Wear of Material Conference

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.

 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

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

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

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

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 [email protected]