AFM Nanoindentation as a Method to Determine Microhardness of Hard Thin Films

Abstract

This paper presents experimental and analytical studies of AFM nanoindentation as a method to determine microhardness of hard thin films. Indentations are performed on Au, Si, and DLC using triangular pyramidal diamond probes to determine microhardness. We examined the effects of indentation force and three different methods to measure the indentation area (direct area measurement for a triangular indentation, size analysis of an inverted AFM image of the indentation, and prediction of area from indentation depth based on a tip shape function). The responses are indentation depth, projection area, and microhardness. Relationship of responses with indentation force is examined. At a low depth range, microhardness based on pyramidal shape function is erroneously higher than the other two methods. However, all three methods generally agree with each other when indentation force exceeds 16μN. Size analysis of inverted images gives more consistent microhardness with the least variability over the whole force (4∼30μN) or depth (0.5∼70 nm) range. Tip shape models are developed to predict microhardness. The ellipsoidal tip model is a good approximation at low depth ranges, while the pyramidal model works better for deeper indentations. The force vs area curves are also significantly nonlinear which can distort the hardness measurements.

Effect of storage solutions on microhardness of crown enamel and dentin

“…However, in this study, hardness of enamel was 177 HV at the end of the 1-year storage in de-ionized water [ Table 1 ], in spite of the fact that nanoindentation hardness is about 10–30% greater than the microhardness. [ 16 17 ] This catastrophic hardness loss observed by Habelitz et al . [ 3 ] as quickly as 2 weeks, can be explained by the submerging of the exposed tissue slices into the storage solutions.…”

Elastomer Application in Microsystem and Microfluidics

“…Indentation technique was first introduced as advent of indentation fracture mechanics 22 in 1975 and ever since it has been developed for characterization of elasticplastic materials using the Oliver-Pharr's method 23 . No valid method was reported for polymer nanoindentation analysis based on stress-strain experiments until the viscoelastic model was proposed in 2004 and other emerging studies that followed 8,24,25 . Because of viscoelasticity, elastic-plastic model cannot be directly used to derive modulus and hardness.…”

Evaluation of the Properties of Thermodifusion Zinc Coating of Couplings of Pump-Compressor Pipes Produced by «ksp Steel»

“…The test was carried out in accordance with the requirements of GOST 9.302 and the technological regulations of the enterprise (Technological regulations "Thermal diffusion galvanizing of couplings"). Microhardness was measured in accordance with GOST 9450 (Bao, 2011) according to the factory method on a Shimadzu HMV-2 series device (PA «KSP Steel» LLP). The microstructure of the coatings was determined according to GOST 5640 on polished, polished and etched with 4% alcohol solution of HNO 3 microsections, which were studied at a magnification of × 60 to × 1000 on an Olympus ВХ51М microscope (Elkoca, 2015).…”