Corrosion processes due to contact with the physiological environment should be avoided or minimized in orthopedic implants. Four metallic substrates frequently used as biomaterials: pure Ti, Ti-6Al-4V alloy, ASTM F138 stainless steel, and Co-Cr-Mo alloy, were coated with TiN using the physical vapor deposition (PVD) technique. These coatings have been screened by polarization curves in physiological solutions. TiN prepared by PVD is efficient as coating for stainless steel. On titanium and alloy there are no benefits concerning the corrosion resistance compared to the bare Ti-materials. TiN coatings have been screened according to ISO 10993 standard tests for biocompatibility and exhibited no cytotoxicity, dermal irritation, or acute systemic toxicity response.

Many papers have been published on a wide range of aspects of the fundamental physics and chemistry of quenching such as: additive technology, surface rewetting, hardness distribution prediction, role of heat transfer and residual stresses, etc.1,2. However, relatively little information has been published on the application of these insightful research results for the solution of long standing quench tank production problems. This paper will address three areas where technical advancements have been, or may be, made. These include discussion of: 1) the application fundamental fluid dynamics to characterize quenching uniformity due to agitation; 2) the use of "waves" to provide uniform agitation during the quenching process; and 3) the use of pressure as a variable to mediate heat transfer throughout the quenching process

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The results of the stress relieving and tempering processes are dependent on the temperature and time of the process, which may be correlated using a parameter such as Holloman's (Holloman-Jaffe) parameter or the Larsen-Miller parameter. These parameters are a measure of the thermal effect of the process on the metallurgical transformation of the steel during tempering. The processes that exhibit the same tempering parameter are expected to exhibit the same effect (such as hardness). However, these more traditional numerical expressions assume isothermal tempering processes which seldom exist in production tempering ovens due to the heat-up period prior to soaking

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Vegetable oils and animal oils have been used as quenchants for metals for thousands of years; however, it hasn’t been until relatively recently that their cooling properties have been studied in a thorough, quantitative manner. This review will focus on the published data relating to the use of triglycerides from various animal and vegetable sources to quench-harden steels. Particular focus will be on the traditional selection and use of different vegetable and animal oils for steel hardening applications and the cooling time-temperature behavior of these fluids to characterize their quenching performance. This information has not been previously reviewed in this manner.

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