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In this study, Mg/SiO2 and MgO/SiO2 multilayer coatings with bilayer thicknesses (Λ) 10, 20, 40, 100, 200 and 1000 nm were deposited on glass substrates using DC and reactive pulsed DC magnetron sputtering processes. The aim of these coatings is to control the initial degradation and provide mechanical strength to magnesium implant during handling and installation. The initial thickness calibrations and deposition rates optimization were conducted using stylus profilometer. After deposition of the multilayer coatings, the values of their bilayer thicknesses (Λ) were obtained from X-ray reflectometery. The mechanical properties, surface morphology and roughness of multilayer coatings were studied using nanoindentation, SEM and AFM respectively. The nanoindentation results showed higher hardness of MgO/SiO2 multilayer coatings compared to single layer Mg. The roughness analyses showed improved roughness for bilayer thicknesses (Λ) less than 20 nm. It was observed from the SEM images that SiO2 coatings has pores. By adding Mg and/or MgO in the form of multilayers improves the pores significantly. The Mg/SiO2 multilayer coatings showed controlled degradation rate when immersed in saline solution compared to the monolithic SiO2 coating. In conclusion, conditions for depositing Mg/SiO2 and MgO/SiO2 multilayer coatings has been optimized. Alternating brittle SiO2 ceramic layers with soft and ductile Mg layers significantly improved the hardness of the Mg coating. Hardness of multilayer coatings can be fine-tuned by modifying bilayer thicknesses. Significant improvement in the corrosion and mechanical properties of the multilayer coatings can be used to protect surface of magnesium implant material during handling, storage and installation.

This research will specifically address the tensile testing of textile products employing high tenacity industrial quality multifilament twill textile yarns. The research reported in this paper is directed toward developing a repeatable and reproducible test method for textile reinforcements. The paper will present a new testing technique, which uses pressure clamping system as opposed to conventional roller grip systems. The pressure clamping system incorporates a technique used in other disciplines for very strong materials. This technique is the application of sacrificial tabs to the clamping area of the specimen, thus permitting very high jaw pressures without specimen damage. The specific concerns about testing of reinforcing products expressed in the literature are: (1) the effect of sample gage (length) on reported values including tensile strength, extension and modulus, (2) the effect of test speed, i.e. strain rate on reported values: one specific issue is the difference between ASTM at 10% and ISO at 20% per minute, (3) the effect of jaw or grip types on reported values, (4) the control of sample slippage in grips, (5) the amount of tolerable slippage in clamping devices, (6) the accuracy of various extension measurement systems, (7) the effect of the extension measurement system on the reported values, (8) the effect of sample width on reported values, (9) the definition, measurement and reporting of modulus, (10) which modulus is important and (11) what portion of the sample does a reported modulus represent. The paper will focus on four of the concerns. The issues addressed are sample length and sample gage (area of extension measurement), method of extension measurement, test speed and modulus measurements.

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