Carbon monoxide carburization with

A. Carburization with carbon monoxide or hydrogen-carbon monoxide... 

Braude and Bruns (16) found that the rate of carburization of iron was greater with synthesis gas (H2 + CO) than with pure carbon monoxide. Similarly, Hall (15) found that the carburization of a reduced iron catalyst at 275°C. was slightly faster with 1H2 + 4CO gas than with pure carbon monoxide. In 48 hours, C values of 0.44 and 0.42 were obtained with 1H2 + 4CO and carbon monoxide, respectively, and fairly pure Hagg carbide was formed in both cases. 

Podgurski, Kummer, DeWitt, and Emmett (14) carburized reduced fused catalysts with propane, butane, and pentane at 325°C. Although x-ray patterns of Hagg carbide were found, the carbon content of these preparations approached 7.5 weight-% as a limit rather than 9.1% which was obtained upon carburization with carbon monoxide. Hall (15) found that during carburization of a reduced fused catalyst (Bureau of Mines number D3001) in n-butane at 300°C., C increased only to 0.22, and the carbide phase was cementite rather than Hagg carbide. Methane is too stable thermodynamically to carburize iron rapidly at low temperatures however, at 500°C. relatively pure cementite may be prepared with methane (15). 

Jack (17) and Goodeve and Jack (18) concluded that the rate of carburization with carbon monoxide of e- or ("-nitrides with N about 0.5 was dependent upon the rate of removal of nitrogen atoms, since the... 

Carburization of t-Nitrides with Carbon Monoxide (FesOt-MgO-KiO Catalyst)... 

Hall, Dieter, Hofer, and Anderson (19) also studied the carburization of e-nitrides with hydrogen-carbon monoxide mixtures and the reduction of e-nitride and e-carbonitride with pure hydrogen. The rate of removal of nitrogen increased with the fraction of hydrogen in the gas as shown in Table II. For hydrogen-carbon monoxide mixtures containing less... 

In the petroleum industry carbon monoxide and carbon dioxide reactions with steel are encountered which may also cause decarburization or carburization, depending upon the direction of the equilibrium. 

Figure 3.20 shows the progress of carburization under different atmospheres with time for a 10-pm W/carbon black powder mixture (containing 6.2 wt%C) on heating to 1800 °C, and then holding for 1.5 hours [3.74]. Under hydrogen or carbon monoxide... 

X-ray diffraction studies on iron samples carburized with carbon monoxide were carried out by Hagg (124), Halle and Herbst (125), Hofer, Cohn, and Peebles (126), Kolbel, Ackerman, Juza, and Tentschert (127), and by Eckstrom and Adcock (128). Hagg prepared his carburized iron samples below 260°C., following a method described by Bahr and Jessen (129), and determined x-ray diffraction patterns, according to Hofer, Cohn, and Peebles, identical to the Fe2C, with a Curie point at 265°C. of Pichler and Merkel. 

Further evidence which indicates that bulk cobalt carbide is not of importance in the synthesis is furnished by x-ray analysis of catalysts which have been used in the sjmthesis. It has been showm (91) that on low-temperature carburization with carbon monoxide, reduced cobalt... 

Preparation of the H8gg carbide was started with a commercial synthetic ammonia catalyst containing 92.6% FesOi, 4.2% MgO, 0.7% SiOj, and 0.4% Cr203. Reduction and carburization were carried out in apparatus similar to that previously described (Hofer and Peebles, 49). A stream of purified hydrogen was passed over the sample held at 450° for 82 hours. The reduced sample was then treated at 240° for 539 hours with purified carbon monoxide, until the carbon/iron ratio became nearly constant, and closely corresponded to FeaC. The reaction vessel was always opened in a carbon dioxide atmosphere to prevent oxidation. 

The experiments and results reported by Hofer, Cohn, and Peebles are as follows A 3-g. sample of raw cobalt-thoria-kieselguhr Fischer-Tropsch catalyst was reduced in flowing purified hydrogen for 40 hours at 400°. The sample was then carburized with purified carbon monoxide... 

Vanadium in a fuel forms various metal compounds with low melting points, and causes molten-salt corrosion of steel called vanadium attack. Another example of high temperature corrosion is sulfidation. Carbon monoxide, carbon dioxide, and hydrocarbons form metal carbides at high temperatures and this is called carburization. Nitriding involves chemical reaction of nitrogen with metal. 

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