Traditionally for the manufacturing of piston of car we use Aluminum Alloy (6061). Due to its following properties, High strength, Low weight, excellent corrosion resistance, Good surface finish, Good workability.

GOALNow our Goal is to replace Aluminum Alloy with best substitute Alloy, which has capacity to perform similar work & also increase efficiency of piston as well as engine.

Substitute Alloy After study different properties of SI3N4, that Alloy is founded as a best substitute for the manufacturing of pistons. Which have, Good strength. Good corrosion resistance to atmosphere. Good surface finish. Low thermal conductivity as compared to aluminum.By using SI3N4for manufacturing of piston , it increases the engine efficiency by reducing heat loss within the piston cylinder thus increasing pressure & reducing the amount of fuel needed for each cycle. SI3N4 shows lowest thermal conductivity. High thermal shock resistance. Low thermal expansion rate.Reasons why we use SI3N4There are many reasons for selecting above mention alloy but here we analysis one property which shows importance over Aluminum, Thermal conductivity analysis: Qout=KA dt/dx We can also write as, Qout= KA TH-TC/L Where, TH=hot temperature inside the cylinder due to combustion. . TC=cold temperature in the system surrounding. L=thickness of cylinder.KTHTCAL

Aluminum 120W/m-k500C30C0.01225m20.005m

Silicon Nitride 30W/m-k500C30C0.01225m20.005m

For Aluminum: QOUT = 120 W/m-k(0.01225m) 500-30/0.005m QOUT = 138 KWFor SIN: QOUT = 30W/m-k(0.01225m) 500-30/0.005m QOUT = 34.5KWDecreasing the rate of heat being lost through cylinder has allowed for a greater power output from the engine, the heat that is stored used for more pressure exerted on the piston, causing an increase in torque on the crankshaft. Using SI3N4 piston cylinder will increase the engine power & provide 7% raise in engine efficiency. Fabrication Silicon Nitride produced by heating powered silicon between 1300 to 1400 in an atmosphere of nitrogen.3SI +2N = SIN For advance fabrication & purification of SI3N4. Four methods commonly used,1. Hot pressed silicon nitride (HPSN).2. Reaction bonded silicon nitride (RBSN).3. Sintered & Reaction bonded silicon nitride (SRBSN).4. Sintered silicon nitride (SSN).RecommendationAs alloy SI3N4 is much more suitable than aluminum alloy (6061) due to its, Good Mechanical properties.Good Thermal properties. Also increase the engine efficiency. pistons should be manufactured by SI3N4 especially in racing cars like Formula ONE.ConclusionAfter the analysis of SI3N4 and study its thermal & mechanical properties, it is best replacement of aluminum (6061). Due to following reasons, Low thermal conductivity as compare to Al. It enhances the engine efficiency. The main limiting factor of using the material will be the, Cost of manufacturing. Its fatigue life.References Silicon Nitride advanced ceramics. Sinternational sylons.NP,2010.web.6 Dec 2010. www.syalons.com/resources/guides/silicon nitride.php Formula engines,F1Technical.F1Technical.net,2004.web. Obert, Edward F.Thermodtnamics.McGraw-Hill Book company Inc.: NEW york 1948.