Characterization, Testing, Measurement, and Metrology

Chander Prakash, Sunpreet Singh, J. Paulo Davim, Chander Prakash, Sunpreet Singh, J. Paulo Davim

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9780367275150
• eBook ISBN: 9781000193350
• Topic: Technology & Engineering
• Subtopic: Mechanics
• Index: Technology & Engineering

This book presents the broad aspects of measurement, performanceanalysis, and characterization for materials and devices through advanced manufacturing processes. The field of measurement and metrology as a precondition for maintaining high-quality products, devices, and systems in materials and advanced manufacturing process applications has grown substantially in recent years.

The focus of this book is to present smart materials in numerous technological sectors such as automotive, bio-manufacturing, chemical, electronics, energy, and construction. Advanced materials have novel properties and therefore must be fully characterized and studied in-depth so they can be incorporated into products that will outperform existing products and resolve current problems.

The book captures the emerging areas of materials science and advanced manufacturing engineering and presents recent trends in research for researchers, field engineers, and academic professionals.

1 Wear Measuring Devices for Biomaterials

Manoj Mittal

IKG Punjab Technical University Jalandhar

CONTENTS

1.1 Wear of Biomaterials: How It Is Different from Other Materials

1.2 Machines and Equipment for Biomaterials: Under Dry Conditions and in Simulated Body Environment Joint Simulators

1.2.1 Six-Station Rolling Sliding Tribo-Tester

1.2.2 How-Medica Biaxial Line Contact Wear Machine

1.2.3 Three-Axis Knee Wear Simulator

1.2.4 Fein Focus X-Ray Microscope and Fretting Wear Apparatus

1.2.5 Wear Testing Equipment

1.3 Conclusions

1.4 Future Scope

References

1.1 Wear of Biomaterials: How It Is Different from Other Materials

The failure of body implant may be due to wear of one of the joining parts in the body environment. The wear in the implant and surrounding bone may be abrasive, adhesive or fatigue. Some wear testing devices are used to simulate the wear in body environment. Using these wear testing machines, a highly accelerated wear environment (as compared to actual body environment) is created for a shorter time span than actual service life of implant. By doing so, the best suited implant material may be recommended by testing the same in laboratories (in vitro). Wear of biomaterials is measured using specially designed simulators. These simulators simulate actual body environment, and original body implants are tested in these machines for lakhs of cycles in a shorter time span than the actual life span of implant. This is done by highly increasing the number of cycles per unit time.

Knee simulator is one of the most complex wear testing devices, which tests actual knee prostheses, and is very costly. Some commercial equipment may cost as expensive as $200,000 or even more. Wang et al. (1999) and Blunn et al. (1991) have reported a comparatively less expensive substitute for knee simulators to examine materials used for knee replacement. Other simpler and inexpensive models for wear testing are pin-on-flat (Van Citters, 2004), pin-on-disc, flat-on-disc and cyclic sliding wear testing machines. Morks et al. (2007) utilized SUGA abrasion tester, which follows NUS-ISO-3 standards (Japan) for testing wear on bio-inserts; a similar wear testing machine is built to calculate the wear resistance of coated specimens by Mittal (2012).

The release of debris due to wear and subsequent tissue inflammatory response has emerged as a central problem, restraining the long-term clinical outcome of total hip replacements (Harris, 1995; MaGee et al., 1997; Wroblewski, 1997; Raimondi, 2001). The key wear mechanisms observed on retrieved knee prosthesis include delamination caused by surface damage of polyethylene, surface pitting, third body wear and adhesive wear (Blunn et al., 2009; Hood et al., 1983; Landy and Walker, 1988; Collier et al., 1991). Low conformity designs were found to be the cause of delamination (Engh et al., 1992), whereas in a relative conforming design, surface damage was found to be associated with entrapped acrylic particles (Hood et al., 1983). The damage may be because of the different kinematic conditions occurring at bearing surface (Blunn et al., 2009). Excessive sliding led to delamination wear, whereas rolling or cyclic loading at the same contact point resulted in minimal wear (Blunn et al., 1991).

Three body wear and production of polyethylene and metallic debris generally occur mainly at articulating joint; however, a little may occur at femoral stem. Mechanical stresses generated by patient on hip implant are supposed to be the foundation of the third body wear. There is a mixed response on the effectiveness of hydroxyapatite (HA) coatings in preventing third body wear. Several clinical studies have revealed that HA coatings had no adverse effects; however, other clinical studies have discovered excessive wear at the polyethylene surface due to the accumulation of calcium phosphate and metal particles due to third body wear (Sun et al., 2001).

Shearing micro-movements may take place at implant and bone interface due to a large difference in elastic modulus of two materials in contact. Insufficient initial fixation (problem in prosthesis design) or movement of limb (which sustains many stresses) in some course of time can also cause micro-movement (Fu, 1999; Walker et al., 1987; Riues et al., 1995). The oscillatory micro-movements at the contact induce fretting wear, fretting corrosion and sometimes fretting cracks, causing early failure of joint prosthesis (Hoppner and Chandrasekaran, 1994; Lambardi et al., 1989). In an investigation by Gross and Babovic (2002), abrasion resistance of coatings was ascertained with pin-on-disc arrangement under unlubricated conditions. A bone analogue made of wood, with φ6.3, was used as pin to simulate cortical bone in terms of hardness and elastic modulus. The result of the investigation showed a weight loss of coating and decrease in surface roughness, and main change in the surface characteristics occurred in first minute of testing (Gross and Babovic, 2002).

Coathup et al. (2005) inserted six different types of hip replacements (36 in total) into the right hip of skeletally mature female mule sheep and revealed that HA-coated implants were more effective than other uncemented and cemented implants in resisting progressive osteolysis along the acetabular cup–bone interface and also concluded the importance of the in-growth surface present on implant. HA-coated porous acetabular implants showed significant results in terms of bone contact and in-growth in the presence of wear debris and in the prevention of interfacial wear particle migration.

Kalin et al. (2003) studied the wear of the hydroxyapatite pins against glass-infiltrated alumina submerged in a static bath of distilled water at room temperature and reported that wear of hydroxyapatite pin against glass-infiltrated alumina occurred primarily by fracture and deformation. The hydroxyapatite wear particulates are mixed with wear products from glass infiltrate in alumina and water to form an intermediate surface layer. Because of this adhered debris layer, steady-state wear is more appropriately described as three-body wear as opposed to two-body wear. Pin-on-disc experiments with HA pins and glass-infiltrated alumina (in-Ceram alumina) conducted by Kalin et al. (2002) showed that the wear volume of HA increased as surface roughness of glass-infiltrated alumina and load was increased, while for a given surface roughness value, the wear factor remained independent of load. Furthermore, polished glass-infiltrated surface showed no evidence for material transfer at low load, whereas mechanical wear with removal of glass infiltrate was observed at higher loads.

Morks et al. (2007) investigated the role of arc current in plasma spray technique on abrasion behavior of coatings and reported that with an increase in arc current, the abrasion resistance of HA coating increases mainly due to the increase in hardness of coating. The resistance to abrasion wear was found to be dependent on coating thickness because the abrasion wear resistance increased as the thickness of HA coating becomes less than 30 μm due to the increase in hardness of thin HA coatings. Morks and Kobayashi (2006) studied the dependence of gas flow rate on plasma-sprayed HA coatings and reported that HA coatings sprayed at high flow rates exhibit higher abrasive wear resistance compared to those sprayed at low gas flow rate due to higher cohesion bonding among the splats and low porosity.

The wear resistance of HA can be enhanced by reinforcing the secondary phase to HA to produce composite coatings. Several researchers have used various reinforcement materials such as silica (SiO₂), titania (TiO₂) (Morks, 2008), alumina (Al₂O₃), zirconia (ZrO₂), carbon nanotubes (CNTs), diamond-like carbon, P₂O₅–CaO glass, yttria-stabilized zirconia (YSZ) (Balani, 2007), Ni₃Al, and titanium and its alloys. A composite powder of HA with 4 wt.% multi-walled CNTs was deposited on Ti-6Al-4V. Both HA and HA-CNT composite coatings showed better wear resistance than Ti-6Al-4V substrate, whereas HA-CNT composite coatings result in reduced weight and volume loss in comparison with HA coatings and Ti-6Al-4V substrate. Low weight loss of HA-CNT coating during wear was due to the under-propping and self-lubricating nature of CNTs and the pinning of wear debris assisted by CNT bridging and stretching (Balani et al., 2007). The enhancement in wear resistance (Tercero et al., 2009) was observed by reinforcing CNT to HA; furthermore, the resistance to wear was increased by increasing the content of CNT from 0% to 20% and this behavior (Chen, 2007) might be attributed due to the increased hardness, strength, and fracture toughness of composite coatings (Lahiri, 2011) compared to pure HA coating (Chen et al., 2007). Alumina offers a very high wear resistance at articulating surface in orthopedic applications due to its high hardness, low coefficient of friction and excellent resistance to corrosion (Cordingley et al., 2003). Wang et al. (2005) had examined the wear properties with respect to partially stabilized ZrO₂ reinforcement to HA against UHMWP in human plasma lubrication and reported improvement in resistance to wear might be due to the addition of reinforced particles. In HVOF-sprayed HA/TiO₂ composite, mutual reaction could be the cause of chemical bonding between HA and titanium splats. The chemical bonding was found to be beneficial for the prevention of release of titanium particles as wear debris which can lead to prosthesis rejection or infection (Li et al., 2002).

1.2 Machines and Equipment for Biomaterials: Under Dry conditions and in Simulated Body Environment Joint Simulators

Joint simulators are standard testing equipment used to measure tribological behavior of actual joint used in repair and replacements of broken and damaged bone and tissues in an artificially created environment. They mimic the orientation and magnitude of the load of actual joint. Ideal simulators are sealed and temperature controlled, and produce a similar type of wear with a similar rate of wear debris that is of comparable morphology as found in actual clinical cases. After completing millions of cycles in a simulator (which take a considerable time), specimens are weighed and the difference in weight loss is measured by comparing with the initial weight of the specimen. A simulator, in general, does not provide quantitative data directly. The wear is also inspected with a scanning electron microscope. These simulators only account for physical tribological factors and do not take into consideration the biological factors that would affect the tribology in a body. Biologi...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Editors
• Contributors
• Chapter 1 Wear Measuring Devices for Biomaterials
• Chapter 2 Closed Form Solution for the Vibrational Analysis of Metal–Ceramic-Based Porous Functionally Graded Plate
• Chapter 3 Functionally Graded Structures: Design and Analysis of Tailored Advanced Composites
• Chapter 4 Heat Transfer in Noncircular Microchannels Using Water and Ethylene Glycol as Base Fluids with Zn and ZnO Nanoparticles
• Chapter 5 Influence of Layer Thickness and Orientation on Tensile Strength and Surface Roughness of FDM-Built Parts
• Chapter 6 Effect of Process Parameters on Cutting Forces and Osteonecrosis for Orthopedic Bone Drilling Applications
• Chapter 7 Fabrication and Machining Methods of Composites for Aerospace Applications
• Chapter 8 Computational Analysis of Aerodynamics Characteristics of High-Speed Moving Vehicle
• Chapter 9 Role of Finite Element Analysis in Customized Design of Kid’s Orthotic Product
• Chapter 10 An Experimental Study of Mechanical and Microstructural Properties of AA7075-T6 by Using UWFSW Process
• Index