Characterisation of PVD-TiN Coated Austempered Ductile Iron: Effects of Nodule Count and Austempering Temperature

Colombo, Diego Alejandro; Echeverría, María Dolores; Moncada, Osvaldo Julio; Massone, Juan Miguel

doi:10.2355/isijinternational.51.448

Cited by 9 publications

(16 citation statements)

References 30 publications

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“…Table 5 reports the roughness data of the polished ADI The Ra values of the uncoated samples increase as nodule count decreases. As the authors of the present work reported previously, 11) this fact can be ascribed to the coarsening of the matrix as nodule count decreases as well as to the partial or complete graphite removal of certain surface nodules during the polishing stage.…”

Section: Xrd Characterizationsupporting

confidence: 49%

“…As reported previously, 11) this increase can be assigned to the attachment of Ti or Cr droplets to the growing film which are generated on the target surface during arc evaporation. The lateral correlation length and the roughness exponent for all the TiN coated samples are close to 12.5 μm and 0.85, respectively.…”

Section: Effect Of Substrate Characteristicsmentioning

confidence: 90%

“…10) Additionally, the analysis of the effects of the substrate characteristics on the coating properties evidenced little influence of the austempering temperature and nodule count. 11) Studies were performed on manual polished substrates with SiC waterproof paper of different grit sizes.…”

Section: Introductionmentioning

confidence: 99%

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Residual Stress Analysis in PVD Coated Austempered Ductile Iron

et al. 2013

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The aim of this work is to study residual stresses (RS) in PVD TiN and CrN coated ADI substrates with different nodule counts, austempering temperatures and surface finishing methods (grinding and polishing). Coatings were applied by arc ion plating using an industrial reactor and different sets of processing parameters. Residual stress measurements were performed by x-ray diffraction using the sin 2 ψ method along two principal axes on the samples surface (parallel and perpendicular to the substrate abrasion direction). The film thickness, hardness and adhesion of each coated sample were also evaluated.The results obtained indicate that RS in TiN and CrN coated samples are compressive irrespective of the different substrates, surface finishing methods and processing parameters utilized. The parallel and perpendicular RS do not vary significantly, indicating a rotationally symmetric biaxial stress state. The RS of the coated samples are not influenced by the different substrate characteristics regarding microstructure, hardness and surface roughness. The microhardness and RS of TiN and CrN coated samples increase with film thickness. The increase in substrate temperature together with the decrease in the values of BIAS voltage, arc current and chamber pressure lead to microhardness and RS reduction. Grinding produces surface hardening and reduction of the compressive RS in the substrates, but causes no variations in the RS of the TiN and CrN coated samples. The adhesion strength quality of TiN and CrN coatings to ADI substrates can be related to indices ranging from HF1 to HF2.

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Section: Xrd Characterizationsupporting

confidence: 49%

Section: Effect Of Substrate Characteristicsmentioning

confidence: 90%

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Residual Stress Analysis in PVD Coated Austempered Ductile Iron

et al. 2013

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“…The parameters of process A were applied in a previous work. 8) In process C, the substrates were placed on a support, used as a backup piece, to allow heat dissipation and thus reduce the effects of the coating process on the ausferritic microstructure.…”

Section: Pvd Coating Processmentioning

confidence: 99%

“…6) However, ADI exposure to high temperature during long periods of time may cause changes in the ausferritic microstructure and negatively affect the mechanical behavior of the material. 7) Studies conducted by the authors of this work 8) with PVD-TiN coatings deposited on ductile iron substrates with different nodule counts and austempering temperatures, using an industrial reactor and under processing parameters specifically selected for this material presented acceptable coating characteristics regarding film thickness, hardness and adhesion, without causing significant deterioration of the ausferritic microstructure. The arithmetic average roughness of the uncoated and coated samples increased as nodule count decreased within the range evaluated.…”

Section: Introductionmentioning

confidence: 99%

PVD TiN and CrN Coated Austempered Ductile Iron: Analysis of Processing Parameters Influence on Coating Characteristics and Substrate Microstructure

et al. 2012

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This work studies the influence of the PVD processing parameters on the characteristics of TiN and CrN coatings deposited on ADI substrates, austempered at 360°C, with different nodule counts and surface roughnesses. Coatings were applied by arc ion plating using an industrial reactor and different sets of parameters, with BIAS voltages, arc currents, chamber pressures and substrate temperatures varying from -100 to -250 V, 60 to 65 A, 0.7 to 2.8 Pa and 280 to 450°C, respectively. The effect of the different depositions conditions on the substrates microstructure was also analyzed. The existing phases, preferred orientation, surface topography, film thickness, hardness and adhesion of each coating were determined. The retained austenite content and hardness of each substrate were computed before and after coating deposition.The results obtained indicate that the different deposition conditions and coating materials evaluated do not generate significant changes neither in the resulting topography nor in the coating adhesion, which can be related to indices between HF1 and HF2. Coating adhesion was not affected by different substrate roughnesses. The combined reduction of BIAS voltage, arc current and chamber pressure leads to a decrease of TiN growth rate and hardness, while high substrate temperatures promotes an increase in TiN and CrN growth rates. Substrate temperatures around 300°C with deposition times of up to 240 min do not promote noticeable changes on the ausferritic microstructure, while temperatures of 400°C and above translate into a clear microstructural deterioration, even for short deposition times.

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