My Ph.D. Thesis - What's it all about?

( or 'Compacted Oxide Layer Formation under Conditions of Limited Debris Retention at the Wear Interface during High Temperature Sliding Wear of Superalloys')

 Mackem_Beefy (or just call me "Ian"!!!)

Ian A. Inman

   ●   What is a Ph.D.?

●   My Ph.D. - what's it all about?

●   My Ph.D. Viva Voce (Exam) ●   Journal and Conference Papers

My Ph.D. Thesis - what's it all about?

So why have I placed my Ph.D. Thesis on the Internet?   As well as this website being meant as a guide to potential students and their friends and relatives, I also have this huge volume of work with lots of information and the purpose of a Ph.D. Thesis is to carry out an experimental programme with the specific aim of adding something new and original to the knowledge database.   Since I passed my oral exam (viva voce) on 3rd March 2004, it dawned on me that the information is just sitting there gathering dust, so I though why not put it somewhere other researchers can make use of it.   Also, people doing a similar document can get a look at it, see how it's structured and probably pick up a few hints for their own work.   So here it is - if you're a non-academic, this is probably where you switch off and return to my main page.

To make things a little easier to follow, I've grouped all the related files into three self-explanatory sections:

Simon, if you're reading this (I know this page is one of the first things that crops up on looking for 'Incoloy MA956' for example), I know you think I'm nuts or sad for doing this (you commented about this back at Northumbria).   This we can discuss in Salford in that pub where Karl Marx and Joseph Engels used to drink.   Ah yes, 'The Crescent', formerly and appropriately 'The Red Dragon'.

The thesis

To summarise, my thesis is about what happens if you slide two metals (Superalloys such as Nimonic 80A and Incoloy MA956 as 'samples' against Stellite 6 and Incoloy 800HT as 'counterfaces' or opposing surfaces) against each other at varying conditions of speed (0.314 m.s-1 and 0.905 m.s-1) and temperature (room temperature to 750oC).   Potential applications for this information are aerospace (though the Superalloys used are a little 'heavy' for this purpose), power generation and (as emulated during the test programme) car piston valve-on-value seat wear.

Click on the links following to access the relevant sections - the PDF files linked to will open in separate windows.   PLEASE NOTE DOWNLOAD TIMES FOR A SLOW LINK CAN BE LONG - IF NOTHING SEEMS TO BE HAPPENING (WITH NO INDICATION OF A BROKEN LINK), PLEASE BE PATIENT - especially if you're still using dial-up or you've a slow mobile broadband link.   Note that I've converted all the information to Adobe PDF format - you can download the Adobe Reader program (completely free courtesy of Adobe) from here.

A brief overview and summary of the wear studies conducted.

  • Complete Thesis

(A paperback version of the thesis can be purchased for $29.95 (at least it was that price the last time I looked) from   Any money I receive from the paperback version will be donated to an animal refuge near where I live.   For reference, this is Bryson's Animal Refuge in Eighton Banks near Gateshead in Tyne and Wear, England.)

  • Contents

This section is self-explanatory, containing the contents and also lists of figures and tables in the thesis.   The "Abstract" can also be found immediately following the "Contents".

  • Introduction, Literature Review, Introduction to Current Investigation

The main part here is the "Literature Review", which covers basic friction theory, adhesion, abrasion, third body wear, glaze (compacted oxide) formation during high temperature sliding wear, the Superalloy materials (Stellite 6, Incoloy 800HT, Nimonic 80A, Incoloy MA956) used in current investigation, wear of alloys with second phase and relevance to current investigation (i.e. carbides within Stellite 6, or oxide dispersion phases in Incoloy MA956).

  • Methodology

The 'Methodology' looks at the actual wear configuration used ('block-on-cylinder') and the characterisation methods (SEM, TEM, STM, micro- and nano-hardness, etc.) used on the generated wear surfaces.

  • Results - Wear, Characterisation and Related Data

Effects of wear at sliding speeds of 0.314 m.s-1 and 0.905 m.s-1 between room temperature and 750oC after 4,522 m (and 13,032 m at 0.905 m.s-1) for Nimonic 80A and Incoloy MA956 as sample materials, when slid against either Stellite 6 or Incoloy 800HT as counterface materials.  

In depth studies include:

  1. Examination of the Nimonic 80A versus Stellite 6 sliding system at varying distances up to 4,522 m at 0.314 m.s-1 and temperatures of 510oC and 750oC, also reversal of sample and counterface and replacement of Nimonic 80A as a sample material with Nickel 200TM (effectively taking chromium out of the way).

  2. Nimonic 80A versus Incoloy 800HT and Incoloy MA956 versus Incoloy 800HT, with reciprocation switched off at 0.314 m.s-1 and 510oC.

  3. Nano-scale studies, including nano-hardness, TEM studies and STM.

Note that the downloading of this file will take a while if you have a slow internet connection.   If you're on dial-up, I suggest you go for a half hour walk!!!

  • Discussion of Results

Discussion of the data and information collected and the use of it to create mini-wear maps for each combination.   Also discussion of nano-data with respect to glaze formation.

  • Conclusions / Summary

Even the "Conclusions / Summary" section is sizeable and requires a reasonable supply of coffee - effectively a summary of all the above if you don't have time to go through all the information.  

  • Further Work

The "Further Work" section includes suggestions for extensions to the nano-scale work, plus possibly adding controlled amounts of aluminium to Incoloy MA956 to study diffusion effects and testing of pure metals and alloy compositions without minor alloying components, to ascertain the exact effect of each individual alloying component.

  • References

The "References" section, as suggested by the title, lists other work referred to in the theses.  


"Appendix 1" (added unofficially in early 2006) also lists journal articles directly related to the research (some of it published after the thesis), plus closely related publications by other authors.   There's also an e-mail link within this file for anyone wanting to contact me!!!

If anyone wished to refer to this thesis in their own work, the reference should take the following format:

[1] I.A. Inman – “Compacted Oxide Layer Formation under Conditions of Limited Debris Retention at the Wear Interface during High Temperature Sliding Wear of Superalloys”, Ph.D. Thesis, Northumbria University (2003).

The extra bits that were withdrawn

As with any thesis, there are always bits that are removed or left out to stop the thesis getting too big and unwieldy - my little effort (at 20 pages for contents and abstract, plus 344 pages for the actual thesis and two extra pages for the unofficial "Appendix 1") was no exception.   So here's some of the best bits that were taken out (again, clicking 'Back' on your browser will return you to here)...

A little extra on the incremental sliding distance tests I did - various distances up to 4,522 m - with the Nimonic 80A versus Stellitie 6 wear combination, with comments on extra testing at room temperature and 630oC added to that covered in the thesis at 510oC and 750oC.

Reversal of sample and counterface work carried out for the Incoloy MA956 versus Stellite 6 combination at 0.314 m.s-1 and 510oC, adding to that carried out in the main thesis for Nimonic 80A versus Stellite 6.

References to this should be done as follows:

[1] I.A. Inman – Unpublished Work, Northumbria University (2003).


One other file you might want to know about is:

Complements the Nimonic 80A versus Stellite 6 sliding wear studies, looking at the sliding wear of Nimonic 80A against itself ('like-on-like' sliding, meaning both sample and counterface are Nimonic 80A) at 750oC and sliding speeds of 0.314, 0.405, 0.484, 0.654 and 0.905 m.s-1, over a distance of 4,522 m.   The objective is to alter the chemistry of the oxides generated by taking away the Stellite 6 counterface (especially at lower sliding speed) and see how this affects 'glaze' formation.

I'm not sending this to a journal, as the necessary characterisation work needed to turn it into a full paper hasn't been completed.   However, if you wish to take a look, go right ahead; this document is freely distributable.

References to this should take the following form:

[1] I.A. Inman – "High Temperature ‘Like‑on‑like’ Sliding of Nimonic 80A under Conditions of Limited Debris Retention", Unpublished Work, Northumbria University (2003).


Associated papers

The papers following are based on the practical work for the main thesis.   Using the thesis as the core work, the data builds on it and takes the theory a little further.   For example, the wear maps mentioned are only fully developed and the effect of oxide chemistry on 'glaze' formation is only properly considered in the papers written following the thesis.   I'm not supposed to do this hence the white / invisible text, but clicking on the paper titles below in blue will allow you to download the papers (bar the work from Birmingham - seriously confidential!).





Journal or Publication

2011 I.A. Inman, P.K. Datta Studies of High Temperature Sliding Wear of Metallic Dissimilar Interfaces IV: Nimonic 80A versus Incoloy 800HT Paper Tribology International 44 (2011) 1902–1919


I.A. Inman, P.K. Datta

Studies of High Temperature Sliding Wear of Metallic Dissimilar Interfaces III: Incoloy MA956 versus Incoloy 800HT


Tribology International 43 (2010) 2051–2071


I.A. Inman, P.S. Datta, H.L. Du, C. Kubel, P.D. Wood

“High Temperature Tribocorrosion”, in: T. Richardson, B. Cottis, R. Lindsay, S. Lyon, D. Scantlebury, H. Stott and M. Graham (Eds.), Shreir's Corrosion – VOL 1: Types of High Temperature Corrosion, Elsevier Ltd.

Book chapter (review)

Elsevier (February 2010)


I.A. Inman, P.S. Datta

"Development of a Simple ‘Temperature versus Sliding Speed’ Wear Map for the Sliding Wear Behaviour of Dissimilar Metallic Interfaces II"


Wear 265 (2008) 1592–1605 


I.A. Inman, S.R. Rose, P.K. Datta

Studies of High Temperature Sliding Wear of Metallic Dissimilar Interfaces II: Incoloy MA956 versus Stellite 6


Tribology International 39 (2006) 1361-1375 


I.A. Inman, S.R. Rose, P.K. Datta

Development of a Simple ‘Temperature versus Sliding Speed’ Wear Map for the Sliding Wear Behaviour of Dissimilar Metallic Interfaces


Wear 260 (2006) 919-932


I.A. Inman, P.K. Datta, H.L. Du, Q Luo, S. Piergalski

Studies of high temperature sliding wear of metallic dissimilar interfaces


Tribology International 38 (2005) 812-823


H.L. Du, P.K. Datta, I. Inman, E. Kuzmann, K. Suvegh, T. Marek, A. Vertes

Investigations of microstructures and defect structures in wear affected region created on Nimonic 80A during high temperature wear


Tribology Letters Vol. 18, No. 3, March 2005, 393-402


I.A. Inman, H.L. Du in conjunction with University of Birmingham

“The effects of pre-oxidation on the high temperature wear of gamma‑TiAl” (confidential and not downloadable)


Unpublished - some of the data appeared in "High Temperature Tribocorrosion" in 2010.


I.A. Inman

"High Temperature ‘Like‑on‑like’ Sliding of Nimonic 80A under Conditions of Limited Debris Retention"

Short report

Northumbria University (2003) - Freely Distributable.   Click here for a description.


H.L. Du, P.K. Datta, I.A. Inman, R. Geurts,  C. Kubel

Microscopy of wear affected surface produced during sliding of Nimonic 80A against Stellite 6 at 20oC


Materials Science and Engineering A357 (2003) 412-422



I.A. Inman, S. Datta, H.L. Du, J.S. Burnell‑Gray, Q. Luo, S. Piergalski

Microscopy of glazed layers formed during high temperature sliding wear at 750oC



Wear 254 (2003) 461-467


References to the above should be done as 'authors' then 'title' then (from the last column on the right) 'journal information'.   Cutting and pasting in that order should give you a complete reference to stick in your 'References' or (if you want to make it sound posh) 'Bibliography'.

'Wear'. 'Tribology International' and 'Materials Science and Engineering A' are all accessible via the 'Science Direct' website run by Elsevier - a simple author search should get you to the papers.   'Tribology Letters' is accessible via the 'Springer' website, which is not easy to navigate around - find the appropriate edition of the journal first then search only that edition.

By now, you'll be just about falling asleep with all this boring stuff, so this is where I'll sign off, call it a day and get on with the rest of my (wear / thesis free) life.   If you're not asleep and want to know more, there's always e-mail.   That's happened a few times with some very strange, weird and sometimes amusing material making it to my inbox (I don't need a stock broker, I don't want to help someone move money out of a West African bank account, I don't want a business partner in China, I don't need a Viagra substitute and I definitely don't need a penis enlargement!!!).   I'll e-mail from my proper address to any genuine people out there who want to contact me.


Many regards and all the best,


Ian, alias 'Mackem_Beefy' (Ian A. Inman)

   ●   What is a Ph.D.?

●   My Ph.D. - what's it all about?

●   My Ph.D. Viva Voce (Exam) ●   Journal and Conference Papers