Development of Lead-Free Al-Sn-Si Alloy Bearing for Recent Automotive Engines

Kose, Akihiro; Koushima, Motohiko; Ukai, Tomohiro; Kawashima, Yuki; Zushi, Kouji

doi:10.4271/2014-01-0995

Cited by 6 publications

(2 citation statements)

References 4 publications

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“…In view of these findings, it was reasoned that applying a DLC coating to the crankshaft main journal would both reduce friction and improve seizure resistance under various lubrication regions. To verify this effect, tests were conducted on actual engine parts in isolation to evaluate the friction and seizure properties of a combination of a siliconcontaining hydrogenated amorphous carbon (a-C:H:Si) DLC-coated journal and a lead-free Al-Sn-Si alloy bearing for recent gasoline engines [10]. The evaluations were performed using a bearing test rig as specified in ISO 21866-1 for automotive journal bearings [11], which makes it possible to examine the properties under fluid, mixed, and boundary lubrication regions.…”

Section: Introductionmentioning

confidence: 99%

Excellent Seizure and Friction Properties Achieved with a Combination of an a-C:H:Si DLC-Coated Journal and an Aluminum Alloy Plain Bearing

et al. 2021

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Friction occurring between the crank journal and main bearings accounts for a large share of the mechanical losses of automotive engines. The effects of higher in-cylinder pressures and narrower bearings have raised the specific load applied to bearings, making it essential to secure sufficient seizure resistance as well. For the purpose of meeting both requirements, we have endeavored to reduce friction and improve seizure resistance by applying a diamond-like carbon (DLC) coating to the crank journal. In the present study, a bearing tester was used that has received international standard certification from the International Organization for Standardization for reproducing the sliding behavior occurring between the crank journal and main bearings in actual engines. Test results indicated that a silicon-containing hydrogenated amorphous carbon (a-C:H:Si) DLC-coated journal showed a definite friction reduction and a marked improvement in seizure resistance. An acoustic emission (AE) analysis revealed that an adhesion-induced AE peak observed for a steel journal was not seen for the DLC-coated journal. Additionally, tin and aluminum elements in the bearing material that were transferred to and observed on the sliding surface of the steel journal were not seen on the DLC-coated journal. Accordingly, the low affinity of the DLC coating with these metal elements presumably led to the clear friction reduction and superior seizure resistance displayed by the DLC coating.

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Section: Introductionmentioning

confidence: 99%

Excellent Seizure and Friction Properties Achieved with a Combination of an a-C:H:Si DLC-Coated Journal and an Aluminum Alloy Plain Bearing

et al. 2021

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“…For example, studies on anti-seizure properties of Al-Sn-Si alloys using a high speed bearing seizure test machine has shown that Al-Sn-Si alloys with 6% of Sn can have comparable anti-seizure properties with that of 10% and 12% Sn content because of improved dispersion of Sn in the Al matrix. 15 Seizure performance of these alloys can be further improved by applying a polymer resin overlay containing solid lubricants such as MoS 2 . 16,17 Copper-based alloys are also improved by incorporating Bi and Mo 2 C. Further improvement in their seizure performance by applying a Bi overlay coating has also been reported.…”

Section: Introductionmentioning

confidence: 99%

Seizure behaviour of Pb-free engine bearing materials under dry condition

Gebretsadik

Hardell

Prakash

2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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Due to new environmental regulations, Pb-free engine bearing materials are becoming more common and there is a need for studying their tribological performance. Under severe operating conditions, failure due to seizure can occur in engine bearings. In this work, seizure behaviour of different multi-layered engine bearing materials has been studied by using a block-on-ring test setup under dry condition. These materials included Al–Sn-based lining with no overlay, bronze lining with polyamide-imide-based overlay containing MoS2 and graphite, bronze lining with two overlays of Al–Sn-based and polyamide-imide-based material, bronze-based lining with Sn-based overlay and bismuth (Bi)-containing bronze with Sn-based overlay. The tests were performed by gradually increasing the load at a specific time interval and in a stepwise manner and at a constant speed under unidirectional dry sliding conditions. The test materials, counter surfaces and the wear debris were analysed using SEM with a view to understand the seizure mechanisms. Bronze-based lining with a polyamide-imide-based overlay containing MoS2 and graphite does not exhibit seizure up to a load of 475 N. For Al–Sn-based lining without overlay, seizure occurs at a relatively lower load of 125 N. The Al–Sn-based lining with no overlay shows higher friction and the polyamide-imide-based overlay containing MoS2 and graphite shows lower friction during the seizure test. In most cases, there is material transfer onto the test ring counter surface. Material transfer onto the counter surface either due to severe adhesion or wear debris adhered and smeared on it. Al–Sn-based lining and an exposed Al–Sn-based overlay show severe adhesion that causes seizure. On the other hand, exposed Pb containing lining and Bi containing lining seize due to mechanical interlocking caused by the adhered wear debris on both surfaces.

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