Pack cementation processes

Mévrel, R.; Duret, C.; Pichoir, R.

doi:10.1179/mst.1986.2.3.201

Cited by 147 publications

(33 citation statements)

References 12 publications

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“…It can be certain that the coating was formed by the inward diffusion of Al as no entrapped pack particles could be observed in the outmost surface of the coating; entrapment of pack powder particles is a typical feature for the coatings formed via outward Ni diffusion [19,20]. It follows that the duplex structure of the coating was formed sequentially by the total aluminisation of the nickel plating first, followed by aluminisation of a surface layer of the steel substrate.…”

Section: Coating Structurementioning

confidence: 97%

Long term oxidation resistance and thermal stability of Ni-aluminide/Fe-aluminide duplex diffusion coatings formed on ferritic steels at low temperatures

2009

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Section: Coating Structurementioning

confidence: 97%

Long term oxidation resistance and thermal stability of Ni-aluminide/Fe-aluminide duplex diffusion coatings formed on ferritic steels at low temperatures

2009

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“…Pack aluminizing is a versatile and economical coating process widely used for high temperature materials [19]. Aluminizing of c-TiAl by pack-cementation produced an Al-rich intermetallic TiAl 3 coating [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Oxidation Behaviour of TBC Systems on γ-TiAl Based Alloy Ti–45Al–8Nb

et al. 2009

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The lifetime of thermal barrier coating (TBC) systems on gamma titanium aluminides was determined in the temperature range between 850°C and 950°C under cyclic oxidation conditions in air. Coupons of the alloy Ti-45Al-8Nb (at.%) were coated by pack aluminizing. A subset of samples was subsequently annealed at 910°C for 312 h in argon. During this heat treatment, the two-phase (Nb,Ti)Al 3 plus TiAl 2 microstructure of the coating transformed into single phase c-TiAl. On pre-oxidised aluminized, annealed and bare samples, TBCs of yttria partially stabilized zirconia were deposited using electron-beam physical vapour deposition (EB-PVD). No spallation of the TBCs was observed in cyclic oxidation tests at 850°C for up to 3,000 cycles of 1 h dwell time at high temperature. The two-phase aluminide coating provided effective oxidation protection due to the formation of a continuous alumina scale. The lifetime of this TBC system exceeded 1,400 cycles at 950°C, whereas an aluminized and annealed sample failed after approximately 500 cycles. The TBC on bare substrate failed when thermally cycled at 900°C. In contrast, no spallation occurred with an aluminized and annealed specimen at this temperature during the maximum exposure length of 1,000 cycles, probably related to an increased aluminium concentration in the subsurface region.EB-PVD zirconia top coats were well adherent to the alumina scale and the thermally grown mixed oxides. Failure of the TBC systems observed with bare and annealed samples was associated with spalled oxide scales formed on c-TiAl.

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“…Examination under the optimal microscope revealed the presence of pack alumina particles in the top surface of the coating. This is a typical feature, suggesting that the coating was formed via an outward growth process involving Co enrichment and the outward migration of substrate elements, Cr and Fe in particular [11,15,16]. Further evidence supporting the suggestion of the outward growth process came from the XRD spectrum measured from the as-coated surface, which is shown in Fig.…”

Section: Coating Of Substratementioning

confidence: 80%

Evaluation of the Parabolic Rate Constant During Different Types of Oxidation Tests for Spinel Coated Fe–17%Cr Alloy

Ebrahimifar

Zandrahimi

2010

Oxid Met

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Oxidation resistance, and the long-term stability of interconnects in solid oxide fuel cells, can be ameliorated by the use of a protective, effective, relatively dense and well adherent, spinel coating. In this study, the pack cementation method was employed to coat cobalt onto AISI 430 ferritic stainless steel. Isothermal oxidation, cyclic oxidation, and oxidation at different temperatures (600-900°C) were applied to evaluate the parabolic rate constant (k p ). In each test, the coated samples demonstrated lower k p, indicating that the coating layer was effective. The formation of MnCo 2 O 4 and CoCr 2 O 4 spinels, during the oxidation, improved the oxidation resistance of AISI 430 ferritic stainless steel.

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Pack cementation processes

Cited by 147 publications

References 12 publications

Long term oxidation resistance and thermal stability of Ni-aluminide/Fe-aluminide duplex diffusion coatings formed on ferritic steels at low temperatures

Long term oxidation resistance and thermal stability of Ni-aluminide/Fe-aluminide duplex diffusion coatings formed on ferritic steels at low temperatures

Oxidation Behaviour of TBC Systems on γ-TiAl Based Alloy Ti–45Al–8Nb

Evaluation of the Parabolic Rate Constant During Different Types of Oxidation Tests for Spinel Coated Fe–17%Cr Alloy

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