Characterization of Wear and Surface Reaction Layer Formation on Aerospace Bearing Steel M50 and a Nitrogen-alloyed Stainless Steel

2006 ◽  
Vol 3 (2) ◽  
pp. 14055
Author(s):  
S Peissl ◽  
H Leitner ◽  
R Ebner ◽  
H Hutter ◽  
D Krecar ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Reaction Layer ◽  
Surface Reaction ◽  
Bearing Steel ◽  
Layer Formation

scholarly journals Real-time Characterization of the Optical Properties of an ultra-thin Surface Reaction Layer during Growth

1996 ◽  
Vol 441 ◽  
Author(s):  
N. Dietz ◽  
N. Sukidib ◽  
C. Harrisb ◽  
K. J. Bachmann
Keyword(s):  
Optical Properties ◽  
Fine Structure ◽  
Reaction Layer ◽  
Surface Reaction ◽  
Turning Points ◽  
Growth Conditions ◽  
Chemical Beam Epitaxy ◽  
Modulated Phase ◽  
Interference Oscillations

AbstractThe average optical properties of an ultra-thin surface reaction layer (SRL) during growth by pulsed chemical beam epitaxy (PCBE) can be quantitatively accessed by p-polarized reflectance spectroscopy (PRS), as demonstrated on the example of heteroepitaxial GaP growth. Under PCBE growth conditions, the surface of the substrate is exposed to pulsed ballistic beams of tertiarybutyl phosphine [TBP, (C4H9)PH2] and triethylgallium [TEG, Ga(C2H5)3]. The pulsed precursor supply causes a period in composition and thickness modulated SRL, monitored as a fine structure that is superimposed on interference oscillations, resulting from back reflection at the substratelayer interface with increasing layer thickness. The amplitude of this fine structure undergoes a period amplitude modulation and exhibits turning points at which the response to the first precursor pulse changes sign. The turning points can be characterized by the expression R4(Φmax)=R4(Φmin), which describes the maximal and minimal values of the temporally modulated phase factor in the SRL, using a four layer stack description. The positions of these turning points are not affected by the thickness of the SRL, which allows the computation of the average complex dielectric function of the SRL independent of its thickness. In the next step, the average thickness of the SRL can be extracted from the amplitude of the observed fine structure.

Wear and Friction Behavior of the Aerospace Bearing Steel M50 and a Nitrogen-Alloyed Stainless Steel Under Lubricated Sliding Conditions

2005 ◽  
Author(s):  
Sven Peissl ◽  
Harald Leitner ◽  
Reinhold Ebner ◽  
Peter Wilhelm ◽  
Boril Chernev ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Wear Rate ◽  
Reaction Layer ◽  
Room Temperature ◽  
Bearing Steel ◽  
Steel Grade ◽  
Material Behavior ◽  
Chemical Compositions ◽  
Material Transfer ◽  
Wear And Friction

The material requirements on aircraft engine mainshaft bearings increase due to an elevated speed index (bearing bore diameter multiplied by rotational shaft speed) and slip ratios [1]. The formation of reaction layers on surfaces in mechanical contact is strongly affected by the tribological loading conditions, the materials used, the lubricant, and the service temperature. An appropriate reactivity between material and lubricant in tribological systems decreases wear and friction and increases the durability [2,3]. Goal of the paper is to compare wear and friction properties of standard aerospace bearing steel AMS 6491 (M50) with that of the high strength stainless steel grade AMS 5898. The nominal chemical compositions are 0.82C-4.1Cr-1V-4.2Mo (wt%) and 0.3C-0.4N-15.2Cr-1Mo (wt%), respectively. In order to characterize the material behavior under pure sliding conditions, ball on disc (BOD) experiments were performed with a contact pressure of 1GPa and a sliding speed of 10 cm/s at room temperature and at 150°C. As lubricant the jet engine oil Mobil Jet II was used. It is assumed that the reaction layer formation depends on the material composition and is also effected by the counterpart and the lubricant additives. Thus, the experiments were performed with two different ball materials. The first ball material was the same standard aerospace bearing steel (M50) as mentioned above and the second was a ceramic (Si3N4). The homogeneity and the distribution of the reaction layers as well as the wear rate were determined in the contact zone by means of optical profilometry, scanning electron microscopy (SEM) and Fourier transformation infrared spectroscopy (FTIR). The study showed that wear is significantly higher on the stainless steel grade compared to M50 (Fig. 1a and Fig. 1b). The dark areas in Fig. 2 are phosphorus rich regions on the wear track of M50. This reaction layer is mainly built up of phosphates, which result from the TCP lubricant additive. In the FT-IR spectra (Fig. 3) absorption bands at 1130 cm−1 (room temperature-BOD test) and at 1160 cm−1 (150°C-BOD test) are visible, which result from the P=O stretching [4]. The shift of the absorption band to lower wave numbers with decreasing test temperature is probably due to hydrogen bonding [5]. Contrary to AMS 6491 no measurable reaction layer was found on AMS 5898 after testing at room temperature (Fig. 1b). The friction coefficients of the two steels against Si3N4 balls determined in the BOD tests are compared in Fig. 4. AMS 5898 shows an abrupt increase of the friction coefficient after a sliding distance of 3.5 m. The reason for that is a material transfer of disc material to the ceramic ball as can be seen in Fig. 5. This transfer material causes a plowing of the disc and thus, an increased wear can be observed. The different Cr-contents and consequently oxide layers of AMS 5898 and AMS 6491, which react differently with TCP, might explain this behavior. AMS 5898 does not sufficiently react with TCP at room temperature to form a protective layer. Consequently, material transfer and increased wear occurs. In case of AMS 6491 an increase of the operating temperature cause a change of the reaction layer (see Fig. 3) and to an increase in the wear rate.

New horizons for the structural characterization of stainless steel slags by X-ray powder diffraction

2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 61-66 ◽  
Author(s):  
B. Peplinski ◽  
B. Adamczyk ◽  
G. Kley ◽  
K. Adam ◽  
F. Emmerling ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Powder Diffraction ◽  
Structural Characterization ◽  
X Ray ◽  
New Horizons

Characterization of Hot-Steam Oxidation Tested Chromosiliconized Heat-Resistant Austenitic Stainless Steel

2012 ◽  
Vol 53 (6) ◽  
pp. 1090-1093 ◽  
Author(s):  
Yasuhiro Hoshiyama ◽  
Xiaoying Li ◽  
Hanshan Dong ◽  
Akio Nishimoto
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Steam Oxidation ◽  
Heat Resistant

Topographical and tribological characterization of some ceramic and stainless steel brackets

2016 ◽  
Vol 58 (7-8) ◽  
pp. 608-611
Author(s):  
Violeta Merie ◽  
Viorica Ţărmure ◽  
Simion Haragâş ◽  
Andreea Pop
Keyword(s):  
Stainless Steel ◽  
Tribological Characterization
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