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WEAR NEWS

VIEWS: 28 PAGES: 6

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									                                    WEAR NEWS
   Volume 4, Number 3                                                                 Spring 2007



Wear of Material Conference
                                                                  It is becoming common to nitride ferrous
The fifteenth Wear of Materials (WOM)                              surfaces that are to receive a hard PVD
Conference was held from April 15th to 19th, 1007                  coating (for better support).
in Montreal, Canada. The conference is focused                    A MEMS system can be used to supply
on the materials science aspects of tribology as                   as-needed lubrication for bearings used in
opposed to the chemical aspects and mechanisms                     space.
of lubrication..                                                  Tetragonal zirconia is more scuffing
                                                                   resistant then cubic zirconia.
The 2007 WOM attracted over 300 delegates from                    A lubricating ball mill is the good “high-
32 countries. There were 196 oral presentations                    stress” abrasion test.
and 59 poster presentations. An exhibit of wear                   Transferred wear films/particles can be
testing and metrology equipment was coupled with                   termed nanolayes(to help funding).
the poster presentation.                                          Ceramic/ceramic couples can survive if
                                                                   the surfaces are laser treated.
Adhesive wear seemed to be the most popular                       Some tribology researchers still think that
subject for papers followed closely by fretting.                   a material (rather than a mating
Other popular topics were PVD coatings, plastic                    couple/tribosystem) can have a coefficient
wear, and abrasive wear. The most widely                           of friction.
discussed “material” appeared to be cemented                      There is a new type of computer modeling
carbide.    One speaker commented that this                        for wear systems that is different from
material has been in commercial use for about 90                   FEM or molecular/atomic modeling; it is
years and it is still being researched. Another                    called a “cellular automation model”.
speaker made the statement that from 10 to 15,000                 Brake materials can be ranked by a
man (people) years have been expended                              frictional heating parameter derived from
researching PVD coating. Thus the conference                       a bench test.
conformed the we still do not an understanding of                 Brake materials are now filled with steel
some widely used material technologies.                            chips and ferrous powder so they corrode
                                                                   badly when used on salted roads.
So what was new in materials for wear                             Brake noise is the highest warranty
applications? The answer, of course, is a matter of                problem for US car manufactures.
opinion, but the following were some “new to me                   WC/Co materials need to be tested wet if
items.”                                                            they are to be used wet; water readily
                                                                   attacks the cobalt.
      There is a chemical etch for UHMWPE                        The ASTM B611 high stress abrasion test
       that reveals the crystallite size and degree                for cemented carbides correlate with the
       of crystallinity.                                           ASTM G65 sand abrasion test, but B611
                                                                   wear rates are 10 times G65 wear rates.



                                                      Page 1
     Protective films from oil antiwear additives                        conference       (in     1997)      was
      like ZDDP preferentially form on the                                recognized for his thirty years of
      pearlite phase of cast iron.                                        continual participation.            The
      Lateral “jets” that accompany impinging                            Ludema Award for Best Paper was
      water droplets have much higher velocity                            initiated for use at future
      (and tendency for damage) than the                                  conferences. The next WOM will
      impinging droplet.                                                  be in LasVegas in 2009. Let’s hope
     Rotating cathodes minimize droplets in arc                          that it will be as great as this one.
      sputtered PVD coatings.
     Twenty to thirty percent of the cost of                    Ken Budinski
      machining is the cost of the coolant (thus                 Bud Labs
      the interest in dry machining).
     The ball cratering test works better if the             Symposium on Wear and Friction Test
      ball is roughened to help entrain abrasive.             Methods for Coatings and Surface Treatments
     Abrasion of ceramics occurs by cracking
      and spalling.                                           The        spring      meeting     of       the
                                                              ASTM Committee G2 Committee on wear and
There were four keynote speakers at the                       erosion included a one-day symposium on testing
conference:                                                   coatings and surface treatment. The following
                                                              are my ruminations of the 14 papers presented.
   Day 1: Flow and mechanical mixing in wear                  The symposium was co-chaired by Steve Shaffer
          surface layer                                       (battelle) and Peter Blau (Oak Ridge National
          (Dave Rigney, Ohio State University,                Lab).
          USA)
                                                                    Prospects for Adopting Current ASTM
   Day 2: Structure and properties of brake                          Wear and Erosion Tests for Bulk
          materials                                                  Materials in Coatings, Thin Films, and
          (Peter Filip, Southern Illinois                            Surface Treatments (Peter Blau) – Peter
          University, USA)                                           performed a Goggle survey on hits of
                                                                     ASTM standards to see which are most
   Day 3: Superhardness nanocomposites for                           cited (used). It was determined that the
          cutting tools                                              G65 sand abrasion test was the most
          (S. Veprik, Technical University,                          (popular wear test) followed by pin-on-
          Munich, Germany)                                           disk G99 followed by G32 cavitation and
                                                                     G76 solid particle erosion. The other G2
   Day 4: Tribology for space applications: In                       tests were cited less by at least an order of
          situ on-demand lubricant coatings                          magnitude. Peter suggested a guide on
          (K. Adoche, Tohoka University,                             using these tests and that we should
          Japan)                                                     diminish the use of mass change in wear
                                                                     testing.
   Overall, this WOM was one of the best
           attended. The venue was great; the                       Microtribological  Investigation  of
           weather horrendous (snow); the food                       Lubricant Films and Surface Coatings
           was great; the fellowship and                             under Ultra Loss Contact Pressures
           technical sharing was excellent. Ken                      (Nick Randall, CSM) – Nick described
           Ludema, the originator of the                             tribometer tests on self-assembled


                                                     Page 2
    monolayer coatings (SAM’s) on silicon.                      dust which leads to abrasion.  The
    They compared two SAM’s and                                 winning coating was a resin-bonded
    determined one to be more humidity                          fluorocarbon.
    sensitive than the other. A second test
    program was described that showed that                     Preparation of Thermal Sprayed Nano
    there was a minimum optimium film                           Structured Al2O3/TiO2 Coatings and its
    thickness that produced the lowest system                   Abrasive Wear Properties (Yang, et al
    friction with mineral and synthetic                         authors, presented by H. Tran) – The
    lubricants.                                                 authors described a novel thermal-spray
                                                                material that has nanoparticles making up
   Evaluating Friction and Wear of                             the aggregate particles that are sprayed
    Coatings Under High Contact Pressure                        and a substitute. A patented process was
    (Greg Dalton, Tribsys Corp) – Greg                          developed to perform the agglomeration.
    described his twist/compression test which                  The specific consumable discussed was
    is like the ASTM G98 galling test, but uses                 13% Al2O3/TiO2. It has better wear
    a larger annulus on sheet metal to analyze                  resistance and fracture toughness than its
    for galling of coated sheet versus tooling.                 non-nano competitor.
    Friction coefficient change is used as the
    test metric; the friction force (COF) spikes               Measurement of the Resistance of
    at the onset of galling. Other studies on                   Treated Metal Foils to Scrubbing
    surface resistance were not successful in                   Abrasion        Using      a      Modified
    pinpointing the start of galling                            Reciprocating Wear Test (Peter Blau,
                                                                ORNL) – Peter described using the Plint
   Effect of High Pressure Hydrogen                            reciprocating wear tester to scrub various
    Exposure to Surface Properties of Tool                      types of Scotch Brite™ pads on stainless
    Steels (Peter Blau) – Peter described a                     steels with various treatments. The 10-
    study conducted to see if high pressure H2                  point height (Rz) of the test surfaces after
    from a hydrogen vehicle engine will have                    rubbing was used as the test metric.
    any adverse effects on the tribological                     Ferritic nitrocarburized surfaces were the
    properties of steels that may be used in                    most scratch-resistant.
    such an engine. Tool steel test samples
    were incubated at 300o C, 300 Bar for                      Wear Behavior of W-DLC Coating
    extended times then subjected to G133-                      Under Reciprocating Sliding Motion
    type reciprocating wear tests.       These                  (R.J. Lise, Caterpiller Corp) – This talk
    preliminary tests suggest that hydrogen                     described techniques to address the issue
    exposure may reduce scuffing tendency.                      that the flat worn or a ball in a ball-on-flat
                                                                test is not really flat and calculation of
   Wear and Friction of Hard and Soft                          wear volume is not as simple as taking a
    Lubricious Coatings in Dry Sliding for                      sector of a sphere. The author described a
    Use in Small Arms Action Components                         3-D profilometry system that produces
    (Steve Shaffer, Battelle Columbus) –                        more accurate results.
    Steve    described     reciprocating    and
    continuous sliding tests on “dry” lubricant                A Study of Thin Coating Wear in High
    coating for actuators in machine guns.                      Density Tape Heads. (The paper was
    There was a need to lubricate guns with                     authored by B. Shi, et al at Aston
    something other than oils since they attract                University, UK and presented by Nick


                                                   Page 3
    Randall, CCM) – This paper described                         indicated by COF increases, sometimes
    wear studies of thin coatings on magnetic                    by acoustic emission, sometimes by
    tape heads. The wear tester was a reel-to-                   electrical resistance.     CETR ha a
    reel tape drive with a head/anvil test                       tribotester that monitors these factors at
    station. The tests yielded wear/ friction                    the same time. CETR also offers a new
    data for chromium oxide that was used to                     tester that can do AFM imaging,
    predict that the coating would last for 12                   nanoscratch and stiffness mapping of
    hours of continuous use in a normal tape                     surfaces.
    recorder.
                                                                Tribological Behavior of Electroplated
   Investigation of Friction and Wear in                        and Thermal Sprayed Coatings Tested
    the MESO Normal Force Range on DLC                           in an Instrumented Rubber Wheel
    and TiN (D. Dries et al, Falex, presented                    Abrasion Test (O. Maranho, et al,
    by Mike Anderson , Falex) – This paper                       presented by S. Shaffer) – The authors
    described using the Falex “MUST”                             instrumented the ASTM G65 sand
    tribotester for reciprocating ball-on-plane                  abrasion test to measure friction and the
    tests of TiN and DLC coatings. They                          modified machine produced good
    essentially use the area of friction loops (a                reproducibility on coating tests. They
    force/time plot of one forward and back                      believe that measuring the coefficient of
    stride) as the test metric. Their results                    friction in these tests will provide a better
    indicated that surface roughness plays a                     understanding of abrasive wear.
    significant role in this type of test and DLC
    is sensitive to humidity and TiN is not (vs              Overall, the symposium was comprehensive
    Si3N4 and Al2O3).                                        in the scope of tests used on coatings and all
                                                             of the talks offered something of value to
   Coriolis Effect Testing of Thick                         attendees. The discussion was lively; the
    Coatings, (Harry Tran, GIW Industries)                   atmosphere was relaxed; the weather was
    – A very interesting erosion rig was                     perfect (but hot); and Peter Blau and Steve
    described that produces slurry jet and                   Shaffer are to be commended for their efforts
    parallel-flow erosion testing at the same                in making the symposium a success. An
    time using the coriolis effect. A slurry is              ASTM special technical publication will be
    pumped into a rotating bowl with four                    published with the papers (in print, I hope).
    tubes exiting from the bowl every 90o.
    Two test specimens are put in each tube,                 ASTM G2 Spring 2007 Meeting, June 20,
    one at the inlet, one at the outlet. The                 2007, Miami, Florida
    outlet Specimen can be angled for
    impinging jet studies. The specimen at the               Abrasive Wear Activities:
    start sees parallel flow erosion. They
    evaluated seven hardfacings and hard                     Steve Shaffer conducted the spring sub
    erosion-resistant materials.        HVOF                 committee meeting in Miami. The G75
    WC10Co4Cr was the winner.                                slurry abrasion test received a negative on the
                                                             re-approved ballot. Jim Miller negotiated the
   Comprehensive Mechanical Testing of                      withdrawal and the standard is re-approved.
    Hard Coatings, (Vishla Kosla, CETR) –                    The Jaw Crusher test standard and the
    Case histories were presented on coatings                gouging abrasion standard were up for re-
    showing that sometimes coating failure is                approval and they were re-approved in the



                                                    Page 4
spring 2007. G132 pin abrasion test and the
G171 scratch test need review for re-approval.              Friction Chair, Ken Budinski (Bud Labs),
                                                            presented a new standard on “Test for the
A new standard on use of the Taber Abraser                  measurement of the rolling friction
for abrasion testing was balloted and received              characteristics of a spherical shape on a flat
a negative.                                                 horizontal plane.” This test replaces the “golf
                                                            ball on a golf green” test. It is the same test,
Erosion Activities:                                         but allows application to a wide range of
                                                            revolute shapes. It was the consensus of the
The cavitation erosion standard G32 was re-                 members in attendance that the new standard
approved and a work item was registered for                 should be sent to the editorial subcommittee
the evaluation of erosion data using Weibul                 concurrent with round robin tests. Several
statistics. It was voted at the meeting to move             people offered to participate: Greg Dalton,
this work item to the Computerization                       Steve Shaffer, Scott Hummel. The test will
subcommittee G02.2. The G75 solid particle                  be a soft and hard ball versus a surface plate.
erosion test has been balloted and re-approved.             The standard will also be revised to reduce
                                                            emphasis on sports balls and reballoted.
Averal Rao (Power Tech) registered a new
work item to use sand in the water in the                   It was also the consensus to proceed with
vibrating horn cavitation test, G32, to simulate            another standard on friction energy
cavitating systems that contain sand. The                   dissipation.  Ken Budinski will draft a
meeting was chaired by Andy Phelps (UDRI)                   strawman for subcommittee ballot.
in the absence of Chair Paul Swanson.
                                                            Computerization in Wear Activities:
Non-abrasive Activities:
                                                            Chair, Greg Dalton, will investigate the
Scott Hummel described that new galling test                possibility of a friction reporting and galling
that was developed to address problems with                 workshop to concur with the spring 2008
stress concentrations with the G98 test. The                meeting at Falex.
annulus on a flat produces a significant stress
concentration. The new test rotates an annulus              Terminology Activities:
on an annulus (same shape) and uses multiple
tests (12) at each of six test loads. Scott will            Peter Blau chaired the terminology for Dave
move on to interlaboratory tests.                           Riley. He will take over the chairmanship
                                                            and review the terms in the proposed Taber
Mike Anderson (Falex) will revise and ballot                Abraser test.
the crossed cylinder test which was withdrawn.
Peter Blau will try to resolve a negative on the            Miscellany:
piston ring/cylinder wear test. Mike Anderson
is going to ballot a pin-on-disk test at the                New member benefit – all members can now
subcommittee level. Non-abrasive chair, Nick                have access to the ASTM Dictionary of
Randall (CSM) will monitor round robin tests                Engineering Science and Technology on line.
on a scratch-adhesion test for the C1624                    Terms defined in ASTM standards can be
scratch test.                                               reviewed and read at no cost.

Friction Activities:                                        Future Meetings



                                                   Page 5
November 7 & 8, 2007 University of Dayton
Research Institute (includes tour and training
workshops in Dayton, OH)

May 7 – 9, 2008 Falex Corporation, Sugar
Grove, IL (Chicago)

Subcommittee Chairs Advised to Improve
Illustrations – A number of our standards
contain blurred or obsolete or hand-drawn
illustrations.  Vice Chair, Peter Blau, is
requesting each subcommittee chair to review
their standards and “refresh” deficient
illustrations.

Membership Promotion Program – ASTM
is trying to increase membership by a
recruiting program.       If G2 wants more
members, ASTM will form a committee and
assign help to solicit membership.




*The information contained in this newsletter is meant to be an informal report of the proceedings of the G2 Subcommittee
meeting of Spring 2007 and in no way is meant to be construed as the approved official report of this meeting.

Comments and/or suggestions may be directed to kenbudinski@hotmail.com




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