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THE REDUCTION OF WEAR AND WEAR VARIABILITY UNDER LUBRICATED SLIDING BY ION IMPLANTATION J.J. AU* AND P. SIOSHANSI** *Sundstrand Aviation Operations, 4747 Harrison Avenue, Corporation, Patriots Park, Bedford, MA 01730

"**Spire

Rockford,

IL 61101;

ABSTRACT Block-on-ring wear tests were performed on Ti-implanted AISI 52100 steel sliding against three commercial alloys: CDA 673 brass, AISI 4140 low alloy steel, and AISI 0-6 tool steel. A turbine oil, meeting MIL-L 23699 specifications, was used as the lubricant. The 52100 wear rings were ion implanted to a fluence of 2 Comparison with 2 x 1017 Ti/cm at 55 KeV or 125 KeV. non-treated 52100 wear rings indicated that ion implantation reduced the amount of wear and wear It is hypothesized that reduced adhesion and variability. improved lubricant film formation due to the presence of the implanted layer was responsible for the reduction in wear and wear variability.

INTRODUCTION It has generally been recognized that ion implantation is most suitable for light load, lubricated sliding conditions owing to the It has also been shallowness of the implanted layer (.02 ;m to .4 pm). shown that implantation of ions such as nitrogen or boron could significantly improve the lubricated sliding wear resistance of many steels [1-4], although titanium appeared to be the only ion species which was effective in reducing friction and wear of AISI 52100 steel [5]. has been Despite the large body of literature on tribology, very little reported on the technologically important problem of wear variability as infantile wear failures or as large scatter in which manifested itself The lack of attention to studying wear variability in part the wear data. could be attributed to the many variables involved in any wear process. For example, any attempt to alleviate wear variability by conventional coating techniques would encounter added variability from differences in Ion implantation appears to be a coating quality and coating adhesion. surface treatment technique which does not have the quality and adhesion problems inherent in other methods. The current paper describes wear experiments carried out to study the effect of ion implantation, not only to reduce wear, but also to The LFW-I block-on-ring wear apparatus was reduce wear variability. selected as the main wear testing tool owing to its capability to produce The scatter in the wear data and thus simulate wear variability. block-on-ring geometry also simulates a certain engineering applicaton at Sundstrand. For this reason, the wear blocks were conformed to a fixed 2 2 The wear rings were 3.5 cm in contact area of 0.1 cm (0.016 in ). Three material diameter and 0.87 cm wide, with a wear track of 0.5 cm. combinations were selected as candidate materials for the intended (1) AISI 52100 steel vs. CDA 673 (Mueller 602) engineering application: brass, (2) AISI 52100 steel vs. AISI 4140 steel, and (3) AISI 52100 steel vs. AISI 0-6 graphitic tool steel. All three steels had a martensitic structure with the following hardness values: 58-62 HRC