Explain me about the process of Carburising in metals?
954322
kakani P wrote an excellent explanation but I wanted to add an example to help you furhter understand a practical application.\n\nThe tooth on the front of a backhoe bucket is a great piece to be carburized.  It could be made totally of high carbon throughout but that would make it brittle and subject to break since it experiences many impacts and shock loads as it encounters rocks (or old concrete from foundations being demolished) and other debris in the soil.  We still would like to have the surface hardened to reduce wearing but we still want the core to be ductile to prevent premature failure.  Carburizing allows us to "have our cake and eat it too".  We can make the surface wear resistent and hard but leave the core ductile and able to withstand large shock loads through the process of carburizing.
315423
all welding uses a heat source to melt the parent metal, parent metal is the metal you are trying to weld.\nWhen the metal melts, it can absorb gas from the air. This is not good, oxygen causes corrosion and hydrogen creates bubbles is the metal which weakens it. So when you weld you need to doo something to keep these gases out.\nOxy-acetalence or oxy-l.p.g. welding uses a gas flame to melt the paretn metal. The ratio of oxygen to acetalene or l.p.g. is critical for burning cleanly and not get oxygen in to the weld. Additional metal is applied by a filler wire, dipped in manually by the person welding.\n\nM.I.G. and T.I.G. use an inert gas (the I.G. in their name) to keep the other gases out.\n\nStick welders (manual metal arc) uses the flux around the welding rod to create a suitable atmosphere around the weld pool.\n\nmig, tig and arc use an electric current to melt the parent metal\n\nwith mig, the machine feeds extra metal in to the weld the whole time.\n\nwith arc the welding rod supplies extra metal\n\nwith tig the operator adds filler wire manually as required.\n\nTig does the nicest welds but it the most expensive as it is slow.
577199
Of course, that is what carburetors do.
125282
Most efficient? If you don't have a lab, then I would assume just doing your best at grinding off the top layer, and trying to melt the shreddings down into a >70% gold alloy. Since gold's melting point is OVER 1000 degrees Celsius, I suppose your best bet is to heat the grindings as much as possible, and then pounding them together into a single mass (like a black-smith...or 'gold-smith'). But you have to realize HOW LITTLE gold is actually on there. The layer is so thin...sometimes merely 2-3 micrometers. You're gonna get a lot of impurities, such as nickel and copper. Gold-plating is usually done on copper or silver; and in the case of copper, a thin layer of nickel is placed below the gold. And since the melting point of nickel isn't that far from that of gold, and copper's is almost EXACTLY that of gold's, you're gonna get a random mixture of crap. I imagine the process is more trouble than it's worth. I'd just go buy gold from alfa aesar or somewhere like that for cheap-as-free.
824325
Pls go to http://en.wikipedia.org/wiki/Carnot_engine
874237
R&D Projects\nAdvanced Computations\n\n \n\nAlloy Selection System for Elevated Temperatures (ASSET)\n \nMany aspects of equipment design and operation as well as alloy selection and design are influenced by the expected lifetimes of equipment in high-temperature, corrosive gases.  Currently, many processes are limited by the inability to predict corrosion rates for equipment used in high-temperature processes. A new database is being developed to enhance the ability of the chemical industry to predict corrosion of commercial alloys.  Benefits in improving the ability to manage corrosion data for alloys in high temperature, corrosive gases will be far reaching in the chemical industry.   Better characterization of alloys under operating conditions will result in reduced energy use and maintenance, increased process safety, cost-effective use of expensive alloys in equipment designs, and improved productivity.   \n\nASSET will be an alloy selection and corrosion prediction system that includes a database linked to thermomechanical calculation programs.  The linked programs will use experimentally measured corrosion data obtained under well-controlled conditions to predict the corrosion rates for commercial alloys.   This project will include data on an extensive list of alloys exposed to a wide range of complex and corrosion gases for temperatures of 250 to 1,150oC.  The considerations being used to generate the corrosion data include oxidation, sulfidation, sulfidation/oxygenation and carburization.  The approach to this project includes improving and expanding the ASSET system and training participating companies in its use.
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assuming you know basic chemistry:\nall metals are cations, right? that means they have + electrons and will bond with non metals easily to form salts. NaCl for example, sodium being the metal, chlorine being the nonmetal.\n\nwell what happens with metal solids and aloys is this: all those extra "valence" electrons floating around their full largest P full shell (you know, 1s2, 2s2, 3p6 and so on..) create a system of delocalized electrons which allow the metals to bond together. since this free system of electrons exists all around the metals that explains why electrons are able to pass through solid metals so easily. (conductivity). the system also give various metals and alloys the ability to be very strong, or rust proof, etc.
170896
You dip the metal you want plated into a solution containing ions of the metal you want to plate with, such as chromium (chrome).  The dipped metal is attached to an electrical current, which induces a redox reaction.  The actual chemistry is a little more complicated, but the easy version is that those metal ions become solid metal attached to the electrode (the metal that you dipped in the solution).  The new metal is now permanently bonded to the old metal, and you have a set of chrome rims.
84628
the study of metals. their characteristics, and behaviours, etc.
1024027
Copper in the metal spark and flame apparatus of the lighter.  The metal is heated by the flame, and electrons in the metal are excited and jump up a few orbitals (energy levels), and on the way back down to the ground state, they release the energy in the form of light correpsonding to green wavelengths.
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react ... water gas that is carbon monoxide and hydrogen gas in presence of zinc oxide and Cr 2 O 3 under 200 atm pressure and 450 degree celcius temperature result will be  methanol .. this process is done on industrial scale as well first the purification and then the compression takes place and into the reaction chamber condensed and got the result ... ok wish u best of luck
181969
It loses electrons, so it gets a higher oxidation state. An example would be iron going to rust (Fe(s) --> Fe+3).
977688
Metals are reductants. that is they cause reduction in a reaction and are themselves oxidised. This means they must GIVE UP electrons. If you look at the periodic table, as you go down a group (say 1st gorup), atoms have more and more shells ( the outer which contains only 1 electron). As you know, the more shells there are, the lesser tehy will be bound to the nucleus (as they experience weak core charge). This means at the bottom of the 1st group, atoms will almost willingly get rid of its valence electron. So that's why as you go down a group, they are more metallic.\n\nAs you go from the left to the right of the PT, there are more electrons in the outer shell. THis means they more and more act as an oxidant (causing oxidation to others, but in turn gets reduced). Thus, they are less metallic
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well if i am not wrong.. they work on the principle of thermionic emission... \n\nnow wat happens is ... at the cathode end ( negatively charged) there is a metal bit.. called emitter  and at the anode end( positive terminal) another metal called the receiver. the tube is vacuated and filled with gas, in this case a halogen vapour. \n\nwat happens is when a potential is applied, when we switch it on, the cathode emits electrons.\nthese electrons pass thru the vapours and ionise them. when ionised these gases emit energy in the form of light..\n\nthis is the explanation in the most condensed form... equations make it complicated for understanding... \n\nhope i did justice to ur query
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It is due to their unpaired electrons in the d orbital, and their ability to form a variety of oxidation states. This means they can readily accept and/or donate electrons to form intermediate compounds. This provides an alternative pathway for the reaction, with a lower activation energy, so it can take place at a faster rate. Once the intermediate compound reacts with another reactant, it will take back or return the electron(s) it used to the transition metal, therefore regenerating it.
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a compound contaning carbon
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The metal starts as flat piece of aluminum. The sheets are placed into a die and drawn to proper depth. The tops are made out of  blank sheet of metal and through a multi strike process are formed. They then go to a secondary process that places the tabs on the lids. They are assembled by seam locking (rolling the top small lip over a flange on the can) then is spun in a curling station to form a perfect seam. Any imperfection in the height of the can is hidden by the seam locking process.  The cans are then painted in a series of single ink applications over a template. The cans are then shipped out to the beverage factories.