. Transactions. int on thecarbon isothermal, there is soot deposition together with carburization. 44 CHEMICAL EQUILIBRIUM BETWEEN IRON, CARBON, AND OXYGEN In other words, a point on the carbon isothermal represents those valuesof P and X at which soot can exist in the system. It is highly probable that some substance showing the same oxygenpressure as that of the gaseous phase is formed in the solid phase if anequilibrium is established at any one point on the carbon if the gaseous phase is always richer in CO than that corresponding tothat point equilibrium is never establishe
. Transactions. int on thecarbon isothermal, there is soot deposition together with carburization. 44 CHEMICAL EQUILIBRIUM BETWEEN IRON, CARBON, AND OXYGEN In other words, a point on the carbon isothermal represents those valuesof P and X at which soot can exist in the system. It is highly probable that some substance showing the same oxygenpressure as that of the gaseous phase is formed in the solid phase if anequilibrium is established at any one point on the carbon if the gaseous phase is always richer in CO than that corresponding tothat point equilibrium is never established there, hence any fixation ofoxygen in the solid phase is avoided even under the pressure representedby the same point. For instance, the point Q never represents the pressureunder which FeO should be formed in carburized iron under every circum-stance of the gaseous phase. Then why has Giolitti and Carnevalisexperiment proved the formation of a thick stratum of compact crust ofmagnetite on the carburized iron?. 0 2 4 6 8 10 Fig. 16.—P-x diagram for 950° C. 12 P In order to solve this problem, let us make a few calculations. Astheir experiments were made between 890° and 960° C, assume that it wasfixed at 900°. Then, calculating from the value of Ki, it is known thatRi must show a dissociation pressure corresponding to x = underthe pressure of 25 atmospheres. Even if it is assumed that Ri is pureiron oxide, its oxygen content does not exceed per cent, at 1075° C,and per cent, at 863° C. (see Figs. 3 and 4); by graphic interpolation,it is found to be about per cent, for 900° C, hence the iron content ofthe oxide, which is a solid solution of Fe304 in FeO, must be at least cent. If any higher oxide is present in the system, no carburizationshould be possible. An analysis of the crust made by the same authors, however, per cent. Fe, so that the crust presumably contained some combined A. MATSUBARA 45 carbon and the oxygen pressure o
Size: 1724px × 1449px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
