Effect of Chemical Composition on the Microstructure and Tribological Properties of Sn-Based Alloys

Abstract

This article presents the test results of two bearing alloys on a tin matrix, differing in the content of alloy additions. Microscopic tests were performed using scanning electron microscopy, along with Brinell hardness tests and tests of tribological properties in the conditions of technical dry friction and wet friction using a TU-32 oil. Additionally, wear mechanisms were analyzed depending on the process conditions. The results indicate better tribological properties of the B82 alloy, with a higher content of antimony compared to the B89 alloy. This alloy contains more precipitates of hard phase b-SnSb, which both influence the level of the mechanical properties and determine the tribological properties. Additionally, it was proven that using the TU-32 oil as a lubricant practically eliminates adhesive wear, and the post-friction surfaces for both alloys are of a similar nature.

Effects of the Processing Parameters of Friction Stir Processing on the Microstructure, Hardness and Tribological Properties of SnSbCu Bearing Alloy

“…Analyses of changes in the coefficient of friction were also performed under conditions of the start–stop test ( Figure 8 e,f), which aims to simulate the actual conditions of intermittent operation of a turbine (multiple start-ups and stops). A detailed description of the start–stop process can be found in the work of Leszczyńska-Madej et al [ 30 ].…”

Effect of FSP on Tribological Properties of Grade B89 Tin Babbitt

“…The combination of such diverse properties can only be achieved by alloys composed of two or more phases with different properties. The basic factor determining the application of Sn-Sb-Cu alloys for bearing alloys is the presence of hard SnSb compound crystals and acicular particles of the Cu 6 Sn 5 compound, evenly distributed in a soft, plastic tin-rich matrix [ 1 , 2 , 3 , 4 , 5 ]. Previous studies show that refinement and a change in the morphology of the hard SnSb intermetallic phases improve, in particular, the tribological properties.…”

Characterization Of Microstructure And Selected Properties of SnSbCu Alloy After FSP

“…The use of FSP modi cation to treat the surface of the SnSbCu bearing alloy causes a change in the morphology of the hard phases, including their strong re nement -con rmed by a rise in the share of the nest CuSn particles with an area under 25 µm 2 and SnSb with an area under 5 µm 2 . In addition, FSP modi cation with the higher rotational speed of the tool results in greater re nement of the microstructure and its homogenization.…”

“…Materials that exhibit such characteristics are tin-based bearing alloys. The microstructure of these alloys is multi-phase, most often in the three-phase form: α, β, η or α, β, ε, where: α -an antimony and copper solution in tin, which is the soft and ductile matrix, βangular SnSb crystals and η -CuSn compound acicular precipitates [1,2]. Due to the growing requirements for bearing alloys such as increasing loads/circumferential speeds and reducing machine sizes, the requirements for the strength properties are also rising.…”