HIGH TEMPERATURE CORROSION IN COMBUSTION GASES
Working conditions of valves in car engines aggressive atmosphere of combustion gases high temperature (T 1173 K) rapid changes of temperature (thermal shocks)
Biocomponent addition to fuels Directive 23/3/EC of the European Parliament and of the Council of 8 May 23 on the Promotion of the use of biofuels or other renewable fuels for transport, Official Journal of the European Union, 23, L 123/43-46.
Currently applied bio-fuel additives Ethanol (addition to petrol) Fatty Acid Methyl Ester, FAME (addition to diesel oil)
The share of biocomponents used in liqiud fuels in the automotive industry 11 1 NCW / % 9 8, 8 7,1 7 5,75 6 5 4 6,2 1, 7,55 6,65 4,6 29 8,45 8,9 9,35 9,75 NWC (National Projected Increase) according to the calorific values [%] 211 213 215 Year 217 219
Market share / % Trend 28/27 / % Fuels used in the automotive industry in Poland 3 2 1-1 State dated for 31.12.28 6 4 2 Petrol Diesel LPG n.a.
The Polish car fleet (31.12.28) Average age of a car - 13,9 years 4 2 3 15 2 1 1 5-2 3-5 6-1 11-15 16-2 21-3 Age of vehicle > 3 Market share / mln pc Market share / % 25
Participation age of passenger cars exploited in Poland 8 The share of a car fleet / % 7 6 55 56,6 56 61 63,3 5 2 22 18,2 19,4 12,7 11,5 1 69,8 Age of a vehicles 5 years and under 1 years and over 4 3 66,1 68,1 11,6 12, 11,7 22 23 24 25 26 27 28 29 Year
Cross-section of four-cylinder in-line engine with spark ignition, Fiat 1 exhaust valve, 2 flue gas outlet duct, 3 exhaust manifold, 4 intake valve, 5 intake channel of fuel-air mixture, 6 combustion chamber 7 cylinder with piston and connecting rod Bernhardt M., Dobrzyński S., Loth E.: Silniki samochodowe, Wydawnictwo Komunikacji i Łączności, Warszawa, 1988, s.327
Construction of an exhaust valve 1 mushroom - austenitic steel Cr-Ni-W-Mo in supersaturated and aged state, 2 handle - Cr-Si-Mo steel thermally improved, 3 place of friction welding, 4 valve face hard coated of stellite Co-Cr-W
Temperature distribution in the exhaust valve - petrol engine with spark ignition
Chemical compositions of an engine gases with spark and spontaneous ignition (wt. %) Components of exhaust gases Units Method of ignition spark ignition spontaneous Toxicity evaluation Nitrogen % vol. 74-77 76-78 neutral Oxygen % vol.,3-8, 2,-18, as above Water vapor % vol. 3,-5,5,4-5, as above Carbon dioxide % vol. 5,-12, 1,-1, as above Carbon monoxide % vol. 5,-1,,1-,5 toxic Nitrogen oxides % vol.,-,8,2-,5 as above Hydrocarbons % vol.,2-3,,9-3, as above Aldehydes % vol.,-,2,1-,9 as above Soot g/m3,-,4,1-1,1 as above 3,4 benzopyrene g/m3 to 15, to 1, carcinogenic Merkisz J., Ekologiczne problemy silników spalinowych Tom I i II. Wydawnictwo Politechniki Poznańskiej, Poznań 1999
Exhaust valves after the 1 hour test - engine with spontaneous ignition a.
Chemical compositions of valve steels used in car engines (% wt.) Type of steel C Mn Si Cr Ni N W Nb X33CrNiMn23-8.35 3.3.63 23.4 7.8.28.2 -.3 19.88 3.64.44.86 2.5.1 X5CrMnNiNbN21-9.54 7.61 S P Mo Fe.11 bal..31 - bal. <.5.14 X53CrMnNiN2-8.53 1.3.3 2.5 4.1.41 - - <.5.4.12 bal. X55CrMnNiN2-8.55.17.17 2. 2.3.38 - - <.5.3.11 bal.
High temperature corrosion of valve steels K. Adamaszek, Z. Jurasz, L. Swadzba, Z. Grzesik, S. Mrowec, "The Influence of Hybrid Coatings on Scaling-resistant Properties of X33CrNiMn23-8 Steel", High Temperature Materials and Processes, 26, 115-122 (27). Z. Jurasz, K. Adamaszek, R. Janik, Z. Grzesik, S. Mrowec, High temperature corrosion of valve steels in atmosphere containing water vapor, Journal of Solid State Electrochemistry, 13, 179-1714 (29). Z. Grzesik, S. Mrowec, Z. Jurasz, K. Adamaszek, The behavior of valve materials utilized in Diesel engines under thermal shock conditions, High Temperature Materials and Processes, 29, 35-45 (21). Z. Grzesik, M. Migdalska, S. Mrowec, Corrosion behavior of valve steels in oxidizing atmosphere containing acetic acid, High Temperature Materials and Processes, 29, 23-214 (21). Z. Grzesik, Z. Jurasz, K. Adamaszek, S. Mrowec, Oxidation Kinetics of Steels Utilized in the Production of Valves in Automobile Industry, High Temperature Materials and Processes, 31, 775-779 (212). Z. Grzesik, K. Adamaszek, Z. Jurasz, S. Mrowec The influence of yttrium on kinetics and mechanism of chromia scale growth on Fe-Cr-Ni base steels, Defect and Diffusion Forum, 333, 91-1 (213). Z. Grzesik, G. Smola, K. Adamaszek, Z. Jurasz, S. Mrowec, Thermal shock corrosion of valve steels utilized in automobile industry, Oxidation of Metals, 8, 147-159 (213). Z. Grzesik, G. Smola, K. Adamaszek, Z. Jurasz, S. Mrowec, High Temperature corrosion of valve steels in combustion gases of petrol containing ethanol addition, Corrosion Science, 77, 369-374 (213).
Scheme of the microthermogravimetric equipment utilized in investigations of the oxidation rate F lo w m e te r s M a n o m e th e r M ic r o b a la n c e S a m p le R o ta tio n pum p O u tle t F u rn a c e B u lb s M ix e r
Scheme of the microthermogravimetric equipment utilized in investigations of corrosion kinetics in multicomponent oxidizing atmospheres containing water vapour M ic r o b a la n c e F lo w m e te r s out B u lb s H e a t in g ta p e S a m p le H 2 O b a th F u rn a c e s
Scheme of the apparatus utilized in studies of high temperature corrosion under thermal shocks
Corrosion test of valve steels under thermal shock conditions in engine house
Hybrid reactive head
Oxidation kinetics of tested valve steels - linear coordinate system 2 1 T = 1273 K X33CrNiMn23-8 po = 2,1.14 Pa X5CrMnNiNbN21-9 po = 2,1. 14 Pa 2 T = 1273 K 5 m/s 1 / mg cm-2 T = 1173 K m/s / mg cm-2 2 T = 1173 K T = 173 K T = 173 K T = 973 K T = 973 K 5 1 5 czas / h 1 czas / h 25 X53CrMnNiN2-8 po = 2,1.14 Pa mg cm-2 5 T = 1173 K m/s m/s / mg cm-2 T = 1273 K T = 173 K T = 973 K X55CrMnNiN2-8 p = 2,1. 14 Pa 2 2 5 czas / h 1 1 T = 1273 K O2 15 1 T = 1173 K 5 T = 173 K T = 973 K 5 czas / h 1
1 X5CrMnNiNbN21-9 p = 2,1.14 Pa T = 1273 K 5 T = 1173 K T = 173 K 1 X55CrMnNiN2-8 po = 2,1. 14 Pa 4 T = 1173 K T = 173 K 5 T = 1273 K T = 1273 K X33CrNiMn23-8 po = 2,1.14 Pa 3 2 ( m/s)2 / mg2cm-4 2 2 T = 1173 K 1 5 czas / h 2 T = 1173 K 1 T = 173 K T = 173 K 1 czas / h 3 5 czas / h 5 ( m/s)2 mg2 cm-4 5 T = 1273 K 2 ( m/s)2 / mg2 cm-4 O2 X53CrMnNiN2-8 po = 2,1.14 Pa ( m/s)2 / mg2cm-4 Oxidation kinetics of tested valve steels - parabolic coordinate system 1 5 czas / h 1
Pressure dependence of the oxidation rate of the X53CrMnNiN2-8 valve steel obtained at 1173 K X53CrMnNiN2-8 T = 1173 K 1-1 kp / g2cm-4s-1 1-9 1-11 1 11 12 po 2 13 / Pa 14 15
Temperature dependence of the oxidation rate of tested valve steels T /K 1-8 1273 1173 173 po = 2,1. 14 Pa 1-9 kp / g2cm-4s-1 973 2 1-1 1-11 1-12 1-13 1-14 X33CrNiMn23-8 X5CrMnNiNbN21-9 X53CrMnNiN2-8 X55CrMnNiN2-8 8 9 T-1.14 / K-1 1
Scheme of the oxidation process under thermal shock conditions
Corrosion kinetics of tested valve steels under thermal shock conditions.5 X5CrMnNiNbN21-9 T = 973 K. m/s combustion gases of fuel oil B5 -.1 m/s combustion gases of fuel oil B1. /g cm-2 / g cm-2 air X33CrNiMn23-8 T = 973 K 1 cycle = 2h 1 2 combustion gases of fuel oil B5 -.5 combustion gases of fuel oil B1 -.1 3 4 5 1 cycle = 2h 6 Number of thermal shocks 3 4 5 X55CrMnNiN2-8 air combustion gases of fuel oil B5 -.5 m/s combustion gases of fuel oil B5 / g cm-2 /g cm-2 m/s 2.. -.5 1 Number of thermal shocks air combustion gases of fuel oil B1 air X53CrMnNiN2-8 T = 973 K 1 cycle = 2h -.1 2 -.1 combustion gases of fuel oil B1 4 Number of thermal shocks 6 1 T = 973 K 1 cycle = 2h 2 3 4 Number of thermal shocks 5
Corrosion kinetics of tested valve steels under thermal shock conditions.5 X33CrNiMn23-8 T = 1173 K X5CrMnNiNbN21-9 T = 1173 K 1 cycle = 2h. combustion gases of fuel oil B5 air combustion gases of fuel oil B1 -.1 -.15 /g cm-2 -.5 m/s m/s / g cm-2. -.1 combustion gases of fuel oil B5 -.2 combustion gases of fuel oil B1 -.3 1 cycle = 2h 1 2 3 4 5 6 Number of thermal shocks.1.1 X53CrMnNiN2-8 T = 1173 K combustion gases of fuel oil B5 1 cycle = 2h 1 2 Number of thermal shocks 3 / g cm-2 -.2 -.1 m/s /g cm-2 combustion gases of fuel oil B1 -.3 2 3 4 X55CrMnNiN2-8 T = 1173 K 1 cycle = 2h air. -.1 1 5 Number of thermal shocks. m/s air -.2 air combustion gases of fuel oil B1 combustion gases of fuel oil B5 -.3 1 2 Number of thermal shocks 3
Corrosion kinetics of tested valve steels under thermal shock conditions.1 X33CrNiMn23-8 T = 1173 K / g cm-2. m/s.5 -.5 -.1 combustion gases of petrol E95 1 cycle = 2h 2 air combustion gases combustion gases of petrol E9 of petrol E5 4 6 8 Number of thermal shocks 1
Comparison of corrosion kinetics of valve steels under thermal shock conditions at different atmospheres
Images of valve steel samples corroded under thermal shock conditions in a number of aggressive atmospheres T = 1173K
Images of valve steel samples corroded under thermal shock conditions in a number of aggressive atmospheres
Phase composition of scales growing on the X33CrNiMn23-8 steel under thermal shock conditions (T = 1173 K) a) after 5 cycles b) after 5 cycles 2 2 steel / a. u. (Mn,Fe,Cr)3O4 1 1 5 5 1 Cr2O3 15 Intensity / a. u. Intensity Fe2O3 Cr2O3 15 Fe3O4 X33CrNiMn23-8 steel X33CrNiMn23-8 steel 2 3 4 5 2 / deg 6 7 8 1 2 3 4 5 2 / deg 6 7 8 9
Phase composition of scales growing on X5CrMnNiNbN21-9 steel under thermal shock conditions (T = 1173 K) a) after 2 cycles b) after 15 cycles 5 5 X5CrMnNiNbN21-9 steel X5CrMnNiNbN21-9 steel / a. u. 2 Fe3O4 3 2 1 1 1 Fe2O3 4 Fe3O4 (Cr,Fe)2O3 NiCr2O4 (Nb,Cr)O2 (Fe,Nb)3O4 Intensity / a. u. 3 Intensity 4 2 3 4 2 5 / deg 6 7 8 1 2 3 4 2 5 / deg 6 7 8
SEM picture of the scale growing on the X5CrMnNiNbN21-9 steel under thermal shock conditions in combustion gases of B1 fuel oil T = 1173 K
SEM pictures of the scale formed on two valve steels under thermal shock conditions in combustion gases of B1 fuel oil X33CrNiMn23-8 T = 1173 K X5CrMnNiNbN21-9
The application of protective coating with TBC layer
Cross-section of a valve steel covered by a protective coating with TBC layer ZrO2 Y2O3 Ni22Cr1AlY o u te r la y e r o f th e c o a tin g in n e r la y e r o f th e c o a tin g s te e l
Surface of TBC layer
Photographs of surfaces of coated and uncoated valve steels after corrosion tests at 1173 K a) before tests b) after 5 shocks a) after 3 shocks b) after 5 shocks
Results of corrosion tests of uncoated and coated valve steels
The results of corrosion tests performed on two different coated valve steels 15 2 Time / h 4 6 8 1 m/s 14 / g cm-2 coated X5CrMnNiNbN21-9 steel. 1 5 coated X33CrNiMn23-8 steel 1 cycle = 2 h 1 2 3 4 Number of thermal shocks 5
Temperature dependence of the oxidation rate of coated X33CrNiMn23-8 steel T /K -1 1 1573 1373 1173 973 Oxidation -2 1 Co-35Cr Ni-3Cr 1 kp / g m s 2-4 -1-3 -NiAl -4 1 Fe-2Cr -5 1 Fe-5Cr-4Al Ni-1Cr-5Al steel -6 1 chromia formers alumina formers coated steel -7 1 6 7 8 9-1 4-1 T. 1 / K 1 11
The influence of small amounts of yttrium on the adherence of the scale
EXPERIMENTAL Materials: X33CrNiMn23-8, X5CrMnNiNbN21-9, X53CrMnNiN2-8, X55CrMnNiN2-8 Specimens: discs: diameter 2 mm, thickness 1 mm weight: 1 g Yttrium deposition: degreasing electrochemical treatment:.1 m Y(NO3)3 solution in C2H5OH U = 1V; I = 1 ma; t = 45 s drying: T = 5 oc; t = 1 min. annealing: T = 4 oc; t = 3 min. Corrosion tests under thermal shock conditions: reactive atmosphere: combustion gases of diesel oil with 1 wt. % addition FAME (B1) temperature range: 295 1173 K time of experiments: 15 shocks x 2 h, quenching cycle: 15 min. SEM, EDX, XRD ANALYSIS of
Corrosion behaviour of unmodified and covered with yttrium X33CrNiMn23-8 steel under thermal shock conditions. steel with Y m/s / g cm-2 -.1 -.2 steel without Y -.3 -.4 X33CrNiMn23-8 steel T = 1173 K -.5 -.6 5 1 Number of thermal shocks 15
m/s / g cm-2 Corrosion behaviour of unmodified and covered with yttrium X5CrMnNiNbN21-9 steel under thermal shock conditions. X5CrMnNiNbN21-9 steel T = 1173 K 1 cycle = 2h -.1 steel with Y -.2 steel without Y -.3 5 Number of thermal shocks 1
Corrosion behaviour of unmodified and covered with yttrium X53CrMnNiN2-8 steel under thermal shock conditions X53CrMnNiN2-8 steel T = 1173 K. m/s / g cm-2 1 cycle = 2h -.1 steel with Y steel without Y -.2 -.3 5 1 Number of thermal shocks
Corrosion behaviour of unmodified and covered with yttrium X55CrMnNiN2-8 steel under thermal shock conditions X55CrMnNiN2-8 steel. T = 1173 K m/s / g cm-2 1 cycle = 2h -.1 steel with Y steel without Y -.2 5 Number of thermal shocks 1
Microphotographs of the scale surface formed on undoped and doped with yttrium X33CrNiMn23-8 steel after 1 thermal shocks
Microphotographs of the scale surface formed on undoped and doped with yttrium X5CrMnNiNbN21-9 steel after 1 thermal shocks
CONCLUSIONS One of the most important conclusions that can be derived from the results presented in this lecture is that the addition of biocomponents to fuel oil increases the corrosion rate of steels utilized in valve production. It has also been found that the deteriorating effect of bio-components increases rapidly along with the amount of these additions, as well as with increasing temperature. The results of thermal shock experiments have demonstrated that small amounts of yttrium electrochemically deposited on the surface of the X33CrNiMn23-8 steel, which exhibits the highest chromium concentration (> 23 wt. %) among the studied valve steels, dramatically improves the chromia scale adherence to the surface of this steel. This can be explained as the result of selective chromium oxidation and Cr2O3 oxide formation. This effect is not observed in the case of the three remaining steels with lower chromium concentrations, because of heterogeneous scale formation. From a practical point of view, it can be concluded that engine valves should be produced in the future only from X33CrNiMn23-8 steel covered by yttrium.
THE END
Consequences of fossil fuel exploitation Depletion of fossil fuel resources Reduction of energy security in various regions of the world Increase in fossil fuel prices Degradation of the natural environment Destabilization of the climate Deterioration of health as a result of high pollution
Forecast of the energy consumption level up to the 254 year Increasing factor: 1.193 every year in 199-25 3,5 12 Natural Gas Consumption 3 2.9365 T m 1 Coal Consumption 6.483 G tons 3, 26.49% 23.25% Coal 8 6 24 Natural Gas Exhaustion 3 171.25 T m Uranium Consumption 78. k tons 2,5 2, 1,5 6.17% Natural Gas 4 1, 2 198 Oil Consumption 3.517 G barrels 36.59% Oil 199 Hydro & Others 7.49% 2 21 234 Oil Exhaustion 1.293 T barrels U Hydro & Others 22 23 Year 24 25 24 Uranium Exhaustion 4.743 M tons Ratio to 199 World Energy Consumption / 118J 14,5, 26 254 Coal Exhaustion 1.1 T tons
Alternative energy sources Solar energy (solar cells and collectors) Nuclear energy Hot and cold fusion energy Geothermal energy Wind energy Water energy Wave energy Biofuels
Energy carriers in the automotive industry Classical liquid fuels (petrol and diesel oil) Natural gas LPG (propane-butane) Biofuels Electric current Hydrogen Others (compressed air, methane, etc.)
Diagram of the Hashimoto concept of utilization of methane as an energy carrier