CETR Adhesion Testing on Glass/Al Surface for Corning Inc.

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Christiana Adela Anthony
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1 CETR Adhesion Testing on Glass/Al Surface for Corning Inc. I. Introduction 1.1 Objective The goal of the study was to differentiate stiction from various glass composites and surface treatments using the Advanced Micro-Tribometer. 1.2 Equipment - The Universal Micro-Tribometer The Universal Micro-Tribometer can be used extensively for tribology and materials research applications from macro- to micro- scale. The photo of the Micro- Tribometer model UMT is shown in photo 1. It is widely used for petroleum, lubricant, coatings, MEMS, electric contacts, ceramics, papers, automotive, material surfaces, machine tools, and other industries. This universal, high precision and automated instrument can accommodate various ideal friction pairs like pin-on-disc, ball-on-disc, 4- balls, ring-on-block, disc-on disc. It can also mimic the real industrial assemblies like piston ring on cylinder, screw-in-nut, pin-in-chain, sliding and rolling bearings, shaft-inseal, etc. The UMT accommodates both upper and lower samples of practically any shape. Dimensions of samples can range from 0.1 mm to 200mm; larger sample sizes can be accommodated without major modification. UMT can provide rotational, translational, reciprocating motions with speeds ranging from 0.1 µm/s up to 10 m/s. The applied load is obtained using a close-loop feedback mechanism for stability and accuracy, and can be kept at constant or linearly increasing from as low as 1 milligram to as high as 50 kg. Temperature, humidity and air pressure can be controlled. It can measure numerous tribological parameters in-situ, including: - Friction force, torque and coefficient, - Normal force (applied load and adhesion/stiction), - Wear depth and wear rate, - Acoustic emission, - Contact electrical resistance or capacitance, - Digital video with magnifying optics, - Temperature. LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 1

Photo 1. Micro-Tribometer model UMT-2. 1.3 Samples and testing procedures Corning provided Glass samples of 5 x5 and Aluminum table of 6 x6 for the glass/ Al adhesion study.

2 Photo 1. Micro-Tribometer model UMT Samples and testing procedures Corning provided Glass samples of 5 x5 and Aluminum table of 6 x6 for the glass/ Al adhesion study. Digital photo of glass sample was taken and shown in photo 2. The adhesion study set-up is shown in Photo 3. In the adhesion test, glass surface was used as a moving upper specimen and Al table was used as a stationary lower specimen. The upper specimen was lowered onto the lower specimen until the normal load reaches 1 N. The normal load was kept constant for 1 minute. Then the upper specimen was pulled up with a speed of 0.5 mm/s. Adhesion force was measured using CETR proprietary strain-gauge sensors. Its maximum at the moment of separation of the surfaces was recorded as the adhesion criteria. Nine samples, 17-1 to 17-9 were tested, first four samples were repeated three times. In addition, sample 17-4 was used for a load varying adhesion test, in which the test was repeated with various normal loads, 1 N, 3 N 5 N and 10 N. Furthermore, Tencor profiler data were taken for samples 17-2 and 17-4 to study flatness of surfaces. LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 2

3 Photo 2. Glass sample provided by Corning Inc. Photo 3. Setup for adhesion measurements. LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 3

4 II. Test results Summarized results of samples 17-1 to 17-9 are shown in table 1 and plotted in column format in figure 1. Sample 17-5 has the highest adhesion force, followed by samples 17-7 and Sample 17-3 had the lowest adhesion. Raw data plots are attached at the end of the report. Sample AdhesionForce (N) Run 1 Run 2 Run 3 Average σ Table 1. Summarized results of adhesion test. Bar Chart of Adhesion Force (Normal Load: 1 N) Adhesion Force (N) Sample Figure 1. Bar chart of adhesion test data. LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 4

5 Load varying in adhesion test Normal load is an important parameter in performing adhesion test. Higher normal load leads to a larger contact area, which in turn, increases the adhesion force. A load varying adhesion test was performed to check the statement above. Results of testing are summarized in table 2 and figure 2. Indeed, with a ten-fold increase in normal load, adhesion force increased almost three folds. Applied Normal Load (N) Adhesion Force (N) Run 1 Run Table 2. Summarized results for the load varying adhesion test Adhesion Test with Varying Normal Load Adhesion Force (N) Run Normal Load (N) Run 1 Figure 2. Adhesion force versus normal load plot for sample LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 5

6 Tencor profilometer data CENTER FOR TRIBOLOGY, INC. Flatness is an important parameter in performing adhesion test. As flatness affects contact area between surfaces, it has direct impact on stiction. Tencor profiler data of samples 17-2 and 17-4 are shown in figures 3 and 4 respectively. Obviously, sample 17-4 is significantly less symmetric than sample It might well be responsible for the lower adhesion force measured on sample Figure 3. Tencor profiler data for sample LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 6

7 Figure 4. Tencor Profiler data for sample LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 7

8 III. Conclusions (1) The adhesion measurements obtained with the Advanced Micro-Tribometer were very repeatable. (2) The Advanced Micro-Tribometer was proven to be capable of differentiate stiction from various glass samples. (3) Adhesion force was found dependent upon normal load. The higher is the load applied, the larger is the resultant adhesion force. (4) Flatness could be responsible for the lower adhesion force measured on sample (5) Humidity and temperature impact adhesion test results. Further investigation is necessary. Evidently, the Advanced Micro-Tribometer utilized in this study is sufficient to perform adhesion test for glass/al surfaces in R&D, QA or FA mode. CETR will gladly support Corning in their product testing, by providing both laboratory support and most advanced testing equipment. In the future, when any special piece of test and measurement equipment will be required, CETR will be happy to either modify the Micro-Tribometer or to develop new custom testers. Director of Tribology Applications Application Engineers Dr. Charles Gao Neil Nguyen Michelle Lam LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 8

9 Sample 17-1 Run 1 Sample 17-1 Run 2 Sample 17-1 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 9

10 Sample 17-2 Run 1 Sample 17-2 Run 2 Sample 17-2 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 10

11 Sample 17-3 Run 1 Sample 17-3 Run 2 Sample 17-3 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 11

12 Sample 17-4 Run 1 Sample 17-4 Run 2 Sample 17-4 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 12

13 Sample 17-5 Run 1 Sample 17-5 Run 2 Sample 17-5 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 13

14 Sample 17-6 Run 1 Sample 17-6 Run 2 Sample 17-6 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 14

15 Sample 17-7 Run 1 Sample 17-7 Run 2 Sample 17-7 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 15

16 Sample 17-8 Run 1 Sample 17-8 Run 2 Sample 17-8 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 16

17 Sample 17-9 Run 1 Sample 17-9 Run 2 Sample 17-9 Run 3 LEADERS IN TRIBOLOGY TEST INSTRUMENTATION AND SERVICES 17

XRAY Series Includes

XRAY Series 2 Finger 1250N, 2200N, 2500N, 4400N XRAY Series Includes XRAY 1250 XRAY 1250 LBR XRAY S 2200 Tandem XRAY 1250 Tandem XRAY S 2200 XRAY Applications: An XRAY S is used to handle a transmission