Experimental method

-Material  : The material used is a bronze obtained by sintering under pressure of a prealloyed powder Cu-10% Sn. -Metallographic Observation Optical observations were performed on an Universal metallographic microscope. The magnification attained in this case is of the order of 500x. For electronic observations, they were performed on a SEM type JSM-6100 equipped with a secondary electron detector, a backscattered electron detector and a qualitative analysis of system elements. The EDX analyzes were also performed in order to confirm a possible diffusion between grains. On the other hand, the microscopy was used to characterize the degradation of surfaces wear, and identify mechanisms that control such wear.-X-Ray Diffraction  The X-ray diffraction is used to identify the phases formed during the elaboration. Analyzes were performed on a SIEMENS D 5000 diffractometer equipped with a copper tube μ = 1.5406 A°, using DIFFRAC Plus software, and TOPAS V2.0 for calculation of the lattice parameters. The analysis conditions are as follows: 0.5 ° divergence slit, rotating sample holder 15 rev / min, scanning 25-95 ° with a step of 0.02 ° and a speed 4 steps / second.- TribometryFor tribological characterization was used a type tribometer ball an disk. This tribometer designed and built by CSEM (Neuchatel, Switzerland) also allows to perform tests under controlled atmosphere and high temperature up to 800°C. - Evaluation of wear After each friction test, the different characteristics to quantify wear: Lus width, depth ZUS and air wear SUS of a wear track section, are determined with a profilometer type Dektak 3030

Abstract

The present study investigated the tribological and microstructural characterization of the bronze alloy Cu-10% Sn sintered under pressure from prealloyed powder. Different experimental techniques have been implemented. Microscopy, we observed that the structure is porous grains have generally maintained their original forms. We have found, by X-ray diffraction, the type a phase Cu17.3Sn. Furthermore, we followed the evolution of the friction coefficient for different conditions. This showed that the contact is very unstable. The coefficient of friction is of the order of 0.3 in the good operating conditions. The wear of the samples was described as abrasive type for the normal force of 1N and adhesive for 3N. Membership debris bronze ball has been proven by weighing and EDX analysis. The bronze debris adhesion on the ball was proven by weighing and analyzes EDX

CONCLUSIONSThe microstructural characterization and tribological bronze Cu-10%Sn sintered under pressure from prealloyed powder was carried out by different techniques. Essential conclusions in this study are as follows:-The structure of the material is highly porous, the grains of powder have powder despite their identities coalescence observed between some grains,- the X-ray diffraction revealed a phase Cu17.3Sn with the existence of tin in solid solution in the following,-The evolution of the friction coefficient showed that the contact between the two pieces is very unstable and this has led to very excessive coefficients and use self-lubrication is essential,- the coefficient of friction remains substantially constant in the area swept slip speed and normal force,- two wear mechanisms controlling the degradation of the sample surface: abrasion and adhesion.

ABILITY OF SINTERED BRONZE PRESSURE FROM POWDER Cu-10% Sn PREALLOYED FOR BEARINGS Fatiha Keraghel(1)* , Kamel Loucif(1), Boualem Keskes (2)

(1): Laboratoire des Matériaux non Métallique Université Ferhat Abbas de Sétif 1 Institut d’Optique et Mécanique de Précision Algérie,(2) : Laboratoire de Mécanique Université Ferhat Abbas de Sétif 1 Institut d’Optique et Mécanique Précision Algérie

Corresponding author: f_keraghel@yahoo.fr

Experimental Result

a: Different pressures b: Different durations Samples diffraction from Cu-10% Sn

Aspect of a wear profile

Microstructural characterization - Metallographic observation

a:T=400°C, P =100 MPa, t= 3h b :T=400°C, P =100 MPa, t =4h

Optical micrograph of samples sintered under different conditions from pre-alloyed powders Cu-10%Sn (500x)

a: (T= 400°C, P = 100 MPa ; t = 3h) b: (T= 400°C, P = 100 MPa ; t = 4h)MEB Micrograph of samples sintered under different conditions

-X- ray diffraction

Tribological characterization - Study of friction

a: Normal force =1N b: Sliding speed= 62.8mm/sEvolution of the friction coefficient in function of time

-Wear of the antagonistic pieces

The wear mass loss is given by the difference of the final mass m f (after wear) than initial mass mi

(before wear):Δm= mf - m

F (N) 1 2 3

∆m Pastille (mg) 1.4 6.3 5

∆m Bille (mg) ~ 0 -0.1

Variation mass loss according to the normal force

a :Sample F=2N,V= 62.8mm/s b : Balle F=2N, 73.26mm/s Wear surfaces of two antagonistic pieces