دانلود کتاب،مقاله،جزوه و نرم افزار مهندسی مواد
کلیه منابع مورد نیاز دانشجویان و مهندسین مواد (متالورژی ، سرامیک ، جوش ، خوردگی ، نانو و بایومواد)دانلود کتاب،مقاله،جزوه و نرم افزار مهندسی مواد
کلیه منابع مورد نیاز دانشجویان و مهندسین مواد (متالورژی ، سرامیک ، جوش ، خوردگی ، نانو و بایومواد)آندایزینگ و عملیات حرارتی تیتانیوم متخلخل
Effects of anodizing parameters and heat treatment on
nanotopographical features, bioactivity, and cell culture
response of additively manufactured porous titanium
اثر پارامترهای آندایزینگ و عملیات حرارتی بر نانو عوارض سطحی، زیست‌فعالی
و پاسخ کشت سلول در تیتانیوم متخلخل ساخته‌شده به روش افزایشی
ABSTRACT
Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20 V anodizing time: 30 min to 3 h) are used for anodizing porous titanium structures that were later heat treated at 500o C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF).
سرامیک های فوق دمابالا جهت کاربرد در محیط های سرسخت
Ultra-High Temperature Ceramic Materials for
Extreme Environment Applications
سرامیک های فوق دمابالا جهت کاربرد در محیط های سرسخت
ABSTRACT
For the purposes of this paper, we will simply define UHTC materials by their usefulness in a real structural (load-bearing) application where the very high temperatures are generated rapidly by burning fuels or friction with the atmosphere (not steady state). This will quickly eliminate most of the materials mentioned above. While oxides are reasonable to consider for use in oxidizing environments, poor thermal shock resistance due to high thermal expansion and low thermal conductivity eliminates them from further discussion. The silicon based refractory compounds (SiC, Si3N4, MoSi2, etc.) possess excellent oxidation resistance up to 1700°C due to the formation of a layer of SiO2 glass that inhibits oxygen diffusion to the parent material.4 This is the primary reason for the popularity of these materials for a wide variety of applications. However, active oxidation (the direct formation ofSiO(g) instead of a protective SiO2 layer) can occur at very high temperatures (> 1350°C, depending on PO2) and reduced system pressures. In addition, decomposition of already-formed SiO2, or the interface reaction between SiC and SiO2 results in SiO(g) formation at high temperatures and reduced pressure environments. Other materials, such as TiB2, TiC, NbB2, NbC, while having high melting temperatures, form oxides with low melting points (TiO2 – Tm = 1840°C and Nb2O5 – Tm = 1485°C). Graphite has the highest melting temperature of any material known, but starts to burn thet 800°C. While it is a most widely used material in high-temperature applications, it must be protected by coatings for long-term use.
خوردگی داغ مواد : مکانیزم جریان سیال ؟
? Hot corrosion of materials: a fluxing mechanism
خوردگی داغ مواد : مکانیزم جریان سیال ؟
ABSTRACT
Hot corrosion is the accelerated oxidation of a material at elevated temperature induced by a thin film of fused salt deposit. Fused Na2 S04 , which is the dominant salt involved in hot corrosion, is an ionic conductor, so that the corrosion mechanism is certainly electrochemical in nature. Further, the acid/base nature of this oxyanion salt offers the possibility for the disso- lution (fluxing) of the normally protective oxide scale. Non-protective precipitated oxide par- ticles are often observed in the corrosion products. In this paper, the status of knowledge for the solubilities of oxides in fused Na2 S04 is reviewed, and the effects of various influences on a fluxing mechanism are discussed. An evaluation of a negative solubility gradient as a cri- terion for continuing hot corrosion is made. © 2001 Elsevier Science Ltd. All rights reserved.
پوشش های هوشمند خود تمیز شونده جهت حفاظت از اکسیداسیون
Smart self-cleaning coatings for corrosion protection
پوشش های هوشمند خود تمیز شونده جهت حفاظت از اکسیداسیون
ABSTRACT
Self-cleaning surfaces have attracted signifi cant attention in recent years for their potential in both fundamental research and practical applications. Under the scope of self-cleaning smart coatings, this chapter explores the principal features of materials that can be used as protective coatings with an emphasis on the photocatalytic materials that have been developed to date. The chapter also highlights the importance of using titanium dioxide (TiO 2 ) as a semiconductor material in industrial applications since it can act as a photoanode for metal cathodic protection.