Accession Number : ADA195623

Title :   Effect of Sample Volume on Quantitation of Ferrographic Data.

Descriptive Note : Final rept. 1 Jul-31 Dec 87,

Corporate Author : AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH

Personal Author(s) : Wright, Robert L ; Centers, Phillip W

PDF Url : ADA195623

Report Date : Mar 1988

Pagination or Media Count : 21

Abstract : For the analytical quantitation of wear debris (i.e., percent area covered (PAC) per milliliter of sample in a microscopic field of view) found in fluid systems by ferrographic techniques, the commonly employed normalization procedure used for variations in sample volume is a linear relationship. In practice, sample dilutions are made or sample volumes are increased until a ferrogram is obtained with 10 to 40 PAC as recommended for quantitative purposes. However, at this level of PAC, localized piling of debris has been observed which suggests that the use of a linear relationship would be inappropriate. Theoretical examination of ferrographic deposition of wear debris and treatment of published data confirm that coverage varies with sample quantity by a power law relationship. Improved normalization and wear trending procedures based upon power curve fitting of area covered measurements versus sample quantities are developed. The new procedures should increase confidence and reliability in both ferrographic measurement and wear severity index trending. Keywords: Curve fitting; Ferrography; Wear debris; Lubricant analysis; Wear severity indexing; Sampling. (edc)

Descriptors :   *SAMPLING, *WEAR, FERROMAGNETISM, CURVE FITTING, DEBRIS, DEPOSITION, FLUIDS, LINEARITY, LUBRICANTS, MEASUREMENT, MICROSCOPY, NORMALIZING(STATISTICS), PILE STRUCTURES, POWER, RELIABILITY

Subject Categories : Lubricants and Hydraulic Fluids
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE