Nanoscale chemistry and mechanical properties of tribofilms on Al-Si alloy (A383): interaction of ZDDP, calcium detergent and molybdenum friction modifier

Authors: Pereira, G.; Lachenwitzer, A.; Munoz-Paniagua, D.; Kasrai, M.; Norton, P.R.; Capehart, T.W.; Perry, T.A.; Cheng, Y.T.

Source: Tribology - Materials, Surfaces & Interfaces, Volume 1, Number 1, March 2007 , pp. 4-17(14)

Publisher: Maney Publishing

Key:
Free Content - Free Content
New Content - New Content
Subscribed Content - Subscribed Content
Free Trial Content - Free Trial Content

Abstract:

The interaction of a friction modifier and a calcium phenate detergent additive, with zinc dialkyl dithiophosphates (ZDDPs) in the formation of antiwear films on A383, has been studied using synchrotron radiation and nanoindentation techniques. X-ray absorption near edge structure (XANES) spectroscopy has shown that films prepared from oils containing both ZDDP and detergent, and ZDDP and molybdenum dithiocarbamate (MoDTC), are chemically similar to, but thicker than those made from oils containing only ZDDP. In addition, wear was greatly reduced in the presence of the detergent which was correlated with the basicity and the presence of the friction modifier. The phosphorus K and L edge XANES spectra show that the tribofilms are polyphosphate glasses of similar nature to those found on steel, but characterised by a shorter chain length. The sulphur K edge shows a MoS2 like film and under certain conditions, the presence of a sulphate species is detected. High resolution topographic images and mechanical properties were determined by atomic force microscopy and imaging nanoindentation. The films formed in the presence of the detergent exhibited similar mechanical responses independent of the conditions tested. The indentation modulus of the films on the Al matrix always appear much softer than the films formed on the Si grains whether or not the lubricant contains only ZDDP, or both ZDDP and MoDTC.

Keywords: ANTIWEAR FILMS; ZDDPS; XANES; MODTC; CA PHENATE

Document Type: Research article

DOI: 10.1179/175158407X181499

The full text electronic article is available for purchase. You will be able to download the full text electronic article after payment.

$51.00 plus tax      Refund Policy

 

OR

Back to top

Key:
Free Content - Free Content
New Content - New Content
Subscribed Content - Subscribed Content
Free Trial Content - Free Trial Content
Share this item with others: These icons link to social bookmarking sites where readers can share and discover new web pages.
Page Help Click here for Page Help
Shopping cart
Tools
Sign in






Need to register?
Sign up here
Text size: A | A | A | A