermal conductivity: ... the amount of heat needed to raise the temperature of one kilogram of mass by 1 kelvin.

Description : Explain the condensation polymerization for phenyl formaldehyde. 

Last Answer : Condensation polymerization for phenol formaldehyde: Phenol formaldehyde resins are synthetic polymers obtained by the reaction of phenol with formaldehyde(Bakelite). used for the production of molded products including ... gives a methylene bridge, and the second forms an ether bridge: 

Description : List any four properties of thermosetting polymers.

Last Answer : Properties of thermosetting polymers:  1.Very poor elasticity 2.sronger attractive forces between chains 3. not soluble in organic compounds 4.can not be remoulded 5. these polymers produces by condensation polymerization

Description : Explain the methods of corrosion prevention.

Last Answer : Method of corrosion prevention: 1. Choice of material 2. Proper design and fabrication of components 3. Use of high purity metal 4. Special heat treatment 5. Modification of ... tightly bonded alloy coating which act as protection.it has lower initial cost, sustainability and versatility.

Description : Explain any four mechanical properties of an Engineering material.

Last Answer : Mechanical properties of Engg. Materials  1.Elasticity: Ability of a deformed material body to return to its original shape and size when the forces causing the deformation are removed. A body with ... referred to stiffness or temper, or to resistance to bending, scratching, abrasion, or cutting.

Description : Give the chemical composition forstainlesssteel, Tungsten steel, Nickel and Manganese steel.

Last Answer : Chemical composition of: 1.Stainless steel: Min 12 % chromium 12 to 30 % Cr 4 to 25 % Ni 2.Tungsten steel: 18 % Tungsten (W) 4 % Cr 1 % vanadium 0.7 % carbon Small amount of Si , S , P ,Mn , Fe. 3. ... 4.Manganese steel: (e.g. C-Mn steel) 0.15 % C 1.4 % Mn 0.218 % Si 0.007 % S

Description : List any four properties of ceramics.

Last Answer : Properties of ceramics:  High Strength. High Fracture Toughness. High Hardness. Excellent Wear Resistance. Good Frictional Behavior. Anti-Static

Description : Explain organic and inorganic insulation with examples.

Last Answer : Organic and inorganic insulation: Organic insulation: Organic insulation materials are mainly polyurethane foam, polystyrene board, phenolic foam . organic insulation materials mainly from petroleum ... antifreeze, anti-aging and excellent performance, low prices , high level fire protection.

Description : List any four properties of ferrous alloys.

Last Answer : Properties of ferrous alloys:  a) Heat resistant alloy steel - i. hard wearing and offer resistance to large variation in temperatures. ii. corrosion resistance iii. oxidation resistance iv. ... to chromium content. ii. Non-magnetic iii. Good weldability iv. Good heat resistant.

Description : Explain the mechanism of corrosion in acidic medium.

Last Answer : Mechanism of corrosion in acidic medium. An acidic environment refers to an environment having a pH value of less than 7.Acidic environments are more prone to cause corrosion than alkaline and neutral environments. ... , If the acid used is HCl, then the corrosion product is FeCl2.  

Description : Explain addition polymerization for polystyrene.

Last Answer : Explain addition polymerization for polystyrene. Ans : Synthesis - Styrene (C6H5CH=CH2) , undergoes addition polymerization to form polystyrene , --( C6H5CH=CH2)- It is prepared by the ... is stronger than the π bond that was broken, thus it is difficult to depolymerize polystyrene. 

Description : Explain crystal structure of Nacl. 

Last Answer : Crystal structure of NaCl. The salient features of its structure are: Chloride ions are ccp type of arrangement, i.e., it contains chloride ions at the corners and at the center of each ... each ion on a edge by four cells and the ion inside the cell belongs entirely to that unit cell.

Description : Give the effect of any two chemical elements on iron.

Last Answer : Effect of any two chemical elements on iron.  Carbon : It increases tensile strength and hardness but lowers ductility and weldability. Chromium : It increases hardenability. It increases ... It improves machinability but decreases ductility and weldability. Its content is limited to 0.05%.

Description : Name the types of iron.

Last Answer : Types of iron are:. 1) Pig iron 2) Wrought iron 3) Cast iron 4) Pure iron (butte iron)

Description : Define thermal conductivity of material.

Last Answer : Thermal conductivity of materials. Thermal conductivity of engineering material is the property of a material that determines the rate at which it can transfer heat. It is a measure of the ... material to transfer heat. Thermal conductivity of material is the property to conduct heat.

Description : Define corrosion.

Last Answer : Corrosion. Corrosion is the gradual deterioration or destruction of materials (usually metals and alloys) by chemical or electrochemical reactions with its environment. OR Corrosion is ... material through undesired chemical or electrochemical attack by its  environment starting at the surface.

Description : Define the Bragg’s law.

Last Answer : Bragg’s law.  “The general relationship between the wavelength of the incident X-rays , angle of incident / glancing angle and spacing between the crystal planes of atoms is known as Bragg’s law.” 

Description :  Define Heat capacity. 

Last Answer : Heat capacity. Heat capacity is the quantity of heat energy needed to raise the temperature of a specific material by one degree Celsius.  OR Heat capacity is the ratio of the quantity of heat energy transferred to a material and the resultant temperature rise.

Description : Give any two properties of biomaterial.

Last Answer : Properties of biomaterials   i) Must be hard ii) must be flexible iii) must not react with any tissue in the body iv) must not be toxic to the body v) v) long term replacement must not be biodegradable.

Description : How alloy steel is prepared by cladding mechanism ?

Last Answer : Cladding mechanism: Cladding is the bonding together of dissimilar metals. It is different from fusion welding or gluing as a method to fasten the metals together. Cladding is often achieved by extruding two ... polymer). Built part is free of crack and porosity. Compact technology.

Description : Explain the effects of following chemical elements on iron. i) Copper ii) Phosphorus iii) Manganese

Last Answer : Effect on iron:  i) Copper: it improves the resistance to atmospheric corrosion. It strengthens steel. It may be added to improve formability. It improves pains adhesion  ii) ... Manganese:it increase tensile strength, abrasion resistance, hardenability and toughness . it decrease weldability. 

Description : Explain the methods of prevention and control of corrosion.

Last Answer : Prevention and control of corrosion: 1.Material selection and choice of materials 2.Proper design and fabrication of components 3. Use of high purity metals: The impurities present in ... and the environment. These are classified as:  Metallic coatings  Inorganic coatings  Organic coatings

Description : Give classification of alloy steel on the basis of its Constitution.

Last Answer : Classification of alloy steels Based on its composition: 1) Simple alloy steels: It is the alloy steel containing one alloying element eg nickel steel 2) Quaternary alloy steel: It is the ... It is the alloy steel containing more than two alloying elements eg. High speed tool steel