Entice

 Fellow Profile: Catia Alves

catia_1_ulfdc9f4aee

Project Title

Lubricants additives optimization for contacts involving iron based or Aluminum Alloys (P4)

Project Vision Statement

Nowadays, there is an increased need to take an environmental point of view of our day to day activities in order to reduce pollution.  As a result of this need, I think that the project, in which I’m involved, has everything to provide good results and contribute to some environmental improvements. As a fellow researcher in this project, I feel it is a good opportunity to grow up as a scientist and as a person.

Project Summary

 

Context and objective

 

Nowadays there is an increasing necessity of finding solutions for variety of troubling issues resulting from man-made contamination. Many of these problems cause long-term damages to the environment. Regarding this aspect a significant contribution is done by the automobile industries. In this way, automobile industry is making a big effort to reduce costs and to improve car design, increasing as well fuel economy and durability. Some studies have been made in order to reduce or replace the cast iron and steel content in engines; the idea consists in a reduction of weight [1-3]. Aluminum is a good candidate to replace iron-based materials in the Internal Combustion Engine (ICE), but itself is a poor alternative because of its inappropriate wear resistance. For this reason, it is needed to alloy some elements to aluminum in order to increase the wear resistance, strength and fracture toughness, high specific rigidity, good thermal and electrical conductivity. Silicon can be alloyed to aluminum to increase the strength of aluminum thanks to a separate hard phase which is formed in the aluminum matrix [4].

 

 

Scientific approach and results obtained

 

The scientific approach used in this work was:

 

In first step base oil and fully formulated oil interactions with steel and aluminum alloy was investigated.

 

The additives that play a main role on tribofilm formation were identified (detergent). Specific tribotests were performed using detergents on steel-on-aluminum alloy contact. In order to approach the fully formulated results different binary combinations with two different types of detergents (salicylate and sulphonate), MoDTC, ZDDP and monoglyceride were also investigated. 

 

In this work all the tribological tests were performed in a mixed/boundary lubrication regime using a reciprocating-linear tribometer with ball-on-flat configuration.

 

Materials used in this work are used in the internal combustion engine (ICE). Steel was used mainly for comparison. For the steel-on-steel contact, AISI 52100 stainless steel specimens with mirror polish (Ra = 10 nm for flat samples and Ra = 30 nm for ball samples) commercially obtained were used. For the steel-on-aluminum alloy contact balls of AISI 52100 stainless steel and 2014 aluminum alloy flats provided by Mercedes-Benz HPE were used. The 2014 aluminum flat samples are polished to 0.1 µm diamond paste.

 

All the tribofilms were analysed by means of X-Ray Photon Spectroscopy (XPS), Transmission Electron Microscopy (TEM) combined to Energy Dispersive X-Ray spectroscopy (EDS), Raman spectroscopy and Time of Flight (ToF) Secondary Ion Mass Spectroscopy (SIMS).

 

 

 

Conclusions

After analysing the tribofilms obtained with different types of surfaces (Al alloy 2014 and AISI steel) using fully formulated and base oil as lubricant, one may concluded that:

 

  • Detergent plays a major role on the tribofilm formation in both cases;
  • In the case of a steel-on-steel contact, the tribofilm consists of a mixed Zn-Fe-Ca-P oxide with traces of S resulting from the anti-wear and detergent additives;
  • In the case of steel-on-aluminum alloy contact, the tribofilm consists of calcium carbonate (as revealed by XPS, Raman and TEM/EDS analyses) in both amorphous and crystalline (calcite) forms.

 

 

In the case of steel-on-aluminum alloy contact, the effect of adding two types of detergents to a base oil has been investigated and the following conclusions could be drawn:

 

  • Blends of base oil and sulphonate detergent result in similar tribological behaviour to that of fully formulated oil on aluminum surfaces;
  • Tribofilm formed using sulphonate detergent is much more homogeneous than that observed when using salicylate one.
  • Independently of the detergent used, both tribofilms consist mainly of amorphous and crystalline (calcite) CaCO3 as revealed by XPS and TEM/EDS.

 

When the different additives were added to detergents (salycilate and sulphonate), the tribological performance of detergent was not affected.

 

 

References

 

1.         Pereira, G., et al., A multi-technique characterization of ZDDP antiwear films formed on Al (Si) alloy (A383) under various conditions. Tribology Letters, 2007. 26(2): p. 103-117.

 

2.         Jiménez, A.E., et al., Surface interactions and tribochemistry in boundary lubrication of hypereutectic aluminium—silicon alloys. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2009. 223(3): p. 593-601.

 

3.         Chen, M., T. Perry, and A.T. Alpas, Ultra-mild wear in eutectic Al–Si alloys. Wear, 2007. 263(1–6): p. 552-561.

 

4.         Pereira, G., et al., Chemical characterization and nanomechanical properties of antiwear films fabricated from ZDDP on a near hypereutectic Al–Si alloy. Tribology Letters, 2005. 18(4): p. 411-427.

 

Educational Background

1. BSc. And MSc. In Physics Engineering, University of Aveiro, Portugal (2010)

  • BSc. thesis: Science Materials (thin films with magnetic properties characterization)

2. MSc. Physics Engineering, University of Aveiro, Portugal

  • MSc. thesis: Science Materials (thin films with electromagnetic properties characterization)

Research Area in ENTICE

Materials engineering (tribochemistry)

Other related research areas/specialization(s)

2 years experience in powder metallurgy

Institute

Laboratory of Tribology and System Dynamics, Ecole Centrale de Lyon

For more information contact Catia;   

E-mail:catia.podence-alves@ec-lyon.fr

Supervisors: Prof. Fabrice Dassenoy and Associate Prof. Clotilder Minfray

Monthly reports

Monthly reports are found here

Secondments

AMG Mercedes (UK)

 

Extended Summary

Context and objectives

Nowadays there is an increasing necessity of finding solutions for variety of troubling issues resulting from man-made contamination. Many of these problems cause long-term damages to the environment. Regarding this aspect a significant contribution is done by the automobile industries. In this way, automobile industry is making a big effort to reduce costs and to improve car design, increasing as well fuel economy and durability. Some studies have been made in order to reduce or replace the cast iron and steel content in engines; the idea consists in a reduction of weight [1-3]. Aluminum is a good candidate to replace iron-based materials in the Internal Combustion Engine (ICE), but itself is a poor alternative because of its inappropriate wear resistance. For this reason, it is needed to alloy some elements to aluminum in order to increase the wear resistance, strength and fracture toughness, high specific rigidity, good thermal and electrical conductivity. Silicon can be alloyed to aluminum to increase the strength of aluminum thanks to a separate hard phase which is formed in the aluminum matrix [4].

 Scientific approach and results obtained

 The scientific approach used in this work was:

In first step base oil and fully formulated oil interactions with steel and aluminum alloy was investigated.

The additives that play a main role on tribofilm formation were identified (detergent). Specific tribotests were performed using detergents on steel-on-aluminum alloy contact. In order to approach the fully formulated results different binary combinations with two different types of detergents (salicylate and sulphonate), MoDTC, ZDDP and monoglyceride were also investigated. 

In this work all the tribological tests were performed in a mixed/boundary lubrication regime using a reciprocating-linear tribometer with ball-on-flat configuration.

Materials used in this work are used in the internal combustion engine (ICE). Steel was used mainly for comparison. For the steel-on-steel contact, AISI 52100 stainless steel specimens with mirror polish (Ra = 10 nm for flat samples and Ra = 30 nm for ball samples) commercially obtained were used. For the steel-on-aluminum alloy contact balls of AISI 52100 stainless steel and 2014 aluminum alloy flats provided by Mercedes-Benz HPE were used. The 2014 aluminum flat samples are polished to 0.1 µm diamond paste.

 All the tribofilms were analysed by means of X-Ray Photon Spectroscopy (XPS), Transmission Electron Microscopy (TEM) combined to Energy Dispersive X-Ray spectroscopy (EDS), Raman spectroscopy and Time of Flight (ToF) Secondary Ion Mass Spectroscopy (SIMS).

 Conclusions

 After analysing the tribofilms obtained with different types of surfaces (Al alloy 2014 and AISI steel) using fully formulated and base oil as lubricant, one may concluded that:

  • Detergent plays a major role on the tribofilm formation in both cases;
  • In the case of a steel-on-steel contact, the tribofilm consists of a mixed Zn-Fe-Ca-P oxide with traces of S resulting from the anti-wear and detergent additives;
  • In the case of steel-on-aluminum alloy contact, the tribofilm consists of calcium carbonate (as revealed by XPS, Raman and TEM/EDS analyses) in both amorphous and crystalline (calcite) forms.

 In the case of steel-on-aluminum alloy contact, the effect of adding two types of detergents to a base oil has been investigated and the following conclusions could be drawn:

  • Blends of base oil and sulphonate detergent result in similar tribological behaviour to that of fully formulated oil on aluminum surfaces;
  • Tribofilm formed using sulphonate detergent is much more homogeneous than that observed when using salicylate one.
  • Independently of the detergent used, both tribofilms consist mainly of amorphous and crystalline (calcite) CaCO3 as revealed by XPS and TEM/EDS.

 When the different additives were added to detergents (salycilate and sulphonate), the tribological performance of detergent was not affected.

 Project outputs

 Two oral presentations:

            - 41st Leeds-Lyon Symposium, Leeds, UK, September 2014

            - STLE Symposium, Dallas, USA, May 2015

  • One poster presentation:

            - 42nd Leeds-Lyon Symposium, Lyon, France, September 2015

  • One paper is being prepared for submission.

 

References

1.         Pereira, G., et al., A multi-technique characterization of ZDDP antiwear films formed on Al (Si) alloy (A383) under various conditions. Tribology Letters, 2007. 26(2): p. 103-117.

2.         Jiménez, A.E., et al., Surface interactions and tribochemistry in boundary lubrication of hypereutectic aluminium—silicon alloys. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2009. 223(3): p. 593-601.

3.         Chen, M., T. Perry, and A.T. Alpas, Ultra-mild wear in eutectic Al–Si alloys. Wear, 2007. 263(1–6): p. 552-561.

4.         Pereira, G., et al., Chemical characterization and nanomechanical properties of antiwear films fabricated from ZDDP on a near hypereutectic Al–Si alloy. Tribology Letters, 2005. 18(4): p. 411-427.

 

Entice logo  

European Union logo  

Marie Curie logo  

 
 

Site Navigation

 

Research Partners

University of Leeds Ecole Centrale LyonUniversity of Ljubljana Mercedes-Benz Act Research Total SKF 


- Designed and © by Potassium Web - Administrative log in -